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Adi's retro projects

Discussion in 'Retro & Arcade Worklogs' started by adicakes, Nov 20, 2021.

  1. badmofo

    badmofo Member

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    Great work! I solved the clearance issue on my SMS Phantasty Star cart by mounting a battery holder on the outside of the cart - I've felt ashamed of myself ever since :o

    I should re-do it properly like you've done :thumbup:
     
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    adicakes

    adicakes Member

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    Sega Game Gear - sound PCB repair

    In this worklog, I improve upon someone's previous work on a Game Gear sound PCB by using surface mount, radial can capacitors.

    This is the circuit board that amplifies sound. These boards were originally fitted with surface mount, radial can capacitors that unfortunately had big QC problems; they usually failed and leaked straight down onto contact pads. Most Game Gear repairers use hole-through capacitors to refurb the board, as shown here. It works, but it's messy and a long way from looking professional.
    193325028_10157875182496496_531230487873999529_n.jpg

    Capacitors from the previous repair have been removed, and the pads have been cleaned up. Still a bit of pad cleaning to go, but looking good so far. :)
    193721953_10157875182476496_2749292073656918025_n.jpg

    Radial can, surface mount capacitors fitted - nice! I'm using Panasonic capacitors here, which have an excellent reputation.
    194655340_10157875182431496_5859441242172408807_n.jpg

    Sound PCB repairs done, the board is fitted back into the Game Gear shell.
    193593998_10157875182401496_6471109938740340007_n.jpg

    By repairing the circuit board using the OEM-style surface mount capacitors, the original RF shield plate can be re-fitted without modification. No need to trim off the section of metal that extends left over the sound board. :thumbup:
    192903470_10157875182366496_1234636705905212325_n.jpg
     
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    adicakes

    adicakes Member

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    Sega Master System - FM sound add-on

    Recently I discovered that the Japanese version of the Sega Master System had FM sound capabilities, and that a bunch of games can make use of it. After all these years, I never knew! The FM sound capability was not included in Master Systems outside of Japan. :( But! Australia's own Tim Worthington has designed an add-on board to bring the FM sound capabilities back into play. :leet:

    The mod can be enabled and disabled, meaning that it's possible to get the best of both worlds -- Master System sound as its ingrained in my memory, but also the FM version which also sounds very cool...a little closer to Megadrive sound. After refurbishing my VA3 Master System recently, I didn't expect to have the casing open again so soon, but here we are. ;) This mod really appealed to me.

    The FM sound board comes mostly assembled, except for the main socket and 3-pin header to switch modes. The main socket has to be soldered in so that it's angled towards the middle of the board. This is to achieve clearance between the board and the top casing when the console is reassembled.
    IMG_20211218_175727195.jpg

    Socket soldered into place at the best angle I could achieve without bending pins.
    IMG_20211218_181211523.jpg

    3-pin header soldered into place. The instructions say to solder it facing the other direction. I guess that's because there's lots of free space to fit the mode switch on the rear right-hand-side of the casing. That puts the switch on the opposite end of the factory-fitted power and A/V sockets, which didn't appeal to me. I wanted to put the switch alongside the standard rear sockets so it looks more "stock".
    IMG_20211218_183107026.jpg

    Rear of the board to show some tidy soldering. :)
    IMG_20211218_183200011.jpg

    Here is the expansion edge built into the Master System 1 motherboard. The cool thing is that this mod doesn't require removal of the blanking plastic underneath the PCB edge.
    IMG_20220108_153249855.jpg

    FM sound board fitted. This photo shows the forward tilt which will help the board clear the top casing when it's re-fitted.
    IMG_20220108_154047788.jpg

    Another shot of the FM sound board fitted to the expansion port.
    IMG_20220108_153949102.jpg

    On the VA3 revision motherboard, capacitor C62 has to be removed. The signal wires from the FM sound board are soldered onto the pads formerly used for C62. The ground shielding wire is soldered to the negative pad of ceramic capacitor C59 (but any nearby connection to a ground plane would be OK).
    IMG_20220108_153228812_HDR.jpg

    I shortened the signal cable and tinned the wire ends, ready to to be soldered to the motherboard. The top wire is the ground shielding. I added heatshrink tubing to the ground wire to avoid bare wire flapping around near the motherboard.
    IMG_20220108_155828060.jpg

    Signal and ground wires soldered into place. From the installation instructions: "The standard (SN76489/PSG) audio signal is sent into the SMSFM board via the white wire, is mixed with the FM sound signal, and sent back through the red wire."
    IMG_20220108_160405983_HDR.jpg
     
    Last edited: Jan 8, 2022
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    adicakes

    adicakes Member

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    Photo showing how the shielded signal wires travel from the motherboard to the FM sound board.
    IMG_20220108_161109160.jpg

    A 3-way on/off/on toggle switch connects to the 3-pin header on the FM sound board. The kit comes with a very decent quality switch, but it's chrome and I wasn't a fan of how it would look when fitted. The rest of the Master System casing is black, and so I bought a black 3-way switch to use instead. It's surprisingly hard to find a black 3-way switch in the mini size!
    IMG_20220108_160611372.jpg

    The switch is double-pole, but that just means I didn't use one row of pins. Double-pole makes the switch body bigger, but it's still small enough to sit above the motherboard. This photo shows the mode wires soldered to the switch.
    IMG_20220108_170125326.jpg

    The shank of the toggle switch is just over 6mm. I need to create a 6mm hole in the rear casing and not bugger it up! Only get one shot at this. ;)
    IMG_20220108_162556101.jpg

    I centred the new hole so that it aligns vertically with the existing case holes for A/V Out, etc. I made sure the body of the 3-way switch would sit clear of the motherboard when the top casing is re-fitted. I used a scribe tool to create a small divot in the plastic. The divot helps the drill bit get started properly and not skid across the shiny plastic.
    IMG_20220108_162956665_HDR.jpg

    Stepped drill bits are the best and safest way to create clean holes in plastic and sheet metal (e.g. RF shields). The idea is that you start off small and step upwards in increments to the hole size needed. In this case it's just two steps - 4mm to 6mm.
    IMG_20220108_163046521.jpg

    Hole drilled and we're ready to fit the switch! :) This was the scariest part of the whole job -- these things have a way of going wrong, even with triple checking. My main concern was to ensure the body of the switch sits clear of the motherboard and allows the top casing to go back on unobstructed.
    IMG_20220108_164357277.jpg

    Mode switch fitted and connected to the FM sound board's 3-pin header. After a quick test, the console casing is screwed back together.
    IMG_20220108_174147434_HDR.jpg

    Et voilà! Really glad I waited to find the black toggle switch -- aesthetically it fits so much better than the chrome one. The middle position selects stock Master System sound. Left and right switch the sound to 'FM (Japan region)' and 'FM' modes, respectively.
    IMG_20220108_174720376.jpg

    Here is a quick comparison between PSG (stock) Master System sound and the FM version.


    ...and here's a whole bunch more Master System FM sound.
     
    Last edited: Jan 8, 2022
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    adicakes

    adicakes Member

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    Commodore 1084 monitor - SCART RGB retrofit

    The Commodore 1084 is a great, versatile little monitor. I've had this 1084 since the start of Amiga 500 ownership and recently dug it out of storage to use with my retro consoles. I discovered that it's possible to add a SCART input to the chassis, bringing RGB image clarity and sharpness. I'm loving it -- all the old games get a facelift. :)

    Here is my faithful old friend, pulled out of storage from my parents' house and dusty as hell. It was mostly covered during storage, but it's been so many years (decades) that heaps of dust has still crept in.
    271818446_10158247640736496_5143803554982384393_n.jpg

    A quick glance shows that it is the 1084-P variant, PAL, made for 230V. There are heaps of 1084 variants, and as I soon discovered, they can differ internally even if they share a model name. It made finding reliable information difficult because often what was written on the web or in technical docs didn't entirely match what I observed on the chassis (main PCB) of this monitor.
    271857208_10158247640721496_695395244605128631_n.jpg

    The half-broken blanking plate is a big clue. It's the shape of a SCART socket, which made me suspect the chassis inside might be ready to accept and work with SCART RGB input if it's wired in correctly. Prior to this, I had only ever used the analogue RGB input (the right-hand circular DIN socket, for Amiga), and the CVBS (composite video) input for consoles and to watch TV via an old VCR's tuner.
    271755070_10158247640511496_7414748829428025717_n.jpg

    Five screws out and the whole rear casing of the monitor comes off. Working on CRTs can be dangerous due to the high voltages involved and the ability for the unit to hold charge even after it's switched off and unplugged. To discharge the CRT, I follow standard advice -- attach one clamp to the shank of a long screwdriver, and the other clamp to a solid ground point on the unit. Then, making sure not to touch any metal part of the screwdriver, guide the tip underneath the rubber cover of the anode and press the end up against the anode connection. There'll usually be a crackle and/or pop sound as stored charge is dissipated. I had a thorough poke around, regardless of whether there were discharge sounds or not. Better safe than sorry.
    271756808_10158247653341496_4799960971062794464_n.jpg

    Ah hah! There she is -- unpopulated pads for a 21-pin SCART socket. Bloody beauty! :leet: Some of the holes have no pads, but that's deliberate -- they're unused and so there's no point in adding pads for those.
    271774935_10158247640436496_893540481288467602_n.jpg

    A view from the other side of the chassis. The location for a SCART socket is clearly marked when you look at it from this angle. Don't stress, this was just an early photo from when I was exploring the situation. I dusted the internals with compressed air and cleaned things up. ;)
    271777172_10158247640476496_4555014384188088965_n.jpg

    A wider view of the internals. There's a helluva lot going on inside a monitor like this! The arrow points to the spot where I'll fit the SCART socket. The rear casing is in the background. I gave the whole casing a good clean, inside and out.
    271763913_10158247640296496_7992489754338030714_n.jpg

    Using a solder sucker, I removed the old solder that was there from the factory. I cleaned and tinned the pads with fresh solder to reach this point.
    271789280_10158247639881496_3464746706594242522_n.jpg

    I bought a couple of right-angled 21-pin SCART sockets from a cheap online store. Think it was only $6 for two, delivered. Only need one for this job, but might as well get a spare while I'm at it.
    271762190_10158247640791496_6330891774115276208_n.jpg

    Here the SCART socket is fitted, and you can see the pins poking through the PCB holes. The socket has two plastic clips (see left/right arrows) that sit very tightly in pre-cut holes of the PCB. The clips give the socket some mechanical support when cables are plugged in and pulled out. Don't mind all the goopy flux running down the board -- that was cleaned up shortly after the pins were soldered. ;)
    271807239_10158247639826496_3644515284894307310_n.jpg
     
    Last edited: Jan 14, 2022
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    adicakes

    adicakes Member

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    Socket is soldered to the board and things are looking good. Nice, shiny joints. :) I touched up a few of the solder joints after this photo was taken, just to add some solder to a few that turned out a bit mingy.
    271762743_10158247639791496_4781715334607710361_n.jpg

    Next I patched SCART pin 6 (audio left) across to the RCA audio input. The 1084-P has mono sound, unlike like 1084S and 1084-PS models which were stereo. In doing this step and eyeballing these photos, I discovered the cause of a separate, mega annoying problem that had emerged back in the day. See next photo...
    271744434_10158247640671496_5815284767877681786_n.jpg

    When connected to the Amiga 500 via the 6-pin analogue RGB DIN, the screen would sometimes lose whole colour channels. Fiddling with the the DIN plug would make it come good, but it was tricky to get the connection to stay good. I remember using a bunch of Blu Tack around the DIN plug to try and get it to stay in place, but it was hit and miss, and pretty frustrating.

    At the time, we asked the (only) local Amiga store and their advice was to buy a new cable at $80. That was a whole bunch of money for a cable back then, and there were no guarantees it would fix the problem. The store wasn't offering 'try before you buy', so we never went ahead with it.

    Looking at the chassis up-close now, it's clear that the problem was caused by cracked solder joints on the DIN socket. The black circles in the solder joints of pins 1, 4, 5 and 6 are breaks in the solder, which has been fatigued by the cable being pushed in, pulled out, and moved around when fitted. Pins 1, 4, 5 carry the red, green and blue channels respectively, so this problem would clearly affect the screen colours.
    271826822_10158247640171496_5673970050118564803_n.jpg

    Moving left to look at the digital RGB input, the situation isn't so bad but still not looking crash hot. I never used this input for anything, which explains why it faired much better than the DIN to the right.
    271771453_10158247640226496_8533915363689717712_n.jpg

    I applied plenty of flux and reworked all of the solder joints of both DIN sockets. Things are looking a lot better now! :)
    271736883_10158247639856496_203526922216324790_n.jpg

    Back to working on SCART RGB input. With the socket soldered into place and the audio line patched across, it was time to give things a whirl. Here are some screencaps from a video of the monitor connected to my Neo Geo AES running Shock Troopers. The good news was that I could see the RGB image coming through and hear the game's audio. The bad news was that there were obvious sync problems -- a very fast rolling image that wouldn't stabilise. The result was the same regardless of whether I used a video source with composite video sync or c-sync. Sega Master System and Megadrive, same deal. I knew the monitor is capable of accepting at least composite video sync because that's how the CVBS inputs work. Hmmz...
    271758633_10158247640261496_7322844158327609084_n.jpg

    I found a forum discussion about adding SCART to a 1084-D, and one of the contributors there had already got this working. The solution is to modify the circuit so that the CVBS inputs aren't disabled when the monitor is put into RGB input mode. To achieve that, I simply had to remove transistor TS509. Luckily the transistor is located such that I could just lift the chassis up a bit to access it.

    Under this approach, SCART pin 20 (composite video/sync) is patched across to the monitor's CVBS video input, and the sync signal will be taken from that input because the CVBS inputs aren't disabled, even when the monitor is in RGB mode. In RGB mode, the monitor will receive R/G/B signals through SCART's R/G/B pins, and decode sync from the signal coming through CVBS.
    271769631_10158247639841496_4633404221122834277_n.jpg

    Here is the transistor removed from location TS509. It's just a BC548 transistor which are super common and cheap as chips. I've stored it away with my spare parts, and made notes about where it's from and why it was removed. But even if I lose the component, another one will only be 60 cents or so. :)
    271805931_10158247640636496_2310605425069164547_n.jpg

    With TS509 removed, the last step was to patch SCART pin 20 across to the CVBS input. I used yellow wire to be consistent with the RCA colour coding. I discovered that the CVBS input will decode both composite video sync and c-sync, which is a handy bonus.
    271790273_10158247640561496_7617370236850441506_n.jpg

    What's the downside to this modification? Well, because the CVBS input remains active when the monitor is in RGB mode, I can't have input devices on both CVBS and RGB (DIN/SCART) inputs and have the devices switched on at the same time. I can have both devices connected -- but only one can be switched on. I've got SCART cables for all of my consoles now, regardless, so I can certainly live with this constraint.

    Hellz yeah! SCART socket fitted and the blanking plate removed from the rear casing. There's a bit of plastic damage to the right-hand side of the casing around the socket, but that's been there forever. Things are looking schwoit now. :leet::thumbup:
    271768774_10158247640006496_5171651460847363418_n.jpg
     
    Last edited: Jan 14, 2022
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    adicakes

    adicakes Member

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    I found it hard to accurately photograph the monitor, but here are some photos to show the results. I'm super impressed with the clarity of the image!

    Sega Master System - Wonder Boy
    271754890_10158249468141496_2621610558438906685_n.jpg 271763600_10158247640366496_3434975537374618784_n.jpg 271853919_10158247640131496_3235579094516435474_n.jpg 271790367_10158247640071496_2333654740529960542_n.jpg

    Sega Master System - Fantasy Zone
    271798510_10158249468416496_2791862370706626138_n.jpg 270254357_10158249468606496_803228111761508042_n.jpg 271817967_10158249468561496_919285319341976542_n.jpg

    Sega Master System - California Games
    271540503_10158249468281496_669293824147147541_n.jpg 271643809_10158249468576496_177904248463566339_n.jpg 271017837_10158249468411496_7266354847279623268_n.jpg

    Neo Geo - Shock Troopers
    270735927_10158249468226496_4256614696452217640_n.jpg 271646293_10158249468296496_4654943803033861020_n.jpg 271599343_10158249468386496_6692085885122856505_n.jpg 271652327_10158249468466496_6856997408385456927_n.jpg
     
    Last edited: Jan 14, 2022
  8. FIREWIRE1394

    FIREWIRE1394 Member

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    Once again. Cracking work! You've inspired me to do my 1084.
    Only problem is my parents gave it away while I was at school one day, along with all my commodore stuff neatly stored in the bottom of my wardrobe.

    I'm certainly not paying the thousand dollars they are apparently worth these days to get another one though. I could if I really wanted to, but it's the principal of it.

    Seeing your work slightly warms my cold, broken and bitter heart.
     
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    adicakes

    adicakes Member

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    Sega Game Gear - VA1 re-cap and refurb

    I bought this Game Gear as part of a set that came with the Sega Deluxe Carry Case, a Super Wide Gear, and some games. The console was sold as not working/for parts, but I could see that it's in excellent condition cosmetically, and there's always a good chance of repairing these units. This isn't my first rodeo with GG repair -- I've brought about 17 of them back to life now and learned a lot along the way. :)

    The GG would turn on, which is a good start. Sometimes internal short-circuits will cause the over-current protection to kick in, and the console will turn itself off after about one second. I inserted a Super Columns cartridge and could see that the game was running and responding to controls. However, the screen was all garbled and mostly just horizontal lines that scrolled top-to-bottom non-stop. The good news was that none of the lines were stationary in a permanent on or off state, which meant that the driver chips in the screen module were probably OK. When there's lines that are permanently black, or wide vertical columns that are brighter than the rest - that usually means an embedded driver chip is faulty, and there's not much comeback in that situation.
    IMG_20211204_161903849.jpg IMG_20211204_161837781_MP.jpg IMG_20211204_161923721.jpg

    I usually start with the easy stuff first, which is re-capping the power PCB. Most power PCBs have three capacitors. They can fail, but it's not usually as spectacular or damaging as what happens with the sound or motherboard capacitors. If there's damage to the power PCB, it'll typically be that one of the caps has leaked juice and damaged one of the surface-mount diodes. This one hadn't leaked, so it was easy to re-cap.
    IMG_20211110_210443403.jpg

    The sound amplifier PCB is a different story. The caps on these boards have usually failed and leaked straight down onto the PCB pads. Some are so bad, they're beyond salvaging. This one was pretty badly damaged, and you can see the Cheetos-style crud around the capacitor leads and PCB pads. The last photo here shows most of the pads restored to a good state, and what the starting point looks like, using C7 as an example.
    175652689_10157941321056496_5218042722850409731_n.jpg 190884723_10157941321046496_8266932571176585494_n.jpg 213945567_10157941321036496_3216259057103062905_n.jpg

    I forgot to take an 'after' photo of the re-capped sound PCB, but here's a photo of one that I did earlier for another GG. :) It looks almost identical.
    194655340_10157875182431496_5859441242172408807_n (1).jpg

    This is a VA1 single-ASIC GG which means that the motherboard has 12 capacitors in the locations highlighted below. They're glued to the PCB and then soldered to the board. To remove these caps, I carefully crack the glue bond by slightly twisting the body of the cap with long-nosed pliers. With the glue bond broken, it's easy to remove the OEM capacitors by adding some flux and fresh solder to their pads, and reflowing the solder while lifting.
    IMG_20211204_162542546.jpg

    OEM GG motherboard capacitors are strange and I haven't seen this type of component used elsewhere. They're really just a traditional cylindrically-canned electrolytic capacitor, but they're mounted in rectangular plastic housings...I guess to make it easier for component pick-and-place machines? Here's a photo of the caps removed from the motherboard. At the front, you can see one of the caps removed from the plastic housing.
    IMG_20211204_171839749.jpg

    OEM caps removed and pads all cleaned up, ready to receive new components. :) It would be nice to remove the old glue spots, but I've found that the risk of damaging the motherboard is too great. It's just not worth it.
    IMG_20211204_171538777.jpg
     
    Last edited: Jan 19, 2022
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    adicakes

    adicakes Member

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    New capacitors soldered to the motherboard. I used ceramic capacitors here, mostly 1206 size but also 805 size for the 50V ones.
    IMG_20211204_182121704.jpg

    I've found that it's important to de-oxidise the contrast and volume potentiometers. An oxidised volume pot will be crackly and annoying, but an oxidised contrast pot can actually cause system instability. My theory is that it's sending random voltage spikes through the circuit as the wheel is turned. A little DeOxit spray does wonders. :)
    IMG_20211204_181824312.jpg

    Motherboard back in the front casing for a quick test.
    IMG_20211204_182710301_HDR.jpg

    Et voilà! The OEM screen is as good as it ever was, and the sound is loud and clear. :leet:
    IMG_20211204_184043340_HDR.jpg IMG_20211204_184056970_HDR.jpg IMG_20211204_183909024_HDR.jpg IMG_20211204_183926292_HDR.jpg

    The original plastic lens on this unit was in nice shape, among the best condition I've seen for used GGs. Having said that, it still has fine scratches on the surface when viewed at an angle, and being plastic, collecting more scratches is always going to be an issue. I decided to replace the OEM lens with a tempered glass one. There's plenty of online shops that sell these glass lenses, but I've discovered that they're not all created equal. There can be noticeable differences in the finish of the glass edge, the quality of the logo and printing, and the adhesive on the rear. The lenses sold by JellyBelly Customs in the UK are consistently top quality, so I shop there. :) I'll keep the old plastic lens in a zip lock bag, just in case it comes in handy someday.
    IMG_20220119_154340169.jpg

    Glass lens fitted and the job is done! Another GG saved from the graveyard. :):thumbup:
    IMG_20220119_154727185_MP.jpg IMG_20220119_154755929.jpg
     
    Last edited: Jan 19, 2022
  11. MUTMAN

    MUTMAN Member

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    Farout that is mint !
    Great rebuild as always mate. Makes me want to play one right now :D
     
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  12. elvis

    elvis OCAU's most famous and arrogant know-it-all

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    Ditto for old amplifiers. I've fixed up a few just by rewetting the solder joints and cleaning the volume pots.

    There's a few "clean and lube" products out there that combine a cleaner/deoxidiser and a very fine lubricant that's perfect for moving parts. Deoxit have one, so do Jaycar (yellow can).

    https://www.jaycar.com.au/contact-cleaner-lubricant-spray-can/p/NA1012

    WD40 have a contact cleaner now, non lubricating, (important to note that it's not their normal WD40 product - they now sell separate contact cleaners like deoxit).

    https://wd40.com.au/specialist/fast-drying-contact-cleaner/

    Bloody brilliant stuff, no matter who the vendor.
     
    Last edited: Jan 19, 2022
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    adicakes

    adicakes Member

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    Sega Game Gear - BennVenn IPS screen install with ribbon

    Recently I discovered that the screen had failed in the first Game Gear I ever owned. Bummer! Unfortunately these problems go with the turf of collecting vintage hardware, and it's just part of the hobby. Not to worry! It's an excellent opportunity to fit the console with a modern BennVenn IPS screen and try out the (relatively new) ribbon install approach. :)

    Sometime in the last six to nine months, the OEM screen has failed. There's obvious vertical banding that obscures the graphics and the vertical driver chip in the centre is particularly glitchy. The screen is cactus, so it's time to fit a BennVenn IPS LCD in its place.
    IMG_20211205_004651216_HDR-COLLAGE.jpg

    This is the original Game Gear that I owned since the late 90s. It's an early VA0 twin ASIC model. It was also the first Game Gear that I recapped, about 3 years ago. When I opened it up, the job was decent enough but my standards and expectations have moved ahead quite a bit since then. Before starting work on the screen, I redid all of the positioning and soldering of the motherboard capacitors. Forgot to take a 'before' photo, but here is the 'after' shot. I'm happy with it now, nice and neat. :)
    IMG_20220118_142732414.jpg

    The rubber screen grommet needs to be removed as part of the BennVenn LCVD installation. There are circular locating 'nubs' on the front shell but they can stay in place because the new screen's frame has corresponding holes which mate up.
    IMG_20220118_143034583.jpg

    This pylon is for a Gamebit screw that comes in from the top-centre of the rear shell. To fit the new screen, most of this pylon needs to be removed.
    IMG_20220118_143044863.jpg

    I used a Dremel with cut-off wheel attachment to cut the plastic, then switched over to a grinding bit to clean up the edges.
    IMG_20220118_143545488.jpg

    First step in removing the OEM screen is to remove the four screws holding the reflector assembly in place. Then, snip the wires providing power to the fluorescent tube. Left and right-hand wires shown below.
    IMG_20220118_143930079.jpg IMG_20220118_143942460.jpg

    This tape holds the flat flex cable in place at the rear of the motherboard. It needs to be undone.
    IMG_20220118_143628507.jpg IMG_20220118_143808480_HDR.jpg

    With the reflector assembly disconnected from the motherboard, the assembly comes away with the fluorescent tube in place. The OEM screen flips out, ready to be unsoldered from the motherboard.
    IMG_20220118_144100914.jpg

    This whole row of pins needs to be unsoldered from the flat flex cable. I applied plenty of flux to the pins, added fresh solder, and then gradually went along with the iron, gently releasing the cable as I went.
    IMG_20220118_144112483.jpg

    OEM screen removed! You can see the embedded driver chips which are often the cause of permanent screen problems: three along the bottom (each driving a third of the width), and one at the right-hand side (driving horizontal lines).
    IMG_20220118_145154634.jpg
     
    Last edited: Jan 20, 2022
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  14. OP
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    adicakes

    adicakes Member

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    To disable the high voltage circuit used by the OEM screen (and now no longer necessary), I need to remove the inductor in position L2. It's not essential to remove the fuses, but I do it anyway to free up some space.
    IMG_20220118_145242807.jpg

    Inductor L2 removed, along with the left-hand side fuse.
    IMG_20220118_150202941.jpg

    Right-hand side fuse removed.
    IMG_20220118_145320456.jpg IMG_20220118_150208376.jpg

    Now it's time to start soldering in place the BennVenn ribbon for VA0 motherboards. The little extension that goes to pin 2 on the top row is for signalling the Game Gear's nifty 'Sega Master System' mode. The row of smaller pins is for screen data, etc. The ribbon makes it so much easier to do this soldering work.
    IMG_20220118_151842657.jpg

    The BennVenn screen uses the D-pad (in conjunction with the 'Start' button) to switch scaling modes and toggle scanline emulation. This length of ribbon folds upward and the two holes need to be soldered to M10 and M11, as indicated.
    IMG_20220118_152039913.jpg

    M10 and M11 connections soldered and the ribbon folded down. A very neat solution! :)
    IMG_20220118_152654443.jpg

    Now it's time to fit the BennVenn screen into place using the supplied bracket. The bracket uses the screw holes formerly used to hold the reflector assembly in place. With the screen in place, I tinned the screen's pads, as well as the lower pad of FB1, and T10.
    IMG_20220118_154720622.jpg

    The BennVenn ribbon wraps around the lower edge of the motherboard to be soldered into place. This photo shows how the little extension legs reach the pads of FB1 and T10. Again, this is so much easier than hand-wiring the screen.
    IMG_20220118_160436908.jpg

    The ribbon comes with a separate horizontal extension that joins capacitor C30 on the left-hand side to pad 1 on the screen's PCB. This is how the screen receives signals from the 'Start' button to set modes.
    IMG_20220118_161713537_HDR.jpg
     
    Last edited: Jan 20, 2022
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  15. OP
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    adicakes

    adicakes Member

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    And we're done connecting the new screen! The motherboard is back in the front shell and there's just a bit more flux clean-up to do.
    IMG_20220118_164234474.jpg

    This RF shield fits to the rear casing -- mostly over the cartridge slot and extending over part of the sound PCB. The vertical legs need to be trimmed down so that they don't press into the BennVenn screen.
    IMG_20220117_160926880.jpg

    Vertical segments of the RF shield trimmed down and folded over. Some modders just throw the RF shield away, but I like to keep it fitted.
    IMG_20220117_162457584.jpg

    Here is the Gamebit screw that would normally mate with the top-centre pylon -- except we removed that earlier. Since I'm not keen on the aesthetic of an empty hole in the shell, I trim the length of the Gamebit screw down with a cutoff wheel, and remove sharp edges with a grinding bit.
    IMG_20220117_155330696.jpg IMG_20220117_160414365_MP.jpg

    Then use contact cement to glue the screw into the hole to maintain 'dat factory fitted look. ;)
    IMG_20220118_170848111.jpg
     
    Last edited: Jan 23, 2022
  16. OP
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    adicakes

    adicakes Member

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    Time for a power-on test. :) Here's Wonder Boy looking awesome.
    IMG_20220118_191459284.jpg IMG_20220118_191530085.jpg IMG_20220118_191654469.jpg IMG_20220118_191820521.jpg

    Sonic the Hedgehog 2
    IMG_20220118_191947070.jpg IMG_20220118_191952946.jpg IMG_20220118_192054553.jpg IMG_20220118_192126389.jpg

    Sonic the Hedgehog: Triple Trouble
    IMG_20220118_192215679_HDR.jpg IMG_20220118_192224922_HDR.jpg IMG_20220118_192341210_HDR.jpg
     
    Last edited: Jan 20, 2022
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  17. badmofo

    badmofo Member

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    I find the flow of projects in this thread to be extremely cathartic and satisfying - or very ASMR as my kids would say. Excellent work :thumbup:
     
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  18. OP
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    adicakes

    adicakes Member

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    Sega Arcade Power Stick II - clean / sticky button fix

    I bought this Power Stick II second-hand in the early 90s. It saw me through many hours playing Streets of Rage II, NBA Jam, Samurai Shodown, Sonic, and others. :) Time to give it some TLC and fix a sticky button problem.

    The joystick is in quite good shape overall, but by the end of the 16-bit era, the 'B' button on this unit was sticking. Very annoying, and I never got around to fixing it. The problem didn't feel like anything was seriously broken...probably just crud causing the button to 'catch' as it travelled up.
    IMG_20220226_170243093.jpg

    The world-outside-Japan model gets a bad rap because the stick isn't microswitched like the Japanese version. True, that'd make it a heap better, but I still loved this one. Let's pop off the metal base to see what's inside...
    IMG_20220226_170309156.jpg

    Barf! :tired: Amazing how much dust and grime gets into what's a fairly well-sealed unit.
    IMG_20220226_170535754.jpg IMG_20220226_170833754.jpg

    Crud all over the button membranes and stick assembly.
    IMG_20220226_171053658.jpg

    The PCB is coated in a thick layer of dust. Amazing it worked at all!
    IMG_20220226_171114920.jpg

    I removed the joystick rocker and its membranes, and used a soft, dry paint brush over the PCB to remove surface dust and crumbs. I then went over the board with a cloth misted with isopropyl alcohol, being careful to work around the conductive pads. The 'C' button pads (bottom-right) have some wear, but it works fine and best left alone for now. I can always add conductive paint down the track, if it becomes troublesome.
    IMG_20220226_181642892.jpg

    Buttons, switches, membranes, and the joystick rocker all cleaned up using an old toothbrush and isopropyl alcohol, then dried with a clean microfibre cloth.
    IMG_20220226_182215370.jpg

    The gentlest way I know to clean the conductive pads on rubber membranes is to give them a very light circular rub on paper. Very light pressure, so that the marks left on the paper aren't solid or dark.
    IMG_20220226_190609780.jpg

    Inside of the top casing cleaned up using a paint brush to sweep out the dust and dirt, then isopropyl alcohol on a microfibre cloth.
    IMG_20220226_181525792.jpg

    Same cleaning approach applied to the backing plate and metal base. They all came up very looking nice. :)
    IMG_20220226_182826307.jpg IMG_20220226_183306530.jpg

    Switches, buttons, and membranes placed back in the top casing, ready for the PCB to be screwed back on top.
    IMG_20220226_184000709.jpg

    PCB refitted with the backing plate on top. The backing plate has elevated sections to support the PCB when the joystick moves and buttons are pressed.
    IMG_20220226_184519015.jpg

    Et voilà! Top casing cleaned with a toothbrush and isopropyl, then shined and sealed using Novus Plastic Polish #1. Base plate fitted to finish the job. All buttons moving nice and free, no sticking. Ready to rock. :leet:
    IMG_20220226_185845281.jpg
     
    Last edited: Feb 26, 2022
  19. OP
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    adicakes

    adicakes Member

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    Sega Megadrive - refurb

    This is the original Model 1 Sega Megadrive that I owned as a teenager. I've been getting back into Sega collecting recently and would like to spend some time playing the 16-bit classics like Streets of Rage II. Time to refurb my Megadrive and start rockin'. :)

    The console is in good condition and works OK, except that the sound output seems a bit low, especially the headphone output. At nearly 30 years old, it can do with a recapping and big internal clean up.
    IMG_20220129_180321957.jpg

    This is a PAL model for the Australian market. It has a VA4 motherboard which is good stuff because that revision has good sound circuitry.
    IMG_20220129_180558062.jpg

    The job starts by unscrewing the two main casing halves. WTF Sega! Instead of wiring the power LED using proper plug/socket style fittings, they've just pushed the bare LED legs through the plug's holes, then bent the legs outwards to keep things together. I understand that companies are always looking for ways to save a few cents per unit, but seriously, this is just shit. :tired: It looks crap, and it's only going to hold up a couple of times (at most) before the LED legs snap off. I'm going to improve this wiring later in the refurb.
    IMG_20220129_180823329_HDR.jpg

    I straightened the LED legs so that the plug fitting could be removed. After that, I used a bit of tape to make a note of which LED leg was connected to the red wire. This will be useful later when I improve the LED wiring.
    IMG_20220129_181257126_HDR.jpg

    Top casing off reveals 25 years of dust. Not as bad as the Master System's build-up, but still quite grotty.
    IMG_20220129_181342331.jpg

    Upper RF shield off reveals yet more dust and grime. Yuck!
    IMG_20220129_181833265_HDR.jpg

    Dusting with a dry paint brush helps a lot. Do the easy stuff first.
    IMG_20220129_182148664_HDR.jpg

    Motherboard out, lower RF shield is the last piece to remove.
    IMG_20220129_190304620.jpg

    More dust and crud covers the lower casing.
    IMG_20220129_182745083.jpg

    Lower casing cleaned up and looking tidy! :lol:
    IMG_20220129_185905362.jpg

    Two LM7805 voltage regulators are screwed to a heatsink. The thermal paste has dried and gone powdery. Not good.
    IMG_20220129_182230270.jpg

    Heatsink removed, here's the rear side of the regulators. In this state, I doubt the thermal paste would be doing much at all to help heat transfer.
    IMG_20220129_183540367.jpg

    The heat transfer area of the regulators has been cleaned up. I was on the fence about replacing these regulators, but decided against it since they're good quality, and my Megadrive didn't see nearly as much use as the Master System.
    IMG_20220129_194620116.jpg

    The heatsink also needs a good clean. The crusty old thermal paste needs to go.
    IMG_20220129_183601447.jpg

    Heatsink after a thorough clean. Much better. :) I'll apply new thermal paste and refit the heatsink after recapping the motherboard.
    IMG_20220219_160305682.jpg
     
    Last edited: Feb 27, 2022
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  20. OP
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    adicakes

    adicakes Member

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    Capacitor kit from Console5. The kit contains excellent quality Nichicon capacitors.
    IMG_20220129_184734116.jpg

    Here is the motherboard after replacing all 39 electrolytic capacitors. I made the mistake of stopping my Google search for a VA4 capacitor map too soon, thinking there wasn't one online. Instead, I replaced the capacitors one at a time - taking one off, noting the polarity and specs, and fitting a new one in its place. My mistake was underestimating just how slow this approach would be! :Paranoid: Got halfway through and felt like the job was never going to end. A few hours after the job was complete, I found a VA4 map online, just a few hits down from where I stopped looking. Total facepalm! Oh well, live and learn. :)
    IMG_20220219_150409366.jpg

    Rear shot of the motherboard. The ceramic caps on the underside are OEM, despite looking like something a modder might fit. ;)
    IMG_20220219_150857924.jpg

    Here are the 39 OEM capacitors that came off the board. They're Rubycon branded - good quality - which probably explains why they hadn't failed and leaked all over the place. Having said that, there were a few early signs of goop egress near the headphone output, which I cleaned up before fitting the new capacitors.
    IMG_20220205_210953495.jpg

    A thin layer of Artic Silver 5 thermal paste is applied to the voltage regulators.
    IMG_20220219_160155683.jpg

    Heatsink refitted with the voltage regulators screwed to it. I used blue thread locker to secure the heatsink to the motherboard, and regulators to the heatsink.
    IMG_20220219_163232822.jpg

    Cleaning the cartridge socket using DeOxit on a cloth that's wrapped over some cardboard.
    IMG_20220219_150644812.jpg

    Back to the LED wiring. It took a while to find the right fitting, but it turns out to be the not-very-helpfully-named '292161-2'. I bought 10 pairs of male and female fittings. The same fitting is used on Game Gear sound PCBs to connect the speaker.
    IMG_20220219_151243149.jpg

    Test fitting that I'd bought the right part, and that it mates properly with the OEM plug. All good! :)
    IMG_20220219_151433976.jpg

    I took the socket side fitting and soldered on a pigtail of multi-strand wire, covering the joints with small lengths of heat shrink tubing.
    IMG_20220219_152849601.jpg

    I then trimmed down the LED legs and soldered the pigtail to them. There's plenty of space for the pigtail to sit between the upper RF shield and top casing, so that's not a problem.
    IMG_20220219_154238474.jpg

    Lower RF shield cleaned and refitted to the bottom casing.
    IMG_20220219_160448134.jpg

    Motherboard refitted above the lower RF shield.
    IMG_20220219_163628688.jpg

    Upper RF shield cleaned and ready for refitting.
    IMG_20220219_163825279.jpg

    Upper RF shield refitted and now we're really getting somewhere. :leet:
    IMG_20220219_165135535_HDR.jpg
     
    Last edited: Feb 27, 2022
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