New Arcade Machine Build (CRT Service Menu issues)

Discussion in 'Retro & Arcade' started by FearTec, Feb 15, 2020.

  1. FearTec

    FearTec Member

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    Hello

    I have finally started building a Arcade Machine for some ROMS, I have a 21" Sony CRT (I bought in the 1990s) Model KV-2185AS.

    I bought a HDMI to RCA converter (PAL or NTSC) and can get an image on the screen but it off centre.

    I bought a new remote to acces the Serivice menu (Display+5+VOL UP+ Power) but its not working (or the test menu (Display+5+VOL DOWN+ Power)?

    Any one have some advice for a 1993' era Sony CRT and accessing the service menu?
     
  2. OP
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    FearTec

    FearTec Member

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    Should I ditch the CRT and go LCD?
     
  3. elvis

    elvis Old school old fool

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    A few of questions:

    1) What inputs are you using on the TV? The yellow "composite" input? Component (red, green, blue plugs)? Something else?

    2) What's the converter box look like. Can you take a picture?

    3) How are you generating the correct resolution for the TV? Are you doing it in software, or is the converter box doing the scaling from a higher desktop resolution?
     
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    FearTec

    FearTec Member

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    Last edited: Feb 15, 2020
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    FearTec

    FearTec Member

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    The downscaling is terrible (and the CRT flicker is too retro) so I might ditch the TV and get a LCD monitor.

    Anyone want a free CRT and HDMI to RCA Adapter (Pickup Tamworth)
     
  6. WuZMoT

    WuZMoT Member

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    Simply put: that conversion process will only output 480i (interlaced). That's why it's flickering and doesn't look right, your goal is '240p' (progressive).
    I went down this path with an old video card that had a TV out port when I first decided to output retro games on a TV. It was probably elvis that pointed me in the right direction, here I am passing on the knowledge - The system works! :p

    Part 1, Section (g) explains this here:
    https://www.aussiearcade.com/forum/...dows-pc-to-an-sd-crt-tv-pvm-or-arcade-monitor

    If the CRT only has composite in the cheapest way to do this properly is replacing the PC with a Raspberry Pi and configuring it to output 240p. This is cheap and ok-ish but you may have to tweak menu themes so text is legible.

    As you mentioned if you're not fussed you can just use an LCD. If you've gone to the effort of mounting the screen in some way then probably go with a Pi.

    If you had a CRT that had component input then you could throw money at the situation to get a better (clear/sharper) result than the Pi.
     
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    FearTec

    FearTec Member

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    Thanks WuZMot, I have a few Pi Zero W's and a Pi 3 I could use. Any tips on getting a Pi to drive a CRT? (Edit Reading Section H now)

    > Even cheaper is to buy an LCD monitor and a jar of Vaseline and rub the stuff into your eyeballs.

    lol

    Thanks
     
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  8. WuZMoT

    WuZMoT Member

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    That link is a long read for sure. I know I found my way back to it numerous times for clarification and understanding when I was fiddling with CRT_emu_driver in windows.

    Since you already have a Pi3 you may as well get the appropriate composite cable for it (3.5mm TRS jack > composite video/audio RCA) and give it a go. It's only about $10 and If nothing else you'll learn something AND see 240p output and realize the difference with your own eyes :)

    EDIT: they're out of stock but this is what you need
    https://core-electronics.com.au/a-v-and-rca-composite-video-audio-cable-for-raspberry-pi.html

    other than that it's basically just a config file edit - you can also adjust the display centering in this config file.
     
  9. elvis

    elvis Old school old fool

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    Yes. You're sending non-native resolutions over a poor scaler to a very low resolution device, and that will look terrible.

    It's definitely not your TV at fault, but the way you're sending data to it. Things aren't quite as "plug and play" when you're mixing tech from vastly different generations, and you'll need to do a few things differently to make it all match up.

    Not only this, but the line count matters. Sending a desktop resolution image out is going to blend and blur and do all sorts of things in an attempt to not lose information, which for a low res video game that was scaled up to scale back down again, ends up being a muddy mess.

    As WuZMoT correctly said, aim for native resolution. Your cheapest option is definitely a Raspberry Pi's native component out, with a very simple line n the /boot/config.txt (sdtv_mode=16 for NTSC [US/Japanese console games, most arcade games], sdtv_mode=18 for PAL [European/Australian console games, most Amiga/C64 games]) to force the display to 240p (i.e.: 240 lines drawn in progressive scan - to find out what that means, read the Display FAQ).

    With that, and RetroArch configured for no filtering/blending, you'll get a 1:1 match of what the old game resolution was to what the RPi spits out, and an image that's both sharper and doesn't flicker, even using merely component out video.

    From there, more complex options include using a HDMI to YPbPr transcoder like this one:
    https://www.aliexpress.com/item/1986500594.html

    The difference between the model you have and this, is that this one doesn't scale. You need to send it the exact right "modeline" (the description of a resolution to an analogue display) to drive your TV. On a RPi, that's easy. On Windows it can be done, but it requires some custom software and a bit of fiddling (WuZMoT 's links above will help). But the end result will be once again a perfect resolution match, but this time with a far cleaner analogue video signal.
     
    Last edited: Feb 16, 2020

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