Commodore 64 restore

Discussion in 'Retro & Arcade' started by badmofo, Apr 6, 2019.

  1. money_killer

    money_killer Member

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    nice job!!
     
  2. OP
    OP
    badmofo

    badmofo Member

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    Real life has been tearing me a new one lately so progress on this has slowed, but in the meantime I've taken delivery of some heatsinks, a capacitor replacement kit, and the recommended TS100 soldering iron. The iron is hilariously toy-like - I'm loving how small it is. I was convinced I had a suitable power pack for it in the shed but apparently not; I'll have a sneaky poke around in the cupboards at work tomorrow and hopefully track something down.

    [​IMG]

    Really looking forward to firing this thing up and replacing those 34 year old capacitors.
     
  3. flu!d

    flu!d Ubuntu Mate 16.04 LTS

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    Those TS100's are actually pretty damn good bits of gear.

    [EDIT] It's interesting, I've got two C64 motherboards here, both are identical to yours but all the chips are socketed.
     
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    badmofo

    badmofo Member

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    Nice! I've only seen ~6 C64 motherboards in my life but none of them had all of the chips socketed - not even all of the major ones. That would save some time when troubleshooting.
     
  5. flu!d

    flu!d Ubuntu Mate 16.04 LTS

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    It definitely does...Even if in my earlier days I removed the SID chip and touched one of the pins, killing the SID chip instantly... :(

    However, that's just my spare C64 motherboard from my original breadbin that I bought off a schoolmate in 1987 or something.
     
  6. Vanne

    Vanne Member

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    Really? Those SID's were that sensitive? Wow, no idea how mine survived. ;)
     
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    badmofo

    badmofo Member

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    Dunno if you can call changing an LED a mod but I'm deliriously tired so why the hell not - I've replaced the classic red power LED for a green one that I found in my stash of treasures. I'm surprised how much of a thrill it gave me to see it come to life - a subtle touch to differentiate this C64 from my other breadbin.

    [​IMG]

    And the ARMSID (http://dzi.n.cz/8bit/armsid/index_en.php) I ordered showed up - well packaged and with some nice instructions (in English which was thoughtful) (it hails from the Czech Republic). Installation couldn't be easier as long as your SID is socketed, which mine was thankfully. It was already sporting the latest firmware but I updated it just to see how it worked - super easy via a little BASIC program - and I was off and running. It's a bit "harsher" than the real thing, maybe harsh is a bit harsh, "brighter" might be more appropriate. Less organic? Whatever, it sounds a little different but not in a bad way, I think it sounds great. There's a good comparison b/w the real thing, the ARMSID, and some other clones here:

    http://kompjut0r.blogspot.com/2018/04/sid-8580-vs-armsid-vs-swinsid-ultimate_12.html

    Very cool:

    [​IMG]

    [​IMG]
     
    Last edited: Apr 18, 2019
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  8. OP
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    badmofo

    badmofo Member

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    Onward and upward - capacitor replacement completed. I'm lazy so just ordered a kit from this dude. I don't know if these are a great brand cap but I used the same kit for my other C64 and have no complaints after years of use.

    I was slightly put out to find that the specs for one of the caps in the kit (which differ by motherboard assembly) didn't match the original's 16v 100uf. The replacement was 25v 22uf, and the Googles were somewhat conflicted as to which was right. The cap in question sits on the reset line, so the thinking seems to be that a higher uf just means a longer pause on boot or reset. I decided to suck-it-and-see and indeed the machine boots noticeably faster now with no ill effects from what I've seen.

    The TS100 works well - I'm using a 19V PSU and the iron reported 300 degrees in about 20 seconds. That wasn't hot enough so a quick mash of the buttons later and up it went to 400 degrees.

    Next up is adding some heatsinks, and then I just need to sort out JiffyDOS and I'll be about done.

    EDIT: for prosperity, it was the cap at C24 that was a different spec to the original (16v 100uf)

    [​IMG]

    [​IMG]
     
    Last edited: Apr 26, 2019
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  9. OP
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    badmofo

    badmofo Member

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    This project has been waiting for the JiffyDOS ROM replacement I ordered to show up - it seems to be MIA ATM but while I wait for that to appear in my letterbox I decided to prepare by removing the existing Kernal ROM and dropping in a socket. That should have been a boring, easy task but I managed to cut 2 traces in the process, which resulted in dead C64. Patching them brought the machine back to life but it's still refusing to load a disk from my 1541UII+. I'm fortunate to have a working C64 here to experiment with and after much probing with my multimeter I'm confident that everything is electrically connected around the new socket, so I'm wondering now if I've killed something else during my f*@king around.

    Happily, detailed troubleshooting guides like this exist:

    https://ist.uwaterloo.ca/~schepers/MJK/dnp.html

    But I'm asking myself how far I want to go with this - I don't have a logic tester for example. I have another working C64 board in the shed, so I could just take the low road and go and hassle that one, but I know in my heart that what I should do is man up and fix what I broke. It would be a good learning experience and I'm in no rush to get this project finished.

    Can anyone suggest a good logic tester? :lol:
     
    Alby1976, Vanne and qwertylesh like this.
  10. Vanne

    Vanne Member

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    sorry, I cant help you with a logic tester, but yeah, id probably wanna fix what I broke in the first place. cant wait to see how you get on. How are you finding that new soldering iron btw?
     
  11. Alby1976

    Alby1976 Member

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    Think I need one of these, just been using a generic 30w jaycar jobbie.
     

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