Quest With Me For The Secret Spell To Resurrect A Commodore 64
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- Опубліковано 15 лип 2024
- It's time for Commodore 64 breadbin #8 in the long-awaited continuation of the 2024 repairathon.
This one feels like adventuring through dungeon catacombs. Traps (bad components), cave-ins (poor workmanship from a previous technician) and misleading maps (my usual oversights) send us in myriad different directions before we can claim the hidden gold.
I hope you enjoy it and can, maybe, boost your XP a bit for your next adventure in retro repair.
Repairathon Playlist
• Commodore 64 Repairath...
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00:00 - Intro
00:43 - Triage for Machine #8
05:37 - Getting Video Out
07:48 - Dead Test
11:57 - Checking the ICs in the ZIF board
17:22 - Retesting
19:49 - Multiplexer Socket Oddity
25:19 - Replace ALL the RAM
26:27 - Test the CPU
27:05 - Check the Clock
29:29 - Replacing the Crap Sockets
37:11 - Recap - Where are we now?
40:19 - Retesting
41:49 - Testing the Address Bus
43:02 - Eureka
46:16 - Testing the VIC-II
48:44 - SUCCESS!
52:58 - Full Diagnostics
53:36 - Summary
54:52 - Outro - Наука та технологія
FYI: I stated, incorrectly, when cleaning the user port, that most or all of the bottom pins were ground. I just discovered I was mistaken. Those pins have other purposes and should definitely be cleaned. Sorry for the confusion.
Another one will keep on living!
Although it may seem that you've replaced the sockets unnecessarily, it is a good practice, those old sockets are always prone to give you problems.
I've no regrets about any of the rework I did. Those sockets were crap and the soldering on them left much to be desired. The MT RAM would eventually have caused a problem, as would the MOS logics. The only thing I regretted on this one was making the assumption that the VIC-II was working. You know what they say about when you assume.
Thanks for the video! I didn't know that the VIC II could be responsible for giving those random RAM flashes with the dead test, good to know
You're welcome. I'm assuming it was because of failing DRAM refresh, but I don't know that for 100% certain. It does seem to make sense, though.
You got it done! Nice work! Thanks for sharing
Thanks 👍
It's always the PLA. Even if it's not 😂😂😂
Still don't understand how I did that.
Excellent work:) glad to see u back. Nice troubleshooting. But I noticed the clocks were off... at the end. Another bad vicii unfortunately:( very well prepped video though. Jumping everywhere, but also wanted to say that I hope everything is all good with u and your parents now❤ looking forward to next part. Wasn't a bad thing changing all the mt ram and mos logic chips anyways:)
Yeah, I glossed over the clocks. The CIA's were otherwise 100% working and I don't think those small variances will really cause much of an issue. I had no regrets about the RAM or MOS logics. As for Mom and Dad, it's an ebb and flow thing. Some weeks are harder than others. We've been working on final arrangements for my dad so we don't have to have the burden when that time comes. Mom had a fall a couple of weeks ago and tore up her wrist pretty badly (not broken, fortunately), but she's healing up nicely from that now. I'm glad to see me back, too. I'm ever grateful for the destressing effect this hobby brings. And the community has been SO supportive. Thanks, Donald!
When you ran the diagnostic test at the end of the video, the CIA timers were not the same. Anyway, thanks for the vid and keep up the good work.
Great eye for detail. Yep, I noticed that, too. Although both CIAs worked completely otherwise, there was a small difference between the two TOD clocks. Both are definitely getting the exact same signal driving the clocks, but they just seem to handle it slightly differently internally. I've never seen that before, but I suppose it could be normal. I don't really know for sure. Thanks for pointing it out.