Commodore 64 Bad Ram . Following the dead test cartridge to repair it :)

Hi ..
On this weeks video we are repairing a Commodore 64 with bad ram . Following the dead test cartridge to repair it :) .
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Steve

[@YogSothoth1969]

Cool you were able to fix it! Always so nice having a fine machine running up again :-) Best wishes, Michael

[@walterbeer2386]

I believe the REV B-3 and REV E columns on the Flash Code Chart are for C64s that only have 2 RAM chips. There are only two possible errors for them, either U9 or U11 or U9 or U10 because there are only 2 RAM chips. The REV A/B column is for C64s with 8 RAM chips. There could be 8 RAM chips with faults. Thus, getting 4 flashes showed that U23 was the bad RAM chip on a board with 8 RAM chips. Enjoyed this and your other videos!

[@8BitRetroReFix]

Hi ... should have noticed Rev E is short board so yeah only has 2 rams i should have known ... and could have discounted it ... leaving u9 or u23.. Serves me right I blame the beers from the night before lol ... glad you enjoyed it ;)

[@FirebayRefurb]

@@8BitRetroReFix REV B-3 = Assy 250466, Rev E = short board (250469) and all the other long boards are REV A/B (Assy # 326298, 250407, 250425)

[@8BitRetroReFix]

@@FirebayRefurb correct ;)

[@tiemanowo]

If this computer was stored and not used, I am surprised about condition of the mainboard. Looks very clean. I don't see much of rust or dust.

[@8BitRetroReFix]

Hi .. ive had it about 6 or 7 years ... kept dry and safe .. now it lives again ;) ... thats for watching

[@jeffnay6502]

You may have been able to piggy back the ram chips, to see which one might be bad, without removing them first.

[@8BitRetroReFix]

Hi .. Yeah the piggy back trick is an option and does work sometimes.. i wanted to show how to find it with the dead test cart ... Thanks for watching ;)

[@Evilslayer73]

Hi where you have find the ram chips for the c64?

[@8BitRetroReFix]

Hi .. They was a cheap pickup on ebay ages ago ;)

[@cesar8ramirez]

Hi I replaced a ram chip today on my sx-64. All works but when I run a diag cart it failed on RAM Test1 and holds the test. Not sure which IC that would be? Could it be one of the MB74LS257?

[@8BitRetroReFix]

Hi .Yes if all the ram is good and dead test is still showing bad ram then yes check the ram logic .