C64: Difference between revisions

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===TODO===
===TODO===
RAM Check...
* Diagnostic guide RAM Check...
* Remove more chips...
http://retro64.altervista.org/blog/commodore-64-repair-a-quick-guide-on-the-steps-required-to-fix-it/

Revision as of 09:34, 19 December 2019

  • Black PSU - 5.1v/10.3v - 5.13v/10.40v
  • White PSU - 5.15v/10.2v - 5.19v10.43v

Dead Drive

Dead C64

VIC-II

RF Mod

TODO

  • Black Screen. Pulses monitor/pops when turned on.
  • Power supply seems ok (5.18v). Fuse replaced (I managed to blow it while poking around with the multimeter :/)
  • Nothing shows up when toggling on and of rapidly (PLA check).
  • Disk drive spins up when turning on.
  • Load "$",8 does nothing (not sure the disk drive is working, had to replace a capacitor). Tried poke commands to make sound without success.
  • Check VIC-II Vcc is 5v. pin 40 is 5v
  • you're looking for the RESET line to be grounded for half a second during powerup. Pin 3 of userport. RST line goes high after half a sec (and stays high)
  • No ram chips over heat. Only hotish chip is 6510
  • Clock in on 6510 (pin 1) *seems* to be toggling (unsure, multimeter measures it lower than 5v but not ground).
  • Clock out from 6510 seems to be stuck at 5v
  • Address lines 0-11, seem to be under 5v but not GND. Except for pin 12, 13, 14, 15 which are 5v.
  • Can I use Chroma/Luma on a composite monitor (ie for just black & white image)?

PLA

Dead Monitor(s)

Power Switch

Games

https://www.youtube.com/channel/UCnhr67lnXf3ZtcKLrr9-hSA/videos


Repair

I need help repairing my C64.

It black screens. I have tried a deadtest cart but it still blackscreens.

The power supply is under 5.2v.

  • I have replaced the PLA with a PLAnkton.
  • Replaced the VIC-II with a new one.
  • Replaced the clock generator with a TOLB (I'm fairly sure I broke the original while poking the crystal with a multimeter).
  • Removed the SID
  • Removed one of the CIA's (the other is socketed)

I am getting 984.9 Khz clock in and out on the 6010.

I have tried using poke commands to generate sound without success. Also tried to make the disk drive do something (but I'm not %100 sure the drive is working).

None of the chips feel particularly hot.

TODO

  • Diagnostic guide RAM Check...
  • Remove more chips...

http://retro64.altervista.org/blog/commodore-64-repair-a-quick-guide-on-the-steps-required-to-fix-it/