C64 capacitor drift

Seek advice, give advice or tell others about your repair and restoration projects

C64 capacitor drift

Postby Clym5 on Sat Nov 19, 2016 11:14 pm

Hey all, finally gotten back into fixing vintage computers after a bit of a hiatus. Today I replaced every electrolytic capacitor on my 1983 C64 and as something interesting, I checked the values of the old capacitors.
All the 10uF capacitors were reading between 12 and 16uF, the 2200uF capacitor was 2866uF and the 470uF ones were 500uF and 522uF.

After replacing them, the C64 is so much better. I'd get the odd brown-out before, where 50hz would come through the speakers and the display would dim, the odd crash too. All fixed now!
Amiga 4000: Apollo Turbo 040, 128MB Fast, 40gb HDD, CD-ROM (needs internet)
C64: 1541U-II, MixSID, WiFi, LumaFix64
ZX Spec, A1200, CD32, MacPlus/SE, A500, BBC Turbo Master (NASA), 2600, Acorn 4000, VIC-20, IBM 5155, GameBoy
Clym5
 
Posts: 284
Joined: Tue Jul 08, 2014 5:23 pm
Location: Meadowbank, Auckland

Re: C64 capacitor drift

Postby ZL2AOX on Thu Nov 24, 2016 1:24 pm

I would suggest that with electrolytics it is more important to focus on checking ESR rather than capacitance.
ZL2AOX
 
Posts: 74
Joined: Sun Sep 12, 2010 12:30 pm
Location: Palmerston North

Re: C64 capacitor drift

Postby Clym5 on Thu Nov 24, 2016 7:55 pm

I would have checked, but I don't own any equipment that could test it easily, and I don't have time to cobble something together. You're right though, in this case ESR would be the better value to check. I'll keep the old caps in case I do one day end up testing them.
Amiga 4000: Apollo Turbo 040, 128MB Fast, 40gb HDD, CD-ROM (needs internet)
C64: 1541U-II, MixSID, WiFi, LumaFix64
ZX Spec, A1200, CD32, MacPlus/SE, A500, BBC Turbo Master (NASA), 2600, Acorn 4000, VIC-20, IBM 5155, GameBoy
Clym5
 
Posts: 284
Joined: Tue Jul 08, 2014 5:23 pm
Location: Meadowbank, Auckland

Re: C64 capacitor drift

Postby ZL2AOX on Fri Nov 25, 2016 9:03 am

I would recommend this which is what I use.
Check caps in situ (no desoldering).
ZL2AOX
 
Posts: 74
Joined: Sun Sep 12, 2010 12:30 pm
Location: Palmerston North

Re: C64 capacitor drift

Postby Clym5 on Thu Dec 08, 2016 7:44 pm

I did what ZL2AOX suggested and tested the ESR. I was getting an average of 6 ohms over all of the caps (highest 11 ohm, lowest 2 ohm). Tested the new replacement caps and I had 0.06 ohm.
Amiga 4000: Apollo Turbo 040, 128MB Fast, 40gb HDD, CD-ROM (needs internet)
C64: 1541U-II, MixSID, WiFi, LumaFix64
ZX Spec, A1200, CD32, MacPlus/SE, A500, BBC Turbo Master (NASA), 2600, Acorn 4000, VIC-20, IBM 5155, GameBoy
Clym5
 
Posts: 284
Joined: Tue Jul 08, 2014 5:23 pm
Location: Meadowbank, Auckland


Return to Repair and Restoration

Who is online

Users browsing this forum: Bing [Bot] and 5 guests

cron