Hi, I have an issue with a Macintosh Classic, Early analog board, fully recapped, no power at all, Fuse is good, RP2 is good, any ideas ?
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Macintosh Classic, no power at all
- Thread starter amedeo_68k
- Start date
All solderjoints are perfect, I'm going to check the components you mentioned. Another issue is that I find a no easy way to test the analog board without the CRT, While on Mac SE / SE30 the PSU is a separate box, on Classic there is the Flyback HV; Working with detached anode cap would be insane, is there a way to disconnect the HV section ?
Thank you, I'll do shortly, meanwhile I tried with another Analog Board (V2) (already fully recapped), with its own CRT, it is easier to say I swapped thr Logic board to another Mac Classic ( that was battery bombed ), I now get this, ideas?
I have two analog board, both fully recapped and one logic board (recapped as well)
- First analog board (rev A), no power at all
- Second analog board (rev B), weird vide and stripes, no sound
- Logic board alone with external power and headphones, I can hear chime
- First analog board (rev A), no power at all
- Second analog board (rev B), weird vide and stripes, no sound
- Logic board alone with external power and headphones, I can hear chime
Hi everyone, on the fully dead analog board I replaced the components as suggested by @dochilli and we are back to life !! Thank you !
There is a little issue. I have some little flickering on screen but only if the internal hard drive is attached. May be some interference.
About the second analog board do you have any ideas ? Thank you. Amedeo
There is a little issue. I have some little flickering on screen but only if the internal hard drive is attached. May be some interference.
About the second analog board do you have any ideas ? Thank you. Amedeo
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I agree on checking voltages. Both without hard drive and again with hard drive connected. Sounds like hard drive is pulling just enough current to pull down the voltage.
@amedeo_68k there is a similar thread talking about unstable voltages here https://68kmla.org/bb/index.php?threads/se-30-sony-cr-44-psu-unstable-voltage-output.33182/
They are discussing SE/SE30 Sony PSU, so definitely different than your Classic but perhaps there are similar parts on your board that perform similar functions.
They are discussing SE/SE30 Sony PSU, so definitely different than your Classic but perhaps there are similar parts on your board that perform similar functions.
I think the issue is more on the 12V side. Btw now I no longer have the logic board. I had two Analog and one Logic board ( one Classic were battery bombed ). Btw I think I can measure voltages on logic board connector without the logic board
I could put a dummy load and check voltages with oscilloscope. I’ll let you know. The frustrating thing is that you cannot test analog board without CRT
Hey, if the screen is flickering with HDD attached, try measuring the 5V line and adjusting the voltage using the trimmer on the analog board (use a plastic tool). If this doesn't help, I'd try replacing the optocoupler again. There are many kinds and the quality is not always the best. I suggest using a CNY75GB. In case it still doesn't help, it could be the flyback transformer as well - but they're hard to obtain.
edit: I believe the trimmer is for the 12V as well but the 5V line is always measured.
edit: I believe the trimmer is for the 12V as well but the 5V line is always measured.
ok, cool, I'm going to try next week, Thank you
