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  1. Hi I have a multitude of faulty analog boards. On many of them the voltage is too high or too low and I think it's related to the trim pots on the board - because some of them do nothing at all. BTW these boards have been entirely recapped by me. I've done about 20 of them so I am familiar with the boards. Many are showing closer to 11v on the 12v Rail and another is showing 12.5v with everything turned down to a minimum. I would like to replace all the resistors on one of the boards. I would remove, check each one and replace. However I don't h
  2. I also just noticed that chip UJ4 is missing one pin - eaten away completely by battery acid.... I guess i'll find out if that pin is used when I realise the board is a write-off but if anyone has dealt with a missing pin on UJ4 before, i'd appreciate any experiences. There doesn't look to be anything left it of it try and reconnect... cheers
  3. Hi I've got a SE/30 and the clock battery had started to do it's worst. I have got the lion's share off and I believe most of the chips can be cleaned and resoldered. However there are two tiny rectangular blocks, each with 3 pins - perhaps transistors. One is completely gone destroyed, but the pads are good. The other is connected but in bad shape. Does anyone know what D1 and D2 are, what they do and any ideas to replace them? Many Thanks Alex
  4. I don't really understand this thread but I have some spare IIfx SIMMS...
  5. Still only 10.4v on the +12v rail. So I'm reaching my wits end now! I've replaced CR20 and 21 with new. I've replaced R39 with new. I've replaced every single cap and then some. I can't understand why the voltage adjustment R59 doesn't do anything. I traced the tracks to R39 thinking it was to do with this but replaced it changes nothing... Does anyone know what allows R59 (the adjustment for voltage) to do it's job? Or it is something else.
  6. Hey everyone I'm still trying to work out why one of my analogue board is giving out low voltage. That saga continues. I bought a second working machine in order to restore and then use as a swap machine to troubleshoot with. I tested all the voltages and it boots up with the chime and disk icon. So I disassembled, recapped the analogue board - triple checking all my capacitor values and replacing like for like.... and then booted it up on the bench with no CRT and the original mainboard - BONG so I check all the voltages on a multimeter post-cap on the bench - all dead on what the
  7. I switched U3 with one from a spare board and it's exactly the same... It could be two bad ones but that's less likely than when I started....
  8. I have 4 x Plus boards which test/boot absolutely fine with a different known good working Mac Plus... I also tested the CRT with another Plus, and it's a brand new flyback....! We're down to the analog board. When I say the 128k works, I'm not being entirely full with the facts - I get a 040A80 sad mac, but I believe this to be a RAM issue with the 128k board. The main thing is that it's booting and working rather than horizontal. I just assumed 128k boards have a much higher tolerance to low voltage than a Plus...
  9. Hi Everyone I've been gradually self-teaching PCB repair and getting better each day. But I'm struggling with my Mac Plus analog board (630-010B) I have replaced all the capacitors, except C1 (sometimes labelled C2, which is the unusual 3.9uf bipolar cap, which I have taken from another known-working-good board) and gone from a non working flyback to a working flyback and it works with a 128k logic board. However, using a Mac plus board I get Horizontal zebra (sisami) stripes - something which nobody online has ever seemed to reference on a plus. Anyway, to
  10. Well, I was tempted to give it a go myself, but I am a real duffer when it comes to soldering. I have a few bad classic 2 boards to practice on (too far corroded to be repaired). I just got the feeling you had to be some kind of neurosurgeon to be any good at it...
  11. Hi There I am sticking my toe in the water here to see if anyone here is in the UK and is proficient at soldering to recap SE/30 / Classic / Color Classic boards? I'm a complete dunce and would happily pay someone to do a good job. Shipping to the US just isn't cost effective... Thanks! Alex
  12. Re: the $470 one on ebay... I've been collecting compact macs for about 18 months now. I've got a few 128ks (here in the UK I'd say a simple unboxed (but non-yellowed) example, working but with maybe a flaky floppy drive goes for about £100-£200. I've been after a boxed one for a while but they're always for silly money. I sat there at 11pm and had a price in mind - I never put in bids, I decide what it's worth to me, considering the shipping as well and put that price in with 3 seconds left. Everything else is obviously pointless. I was prepared to go to about $685 I think. This got
  13. That'd be me! I won it. The analog board is fried, which I found out after, but still took it because I have spares and can repair it.
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