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As title says. Basically, my IIfx isn't giving any sign of life, and here's what I observed so far: UJ7, UK7, UL8 and UN9 get really hot. Not sure if that's indicative of any fault? These chips seem to be GAL16's. I'd understand why one would fail, but... all of them, at once? So I'm unsure...

Well, for the first part, turns out UI18 went bad. After replacement, the start-up circuit is behaving normally. However, I'm still not getting any sign of life... blarg.

Long time no see, thread... seems some of it has been lost? Regardless, I decided I was gonna reorganize my apartment, and put the IIfx to use, so I installed it with the TV for a test run... ...and somehow, it died. I've been trying to troubleshoot it, but I'm clueless so far. First fault...

Just wanted to chime in about this: I have observed, atleast on the LC, that the motherboard uses separate digital/analog ground planes, and these aren't directly connected -- instead, the analog ground goes through the RF shield and the power supply case. I wonder if replacing the power supply...

So what have we been up to since the last time? - My IIfx now has a whopping 20MB of memory. I basically sacrificed the extra 1MB SIMM I had, seeing as it wasn't gonna be useful for anything anyway, and replaced the chips with compatible 4MBit chips. I had to rewire one connection, too. I'm...

I don't know about the Mac II video card, but I have a high-resolution video card too, and it outputs interlaced video. That may be part of your problem. My LCD doesn't like the interlaced signal, it atleast displays something but it's real ugly.

heheh - Lil' update on the floppy drive, again: I rooted through my spare parts to find a replacement for Q4, for the sake of testing. So basically I tacked on a through-hole transistor, but as long as it's the correct type and can withstand the load, it'll be good for testing purposes...

I figure, given how rare that RAM is. I'm going to consider this, I may go for a 64MB set.

Thanks  :p re: RAM That's a nice option to consider, quite pricey tho (a full 128MB set would be more that what I got the Mac for, heh). I wonder if it would be possible to make compatible RAM sticks using more modern chips (but I doubt they make low-capacity chips these days, so, yeah). re...

Lil' update for tonight: Reset switch is fixed. There was a flaky via which I'd missed in the reset circuitry, and R11 was bad too -- the resistance was too high for the reset-button circuit to function. So I had to go hunting for a 100ohm SMD resistor... lots of fun. The video card supports...

Nice! You're lucky to have the full 128MB, too -- these RAM sticks are rare af these days. My IIfx came with basically 17MB in unusable mismatched sticks (what the...???), so I only get a usable 4MB, but I'll try to cook up something :)

Well... looks like I finally got that F573. Of course I immediately went to solder it in place, and... Side notes since the video: * sad-mac tone happened because, as I feared, the RAM is mismatched -- there are 5 1MB sticks and 3 4MB sticks. I'll have to see what I can do there, but for...

Another lil' difference: on revA boards, within the spot for Y1 (RTC crystal), there are alternate pads for a SMD crystal; on revB boards these pads were moved to an empty spot below the RTC chip. Speaking of, were there any boards fitted with SMD crystals? All the ones I see around have...

I actually used a manual solder sucker, and it took forever. I since ordered an electric one. Key is to ensure that all the pins are loose before trying to pull out the socket. Good luck with your fix0ring, btw :)

Thanks :P Regardless, here's where we are this morning: The through-holes are installed. Except for the RAM socket, I will do that one after I have received and installed the F573 -- it would hinder my already limited ability to solder that SMD chip in place. As usual, all connections have...

Lil' update! Picture might not be that good, but basically: * all SMD parts are resoldered, except for the F573 for which I haven't received the replacement part yet * all damaged traces should be fixed, everything had its connections checked thoroughly before being soldered back * a few...

The power supply may need a load to properly regulate. I know the LC power supply does, without a load it will keep clicking on and off, and one will observe similar jumping-around voltages out of it.

Seeing as I can't really do much until my orders arrive, I looked closer at the RF shield... The rust on the RF shield is typical of a Maxell bomb, from what I've seen. I hadn't noticed how bad it was near the speaker. I might need to get this shield out somehow, derust it and maybe polish...

I had similar issues when I recapped my LC. In my case I hadn't cleaned the capacitor pads well enough. Better get them completely flat and shiny, if you haven't already. Seeing as you're getting good voltages, your analog board is probably fine, did it have any cap leakage before the recap? I...

They're probably the same thing, couldn't find much about that though. Couldn't find a revA picture with enough detail to identify these components. Ssearching the part number I have on mine gives no results whatsoever. In any case, the writing on them says: TOKIN / 551-0007-F / 93Y9. Shrug...