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I think they are the same parts. If they are readable, that is the best scenario. But, I am trying to see what I can find out on other fronts. The problem may not be the parts and could be in the pcb. Or if it is definitely the parts, there may be other (harder) solutions - but...it becomes a...

To demonstrate properties of capacitors: Below are some example measurements on "new" (old) caps of different types showing their capacitance and resistance. If you have a capacitor and it is not showing very high (mOhm) or infinite resistance when measuring with an ohmmeter, then it is probably...

I can check C13 for you.

Yes! Lattice definitely rings a bell. But, I also think I remember seeing National Semi logos on the original boards -- possibly also the PAL design that later switched to GALs. I reached out to another contact and will try to find out some specifics. The parts are ca. 1988-89. -> Definitely...

For the RC part -- it's possible that it is part of an adjustable RC network and the RC designation was a way to flag it vs. other standard discretes. The design supported multiple SKUs with some alternate components. So, it could be a multi-function site - but just guessing. If you want to know...

Don't mix them up. o_O If you heated that area and it resolved the problem and those 2 pins were still testing as no-connects when the board was warm/working correctly, then that's probably not the issue. But, continuity might show something. Otherwise, you are down to things like: residual...

L designations are for inductors. Diodes are D. RC could be a resistor or cap -- or maybe a ceramic resistor -- or maybe a fuse. You will have to check it. A cap should have very high (infinite) resistance -- if there is low resistance across a cap (removed from a PCB), it is probably bad. Also...

Nice - you could try just sucking out all the old solder on that device and resoldering it. Also, when the solder is out, remove the PAL/GAL and check the path from the vias to the connector / other devices.

Maybe a bad connector, connector tolerance or trace/via issue. The failure looks like an address translation problem, which may point to a marginal open/bad contact somewhere (that improves/closes when you heat the green area) - maybe just a single intermittent line. During the original thermal...

Good debugging. It looks like either a thermal issue with a component, a fractured via/trace, or most likely just bad/old solder or a void. To rule out bad/old/crappy solder, you can flux all the solder-side pins (water-soluble is best) on the accelerator card and thoroughly reflow them with...

Great - so not an issue. I didn't remember that the IIci addressing was different from the IIcx - thought it was also $9-A-B. But - I'm pretty sure the board issue was with slot $B address decoding...hmmm...I think it was a 24-bit issue - address ranges from $fbbxxxxx. The fix was "don't use...

It's possible that there could be an accelerator timing issue. You can try lightly and evenly warming the board and accelerator with a heat gun to see if the artifact behavior tracks temperature...but don't overheat it. And generally speaking, you should use the v1.1 ROM. Also - avoid using...

Re: Hardware: What other hardware is currently installed? If you have other hardware add-ins -- like PowerCache, etc., you could try removing them. The solder side of the daughter card looks like it could use some cleaning with flux remover and a horsehair/bristle brush. Are you sure you don't...

It is not a problem with bad RAM. If you try the board without the accelerator, you will likely see that 24-bit mode works normally (and uses the same on-board RAM) - or maybe you have already done this test -- or reported in your earlier testing. The issue is with acceleration and QuickDraw 32...

Yep - I was in a hurry - thanks for the swaperoo. Ugh - can't edit it - @moderator -- please change that text so that the post is correct.

It looks like Q1 is a 1AM transistor, which is an NPN 2N3094. Q2 appears to be the corresponding 2A transistor, which is a PNP 2N3906. The dark (reddish) stuff I was seeing is probably just adhesive from the SMT process. As for the ceramic caps, my best suggestion is to desolder one or more of...

I found a relevant board and also my cap meter. I will try to check it out later today.

I will look for my board. What is going on with C6, C8 and RC5? Are those parts burnt or is it just an artifact of the picture? Also, if R44 and R52 were blown, you might be right to suspect Q1 and Q2.

If it's really a 1206, it's probably just bulk capacitance, but I didn't think there were any 1206's on that board. Are you sure it's not an 0805 part? The majority of parts were 0805 or, maybe, 0603. SMT process from that era for the boards rarely (if ever) used 0402s. If you have a specific...

Correct - if you remove the cap from the board, you should be able to tell if it is good or blown/shorted. Also, there are a zillion web guides. re: Spec/24 III - great! You should be good to go, since you have the v1.1 ROM.