Recent content by TrueNorthStrong

I was hoping there was a trick to avoid taking it apart but I guess not. That won’t be an issue though. And good I asked; I only have red Deoxit. So I won’t be using that. I’ll try what I can with iso, and if needed I do have a (crappy) ultrasonic cleaner. Thank you!

There’s plenty of info online, but given that this is on a very nice looking Monitor 100 I’d like to get a second opinion untainted by AI before I go about it. The contrast adjustment was stuck fast on it at first. I removed the PCB from the housing, sprayed in some contact cleaner, and...

Yep. I previously put down the FL version of these chips, which are pin compatible but in a thicker package. Since the proper FTL chips popped up on eBay I bought them and swapped it out.

Could be that but my soldering work is suspect enough. I had a few m ad connections already. Far be it from me to have missed more. Not using hot air for the soldering. I only heated the ones I put down before to get them off. Hand soldering the new chips down.

As it turns out the pads weren’t lifted. I guess the solder never correctly bonded to the pads. I replaced all the chips I had previously tacked down. Now that they’re the correct package they’re much easier to fit. Unfortunately, still no luck with it; death chimes on boot after the boot sound...

Got around to stripping the old chips off the expansion card. I was too hasty with one chip and lifted two pads; pins 17 and 18, I/O 4 and 5 respectively. If anyone could confirm, I can just run a wire over to the adjacent chips' pins 17 and 18, correct? The I/O pins are commoned together?

I gotta learn to test before I post. Q1 checks out too on the bench. Darn, I really thought one of these might have been it. Unless I've misinterpreted these tests, they all seem to check out.

Ah, well I spoke too soon. MBR1 and MBR2 checks out. MBR1 has a forward voltage drop of about 0.25v, and MBR2 has 0.16v on both legs. 0L in the reverse direction. Tested out of circuit. I did notice that in circuit MBR1 initially looks like it was failed but guess that was a false positive...

I haven’t had the opportunity to resume this project but I should soon. But I had a thought, it may very well be MBR1 or MBR2. Earlier in my post I mentioned that I had a short somewhere after I replaced the caps, and blew the fuse. Never happened again, but the thing I adjusted was making...

I was looking to mostly scrutinize the clock, as you had pointed out I did replace just about everything in that area short of the clock chip. I’ll see about that software. How do you feel about Snooper’s clock testing? That did pass, and the computer is otherwise functioning completely normally.

I wasn’t able to locate an English copy of Mactest SE/30, so I got Mactest MP. That does run but it presumably isn’t designed with the SE/30 resolution in mind, I can only barely select the options for the display tests at the very bottom edge of the display. Whatever tests I can get it to run...

Hmmm, scratch that. There's different values for different board revisions. I can't seem to definitively find my board revision. I have two 4 digit codes on the board, which don't line up to the list on appleiioz.com. Even so, I did keep the original caps, and C4 and C5 I removed are 100uf...

So, caps are all the right way around. But, in checking, I managed to notice a mistake I made a while ago; Caps C4 and C5, for some silly reason I put in 100uf 250v. They need to be 150uf. Can't believe I missed something so basic! But at least there's something clear about a next step. Thank...

A good question, I’ve installed caps backwards before. The board is pretty well marked, but I’ll double check against a schematic available online tomorrow to be certain they are installed correctly. I’d generally expect a cap backwards to just pop, though, unless it’s a particularly large...

Yes, that’s the aim but I’m stuck with what next to check. I haven’t the experience to troubleshoot a PSU beyond the basics that I’ve covered here. Let’s hope someone can come to my rescue!