Recent content by ravuya

The error does follow the 4332, so at least the startup "diagnostic RAM" test is telling me something consistent. However, on initial startup it will flag all the 4332s as bad. I probably won't be able to work on this until next week, but I'll build some 4164-into-4332 hackjobs using Joe's guide...

Unfortunately, there's not all one type of RAM on this card - the "B" row are the gold-plated MK4332 "stacked" RAM. I need to look up the pinout and figure out if I can easily cobble something else together. That said, I should be able to move them around and see if the error follows the IC...

Small update: I manually pulled and tested some of the 4116s from the RAM board, using an eBay DRAM tester. This produced one "definitely bad" and two "kinda spotty" chips, so I replaced them with TMS4116 chips which tested out green. Additionally, the 74LS51 at B11 was fingered by the Apple...

Update after a little while! I've managed to boot the system off of a Floppy Emu by using this adapter by ThorstenBr (only the internal floppy connector works to boot; I was mistakenly chasing a decode or disk controller problem for quite some time before realizing this.) I can now boot into...

Yeah, I've seen some PS/2 mice that contain a "USB" microcontroller and optical sensor. They just fall back to PS/2 after a couple seconds of not getting a USB poll, or probably after getting a PS/2 reset. Probably the same thing is happening here, or the ADB cable has a magic resistor in it to...

I also used to have a lot of problems with Sound Manager 3+ on my original LC, so you could try swapping that out for an earlier version if you do have that one loaded.

There is a person in Italy making new cleaning disks. I don’t think isopropyl works as well as whatever they used to use (Freon?) but I’m happy with mine. The seller is also super nice. Q-tips don’t work as well for me as those flat foam swabs. https://www.ebay.ca/itm/275298232195?

Just got my heavily contaminated Apple III logic board cleaned up, plugged into my (mostly) recapped power supply and fired it up. The floppy drive and keyboard are not connected, because the keyboard needs a little more TLC and I didn't want to get involved with floppy drive madness at this...

That's a really good tip, thank you. I had assumed I'd have to be the one making a new one, or hunting down a replacement part, but I hadn't done any research yet and wanted to see how bad it would be once I cleaned it. Maybe Jcm has a test method I can borrow :) I think this machine was pretty...

I started stripping mine down. A trip to the sink has helped a lot, but the keyboard controller IC looks pretty rough. The plastics were grotty but have cleaned up alright with a toothbrush and a baking soda/water mixture. I washed the aluminum unibody in the shower and it turned out okay. I...

Hooray! I can’t believe these sockets are so bad.

Cheapo hardware store multimeters often have a capacitance test. I think my Canadian Tire $8 special can do it.

I’ve tested suspect sockets before by doing a continuity test on the multimeter from the leg of the chip to the socket’s solder joints on the other side of the board. You can’t press too hard, or you may force the chip’s leg temporarily into the socket and get a false reading, but it generally...

I’d like to build a clone some day, since the supply is a little constrained and prices are trending up. Seems more feasible than I had first assumed.

The other nice thing about having an aftermarket BBU that we know about is that it opens up another set of engineers that we could potentially track down and ask questions of. AF had some drivers here, but the link seems to be broken now.