Macintosh SE/30 logicboard recreation (thread revival)

[igowen]

the CPU walking the bus is a really good sign -- a lot of things have to be going right for that to happen. UK6 is the video ROM, right? pins 2-10, 21, and 23-25 are just the address lines (i.e., inputs) so i wouldn't expect swapping the chip to affect anything there. i'm assuming that you're only observing that behavior with the ROM present? that plus the lack of startup chime seems consistent (imo) with the CPU having trouble accessing memory (which could be caused by any number of things).

 

[ThisDoesNotCompute]

Another thing that's crossed my mind is the chips -- some of them were populated at the factory when the board was made, and the rest are a mix of transplanted and NOS parts. I've attached a high-res photo of my board, maybe someone can spot something wrong? (It turns out the pin probes I ordered for my multimeter are backordered, so it'll be a while yet before I can test the connections between the PLCC chips and their sockets.)

 

[igowen]

the only thing i noticed in the photo is that C12 is wonky and one side of it might not be in contact with the pad on the PCB, but i kind of doubt that alone explains any of the issues you have.

 

[ThisDoesNotCompute]

Yeah, C12 is intentionally crooked because JLCPCB didn't do a very good job packing the boards, and a couple of them had their caps torn off in shipping. Both pads for that one are completely gone, so I had to get creative with fitting the replacement cap.

 

[daanvdl]

Dear all,

For those who are interested, I have a few (unpopulated) SE/SE30 analog boards left from my SE analogboard recreation project.

https://airtalk.shop/product/macintosh-se-and-se-30-analog-board-recreation-630-0147-c

These boards are electrically fully functional but have one silkscreen error (W2 is labeled as W1). Furthermore no issues.

 

[obsolete]

I know Bolle has mentioned that "Certain low power ATF16V8B don't work." I assume this refers to the ATF16V8BQL. Has anyone tried any of the half or quarter-power GAL16V8s or PALCE16V8s? Just wondering if it might be possible to reduce the heat generated by the PALs.