Recent content by Kai Robinson

Would help to know where you're based - due to tarriffs putting the kibosh on international shipping right now, makes sense to recommend services as local as possible.

IIRC @This Does Not Compute tried this with a 540c and....no luck.

Just so you know the SND is not a Programmable device, it's fixed state hardware using logic gates and discrete components. You'll want something like a TL866 programmer for SPLD, ROMs and use them for testing 74 series logic.

If CPU wasn't working you wouldn't be getting a chime, likewise with the GLU - honestly i think it's either RAM MUX/resistor packs, something to do with the PAL logic.

I'd imagine the ROM is fine, given the death chime. When my Iifx went wonky, turned out to be poor oscillator connection and clock signal.

Hi Steve - hope you don't mind me undeleting this - it's a valid question that others might find useful to leave up and around. Also the IIx and IIcx GLUE is the same, iirc, as the SE/30 is a IIcx in a compact chassis with 1-bit video.

As long as you can see the waveform shape and aren't measuring high clock rates, for basic stuff, that should be OK.

Go for it!

Hi - I merely posted the link, i've not used the tools - check the link itself in the initial post, which will send you to GitHub and explain more than this thread.

Checkerboard like that indicates that the CPU is running, it's not being held in RESET and the ROM is working - you're experiencing a RAM issue. Check all the RAM SIMM's are installed correctly, and the jumper is left OPEN unless you're using 256k SIMM's

At this point I'd order replacement chips and transistors, they're pennies each.

Just as a curio: https://siliconpr0n.org/archive/doku.php?id=bercovici:apple:344s0602-a Thats the die image of the VTi (VLSI) Gate Array (it's a VGC1900 series part), only 858MB! :D

Correct - GLU is a custom ASIC (VTI Gate Array), SWIM is a custom ASIC, the ASC is a custom ASIC, the SND has been reverse engineered, the RTC too, the VIA chips are merely 65C22N's from WDC, the GAL's have been reverse engineered and made available and the rest is off the shelf.

Well the SE/30 has a few options for programmable ROM SIMMs - the EPROM on the board is the video ROM.