Recent content by campbellashe

Just posted my new version working.... RAM Expansion Card v 3 Git...

Just wanted to share a new board for the Macintosh Portable RAM Expansion. Uses the RAM slot. Configuration to include sequential RAM addition from 2, 4, 6 and 8 RAM. Mode select for Portable Model (M5120 or M5126 - backlit limited to 7 MB total). Drives DTACK on pin 7 of the PDS slot with...

I had to source from a non working Powerbook 100 that I got online. I felt guilty, but I'll still work to get the Powerbook working again if I can. Need to really see if the community can help recreate the PMGR chip in some fashion.....

Well. Fixed, it was the PMGR and all is great... so awesome to hear the chime.... now back to my RAM card

Okay here is a new problem. No 12 Volt line..... Current measurements with bench supply at 6.5V: ALWAYS ON +5V (hybrid pins 11/18): 5.2V ✓ Main (5/0) rail (J11 VCC): 5.2V ✓ +12V rail (J15 pin 9): ~0V ✗ Q14 gate (IRF9230, P-channel): 6.5V = Vgs 0V = OFF Q14 source: 6.5V VR1 LT1070 pin 5 (VIN)...

I tried injecting 2.4 volts via the R151 after isolation. No chime and no change. I'm moving to Hybrid replacement next and awaiting my replacement PMGR.

Recap: After correcting the J15 power tap wiring, the Portable stopped booting. SYS_RST*/PMGR_RESET* stuck at 0V, F1 good, PMGR clock running. Traced PMGR_RESET* (J21 pin 46) to U15H pin 18 — the PMGR's hardware RESET input — confirmed via two independent schematic sources. The physical RESET...

Yeah. The pin 52 and the hybrid are the same at 2.7. I'm concerned that I fried my PMGR....

Thanks David. I’ll work on it tonight. Puts my RAM card development on hold…

Okay. I was getting excited and tried to internally power and LCD replacement off the J15 connector -- using 4 12 volt lines and 4 GND lines to power a barrel connector and a 12 volt LCD -- yep. Shouldn't have done this. The LCD did power on; but now my computer will not boot. NO smoke; no pop...

I'm working on my version 3 board already; will integrate what I learned from version 2 and will include a jumper for the two Mac Portable Versions (as you mentioned above). It will also have a pin to easily route a wire to the PDS for the DTACK. I don't have a backlit but will make the...

Okay. Wow. What a difference the bodge wire and code logic change made with driving DTACK Now no slowdown at all on the 8MB card.... The numbers are better than ever.... The fix: the ATF1502ASL CPLD on the RAM card now asserts /DTACK itself, via a bodge wire from CPLD pin 42 to PDS slot pin...

Running: Portable M5120 (non backlit) (BlueScsi as drive) Speedometer 3.23 "Performance Test" Snooper 2.0 "Memory Benchmark" System 7.1

Agree. I got in contact with Reza and he confirmed the use of the PDS and DTACK, I’ll try to place a wire to the DTACK pin on the PDS from my CPLD and rewrite logic. Give me a bit to wire something up and i will let you know. Reza: “For my PDS RAM card designs, they assert /DTACK on their own...

This is the baseline Memory Benchmark on the non back lite running Snooper 2 and OS 7.1. Bluescsi as drive.