Ok, before I get too happy, I noticed no A/B or Trash Icons, looks like I have the TOS 1.62. I plugged in the floppy drive, and power. When turning on the machine, I see the drive access light come on, then off. If I stick a floppy in it spins for a few seconds, so it gets power. Perhaps this is why...

Without the harness, does this seem normal?

Ok, this is like a TV show with a cliff hanger for me. I couldn't wait and its against my OCD to use my cheap 24 pin sockets, but after toning out all the VIAs, I installed two 24 pin crappy cheap sockets, cleaned up the 68901 pins to be solder free and smooth as possible. Installed and... signal-20...

My fancy bodge for pin 83, now tones out to pin 45 on the MFP :) That was fun... After looking at the photo, I went and bent the wire a little at the curve to take strain off the package's leg/solder pad mechanical connection. It's perfectly horizontal now, so no one follow my example ;) Needs a lit...

Ah crap, I measured from the DMA chip for some reason. So IACK does goto the GST. Well its why I shouldn't reply to people in the middle of the night. Its 4am now :lol: So IACK does seem broken on your machine. But do the IPL pins show all high now anyway ? Happens to me too :) I want what I paid f...

So I removed the MFP, for those that don't have one, a cheap ebay hot air rework station works great as the last step! Especially for a large package like this with 48 pins. I added fresh solder, and sucked as much as I could with a solder sucker, then using copper braid removed as much from the top...

exxos wrote: ↑Sat Dec 10, 2022 1:02 am Have you looked here viewtopic.php?f=31&t=149

Thank you, looks like the one marked in german is it!

Ignore my pin numbers , I was looking at the PLCC MFP. I figured it out for the 48 PIN MFP :) Realized too that I don't have a pin out for the GST chip that has the integrated blitter, google returns zero results. Found a service doc about shifting the chip when installing on a mega ste for an upgr...

Pin 32 will always be low because ( I assume) you are using a mono monitor ? But also the GST has to request the data from the MFP so the GST IPLx pins should not be low all the time. Pin 52 is the MPF_CS line which is driven by the GST.. That should not be low all the time.. *unless* it never gets...

So I dug for a few minutes on the internet, looks like all these later ste service manuals are based off the original 1989 docs, when the gst and blitter I think were separated. The 1989 docs that still have hand drawn schematics show the ack pins for the gst and mcp connected. Does anyone have sche...