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I know I can purchase the a2heaven ram expansion for $70 when instock. However, looking at the schematics of the IIc's expansion port and reading the disassembly of the ROM code that deals with it, it seems that this is just RAM connected to slot #4 with ROM code to let you treat it like a...

I have a IIc... Works fine without the unidisk connected. Normally works fine with the unidisk connected. However, sometimes, when I power on, it will beep and begin to spin the drive and then "power off."... It looks like over-current protection, but I need some guidance about where I should...

Can someone give me a sanity check? I've desired a 1581 for years. I very nearly bought one yesterday, but when the last 10 second price skyrocketed to > $450, it was way more than I'm willing to spend... I'd spend up to $200 or so. Anyway, I have entertained thoughts of just creating a 1581...

I have a C128-DCR here plus an external 1571 (and an external 2031LP over IEEE, but that's another story)... I purchased the JiffyDos images for everything and have a problem. The install into the 1571 and 1571DCR is trivial. The problem is how and where to burn the images for the 128. It...

This had started as a result of someone saying that they were looking for an O2, but that person has since gone silent and hasn't responded to my PMs... so.... ---- I've pulled the O2 out of my office closet; there was a stack of stuff waiting to get sold on eBay in front of it! This is a...

Hello again! Yet another project I've just started on... I have a C128 DCR which is all in order (recently finished that one)... I just picked up another 1571 as an external drive. Currently, I'm controlling it via ZoomFloppy on my Mac. Before I pull the 128 out of it's nest, I want to have...

Hey there! As I continue working my way through my PET gear, I've turned my attention to the 2031LP and the 8050 drives. There's definitely something up in my PET and I'm awaiting 3446 chips. In the meantime, I hooked an edge connector up to my ZoomFloppy to give it a GPIB interface. Does...

Hello! I've moved on to solving problems on my 488 interface. I know that I have at least one failed MC3446 because one leg was disintegrated. The other two are unknown... However, I purchased a pair of MC3446N chips and tried swapping between them... The GPIO diags that Frank referred me...

I thought I'd post a clean follow-up on the really troublesome PET 2001-32N. Many thanks, especially to Dave_m, daver_2, and Frank (sorry, I don't remember your callsign on here!). While there were some bad components, this board was especially a lesson on the harm that someone using incorrect...

I posted this over on the Commodore forum, but after thinking about it I realized this might be a more appropriate spot. I've recently gotten my 128DCR into good working order and have managed to create a bootable CPM 3.0 disk. I've yet to successfully create a ZPM disk (the images seem to be...

I've just finished getting my metal cased C128 into fighting shape. With that done, I've been fooling a bit with the SDIEC that I have installed (it might be an SD2IEC, or a uIEC, I'm not 100% sure). Does anyone have any knowledge or experience accessing it via CP/M? I can't seem to find any...

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I'm seriously considering hiring someone to resolve the lingering issues on a PET 2001-32N board. Check the Commodore forum for the latest thread on this board. If you consider taking this on, I would ship you *only* the main board. At this point, the CRT and keyboard are completely...

I've spent many long hours working on a PET board that was apparently closer to death than I thought. While I'm going to continue to work on it, I've now reworked so many circuits that it is far from original. I'm curious if anyone has a PET 2001 board, preferably a 32N, but that's not a...

I'm a bit stumped on this one. I'm waiting on some LS TTL parts to come to replace some marginal components in the video signal circuit on the motherboard, but I have things working well enough that I get a pretty solid composite signal out. I've also decided to move forward with replacing the...

Hey- My life is still in turmoil, but I decided to have a go at my PET before moving it on to a new home (yes, some of you know who I'm looking at). At this point, it is semi-conscious again... but... I appear to have a strong clock, phi1, phi2, and there appears to be data appearing on the...

Hiya- With my HxC up and running well, I wanted to take some of my tinkering on the road. I've managed to get MESS working with the Model II ROMs and a P&T floppy image but I've run into an interesting issue. While I can read an IMD with no problem, I cannot seem to read a floppy image (raw...

I'd really like to cross post this to the CP/M forum as well, but I can't see a way to do it. I wanted to share my success and document it for future experimenters. My Model II is not only up and running but I now have a fully functional Kermit 4.11 and Z80 assembler on it! To get this done...

Just documenting for any future folks who choose to go down this path.. :) First, the Model II under CP/M seems to be extremely unhappy with bypassing the special system functions in P&T, instead using port $FF directly to gain access to the video memory. After fighting with this for an hour...

Greetings- Now that I have my model II mostly fully functional once again (and have managed to create a new P&T disk.. whew.. that 8" media that is tandy compatible is hard to come by), it's finally come time to think about and resolve a pesky problem. With the system running I will get...