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Recently got a batch of Z80 CPUs and wanted to test them for functionality. I first used a Z80 NOP Tester to test them all. This basically straps the Data lines to 00h and then monitors the Address lines as the CPU cycle through the full memory map. The clock is only about 10Hz, allowing you to...

Started on this 3032 today. 1. With onboard ROM and RAM the machine won't boot, though the random display screen shows. 2. With all ROMs and IO chips out and with a RAM/ROM replacement board, mapped to BASIC 4 and 32KB of RAM, the machine boots to the BASIC 4 boot screen (but clearly no...

Got a couple of PET monitors to repair. To make this easier on the bench, the idea is to make a circuit that will generate a video pattern, allowing the monitor to be repaired without having a PET motherboard involved. /full disclosure: The last time I worked, in any anger, with analogue...

Hey everyone! Chicklet 2001's are super rare in my neck of the woods (South Africa) and, after many years of searching, I eventually found one. :) I've repaired many a vintage computer, including a bunch of 8032s (with the help and guidance of the two Daves, and the likes of Mr. Holden, on...

Looking for any information and, especially disk images, for the ADDS Multivision system, if anyone can help, please. In general, where are the good online sites to find obscure disk images?

Busy restoring a Model I. It cam with two Micropolis 1015-IIB drives but, for the love of me, I can't figure out how to latch the mechanism down so the disk latches onto the drive spindle. The floppy inserts and the mechanical latch that holds it in place works fine. Pulling up on the latch...

TRS80 virgin here (so please be gentle! :) ) Started up my first Model I and it does boot with the following symptoms; 1. It turns on with a screen of garbled characters. 2. It then starts on the bottom right and start filling the screen up with the character 'A", from bottom right to top...

My first attempt at repairing an 8032 monitor. Read about R572/573 being a common failure and, indeed, R572 is open circuit. Just to confirm: - They're both 56 ohm? - R72 is blurred on the circuit I have but the colour code seems to also say 56 ohm. - Sounds like one should use a higher...

Question for all, but clearly daver2 is the man that will know since this is his baby. :) I downloaded PETTESTER V04 from this post . Trying it in a 8032 (50Hz, Business keyboard), gives me intermittent, and non-repeatable, results. I've seen it load and run on a 50Hz system, more often that...

This machine is the 5th in a batch of 5 faulty 8032 boards I'm slowly making my way through with lots of help from this forum and - especially - the Daves. :) Turning it on gave no display. Did hear a very garbled startup tone though. Supply, reset and clock all looks fine. - The CRTC did...

Joined recently to get help on a Commodore PET problem. Created a thread and are getting good support which is great. However, as a newbie, my posts need to be approved (no problem with this, good thing) but it takes days for a post to be approved. How can I get a moderator to approve quicker...

Acquired a 8032-SK that spend many years in a barn in a coastal city. This has caused a fair amount of corrosion on the IC pins that are socketed, to the point that many of the pins literally fall off. This is on top of the hornets nest inside the machine! :) First order of the day was to...