Retro Tech Dan

01/20/2023

https://youtu.be/Q3NK8uwvI8M

Simple speaker replacement on a Commodore 1702 monitor with an interesting twist.Speaker I used in this video:https://www.parts-express.com/Visaton-R10SC-4-F...

05/03/2021

Nice article about the first computer I owned back in 1982.

In 1981, Commodore released the VIC-20, a low-cost mass-market home computer that served up great video games and taught a generation of kids how to program. It sold millions of units and inspired a generation of programmers. Here’s what made it special.

04/12/2021

https://youtu.be/dPM9oA72iQw

T.P.U.G. meets regularly at Starbucks to play games on their old school Commodore computers, always inviting laptop and smartphone users to join in.

03/24/2021

YouTube channel up with the first video. A Commodore 128 board repair.

The first one out of two Commodore 128 boards needing repair.Sven Peterson's Diagnostic Harness - https://github.com/svenpetersen1965/C64-Diagnostic-Rev.-586...

03/18/2021

Received a TRS-80 model 1 with expansion interface to repair. Unfortunately the outer case was damaged in shipping. Regardless I was able to track down the issue. There were 2 address lines shorted together where the keyboard connects to the motherboard. I was able to test it standalone as well as with the expansion interface. Unfortunately it isn’t very stable, so I’m going to recap it and then see if there is anything else needed.

02/04/2021

A Commodore REU 1764 came in for repair. One of the 41256 RAM chips needed to be replaced as well as a cracked PLCC socket. While I had it, I also upgraded it from 256K to 512K per the owners request by adding 8 more RAM chips in the unpopulated slots. It is working great!

10/26/2020

This Commodore 128DCR was sent to me because the disk drive wasn’t work 100% of the time. From what I understand, the drive ROM was removed and socketed for JiffyDOS but unfortunately it didn’t go so well. Some of the traces were lifted resulting in many bodge wires in an attempt to repair the damage. I believe this is where the intermittent problems lie. Time to get to work!

10/19/2020

After replacing all 16 RAM chips, all 4 video RAM chips, 9 of the buffer chips, the character ROM, and repainting the conductive carbon on each key, this Commodore PET 8032 is finally working! Oh yeah, and also replaced a blown resistor on the CRT circuit board. Now I need to test the external ports...

10/14/2020

This SX-64 needed a new PLA. The GAL PLA board would not fit due to the owner having put in a dual SID modification years ago. I ended up making an XCPLA because of the smaller footprint. Check out all of the switches!

10/13/2020

I finally got around to replacing the keyboard membrane on my own Commodore SX-64. It wasn’t too difficult. The keyboard works again!

10/09/2020

The screen is now readable on this PET 8032. The video RAM and some of the buffers needed to be replaced as well as the character ROM. The diagnostics software will now run which reports bad RAM, but all of the RAM has been replaced and tested good, so this is most likely another 74LS244 buffer.

09/30/2020

The CRT is finally working on this PET 8032. Now it’s time to get the main board fixed!