Picked up two new items this fortnight.
This is often considered the “holy grail” of Commodore monitors. It supports just about any signal you can throw at it, including composite, s-video and RGB.
This one I found while at my local maker space, Artifactory, in the “Virtual Recycling” pile. It wasn’t quite “in” the pile so I enquired and was told “yes, it’s dead. Feel free to get it working if you can”.
First thing I noticed was that the screen would power up, there would be static build up on the screen surface and I could hear the familiar monitor “whine”.
I plugged in a video source (The spectrum was easy and small) but only got a black screen. I also noticed the power button was a bit flakey. If I turned up the brightness the screen went grey so I was getting a raster.
While I am actually trained to work on CRTs, I really don’t enjoy it, but it was time for me to do so.
I cracked the back and gave a quick visual inspection. Everything was neat and clean, so always a good start.
I started by replacing the power switch. I had one more switch from an order I must have placed 5 years ago, when I was working on a Commodore 1902 monitor many moons ago.
It was an easy swap and now the monitor can easily be turned on and off.
While inspecting my work with a small hand torch I spotted several cold joints around the video input connectors. I reflowed these, adding plenty of fresh solder.
Being very careful, I turned it on and plugged it in and there was a picture! Excellent!
After that it was a simple matter of reassembling the system and giving it a good clean. I’m going to need to make up various cables needed by the monitor for various other systems I have.
This one was a big surprise. I logged onto LinkedIn to check my messages, to find a message from two days ago from an old friend asking if I wanted some retro-computing bits and pieces he’d found laying around. Of course I said “yes!”.
Well, there was some useful soldering equipment, a nifty set of ISA cards for the PC, (Several sound cards, some serial / parallel cards, a network card, some video cards) and some keyboards, mostly in PS/2 but also including a Sun keyboard and Mouse. (As I have a Sun box in my collection, this will be useful)
There was also another Microbee. A full Computer in a Box. With Monitor.
For those counting at home, this is number 5. Remember when I was lamenting not having any? 😀
This one is still undergoing repairs.
I have replaced RIFA caps on the power supply, and as expected, about 1/3 of the keys don’t work, so they’ll need to be desoldered, disassembled, cleaned and reassembled. Not a job I look forward to I can tell you.
The monitor is completely dead. Not even any HV that I can detect.
Some interesting things about this system:
- This is a 64K system with the “red” GAL in it. This limits the amount of RAM that can be fitted. I have a suitable JED. I’ll have to look through my collection and see if I have a suitable GAL so I can upgrade to 128k with the “white” GAL.
- The CIAB Drive / PSU is rivetted shut. What on earth? I’ve been replacing the rivets with bolts and nuts where possible. There’s one right net to the PSU I’m replacing with a nonconducting nylon bolt.
- I finally have a legitimate data / power cable. Up until now I have been making my own.
- The Drive / PSU needs a case. I’ve been working towards building my own case, so I’m pretty confident I know how to build this. I just need to get the parts and, y’know, build it. Cardboard, cloth and PVA glue are the order of the day. Then I’ll need to make a silkscreen and stick a logo on the side 🙂