New Pickups

Picked up two new items this fortnight.

Commodore 1804S

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!

The Speccy makes a useful Composite out source.

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.

Microbee CIAB

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.

Not sure about this case. It looks like it’s the Premium case.
It has joined the Choir Invisibule!

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.

3 RIFAs. I have replaced all 3.

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 🙂





Leave a Reply

Your email address will not be published. Required fields are marked *