Commodore 1084S Monitor Power Switch

4Mar/200

Commodore 1084S Monitor Power Switch

As per usual, I saw an auction on eBay and thought I'd have a crack. It happened to be 3 Amiga 500s with a lot of paraphernalia. Included, if I picked it up personally, was a beautiful Commodore 1084S monitor, with a faulty power switch.

After a quick message to a good friend in the Amiga community (thanks Steve!), I had a link to a fellow Australian's anonymous blog on blogspot under the name Random Mayhem. Here's the link to the article, but it seems to have disappeared in the time that I've now come around to writing this post. I picked everything up mid-february, got around to purchasing the items soon after... but now two weeks later the blog is gone! Thankfully, here's the cached version from Google. I have no idea how long that'll be around.

Thankfully, the whole process is very straightforward. First up you'll need to buy a replacement switch from Wagner Electronics Super Store in Sydney. From here, we make minor mods to the switch, as it now has a secondary pole, and then swap it in.

Opening up the Monitor

CRT Monitor contain high voltages, which can be stored for long periods of time. BE CAREFUL! Yes, the usual warning. The large capacitors in CRT monitors will hold charge and need to be discharged if the monitor has been on recently. Grab an insulated flat-head screwdriver and bridge the pins on any capacitor. If you get a spark out of it, then you've probably just saved that spark from travelling through your finger.

There's around 6 screws to remove to take the main housing off. From here, don't pull it away with speed. There are two speakers in the housing and these are connected by relatively-loose cables that run to the front-left of the monitor, where the headphone jack is. You'll need to lift the housing around 5cm off the chassis and then unplug these two cables. Once done, you can remove the housing completely.

From here, give the internals a good clean-up... my unit sure did need it!

Removing the existing switch

The switch is held in with 6 pins: 4 electrical contacts and two for the support bracket. Removing it will involve removing the solder from the pins and then 'walking' the switch out. The basic idea of 'walking' is to heat up the pins on one side of the switch and prise it up as high as possible, only moving it millimetres at a time. From here, heat up and loosen the pins at the other end and prise that up. Once you've got one end clear of the solder pads, heating up the other end should see the whole switch come out.

With the switch out, we can now remove the support bracket. This is held in by two bent tabs on the top side. Grab a set of reverse pliers, the ones that open when squeezed, and slowly bend the top pins open. We want to re-use this support bracket, so try not to snap the tabs off! They should bend relatively easily. Test if you can wriggle the switch vertically out of the bracket each time to prevent opening up the tabs too much. Too much flexing of the tabs could weaken and see them tear off.

With everything apart, we can now install the new switch.

Modifying and installing the new switch

First up, you need to cut off the three pins on the new model. We don't need these on our old monitor. I grabbed my sharpest pair of pliers and cut the tabs off right at the base. I suppose you could use them for a mod if you wanted? LED lighting? an extra amp for the speakers? I had no use though.

Once done, you can slide the support bracket on and gently bend the tabs back into position. The whole switch will then slide perfectly into the previous switch's position. If not, just make sure all the solder holes are clean. Once in place, solder away!

Re-assembling the housing

Just a quick note here... make sure you run the speaker cables correctly. One runs internally around the entirety of the housing so as to keep it from electrical interference produced by the circuitry. I assume there's also heat concerns, so make sure it's not running too close the to main tube. There are actually little plastic tabs where you can push the cable into, to keep it in position when you push the housing onto the chassis.

Also, when plugging the cables back in, make sure you have them the right way around. You wrote down the order, didn't you? Or did you take a photo prior!?

Testing... or... please keep the magic smoke in!

I bit the bullet and just applied power and video data. Thankfully, I got a Kickstart 1.2 boot screen! I knew the Amiga already worked, as I'd tested the black-and-white composite out. I was very happy to see this crispy screen come to life.

As you can see... it was time to load A-Train, which I'd bought whilst I had the A1200, but which had arrived after I'd sold the A1200.

A-Train disks on the Amiga

A quick note here... if you look at the final photo above, you'll notice A-Train is asking for 'Disk 2'.

Uh... 'Disk 2'? I'd booted off 'Lo-res', so I slapped in 'Hi-res'. It worked, but the disk naming is terrible. Nowhere on those disks is the number 1 or 2?

Monitor built-in stand

Just in-case you didn't notice, there's a built-in stand in the base of the monitor. The stand consists of two plates of plastic that are hinged to provide a triangular stand, supporting the rear of the monitor. This is specifically to be used when the front half of the monitor is sitting on the rear edge of your Amiga.