Work Day 10th October 2020

There are lots of things going on in the background and one of those is refurbishing our stock of spare power supplies. I have refurbished a G6 20S over the past couple of days. The attached shows the PS in it’s rusty state (on the right) next to a previously refurbed 24V supply.

The refurb task is clean, replace all the corroded screws etc. and replace all the RIFA X2 capacitors. Switch on and hope the LED comes on; in most cases it does. Then check the volts adjustment and leave running for a couple of hours to check the electrolytic and tant capacitors are OK. I have a number of these power supplies that were a job lot found on eBay a while back, obviously salvaged from somewhere. For this power supply there was not lot to lose (I have plenty) so to clean all the grot from the inside I broke it open and carefully washed it with soapy hot water! I did take care not to get water trapped anywhere and then dried it off overnight by our stove. It now looks like new, well it will do when I replace the last of the rusty screws.

I’m sorry to say that the LCP has lost its distinctive smell generated during its operational life, it now smells of fresh paint! Anyway, yet more painting took place, mainly second coats below roof level. There will be the odd touch up places left but it’s time to start getting the LCP back to normal so next week it’ll be making up the shelf on P Rack, removing all masking tape and cleaning. The shelving above L Rack has been put back. I have now reinforced the shelf and it lifts out in two sections.

The Swiss have also ‘shelved’ gaps on of their LCP rack tops, see attached photos as to why. The Swiss had modified their monitor panels to remove the scope feature (why have four!!!!) and used an ‘ordinary’ scope which sat on top of the rack and can be seen in one of the photos.

Notice the additional mains trunking in one photo with Swiss sockets above the racks. A printer also sits above the FT81 so the top of that rack had to be levelled off with a shelf as well.

While looking at the Swiss LCP photos I noticed the power supplies in their computer rack all have all sense wires connected (the thin black and white wires), the UK LCP only has the main 5V 120A power supply with sense wires connected. The sensing compensates for any volts drop between the PS and the item using the 5V. Looks to be a Ferranti mod for the Swiss but why not for the RAF; guess the RAF were happy to set the heavy current supplies a bit high to compensate for the volts drop. as that is what we do!

What do you think of the attached photo of rusty screws? I did some magnetic fishing down the gap between the trunking between F and M Rack (below where the 0V test set is kept). Probably ‘bits’ that were dropped after many years of carrying out mods. Anyone know what the small cams were used in/for?

Let’s hope the new restrictions don’t cause problems with access again. I’m fortunate to live in a low infection area but Cosford may increase access restrictions again, let’s hope not.

Pete H.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.