Work Day 24th October 2020

With the repainting of the internal cabin walls of the LCP complete it was a chance to clear it out and create a photographic record. Four accompanying photos show the internals of the LCP taken yesterday.

LCP Entrance

Prismatic Light Diffusers
Repainted Walls and Full-Level Lighting

Repainted Walls and Full-Level Lighting

The LCP’s computer system and display console have not been run for many months so it was time to start switching it on again. The LCP is in an unheated and, therefore, damp hangar. This, coupled with the age of the equipment, means care is needed with switching on in stages with checks at each stage. The Argus 700 computer was first to be switched on and it wasn’t long before its 5V 120A supply failed due to an X2 filter capacitor literally boiling its dielectric. This is a common problem and can be rectified.

Over the past few years some interesting items turn up. We have now found two screwdrivers that will be instantly recognised by anyone who serviced electronic equipment in the RAF, see accompanying photo. Can anyone help identify where these screwdrivers were used, one is marked ‘MS6’ and both have what is assumed to be an inventory number starting ‘BSYY–’.

RAF Screwdrivers with MS6 – BSYY– markings

Off site news:
This is the culprit for yesterday’s smoke screen. It’s one of the later RIFA
X2’s as identified by it’s mottled appearance. Search YouTube with ‘RIFA X2
capacitors’ and lots of videos showing these capacitors blowing up.

X2’s come in different technologies, e.g. polypropylene (MKP). I’ve already
bought some MKP capacitors to replace the problematic RIFA Metalised Paper
capacitors. It is concerning that having checked our power supply records to find that the RIFA X2’s on the 5V 120A PS were definitely changed during the initial power supply refurb program so that capacitor was not that old; or was it new but old stock?

The culprit!

Pete H

Work Day 17th October 2020

Painting the internal walls and roof of the LCP is now complete so work is now underway to get the LCP back to an operating state. Items are being refitted previously removed to allow painting of the cabin walls, or to be refurbished.

The shelving on top of the P racks is completed
The paint finish above the racks is a huge improvement on its original state:

Two accompanying photos show the frame for holding test equipment back in place and a cable duct cover replaced, this cover has been refurbished and repainted to treat a large corroded area.

Test Equipment Frame

Duct Cover

We have achieved a good match with the hammer-finish paint; better than had previously been achieved when in-service!

Minor repairs are still being carried out in the LCP and the accompanying photo shows the rectification of a problem where the original holes for self-tapping screws for a roof access panel had been stripped.

All dust covers have been removed from inside the LCP and a start made on cleaning before the simulator is tested, something planned in the next few weeks.

Pete H

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.

Work Day 3rd October 2020

After refurbishing the light fittings, switches and power outlets in the LCP
it was time to complete the refitting of these items and get the power back
on in the LCP. Two accompanying photos shows the light switch, not a major
item but once again it serves to illustrate what’s involved in the
restoration of the LCP. One photo shows the refurbished switch and cabin

The second photo, the condition of the same area in LCP 1008 at
Duxford before it was removed from display.

At the end of the day power was back on in the LCP and yet more
painting of cabin walls carried out.

Away from Cosford it was a return to power supply refurbishing. The plan is
to get all spare power supplies to a serviceable condition. We have been
fortunate to receive power supplies from donations but after being in
storage for many years these power supplies need their metalised paper X2
filter capacitors replaced. An accompanying photo illustrates what happens
if these capacitors are not replaced.

The power supplies in question are Farnell G Series and are 5V, 12V 15V or 24V models ranging from 120 Watts to 600 Watts. There are a total of fifteen of G Series power supplies in the LCP and an accompanying photo shows a bank of several power supplies in the computer rack.

Pete H

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