Work Day 26th February 2022

Type 86 Radar

One main T86 task that we have been working on is the pedestal RAM. The Sika 221 paint used is ‘rubberised’ and normally used to seal cracks in flat roofing. This photo shows the end result. The shine is because it’s still wet and the colour will turn black once the paint dries, it is dark blue when first applied.

Back to working on the radar’s chassis. Quite a bit of work has already been done on the chassis but working underneath is no pleasure especially in cold weather. The current plan is to do whatever is possible from available access via the wheel arches. See the accompanying photo that shows the general condition under the chassis.

Dirt and loose paint has already been removed and corroded parts wire brushed. Not a lot of paint left! A further photo shows corrosion treatment of a spring and other corroded areas in a wheel arch. The chemical corrosion treatment is blue but turns black when cured. Anti-corrosive primer is next followed by a special ‘chassis’ paint.

Launch Control Post

Two damaged sections of torn aluminium on the LCP cabin’s rear wall were cut out some time ago so this week it was time to start the repair. The next photo shows a BMPG team member manufacturing the first repair patch plate.

Here is the first riveted in place. It is flat, reflections are making it looked bowed.

Pop rivets had to be used and the spindle holes of the rivets will be filled to prevent any possibility of water ingress. A waterproof adhesive sealant was also used under the repair patch.

The simulator was given a run and remains serviceable.

Pete H

Work Day 29th January 2022

Pre-visit 3rd Line Power Supply Work

We have these additional power supplies in test and repair that have been gifted to us:

Gould Hiflex Hi-750 5V and 2V – one ‘S’ one ‘U/S’
Advance A1500/24 24V – one ‘S’ one ‘U/S’
PowerTec 9K24 – three U/S

Looking to the future, a possible task would be to power the LCP rack units indicator lamps to simulate a fully operational system, the 24V supply would enable this.

Gould 5V and Advance 24V Power Supplies

Gould Hiflex Hi-750

Advance A1500/24 24V

For the Gould and Advance we won’t waste time trying to fix these leaving them as a potential source of spares. One has a large smoothing capacitor which has obviously been leaking.

PowerTec 9K24


In trying to fault find the three PowerTec’s one defective transistor on a controller card has been found and replaced but still no output. The controller uses an MC3423 which closes down the controller if there is a short on the output, it’s there to reduce the risk of fire! It creates a closed loop as if anything reduces the expected O/P volts the MC3423 shuts it down. I may be barking up the wrong tree here but it’s the only thing I have to go on. All three controllers from these power supplies are the same re voltages etc.

Here is a photo showing the very poor ESR tester reading (7.1 ohms) on one of the PowerTec smoothing capacitors. There are three in each and replacements are £36 each! It’s not a problem with the ESR tester as it shows the correct measurements for the Gould smoothing capacitors as a comparison. For now these are also shelved.

So to Cosford again ….

LCP

Following the replacement of the metalised paper X2 (RIFA) with MKP X2 capacitors in four power supplies that we reported on last week’s the last of these power supplies was reconnected in the console and the simulator run up to check it remained serviceable, it is. One of the power supplies is the programmed 24 volt supply for the console lamps and was checked using Test Lamps and the dimmer control. See accompanying photo that shows the EC’s keyboard. Note the white lamp which is much brighter than the others. This is a suspected fault with lamps supply as it remains bright while the software is not running but once the simulator is running its brightness level returns to normal.

Another task for the To Do list: On running the simulator the 5V 120A supply for the I/O rack was found to be getting very hot. Found after an overheating smell permeated the LCP. Checks made on if it was a loading problem rather than the power supply. Confirmed it was the power supply so it was removed and replaced with a spare.

T86

After using adhesive sealant to stick down the top RAM on the pedestal base the edge of the RAM was sealed to stop any future water ingress under the RAM.

PS – Away from Cosford

I’ve now swapped all the RIFA’s from the 5V 120A PS that was getting very hot to the touch. After removing the covers for the power supply I gave it a check over for obvious signs of burning and the only thing I found was two split 22nF RIFA’s in the area where the case was getting hot. I suspect these had failed and were acting like mini heaters. Fortunately they are not PCB mounted so no other damage from heat was found. All other RIFA’s in the PS were in A1 condition so yet again it’s a failure of the 22nF capacitors, as it has been for all the recent power supply faults. It’s a good days work to replace the RIFA’s but this PS has now been checked with its new MKP X2 capacitors. The 22nF’s must have been an old, out of date or faulty batch!

When I tested the PS the 5V was et to 5.81V! The 22nF capacitors loading down the PS me thinks.

Next job is to fix the monitor that has white horizontal lines (vertical in the LCP). I’ll get around to that when I remember to bring the spare CHARGE cards back from the LCP so I can set up the test rig at home. Thankfully we have a spare CHARGE chassis courtesy of wrecked kit that was discovered.

Pete H

%d bloggers like this: