PAL (Programmable Array Logic) Devices

We are currently building up a spares inventory of obsolete components.

One of those component types is Programmable Array Logic devices which needs a specific programmer. The specific devices are PAL 16R4CN and PAL 16L8CN.

Before I spend time constructing one can anyone please assist us with both a programmer for these and some unprogrammed devices of these type numbers would be very helpful?


Workdays 9th, 16th & 23rd April 2022

T86 Radar

9th April
They used to say the Forth Bridge was a never ending paint job; I now believe the T86 chassis is in the same category but we are getting there. See the accompanying photo of a repainted wheel arch and Ian deserves thanks for spending the day bent double with a paint brush.

An observation; it is obvious that in service the underneath of a T86 may have had a quick waft over with a spray gun, there was no attempts to do a proper paint job.

16th April
Work on site at Cosford was all on priming and top coating T86 chassis parts (again). The totally wasted cable for the cabin running lights cables  have been cut away and it was intended two remove the two air hoses. Only one air hose removed as a chisel was needed to snap off a badly corroded jubilee clip but I couldn’t find the chisel. See accompany photos.

The chassis is looking good from the front but the rear axle etc. have yet to be started; the rear wheel arches have now had a top coat.

23rd April
As a change from priming and applying a top coat the sides and rear of the chiller boxes were finished in NATO Green. The chiller boxes had previously been rubbed down, corrosion treated and where necessary primed. Two accompanying photos show a ‘before and after’. The photos also show the general condition under the chassis, after dirt and lose paint has been removed.

A start had been made previously on trying to remove old grease around the housing for the hand brake. The grease had dried out years ago and formed a hard crust over the not so good paintwork. To make life easier on removing the solid grease the hand brake wheel was removed. Old grease chipped away and flaking paint now removed. See accompanying photo.


9th April
A second patch repair was applied to what was previously a torn aera of the cabin’s skin. See accompanying photo. An excellent job by Pete M and Ian.

Once the patching was complete the next task was to replace a monitor in the display console. One installed monitor was losing its vertical hold causing the display to jitter. Setting up of the replacement monitor took some time, not a straight forward task. The set-up task is made easier by removing the monitor from the display console. Replacing and setting up a monitor is a two man job (sorry two person job).

The simulator continues to remain serviceable.

16th April
The simulator wasn’t run this week but will be next Saturday.

23rd April
Testing of four CHARGE Pixel Stores which had kindly been donated to us was carried out. All four stores were serviceable and created the correct displays on the monitors. One of the Pixel Stores was a repaired card. Repairs and testing can be undertaken off site but exercising the full functionality of a Pixel Store can only be checked when running to create the simulator displays. The accompany photo shows how highly concentrated the chip count is on a CHARGE Pixel Store.

After card testing the simulator remained serviceable.

Pete H.

Work Day 3rd April 2022

More of the usual prep and paint on the T86 chassis, it is time consuming as each stage has to be left to dry (a week) before moving on. Once the weather improves I still intend to get more time in at the hangar.

To remind folk what we have here is a photograph of our LCP and T86 in their current state. Note that they are covered to protect them from the concrete dust that falls from the hangar roof.

I took time out from painting duties yesterday to power up the Simulator and run a few commands from the CHARGE test software contained in the operational software. Access to various test routines is gained by stopping the Bloodhound software then  running the required test routine. To stop the Bloodhound software use the Argus 700 monitor (FT81) and enter Ctrl + A then %BHSTOP. Tasks are stopped and listed on the FT81 and once complete enter Ctrl + A then $CHGTEST. It would be interesting to know if any of the test programs, e.g. CHGTEST were run on operational LCPs?

Repairs have been recently carried out on a monitor and a CHARGE Pixel Store and the CHARGE test utility creates circles on a display monitor so the linearity of the H and Y deflection can be checked, linearity is adjusted during the setting up of a monitor. See accompanying photos of a single display and all displays with the circle test screen.

The single circle display on one monitor shows a problem with linearity, the right hand side of the screen appearing a bit squashed.

The simulator system continues to run without a problem.

3rd Line

Following the repair of a monitor our spare CHARGE controller and two Pixel Stores were checked. Unfortunately one Pixel Store had a fault. See accompanying photo of how the fault was presented on a monitor, the dashes shouldn’t be there!

The fault was due to a faulty 64K x 1 DRAM. We are able to bench test CHARGE Controllers and Pixel Stores of which the main component is a CHARGE chassis recovered from LCP 1006. Fault finding is a case checking the logic on a good Pixel Store with a bad Pixel Store. The faulty DRAM had a pulse output at the data output pin which was a copy of the data input pin, RAS and CAS appearing to have no effect on the DRAM. Pixel Store now serviceable again. Note: Only one Pixel Store is needed to test a monitor.

Pete H

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