Work Day 8th April 2017 – Pt 2 Technical

Technical
Engagement Controller’s Monitor

Following the changing of the Technical Supervisor’s monitor the previous Saturday the EC’s monitor went a bit ‘funny’, the colour wasn’t right. After a short investigation of the obvious – and after the Red channel of the RGB video input disappeared – it was found that the Red channel termination switch, it switches in or out 75 Ohms, on the rear of the monitor had been switched over or stuck in the middle. Obviously accidently touched the pervious Saturday. With the switch now in correct position the monitor display is back to normal. We like these sorts of ‘faults’; keeps us on our toes!

Displays with SCSISD wm.jpg

SCSISD
After successfully formatting the SCSISD, see previous blog, and loading it with the Bloodhound software (SCSISD is a SCSI-2 hard disk emulator, it replaces a SCSI disk with a micro SD card!) in the workshop it was time to see if would run the LCP – answer; it does. The SCSISD is not as fast to boot the LCP as the original SCSICF product (CF card) we used for SCSI-2 disk emulation but it works! Slower it may be but still a lot faster than the original CDC Winchester disk. The SCSISD emulator is about a sixth of the cost of the SCSICF emulator but there is a very good reason for this. SCSISD is an open source item aimed initially at the Amiga computer (yes the original Amiga) whereas the SCSICF product is aimed at mission critical applications in industry. For our use the SCSISD is fine as the days of the LCP being ‘mission critical’ have long gone. Performance of the SCSISD is less than the SCSICF at boot but the LCP appears to perform normally when using the SCSISD, see the accompanying photos of the displays running with SCSISD and the SCSISD card under test in the Argus 700 disk/tape shelf. One issue with SCSISD is that on switching on the Argus the Argus has to receive a reset before it boots from the SCSISD. This issue will be looked at but if it turns out to be a ‘feature’ of the SCSISD it is not a problem, particularly where costs are involved.

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Work Day 8th April 2017 – Pt 1 Mechanical

Painting and Scraping

Work has started on the preparation needed to repaint the LCP roof. When the many coats of paint were being removed, with a heat gun and scraping, a significant number of rivet heads came off. The reason being that the hole in the centre of the pop rivets had not been sealed and over the years water ingress into the centre of the rivet had caused the aluminium shaft of the rivet to corrode through. All the pop rivets that had lost their tops through corrosion had previously been replaced but the task on Saturday was to seal the tops of the replacement and original pop rivets to prevent any future water ingress. Isopon car body filler was used for this purpose. Next Neil used ‘wet and dry’ paper to rub down the roof, with plenty of wet, and is now ready to receive its coat of primer next Saturday. Neil also worked on creating a cover for the LCP roof to protect it from dust once repainting starts in earnest.

The underside of the steel section around the base of the LCP cabin was given a good going over with a ‘stripping disk’ (far superior to a wire brush for flat surfaces) and once cleaned of any corrosion and loose paint received corrosion treatment before primer will be applied next Saturday. Generally, the underside of the LCP is in a good condition considering its age and the years it spent dumped on the bare earth, subject to whatever the weather could throw at it. Two accompanying photos show the two worst cases of corrosion found, both at the ends of the LCP, these areas will be treated and repaired. The underside of the LCP is constructed from a perforated steel sheet on which five steel skids are fixed. The perforated steel sheet is covered in what looks like a resin coating, this can be seen in  one of the attached photos where the steel sheet has been punctured at some time in the past.

LCL Cabin Underside 3 wm.jpg

 

LCL Cabin Underside 4 wm.jpg

It was also decided that items that can be refurbished away from Cosford, e.g. cable duct covers, will be done so. All work at Cosford is then concentrated on the LCP cabin and the T86 cabin in its turn.