UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

TonyDuell · 27th May 2019, 5:55 am

I am not sure which section to put this in, it could also go under 'Components and Circuits', 'Test Equipment' or 'Vintage Computers'. I am putting it under TV as I suspect the people who read this part will have the most experience in this area, but if the mods feel it should be elsewhere then please move it.

I have a piece of vintage datacoms test gear, the display section of which is a 9" raster-scanned monitor.

Unfortunately before I got the instrument it was dropped (looks like from a great height). The plastic outer covers have minor damage, the chassis is twisted and the cartridge tape drive needs a lot of work. But the PCBs are all intact.

But the main problem (and the reason I am posting here) is that 9" CRT. It is intact I think. But the impact has forced it backwards and it has come out of the implosion protection tension band. It is essentially held against it by the tenson springs that earth the outer aquadag coating. Surprisingly there is no real damage to the front panel of the instrument, or to the smoked plastic screen over the front of the CRT.

It's a normal CRT arrangment with a B7G base (and the seal-off tube in the middle), an anode cap connector on the side of the flare and deflection yoke held on the neck with a screw clamp.

I feel it is not safe. My late father did a lot of work on vacuum systems and stressed the dangers of a glass system impoding. I feel I should probably remove the CRT, let the vacuum out safely and fit a replacement.

What is the safest way to do this. I want to save as much of the unit as possible (such as the deflection yoke), but I am rather worried about cracking the CRT when I try to get the yoke off.

Any suggestions/comments?

27th May 2019, 5:55 am	#1
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	CRT lost its tension band I am not sure which section to put this in, it could also go under 'Components and Circuits', 'Test Equipment' or 'Vintage Computers'. I am putting it under TV as I suspect the people who read this part will have the most experience in this area, but if the mods feel it should be elsewhere then please move it. I have a piece of vintage datacoms test gear, the display section of which is a 9" raster-scanned monitor. Unfortunately before I got the instrument it was dropped (looks like from a great height). The plastic outer covers have minor damage, the chassis is twisted and the cartridge tape drive needs a lot of work. But the PCBs are all intact. But the main problem (and the reason I am posting here) is that 9" CRT. It is intact I think. But the impact has forced it backwards and it has come out of the implosion protection tension band. It is essentially held against it by the tenson springs that earth the outer aquadag coating. Surprisingly there is no real damage to the front panel of the instrument, or to the smoked plastic screen over the front of the CRT. It's a normal CRT arrangment with a B7G base (and the seal-off tube in the middle), an anode cap connector on the side of the flare and deflection yoke held on the neck with a screw clamp. I feel it is not safe. My late father did a lot of work on vacuum systems and stressed the dangers of a glass system impoding. I feel I should probably remove the CRT, let the vacuum out safely and fit a replacement. What is the safest way to do this. I want to save as much of the unit as possible (such as the deflection yoke), but I am rather worried about cracking the CRT when I try to get the yoke off. Any suggestions/comments?