Fixing CRT heaters (was: Re: CRT Problems)

Hi, On Wednesday 13 December 2000 01:03, you wrote: Great, then it's not a burn, it's a good sign. If the silvery deposit becomes hazy or translucent, it means that the tube is losing vacuum. Tubes with weak vacuum run hot, which compounds the loss of life. However, your problem with the intermittent heater is a pretty common thing to have happend in the old days. There is a way to fix it, usually... You will need to find someone with a picture tube tester that has the filament 'repair' feature. What this really is, is a fairly large (500uf or better) capacitor, that gets charged up to about 250VDC and then is applied across the (open) heater contacts on the tube. It helps to first jar the tube slightly, and test to make sure that the heater is (at least at that moment) totally open, before applying the voltage. Now the voltage is applied. The tube is then jarred slightly, until the open heater makes a light contact, at which time the cap discharges like a mini arc-welder and tags the heater filament back in place. This works well, and can be done many times. If your heater is open internally, this is the best (and only) route for effecting a repair. Good luck, I hope you are able to fix it. -- Bill Layer Sales Technician <b.layer(a)vikingelectronics.com>