Cary,
First congratulations on getting one of the more complicated vintage TV sets, or I should say "systems," lighting up! These early Du Mont's are not what we call starter sets!
That set must have had years of dry storage storage! Usually one can hear the HV crackling up for the first time, but I forgot that you were from the driest area of the US.
Quote:
Originally Posted by CaryLee
I'm not sure what to use for signal source.."earlyfilm" mentioned a slight voltage travels through the chassis on this set that could travel the lead and damage a transistor device...might it damage a VCR or DVD player?
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Sorry I confused you. I was talking about modern AUDIO devices. Many of these are not protected against for this issue. Anything that is supposed to go through an antenna or video feed should be OK. Also, older tube era phonographs should be OK.
I'd try a your cable box if you have cable and it has an RF (channel three or four) analog output. If not, find one of the used set top boxes used to convert digital over-the-air programs in the early days of digital, that will be better. The most common problem with both of these is their output is slightly stronger than old high performance fringe area sets like your DuMont is expecting and that may cause sound buzz or picture bending, or even the picture flipping to negative.
The first thing to remember about a tube checker is that it also has to be recapped and then possibly recalibrated, since the same parts in them age just as a TV does.
Also you need to try to see if the focus control is just dirty or if it has failed. You have pretty high voltage there, so after cleaning, be sure to let the control
completely dry before powering up the set, or you could fry it. This control is center fed from the raw B+ and helps provide both the 300v and 200v sources.
James