1950 Admiral 16" Set; Recapped... No Picture!!

[Magnavox300]

Originally Posted by Magnavox300

Thanks for all the help...
I was wondering why the HV lead wire cap didn't fit on the top of any 6BQ6 tubes I had!
I'll have to just go ahead and order a 6BC6 tube...
Of course I have a million tubes, but not a 6BC6!!
I am assuming they stamped both numbers on the chassis next to the socket for different chassis circuits?
Will update once I get the new tube!
Thanks again!

I meant a 6CD6!!!!
Im must be getting old!!

[Magnavox300]

Originally Posted by Electronic M

Doorknobs tend to fail leaky or shorted so a DMM won't catch it unless it shorts badly....I had one that leaked intermittently sometimes the set would wakeup and work normally other times it had absolutely no HV.
The best way to test a doorknob when you suspect it is the cause of no HV is to disconnect it on one end and keep use a glass object to prevent the HV from arcing at the disconnect point. Bypassing the doorknob cap (by that I assume you mean putting a short across it) is about the same as putting a gun to your foot and pulling the trigger...
The resistor in the rectifier base that has doubled in value is VERY bad and should be changed...that resistor is designed to limit the rectifier filament voltage and it's value must be precise. Too low and the HV rect filament is overvolted and dies fast, too high and the HV rect filament does not heat up enough for HV to pass through the rect to the CRT.

Your incorrect H output tube is your biggest problem right now though...Get that tube right first and then worry about the rect and doorknob if the HV stir ain't working.

Thanks, will change out that resistor as well!

[old_coot88]

Originally Posted by Magnavox300

I meant a 6CD6!!!!
Im must be getting old!!

Me too. If you got a good 6BG6 in your stash it should sub in a pinch.

[Magnavox300]

Originally Posted by old_coot88

Me too. If you got a good 6BG6 in your stash it should sub in a pinch.

I do!
I'll try it now...

[Magnavox300]

Put in the 6BG6 for a test...
Finally got a quick light up on the screen! Not very bright though, and then screen dies after 30 seconds...
At least it shows something starting up!

[EdKozk2]

I just finished up an Admiral 24E1 chassis, looks very close to yours, same crt.
It looks like you may be missing the fuse and clips. there were two fuses used in those sets. One for the AC mains 120 volts and the other for B+ to the horizontal output tube / flyback circuit. I normally see a bit of blue glow in the horizontal output tube if the B+ is working correctly.
Ed

[old_coot88]

Getting the right value for that 1B3 filament resistor will help sustain the HV.

[Magnavox300]

Thanks to Old Coot's suggestion for a temporary use of a 6BG6, I finally got some good brightness, and life!!!
Picture was dying quickly at first, then I remembered the ion trap wasn't positioned properly...
Here's what I got after only 15-30 seconds, didn't want to leave it running too long with the wrong tube in place... Will now order a new tube, and change out that 1b3 2.7 ohm resistor...
Thanks to all your good help, I'm back in business!
I almost gave up...thanks again for all the help!!!!

PS... There is a 6H6 in the socket of what says:" 6AE5 or 6H6"
Wonder if I should I use a 6AE5 instead?

[old_coot88]

Can't find any listing for 6AE5. keep the 6H6 in. You should be OK running the 6BG6 temporarily. Just in case, watch it for any sign of red plating or sweep width diminishing.

[Electronic M]

Some sets made around the Korean war had changes to the tube line up and other weirdness to account for shortages. Check the base wiring of that tube against the schematic...if it matches that of the tube of the schematic but not the one in the set then the schematic is right, but if it is significantly different from the schematic it may be a production change not documented on the schematic you have.

Other weird things they did included using odd looking German resistors and or American made factory rejects where the marked value was wrong but the measured value was right...

[EdKozk2]

Please disregard what I said about the chassis your sets fuses are. It looks like you have the Admiral 21E1 chassis. It used a 6H6 in place of a 6AL5 some of the production runs.
Ed

[Magnavox300]

Originally Posted by EdKozk2

Please disregard what I said about the chassis your sets fuses are. It looks like you have the Admiral 21E1 chassis. It used a 6H6 for the some of the production runs.
Ed

Thanks for your input, good eye!
Actually there are two fuse holders, one was never used...
When I took the fuse out to check it, the holder broke and came out with it!
So , I used the spare fuse holder.

[dieseljeep]

Originally Posted by Electronic M

Some sets made around the Korean war had changes to the tube line up and other weirdness to account for shortages. Check the base wiring of that tube against the schematic...if it matches that of the tube of the schematic but not the one in the set then the schematic is right, but if it is significantly different from the schematic it may be a production change not documented on the schematic you have.

Other weird things they did included using odd looking German resistors and or American made factory rejects where the marked value was wrong but the measured value was right...

I remember seeing German Siemens resistors with the flat leads and Koaohn
Japanese resistors. Those are the dog-bone style. Also series-parallel combinations used. I saw it more in Admirals, than outer makes.

[Magnavox300]

Originally Posted by dieseljeep

I remember seeing German Siemens resistors with the flat leads and Koaohn
Japanese resistors. Those are the dog-bone style. Also series-parallel combinations used. I saw it more in Admirals, than outer makes.

Thanks, yes I did see at least one “dog bone” resistor in there, didn’t know they were Japanese! Also funny to see all the parallel resistors in there...
Could I simply replace them with half the value? Or were they done that way for a reason?

[EdKozk2]

Originally Posted by Magnavox300

Thanks, yes I did see at least one “dog bone” resistor in there, didn’t know they were Japanese! Also funny to see all the parallel resistors in there...
Could I simply replace them with half the value? Or were they done that way for a reason?

Half the value,( sum of resistance in parallel ) is O.K. Just be certain to maintain the sum of the wattages or better. E.I if you have two 2 watt resistors in parallel use a 4 or 5 watt.
Ed