admiral 24c15 with 20b1 chassis attempt at restore

[bandersen]

Yep, TV only for sure. All the tube filaments are wired in parallel. What's your line voltage going into the set? Should be at least 117 VAC. These sets draw quite a bit of power. Could be your line is sagging.

[fumplet]

Other tube filaments do not dim. Only the tubes 6bg6 and 1b3 get dim when screen goes away if i turn up voltage past 90. Screen faded once when i had it at 90 too.will check line voltage at tv chassis but dont think voltage is dropping

[fumplet]

Must fix weird 6bg6 filament works/then doesnt work issue...I wonder if its arcing making filament do that

[bandersen]

You are running the set on only 90 volts? Use 117.

[fumplet]

Ok then run on 117 and test....i guesss alll caps are replaced except for the single wire can that just says a part number on it...no value on it..havnt looked it up on parts list yet.
I do still hear vertacle buzz when picture is faded out and or 6bg6 isnt lit. Can also vary the buzz with front control knob. Makes me also wonder if a resistor is getting hot and opening. Restors are next anyway.
Fascinating! I just figured the high voltage was going away when I cranked it to 117 volts. Its not. Screen lit about 100 volts measured and high voltage is about 7k. When I crank it to 117 volts the high voltage goes to 9k which is what schematic says. Weird its like somebody cranks down the brightness to zero with in 5 seconds after I crank up line voltage to 117.
I did manage to check the 6v6 audio output tube to see if somebody biased it differently because it had a 6k6 installed. Seems wired for 6v6 so I popped in a 6v6.

[fumplet]

I decided to mess with ion trap magnet. and adjusted it for full brightness. Low and behold 117 volts and I got a screen! So, because I only know that the magnet redirects the electrons back to the screen, very fascinating that with the ion magnet off... screen is affected by line voltage level almost like line voltage affects when screen electrons hit screen.

[bandersen]

Line voltage will affect the current flowing through the focus coil which interacts with the ion trap magnet. It's all connected.

[fumplet]

Still trying to wrap my head around ion trap being off and raster showing up then fading out the second i turn up line voltage to 117 volts. Would have thought raster would still be visable just not as bright. So the second i turn up line voltage i guess the warm up of tubes changed something the same amount of picture raster fade time

[Yamamaya42]

As bandersen mentioned, they are interactive, the fields for the focus magnet AND the ion trap, the tube was designed to work with a combination of both to deflect ions away and electrons to the front, as bias is slowly raised, this will cause a respective ramp up in the electromagnetic field of the focus coil, and w/o the ion trap in place, you can expect weird stuff to happen as it rises to full power.

[bandersen]

Absolutely. The magnetic fields interact. Always run the set at full line voltage, adjust the ion trap magnet and carry on

[fumplet]

yeah the only reason for power up was recapping and checking like old radios. The ion trap was in place and close eyeballing where it had been when I took it off but not exact. When I saw it dim out as voltage passed 100 volts, I thought something was shorting out or burning up.

[fumplet]

I do not have a 4 mfd capacitor that c207 is and its on pin 5 of the 6al5. Im going to guess a 10uf may work. I might have a 4.7 mfd somewhere but dont remember the voltage of it. max volts on parts list shows 50 volts. WELL I just found it. 4.7uf at 450 volts. Installing it now.

[fumplet]

Well I have recapped the 4 mfd cap and replaced my dual caps 153k and 333k that made .05uf twisted together with actual .05uf mpt caps. Focus adjustment used to work, now it doesn't focus or seem to focus.
More possable problems is the 1b3 filament seems way too bright at 117 volts. I know this tube is powered off the flyback so whats up with that? Adjustment way out of whack causing it to draw more filament current or a bad 1b3?

[fumplet]

is this tube too bright. I have read that a 1b3 is barely able to throw enough light to be detected unless room lights are off!!!!

[Yamamaya42]

Originally Posted by fumplet

is this tube too bright. I have read that a 1b3 is barely able to throw enough light to be detected unless room lights are off!!!!

looks normal to me!

you want to see abnormal...
​​http://suzaku.live-evil.org/0317201339a.jpg