Hello..my first TV

[old_coot88]

Seleniums don't age well. I'd replace it with Si diodes. Then if the supply is outputting more than 6.3 VDC under load, bump up the value of the 1 ohm resistor as needed.

[Donj]

Tomorrow's task... Just as the schematic shows for the selenium I expect... ac in at both anodes and dc out at the junction of the two cathodes?
(my inexperience is showing..

[old_coot88]

Originally Posted by Donj

Tomorrow's task... Just as the schematic shows for the selenium I expect... ac in at both anodes and dc out at the junction of the two cathodes?

Yupp. And with Si diodes, the banded end is cathode.

In the future you'll probably encounter seleniums having a + sign on the cathode, which seems dumb as heck. The only rationale would be "The B plus comes outa here"

[Yamamaya42]

Originally Posted by old_coot88

Yupp. And with Si diodes, the banded end is cathode.

In the future you'll probably encounter seleniums having a + sign on the cathode, which seems dumb as heck. The only rationale would be "The B plus comes outa here"

they taught us how to remember diodes LONG ago in electronics class, " A = arrow for anode "

also the mnemonic for resistor color codes that was VERY un-PC

[Donj]

Thanks guys..

[Donj]

Another question. With all the interconnect wires coming out of the chassis, I failed to notice, until now, a somewhat random looking wire emerging through a non-factory looking hole on the rear of the chassis. No connector, in fact no exposed conductor. Tracing the wire to its source, I find it attached to the plate of the 6AL5 "clamper" tube. Now, the socket of this tube is enclosed in a screwed down metal shield so access for any reason would necessitate first removing the shield. I am wondering if this was added sometime in the set's life to enable plate voltages to be measured for service purposes..
Stupid question...Should I just leave it hanging out? Could leaving it there possibly introduce any instability due to the fact that it originates in a shielded part of the circuit?
Also, the 1/2 watt resistor that is also attached to pin 2 is reading high , about 2.3 meg should be 1.5 meg according to schematic was getting ready to change and just looked at the parts list to confirm the power rating. Parts list call for 3.9 meg. I suppose I should go with what's already there. I'm colour blind but wifey confirms its brown, green, green.

[old_coot88]

The 6AL5 is associated circuit-wise with a 6SN7 (V11). What circuit is this in? Sync?

[old_coot88]

Originally Posted by Donj

...a somewhat random looking wire emerging through a non-factory looking hole on the rear of the chassis. No connector, in fact no exposed conductor. Tracing the wire to its source, I find it attached to the plate of the 6AL5 "clamper" tube.

To venture a guess, maybe it was a test point that someone wanted to monitor with a scope.