AVO Two Panel Tester

[User211]

Just dug this out.

Tried to test a 45. Basically it doesn't work.

It powers up fine. Heater voltage set to 2.5V and looking at the filament that looks about right in terms of glow for a 45. Set 4V and it's too bright. I therefore believe it is supplying about the right heater voltage.

Anode is set to 100. Select anode set to normal. Set mA/V switch is set to mA/V marking.

With these settings it should be possible to set the meter to read zero. However, that's impossible and the lowest value I can back it off to is 4.8 mA/V. But then it slowly rises see 2nd pic.

The Philco 45 is working and known to be good. The switch settings for a 45 are correct according to the AVO Data Manual.

Conclusion is it is bust. I have known that for a long time.

Anyone on the forum know how to fix these meters?

Mod fix the title to AVO?

Cheers.

[Firebottle]

I could take a look at it for you Justin old boy.
I like a challenge

[User211]

Alan like the sound of that.

Will PM at some stage over the weekend.

[User211]

Just spotted in a computer repair shop in Clifton...

Retro cool.

[thingfish]

A O Tester....?

What....... Tests Amps, Ohms but no Volts.

[User211]

A few internal shots.

Couple of caps which I suspect are from around 1938.

The main concern seems to be the state of the large tranny.

Alan please take a quick look. I don't know whether that looks repairable. Don't want to send it on if it looks doubtful. But we do know that large tranny supplies about the right heater voltage (amazingly).

[User211]

Some more...

[Firebottle]

It looks old, it is old, with insulation materials to match.
I will definitely replace the two wax capacitors but I doubt there will be a problem with anything else.

[User211]

OK will try and post out tomorrow.

The wiring insulation is shot in places. But I can't see anywhere where it would cause an actual problem. It may be prudent to correct the obvious issues where they can be seen.

I think the issues it has are deeper rooted than the two caps and wiring, so enjoy trying to suss it out

[Firebottle]

Does the unit have a 4 pin socket suitable for 211 valves?
If not have you a spare 4 pin socket you could send as well?