TV-2 Tube Tester Problems

[Paully]

I posted on TUB DIY but hoping some of the experienced members here might be able to help.

The main meter on my TV-2 tube tester isn't working though all the other meters are. I move the screw on the face of it and I can get it to jump a tiny bit but then it goes back down if I move the screw any further. I was told to replace the capacitor that goes across meter as it is the most likely culprit. I think they said it was 5uf but am not sure.  I open it up and I can't see a capacitor anywhere near that meter and below it is an absolute mess of wires.  I measure .5K ohms across the TV-2 meter.  The schematics I have found on the web aren't legible and there isn't one in the manuals I have.

 

[Grainger49]

If you mean the screw at the bottom of the meter it is for mechanically zeroing the meter.  500 ohms might be a good resistance for the meter movement.  Did the meter needle move when you measured?  Resistance measurements use a DC source to measure.  Try with the probes swapped to. 

Somewhere on the face of the meter there will be some spec like 5VFS.  Which would mean 5V DC reads full scale.  It could just as well be 10mV (0.01V) for full scale.

How about posting a picture of the mess of wires to see if we can trace the wires somehow?

 

[Paully]

I was just measuring the resistance across the tabs with the tube tester off.  I don't think I would test with it on.  But at least it seems that the meter needle isn't stuck.  It says R=250ohms +-10%.  I don't see anything that says voltage.

A picture isn't going to help.  the wires get bundled with other wires and then disappear down a panel that would block any photo.  I think there are discs for sale on ebay with all of the manuals.  One probably would have the schematic in it.

 

[Grainger49]

Yes, measure resistance across the meter terminals with it off.  The back of the meter may give the movement sensitivity, the full scale voltage.  And forget the picture of the wiring.

 

[steel]

Try link below：

http://www.militaryradio.com/manuals/TV-2_Series_Tester/tm11-6625-316-35.pdf

 

[Paully]

Thank You!  Very Much!  From my initial glance that looks like it has some legible schematics in it.  Grainger, if you have a chance to look that over I will try to give you a call tonight or tomorrow once I have had a chance to look it over as well.  Trying to see what is connected to the main meter.

 

[Grainger49]

As I look through the schematic linked above, thanks that is great and I'll save it, I first come across the transformer lug 9 which feeds the meter.  The meter is then has a trim on a 1k ohm trimming pot back to the tube's cathode (Page 15).  If the 1k pot or the wire going back to the cathode (it must go through a selector switch to get back to the cathode) is open then the meter will not read.  The cathode seems to be common too.

That is my first read.  More later, less sooner.