Hey Guys,
Im back again with a new reno.
I found an HMVC23B in a mates shed.
I later discovered that he pinched it from his Dad.
This radio used to play in Saw Doc Benalla.
I have had it working and it sounds great but there is a charred remainant that could have been a capacitor.
I cannot tell you much about it other than it could have been a Wax Ducan; or maybe some type of Crecote creation? It goes from the red leads of the transformer to a 6v6. Ideally I need a schematic as there are other similar but not so charred components in this radio.
I would like to fix this so can give it back to old Colin.
Can anyone help? I am prepared to pay.

X61M, AR7GT, 6U7G, 6V6GT, 5Y3GY.

Actually correction to the above, the cap is in series with a resistor between pin 5 and 6 on the 6V6

Hi there,
look up the valve data sheet on the net. The 6v6GT is the audio output valve of your radio. Pin 5 is the grid and pin 6 is unused. Therefore the capacitor is the coupling capacitor from the previous stage and the usual value would be 0.05uF.
No charge for the info and happy to help further.
You need to change all of the paper capacitors if you want to have a reliable radio, and check the resistors as well.

Forgot to mention, this particular capacitor is probably the most important to replace as it can damage or destroy the valve, or in worst case destroy the output transformer as well

That will be 6AR7.

Pin 6 is a spare it is not connected to the 6V6.

There should be another resistor to chassis from pin 6. It is 500K (470K) and the one to pin 5 (grid stopper) will be 50K (47K). Check them both as well. I find they have a very high attrition rate.

Cap (C32) is 0.05 (0.047 630V)

Check the cathode resistor 250R but not with the cap on it.

If there is a 0.02mfd paper cap on the plate in series with a IK0 resistor I would be tempted to change it as well.

Paper caps should really all be changed out.

Marc

Maybe my pin numbers are a bit out; looking from the top of the chassis.? Gee quick replies thanks guys!

I better check again I am dsilexci.

Pin numbers should be viewed from under the chassis. Numbers run clockwise starting with pin 1 next to the locating spline

It is rare to find a 6V6, 6F6, 6L6. with a pin 6 in the base of the valve. In many sockets you can see that it is missing.

Personally if it has been sitting for years, I would not bother to turn it on until I checked the mains; transformer & threw out every paper cap & electrolytic in it..

Use 500V Electrolytics on the HT. I do have the circuit (thats how I knew the cap). Three pages.

My parts have just taken a hit from a 16 valve Midwest but I would say, if there are no major transformer issues changing the caps & dud resistors could be achieved in a few hours.

Marc

When a valve pin is not used, radio manufacturers sometimes use the corresponding socket "pin" as a convenient connector -- like a sort of single tag strip.

Circuit sent.

Would agree with pin use. This can / has lead to some interesting results when a metal valve of the same type is put into a set with octals and pin one has something other than nothing on it, or pin 1 is not grounded.

Be aware of the pinouts.

Many thanks to all.
I received the schematic Marc thanks again.
Pin Number tutorial in also much appreciated.
Will get to work on replacing those caps now!
Will keep you posted.
Billycamera

Thanks guys,
and special thanks for the schematics
All recaped and so far beautiful.
A great unit worth restoring
Bill