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UPDATE: Tubes tested. Canadian Philco Radio: ID and repair needed - Printable Version

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RE: Update with Pics, New Canadian Philco Radio: ID and repair needed - Radioroslyn - 03-10-2015

Yep that's them alright. Ok next measure the voltage between pins +3 -7 of the 1A5's also check voltage between pin +4 and-7. The + and- symbols are for the + and - meter leads.
If all is well should have about +85v on both.
Terry

RE: Update with Pics, New Canadian Philco Radio: ID and repair needed - Ritchie - 03-11-2015

correct. all points tested 87v. 3 and 4 pins positive wrt pin 7.

RE: Update with Pics, New Canadian Philco Radio: ID and repair needed - Arran - 03-11-2015

 One piece of advice though, you may want to fabricate a new battery cable if you intend to operate this set on a regular basis, the original cable looks like the same crappy rubber/gutta percha wire that the U.S Philcos used to use in that era, I'm not sure about the wiring in the IF cans or the rest of the set. Yes, you can restuff the capacitors, in fact that would be a nice touch, and check the values of the carbon comp resistors whilst you are at it. One thing to watch on any battery set are the grid caps and the grid cap leads, the wire sometimes breaks down or the solder joints need touching up on both. The schematic for this set should be in the Radio College manuals should you need one, I don't have many manuals specifically for Canadian built Philcos, most cross reference but some don't.
Regards
Arran

RE: Update with Pics, New Canadian Philco Radio: ID and repair needed - Radioroslyn - 03-11-2015

Go ahead and do the caps and resistors. Clean the tube sockets with Deoxit. We are dealing with a set that voltages are low (90v) and low current this means that any resistance at contact point can cause problems.
Terry

RE: Update with Pics, New Canadian Philco Radio: ID and repair needed - Ritchie - 03-11-2015

Thanks guys,
I think we are definitely at the cap replacement stage. I have removed the old batt cable.
I'll also take a look under the cans.
Deoxit is as rare as hens teeth in Canada. I guess they wont put French on the label for import.

I'll report back after the cap job. Might be tubes after that. Icon_sad

-Ritchie.

RE: Update with Pics, New Canadian Philco Radio: ID and repair needed - Ritchie - 03-12-2015

Got a Mystery Part here..... component measures exactly 600R Which is my first clue that it's out of spec....

It was located at the highlighted location. This schematic is from a 41-95 but the component locations are exact in the amp section though different values. the 41-95 schematic lists this value as 680R 1/2W

this one's seen some heat.

RE: Update with Pics, New Canadian Philco Radio: ID and repair needed - Ritchie - 04-28-2015

Hey guys.

All electrolytic caps replaced and re-stuffed the old paper tubes. Took my tubes to Columbus Radio here in Winnipeg and got the tubes emission tested. All tested within spec.

Also found de-oxit on the shelf at Advance Electronics in Winnipeg.

Anyone help with diagnosis?

RE: UPDATE: Tubes tested. Canadian Philco Radio: ID and repair needed - PAradiogeek - 04-28-2015

Hi Ritchie,

Have you checked to see that your oscillator is running? In this set it is part of the mixer (1A7) circuit. You can do this easily if you have another working AM radio. Tune your Philco to 1000 KHz, then tune your other radio to 1000 KHz+ 465 KHz = 1465 KHz and place it near your Philco. Then move the dial up and down a little on the second radio. If the oscillator circuit in your Philco is working, you will hear some squealing (that changes as you adjust the dial) coming from your second radio.

If you hear nothing, then it is a good indication that the oscillator is not working on the Philco which might explain the lack of sound.

Good luck,
Jon

RE: UPDATE: Tubes tested. Canadian Philco Radio: ID and repair needed - Ritchie - 04-29-2015

A great tip Jon, thanks. I'll dig up an AM radio and give it a try. There's a switch on the side of the radio for AM/SW, no idea what position is which at this point.

Also, can the amp section be tested by injecting audio somewhere?

RE: UPDATE: Tubes tested. Canadian Philco Radio: ID and repair needed - Radioroslyn - 04-29-2015

You can touch the grid cap on the 1H5 (grid cap is the connection on the top of the tube). That will inject a 60 cycle hum in the audio amp. If working will buzz loud. Replace the 680 ohm resistor it's part of the grid bias network for the output stage.
Terry

RE: UPDATE: Tubes tested. Canadian Philco Radio: ID and repair needed - Ritchie - 05-30-2015

Well, despite the tube emissions testing, 2 tubes were dead. 1N5G and the 1A7G were toast. They have been replaced and the set plays.

However, it's very Squealy and extremely Quiet. Does this mean the IF etc needs tuned?

The SW also seems dead. Ive read this may be a wartime censorship move? How can I test this?

-Ritchie.

RE: UPDATE: Tubes tested. Canadian Philco Radio: ID and repair needed - PAradiogeek - 05-30-2015

If BC works and SW doesn't, there are two likely culprits.  The first being the bandswitch, and the other being the oscillator.  Oscillators sometimes work on one band and not the other, usually due to failed or out of tolerance components.  
I recommend starting with the bandswitch.  Try ohming out the connections that go through the bandswitch when SW is selected.  Readings of more than a couple of ohms are an indication of a problem.
G.L.

RE: UPDATE: Tubes tested. Canadian Philco Radio: ID and repair needed - Radioroslyn - 05-31-2015

I would make sure that any tube shields are in place. Try bypassing the the HV in the set. Can be done with a mfd or two  to gnd. If it still persists narrow down which stage is oscillating that shouldn't be. This can be done by touching the grid cap of the tube till you find the one that cause the oscillating to stop. If it turns out to be the IF amp you can try adding a bypass cap to the screen grid to gnd and or to the B+ side of the IF transformer. You can detune the IF transformer but there will be a sacrifice of gain.

Oh also be sure that your A and B voltages up where they need to be. Too low can cause stages to be unstable.

Terry