Is the dial bulb #44?

I have a good #84 tube, a bad #7J7. Before I invest the customers money what's the best way to test this transformer?

The E caps are original and probably bad, I can replace them before any tests, cheap enough for testing purposes.

Waiting for response.

Thank you,

Mitch

Mitch

Pull the 84 tube and operate your radio. Other tubes will light but the transformer should be only slightly warm. If hot it has a problem.

http://www.nostalgiaair.org/Resources/337/M0013337.htm

A 7J7 is replaceable by 7S7, if you have that one.

Electrolytic caps need to be replaced. Shorted they will damage the transformer and 84 rectifier tube.

Use a #44 lamp. If you don't have that #47 will work but not quite as bright.

Norm

:Hello everyone,
:
:Is the dial bulb #44?
:
:I have a good #84 tube, a bad #7J7. Before I invest the customers money what's the best way to test this transformer?
:
:The E caps are original and probably bad, I can replace them before any tests, cheap enough for testing purposes.
:
:Waiting for response.
:
:Thank you,
:
:Mitch

One other thing.. Other caps should also be replaced as they likely will be leaky. This can cause distortion and too much current to be drawn.

Norm

:
:
:Mitch
:
:Pull the 84 tube and operate your radio. Other tubes will light but the transformer should be only slightly warm. If hot it has a problem.
:
:http://www.nostalgiaair.org/Resources/337/M0013337.htm
:
:A 7J7 is replaceable by 7S7, if you have that one.
:
:Electrolytic caps need to be replaced. Shorted they will damage the transformer and 84 rectifier tube.
:
:Use a #44 lamp. If you don't have that #47 will work but not quite as bright.
:
:Norm
:
::Hello everyone,
::
::Is the dial bulb #44?
::
::I have a good #84 tube, a bad #7J7. Before I invest the customers money what's the best way to test this transformer?
::
::The E caps are original and probably bad, I can replace them before any tests, cheap enough for testing purposes.
::
::Waiting for response.
::
::Thank you,
::
::Mitch

Thanks Norm,

I must change the E Caps first, tested shorted in chassis.

One cap does have the isolator plate between the can ground and chassis the other does not, voltage divider resistors measure good values, center tap of transformer is my ground potential to work from.

I have had to order a 7J7 but the other tubes should light as you describe and the transformer should stay just warm on the filament current.

This one is a mess, many prior repairs, but we (the forum) will hear it play again.

Thanks again,

Mitch

Hello again,

Can anyone send me the info, block diagram on the bakelite capacitor block for the AC input protection?

My chart only goes to 1938.

The cap block # is 3903DG, looks like two 0.01 Mf caps.

Someone wired in a new three prong line cord and wired the ground to one of the caps, the cap block is split in half, burned wide open.

Thank you,

Mitch

http://www.philcorepairbench.com/bblokcap.htm

I installed the X-Caps, removed the three prong and replaced with a vintage line cord.

I replaced the filter capacitors and installed a good 84 tube. No 7J7 yet (USPS).

I restored the dial light assembly (make sure you have a #4 and #6 fiber washer, #6 was too large for this bulb socket) and used a #44 bulb.

Without the 7J7 installed I brought the radio up on a variac, all filaments lit and the filter caps charged.

No explosions or smoke, dial light lit also.

At 120 VAC I had a very low hum from the speaker and the radio was drawing 53 Watts.

I do not have the electrical specifications, does 53 Watts seem correct for this radio?

I have not changed the paper capacitors yet.

Thank you,

Mitch

Hello again gentlemen,

It is not my plan to just change all of the paper capacitors before I have the 7J7 tube. I would rather have the new tube installed and determine if the radio works first, troubleshoot if necessary and get the radio working then replace the paper caps.

I would like to test the radio with a RF signal or modulated signal generator beyond the 7J7, perhaps a signal injection just past the 7J7.

Ideas on this are welcome.

Thank you,

Mitch

I will wait for the tube, then proceed.

Thanks much for the replies.

Mitch

Hello all,

I installed the 7S7 tonight. The radio is drawing 60 watts. Good transformer as well as filament and B+.

My problem is with the long paper tube antenna that mounts in the back of the cabinet behind the radio. It was disconnected from the chassis with no connection numbers or letters to reinstall it. There are no markings on the wires and they are all taped over bare wires.

So, I connected (by trial and error) an old loop antenna to the terminals and finally got a SW station to come in, loud and clear. Radio works!

I cannot be sure of anything else until I know how this tube type antenna is supposed to be connected.

All I got on BC was really good noise.

I can post photos of the antenna assembly and the radio antenna connection plate tomorrow, too tired now, but I did listen to the radio tonight.

None of the paper caps have been replaced yet.

Help appreciated,

Mitch

It's fairly common for these sets to work on one band but not another, due to dirty bandswitch contacts and/or an open antenna/oscillator coil winding.

An ohmmeter and the antenna winding resistance values given on the schematic should allow you to identify, re-label, and re-connect the original loop antenna wiring once you get the radio playing on all bands. This set is a little unusual in that it has two separate antenna windings, one for BC and lower-range SW, the other only for higher-frequency SW. If all else fails you can peel off the antenna's paper covering and visually determine the loops' end connections and taps.

Having said that, you can bypass the antenna switching altogether and just inject modulated RF into the grid of the RF amp tube. That will allow you to assess the set's band switching without having to worry about the antenna.

Thanks for the input,

I have not tried the signal injection yet.

I connected the antenna as best I could from pictures I found on the web.

In the AM mode I do receive three stations from the push button selections, noise on the other buttons.

Haphazard connections of the antenna brought in one SW station.

There is no station dial in from the tuner, just noise on all bands.

The radio plays very loud and clear on the several push button selections.

Is it a incorrect antenna setup or perhaps a bad antenna assembly?

Thank you,

Mitch

What appears to be happening is that the radio doesn't work in "manual tuning" mode. The eighth pushbutton on the set (would be the one on the extreme left or extreme right, not sure which one) is the one that switches you out of "automatic" (pushbutton-preset)mode and into "manual" mode. It must be depressed in order for the tuning knob to work. Sorry if this seems like stating the obvious, but might as well get simple problems out of the way first.

If the "manual tuning" button is depressed and the set doesn't respond to the tuning knob at all, which I assume is what is happening, it's possible that you have dirty contacts in the pushbutton switch matrix. It's also possible that you have a open fixed coil or a shorted variable capacitor section. The "automatic" presets bypass both these elements (substituting individual, tunable coils and capacitors for the variable caps and fixed coils used in the manual tuner section) so they will allow the set to work even if there is a fault in the manual-tuning parts for the reasons already given.

Try giving the pushbutton switching matrix a shot of whatever your favorite electrical-contact cleaner happens to be, and if no stations are forthcoming in manual tuning mode, move on to using an ohmmeter on the main variable tuning cap and associated coils. Best-case scenario is that you have dirty contacts; worst case is that a coil has opened up. Shorted tuning caps can usually be fixed with a little cleaning and plate-tweaking.

I have the radio working in manual mode for BC and Police bands. BC across the band and I did pick up a station at 3 MHz on the police band, a baseball game.

SW has a separate antenna installed in the top of the cabinet, I did finally find it after a trip into town from my shop.

Thus far I have replaced the filter capacitors and replaced two tubes. The B+ is fine and the radio is only drawing 51 Watts.

The dial pushbutton is #8, far left on the radio, I knew this but it has been a long time.

I am still not sure of the rotatable antenna connections as I have to us a 30 foot wire antenna on the connections to bring in all of the stations.

More info on this would help, I do not mind taking the long tube antenna apart if I new what I was looking for.

Two problems here, my forgetting to set the pushbutton to manual (DIAL MODE). Second problem was a wire connection that Joe the plumber made grounding the tuning capacitor to ground.

I have not wholesaled the change out of the paper caps yet?

The photo attached shows the white wire that grounded the tuning capacitor to the ground lead of the IF can.

All comments welcome, photo attached.

ps, listening to NY, PA, NJ, OH, Canada.....

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