The PHILCO Phorum

I was given a basket case Philco 40-180 chassis. I replaced the electrolytics and signal caps and some resistors. I can get a bit of sound through the speaker, but not any stations. The Rider schematic has some voltages, but not a voltage chart.
Does anyone know where I can find a voltage chart for the 40-180?

I took some measurements, maybe someone can confirm if they are correct or not.

41A: P 177VDC, G2 180VDC, G1 -11.4VDC, K/G3 0
41B: P 177VDC, G2 165VDC, G1 -11.4VDC, K/G3 0
7C6: PT 148VDC, GT -.82, PD2 -.62, PD1 -.32, K 0
7B7: P 180VDC, G2 81VDC, G3 0, G1 -.6VDC, K 2.4VDC
6J8: PHP 175VDC, G2HP/G4HP 81.6VDC, GT/G3HP .1VDC, PT 144VDC, K/G5HP 2.4VDC, Grid Cap 0
1232: P 160VDC, G2 95VDC, G3 -.02VDC, G1 -.9VDC, K 1.9

All heaters were 6.75 VAC

I tried injecting a 2.8v sine wave into the volume control wiper and got only 6.8vac across the speaker secondary. The speaker and field coil ohmed out OK, but the sound was low.

Tried pulling one of the 41's b/c I was suspect of the G2 being higher than the plate, but it didn't seem to matter.

Finally, I really don't care about the SW band too much, just AM broadcast. Can I remove the push buttons and bank of coils and padders and still get AM reception?

radlam

Hello and welcome.

Philco did not publish a voltage chart for this model. Philco's service bulletins, like their radios, became rather chintzy from 1939 through 1942. (Philco's service information was VASTLY improved after the war...but I digress.)

The voltages you have recorded seem to be well within the ballpark. You should look in a tube manual to confirm, or one of the online tube manual sources such as Duncan Amps' Tube Data Search.

You should replace ALL paper and electrolytic capacitors when restoring a vintage radio. You have already replaced the electrolytics and some of the paper caps; for best performance and reliability, you should replace all remaining paper caps in this radio.

Take a large capacitor, say 0.1 uF or better. Hold one lead of the cap, and touch the other lead to the center terminal of the volume control. You should get a loud hum. If not, you have trouble in the audio circuitry. (Many will recommend touching the volume control terminal with your finger; I suggested using the cap between you and the control for safety, although there shouldn't be any significant voltage at the volume control.

You could remove the pushbutton assembly, but why would you want to? The pushbuttons are for you to set up AM stations, not SW. I have found that on the later Philcos, it is quite convenient to set up the pushbuttons to receive certain AM stations in my area. It would leave eight gaping holes in your set's escutcheon. Not to mention you need the eighth button to switch between regular AM and pushbutton tuning. You could wire it so that the eighth button is no longer required, but I strongly suggest you give that a second thought.

I was just informed that pin 5 of the 6J8-G needs a negative bias of several volts or the oscillator might not be working properly. That pin is the GT/G3HP. It makes sense that a grid should have a negative bias, so i will check for continuity of this oscillator.

Thank you for the help.

radlam

The osc. failed the continuity tests as shown on the schematic. Perhaps I will just part this one out in hopes of finding a semi-functional 40-180 in the future.

Thanks again.

radlam

-3 volts on pin 5, according to the 6J8G data sheet I just looked up online.

Before giving up on this one, perhaps you might consider acquiring an oscillator coil from a junker? And replacing any remaining paper caps?

Just FYI, models 40-150, 40-155, 40-180, 40-185, 40-190 are all basically the same, and will use the same oscillator coil.

Someone else suggested I try Antique Electronics Supply and install one of their universal AM broadcast coils.

At any rate, I might as well keep trying to get this old 40- 180 clunker to work. Thanks.

radlam