View Full Version : Philco E-3034 Tuner


Doug66
08-31-2015, 07:22 PM
I've been working on this set for over a year. Every time I get it playing and am ready to put it back in the cabinet, the next day, something else goes wrong.

Now I am having tuner troubles, and I know noting about tuners. I'm getting a raster with lines and audio snow. I bought a tuner subber, hooked it up, and got a great pic and sound. I just tried new tubes in the tuner with no results. Checking voltages are ok. When I touch the meter probe to pin 5 of the 3BC5, I get weak audio. Touching it to pin 1 gives strong audio but no video. Voltage is ok on pin 5 and -1.2 on pin 1. Any ideas?

Electronic M
08-31-2015, 09:57 PM
If that is a split chassis set, spray the tube pins with contact cleaner then insert and remove the tube from the socket a few times. Put some contact cleaner on a Q-tip and with the tuner cover off wipe the electrical contacts, turn the knob and repeat. If still bad try bypassing the tuner's Balun.....Beyond that are resistance and tube subbing, and if all else fails a new tuner.

I have a split chassis parts chassis I could pull the tuner from if needed.

zeno
08-31-2015, 11:46 PM
Sounds like your meter is acting as an antenna & the
RF amp is working OK. That leaves the AGC, balun &
rf switching. The balun is where the antenna hooks on.
All it does is change the balanced 300 ohm to unbalanced
75 ohm. Check ohms with a meter. Dont know the specs
of the 3BC5 but -1.5V may be enuf to turn the tube off.
Remove the AGC line & see what happens. You can
also use a wire to inject the signal along the path til
the RF amp tube.

good luck

Zeno:smoke:

Doug66
09-01-2015, 05:37 PM
When you refer to the balun, is it the terminals in Pics 1 & 2, or is it the two strips at the tuner bottom in Pic 3? I cleaned all contacts. With the fine tuning in 1 extreme, I can get a weak pic and weak audio. At the other extreme, I lose the pic, but the audio gets stronger.

As far as measuring, do I need to measures the two input screws on Pic 1? They measure open, and so does the two pins where the twin lead connects at the tuner.

Electronic M
09-01-2015, 06:19 PM
The tuner balun I was talking about should be the part on/in the tuner chassis that the antenna twin lead entering the tuner chassis connects to.

The blue item in the first picture is an external antenna balun, NOT the tuner balun, but it should also be checked by substitution with a known good one....I should have said to check that too originally...

IIRC there should be some continuity between the antenna terminals on most sets.

Doug66
09-01-2015, 07:28 PM
I took the tuner out completely and recleaned all the contacts. If the balun is those two white strips inside the tuner with fine wire coiled around them; there appeared to be one wire connecting the two and it was broken. I resoldered it, and that didn't make any difference. With that wire resoldered, still no meter reading.

Electronic M, please PM me about that spare tuner you have. I am definitely interested in it.

Doug.

Don Lindsly
09-01-2015, 11:06 PM
Made sure all the rotary discs are firm on the shaft. Make a slight increase in the contact tension while the shaft is out.
Check for cold rivets on the discs. If the signal is better by touching the RF grid and bypassing the balun, then the balun is suspect. They were a common failure due to lightning and other stress. Look for an open resistor in the RF decoupling supply, usually around 1K to 2.2K. No plate voltage is a clue. The grid voltage divider resistors may go bad. Remove the tube and check values.

Check for proper voltages on the RF stage. Easily done with a socket extension or slightly rocking the tube to allow each pin to be tested.

Overall that TV is a hot performer and works much better than the E-Line 14 inch model.

zeno
09-02-2015, 11:43 AM
The balun will read near 0 ohms across the antenna input
AFTER the networks on the ant terminal board.
Each leg will also measure near 0 ohms to ground. Its
marked L1 on the schematic. Also test L2 for an open.
Cant tell by pic where yours is BUT they are usually mounted
outside the tuner on the rear. Usually standing up,
sometimes pointed back. Two antenna wires hook to it &
one wire goes into the tuner. In this case it may have been
built into the tuner. I have little experience with pre 60's
sets, they were quickly junked due to no UHF tuner.

BTW you can inject a signal as far as the RF amp GRID
using the center of the coax from an RF source. Be
SURE to use an isolation transformer.

73 Zeno :smoke:

Doug66
09-03-2015, 06:56 PM
Everything points to the balun being bad, as it measures open. During restoration, the signal kept getting worse until what I have now.

I have a few junk tuners laying around. Could I use the balun out of one of them, or do I need the correct part for that tuner?

old_coot88
09-03-2015, 09:09 PM
If this is a wafer type tuner, a not-uncommon problem was a stripped wafer, i.e., one of the wafers failing to turn with the shaft. Examine the wafers carefully while turning the shaft in both directions. Check for one that's sloppy on the shaft, or failing to turn altogether.

zeno
09-05-2015, 09:19 AM
They all do the same thing except some have isolation
built in to them. Yours dont. Try one on it, cant hurt.
Check the wafer also as old coot says. We used to see
a lot of westinghouses with that. Used tooth picks & glue
to fix them.

73 Zeno:smoke:


Everything points to the balun being bad, as it measures open. During restoration, the signal kept getting worse until what I have now.

I have a few junk tuners laying around. Could I use the balun out of one of them, or do I need the correct part for that tuner?

old_coot88
09-05-2015, 02:20 PM
We used epoxy, after thorough de-greasing of the journal. Of course you gotta be super-certain it's in the correct position.

Don Lindsly
09-05-2015, 03:39 PM
I have one NOS Philco OEM replacement coil; PN 32-4725-1. Early replacements required replacing the entire tuner back plate. It takes some digging to get the number for the coil.

If that helps let me know and I will send it for a couple of bucks to cover postage. Pay when you get it.

Don

Doug66
09-05-2015, 06:59 PM
Don, is this what you are referring to in the pic? I think this is what's bad in my tuner. I did fine 2 broken fine wires on one of them and am trying to find the broken end to repair it. If this is what you have, that would be great.

Doug

Don Lindsly
09-05-2015, 08:41 PM
I have one of the two similar long coils shown on the picture. Don

Doug66
09-05-2015, 09:15 PM
Don,

PM Sent

Doug