Philco amp re-build.

john8750 · **Posted:** Sep Wed 20, 2017 5:02 am

peter! Why didn't you get me some of that wire?
You should of known I needed it.
BTW- here is the Magnavox power filter cap.
Its the sweet potato thing in red circle. Aint it a thing of beauty..
3 sections, 100-300v/75-300v/70-40v I will replace them
with 100/100/100 all 500v cause I have them already.

Attachment:

mag cap.jpg [ 109.75 KiB | Viewed 3070 times ]

john8750 · **Posted:** Sep Wed 20, 2017 8:19 pm

Changing out that sweet potato solved the problem. But the phono wont turn, and must have an open in the chassis bond.
And, it is a GE, not Magnavox.

Pbpix · **Posted:** Sep Wed 20, 2017 11:03 pm

john8750 wrote:

Changing out that sweet potato solved the problem. But the phono wont turn, and must have an open in the chassis bond.
And, it is a GE, not Magnavox.

So the radio am & fm do work ok?

Listen to it for a while to be sure you don't have a ny other leaking capacitors or faulty IF cans.

Listen on AM for random crashing sounds like lightening. That may indicate a faulty IF can.

john8750 · **Posted:** Sep Thu 21, 2017 2:03 am

Pbpix wrote:

john8750 wrote:

Changing out that sweet potato solved the problem. But the phono wont turn, and must have an open in the chassis bond.
And, it is a GE, not Magnavox.

So the radio am & fm do work ok?

Listen to it for a while to be sure you don't have a ny other leaking capacitors or faulty IF cans.

Listen on AM for random crashing sounds like lightening. That may indicate a faulty IF can.

Thanks Peter. I will do that, but will need to fire up my AM transmitter for the AM band.
No AM reception out here at all. At least not without a better antenna.

Pbpix · **Posted:** Sep Thu 21, 2017 3:32 am

john8750 wrote:

Pbpix wrote:

john8750 wrote:

Changing out that sweet potato solved the problem. But the phono wont turn, and must have an open in the chassis bond.
And, it is a GE, not Magnavox.

So the radio am & fm do work ok?

Listen to it for a while to be sure you don't have a ny other leaking capacitors or faulty IF cans.

Listen on AM for random crashing sounds like lightening. That may indicate a faulty IF can.

Thanks Peter. I will do that, but will need to fire up my AM transmitter for the AM band.
No AM reception out here at all. At least not without a better antenna.

Try it late at night... AM gets better then.

Pbpix · **Posted:** Sep Thu 21, 2017 3:36 am

How about KMET?
http://onlineradiobox.com/us/kmet/

also.. FM and AM listed here:
https://radio-locator.com/cgi-bin/locat ... g&state=CA

[BC] [Info] KFI 640 AM 85.1 mi.Signal Strength 3 Los Angeles, CA Talk
[BC] [Info] KKGX 920 AM 3.1 mi.Signal Strength 5 Palm Springs, CA Talk
[BC] [Info] KXPS 1010 AM 6.0 mi.Signal Strength 4 Thousand Palms, CA Sports
[BC] [Info] KNWQ 1140 AM 4.2 mi.Signal Strength 5 Palm Springs, CA News/Talk
[BC] [Info] KPSF 1200 AM 6.0 mi.Signal Strength 4 Cathedral City, CA Business News
[BC] [Info] KVGH 1270 AM 8.1 mi.Signal Strength 4 Thousand Palms, CA Classic Hits
[BC] [Info] KWXY 1340 AM 4.2 mi.Signal Strength 4 Cathedral City, CA Easy Listening
[BC] [Info] KCOD 1450 AM 4.2 mi.Signal Strength 4 Palm Springs, CA College Of The Desert Variety

john8750 · **Posted:** Sep Thu 21, 2017 4:06 am

It gets a few FM stations real clear. The speakers sound good. No rattling.
Am, not so good. But did get one around 1200KC. It was Country and sounds good.
Found a broken wire on the turn table, fixed it. The tone arm cartridge was loose,
tightened it and fixed the bonding problem. But, the turntable gets slow when ejecting
the tone arm, so needs a cleaning and some lube. Having a good time working on this
50 YO console.

Pbpix · **Posted:** Sep Thu 21, 2017 4:13 am

john8750 wrote:

It gets a few FM stations real clear. The speakers sound good. No rattling.
Am, not so good. But did get one around 1200KC. It was Country and sounds good.
Found a broken wire on the turn table, fixed it. The tone arm cartridge was loose,
tightened it and fixed the bonding problem. But, the turntable gets slow when ejecting
the tone arm, so needs a cleaning and some lube. Having a good time working on this
50 YO console.

So I hope your friend pays you a nice gift for the repair.
I'll bet you could now hang out a vintage radio/repair shingle and have fun and make a little money too.

john8750 · **Posted:** Sep Thu 21, 2017 6:33 am

Pbpix wrote:

john8750 wrote:

It gets a few FM stations real clear. The speakers sound good. No rattling.
Am, not so good. But did get one around 1200KC. It was Country and sounds good.
Found a broken wire on the turn table, fixed it. The tone arm cartridge was loose,
tightened it and fixed the bonding problem. But, the turntable gets slow when ejecting
the tone arm, so needs a cleaning and some lube. Having a good time working on this
50 YO console.

So I hope your friend pays you a nice gift for the repair.
I'll bet you could now hang out a vintage radio/repair shingle and have fun and make a little money too.

I'm sure he would pay anything when he hears it playing again. It means a lot to him.

Peter, if I was to repair these old radios, I would drive you crazy for advise.

Pbpix · **Posted:** Sep Thu 21, 2017 8:30 am

john8750 wrote:

Pbpix wrote:

john8750 wrote:

It gets a few FM stations real clear. The speakers sound good. No rattling.
Am, not so good. But did get one around 1200KC. It was Country and sounds good.
Found a broken wire on the turn table, fixed it. The tone arm cartridge was loose,
tightened it and fixed the bonding problem. But, the turntable gets slow when ejecting
the tone arm, so needs a cleaning and some lube. Having a good time working on this
50 YO console.

So I hope your friend pays you a nice gift for the repair.
I'll bet you could now hang out a vintage radio/repair shingle and have fun and make a little money too.

I'm sure he would pay anything when he hears it playing again. It means a lot to him.

Peter, if I was to repair these old radios, I would drive you crazy for advise.

Yes and other too on ARF.. for a few weeks maybe.. even a few months. But by then you'd not only have no more troubles but you'd probably be answering other people's questions.

john8750 · **Posted:** Sep Thu 21, 2017 7:30 pm

Here is what I replaced the sweet potato with. Not the clearest shot, it was dark in there.

Attachment:

gea.jpg [ 76.3 KiB | Viewed 3027 times ]

Pbpix · **Posted:** Sep Thu 21, 2017 9:52 pm

john8750 wrote:

Here is what I replaced the sweet potato with. Not the clearest shot, it was dark in there.

Attachment:

gea.jpg

I wonder why those 1st two caps you replaced had a 300v rating?

Typically sets like that one didn't use anything in B+ of over about 150v

And that last 70uf cap was only 40v so you can pull out your expensive 500v cap and use anything smaller if you need to use those costly 500v caps elsewhere.

What is that GE model number.. I'd like to look at the schematic.

john8750 · **Posted:** Sep Fri 22, 2017 1:01 am

Pbpix wrote:

john8750 wrote:

Here is what I replaced the sweet potato with. Not the clearest shot, it was dark in there.

Attachment:

gea.jpg

I wonder why those 1st two caps you replaced had a 300v rating?

Typically sets like that one didn't use anything in B+ of over about 150v

And that last 70uf cap was only 40v so you can pull out your expensive 500v cap and use anything smaller if you need to use those costly 500v caps elsewhere.

What is that GE model number.. I'd like to look at the schematic.

I have looked all over and found no model numbers. I found a paper stapled inside that has the tube location. And a brown cardboard glued on the back, but all lettering has disappeared. The caps were not very expensive at all. About 1.50 each, so no big deal there. It sure sounds good though. The phono has a problem with the eject system. It gets stuck.

john8750 · **Posted:** Sep Sat 23, 2017 5:59 pm

The Philco amps are playing with my shop speakers. Enjoyable listening. I turn them on while in the shop. Should be a good match to the Zenith. Something about a tube amp, I like.

john8750 · **Posted:** Sep Sat 23, 2017 10:17 pm

Peter
Here is the GE amp I am working on. Still don't know the part no.
B+ is 268 volts.
2-6AQ5/12AX7/6CA4

Attachment:

2ef88pu[1].jpg [ 151.24 KiB | Viewed 2982 times ]

Pbpix · **Posted:** Sep Sun 24, 2017 12:18 am

john8750 wrote:

Peter
Here is the GE amp I am working on. Still don't know the part no.
B+ is 268 volts.
2-6AQ5/12AX7/6CA4

Attachment:

2ef88pu[1].jpg

Remember that 6AQ5 is an exact 6V6 tube in a 7-pin bottle.
Must be using a voltage doubler power supply.

Pbpix · **Posted:** Sep Sun 24, 2017 12:29 am

John:
That GE looks a bit like this RC1671A set.

http://www.antiqueradio.com/Jun10_Schoo ... ation.html

Flipperhome · **Posted:** Sep Sun 24, 2017 1:18 am

Pbpix wrote:

john8750 wrote:

Peter
Here is the GE amp I am working on. Still don't know the part no.
B+ is 268 volts.
2-6AQ5/12AX7/6CA4

Attachment:

2ef88pu[1].jpg

Remember that 6AQ5 is an exact 6V6 tube in a 7-pin bottle.
Must be using a voltage doubler power supply.

While that's physically true you have to remember that the 6AQ5 voltage limits are less than a 6V6.

Pbpix · **Posted:** Sep Sun 24, 2017 1:52 am

Flipperhome wrote:

Pbpix wrote:

john8750 wrote:

Peter
Here is the GE amp I am working on. Still don't know the part no.
B+ is 268 volts.
2-6AQ5/12AX7/6CA4

Attachment:

2ef88pu[1].jpg

Remember that 6AQ5 is an exact 6V6 tube in a 7-pin bottle.
Must be using a voltage doubler power supply.

While that's physically true you have to remember that the 6AQ5 voltage limits are less than a 6V6.

Yes.. true... but GE set the parameters for this circuit design.

Data sheets show 6V6 max Plate +315v and only +250 for 6AQ5.

In MY 6v6GT / 6AQ5 amp I run 292v on the plate.... so far hasn't exploded.

Flipperhome · **Posted:** Sep Sun 24, 2017 2:16 am

Pbpix wrote:

Flipperhome wrote:

While that's physically true you have to remember that the 6AQ5 voltage limits are less than a 6V6.

Yes.. true... but GE set the parameters for this circuit design.

Data sheets show 6V6 max Plate +315v and only +250 for 6AQ5.

In MY 6v6GT / 6AQ5 amp I run 292v on the plate.... so far hasn't exploded.

What does 'GE" have to do with the circuit design?

You're closer than you think because plate is actually B+ minus cathode voltage.

Philco amp re-build.

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