[mikeyhitchfan]

The power cord is wired to the same points, although I removed the tape and soldered the leads directly as there was enough cord left. The chassis is not hot but I'll double check polarized end.

I'll do another wiring and tube pin count check when I get home today and post again. The loctal bottoms are a bit tricky so I don't want to change anything until I'm sure.

[Squire]

If they wired the power cord wrong it will cause problems. You have to do a bit more than just reverse the hot & neutral if you want to make the chassis "safe".

[morzh]

The power cord does present a safety issue, so does, for that matter, the whole AA5 radio idea, and absolutely do make it right, but in the meantime it does not affect the radio's operation.

[Squire]

OK. I just mentioned it because The first time time I tried to wire one the other way I got it wrong and got symptoms a lot like he's describing. When I put it right the radio worked fine.

[mikeyhitchfan]

I have rewired the switch on another unit where it needed a new cord and know how to do that. I usually leave things as original as possible but they can be dangerous and I know when it's plugged in it's not hot if the switch is off. Switch on hot I'm not sure about. I'll have to check which side goes where later. I'm not sure how this would affect the audio if it was wired to the opposite side of the plug.

[morzh]

Just buzz the wider prong to chassis when the switch is ON.

It does help better reception to have chassis on N as N in essence is Ground in 110V system.

They had non-polarized plugs before. Sometimes when having noisy reception reversing the plug helped, but there would be, neverthelrss, reception, as for RF purposes L is grounded.

[mikeyhitchfan]

morzh,

Transformer (#29, not 33) goes to pins 3 & 4, A5 to pin 4, A6 to pin 6 ..which tube are you talking about? 7A8, right?

What about that center wire coming off the post of the tuner that's going to pin 5 of the tube 50A5?

[morzh]

You meant 33, not 29? (you have it backwards). Yes 7a8.
The pin 5 of the 50A5 is a no-connect pin, it is used as a binding post.

This is the way the sch is, you said pins 4 and 6 are swapped in your case.

[mikeyhitchfan]

Looking at the pictures with numbers given to parts on the service sheet it shows 33 as the speaker transformer and 29 is the oscillator coil.

The antenna loop has a connection to A5 lug, and the other is on the top connector which goes to pin 5 of the 50A5 tube, which then connects to pin 5 of 14B6. Is that correct?

[morzh]

http://philcoradio.com/phorum/attachment.php?aid=5066

The link from the page 1 of this thread.
Look at the sch and the chassis picture.

Always go by the sch. Do not go by anything other than the schematic. It screws up communication, complicates life and spoils karma.

[mikeyhitchfan]

OK, I swapped the 2 7A8 connections from the bottom of tuning condenser. No change. What 2 points should the loop antenna be connected to? Still not sure it's right.

[morzh]

Look at the sch. Item 32 (a square) is the loop.

Connected to the cap #12 with one end, and to the tuning cap and the 7A8 pin 6 with the other end.


On your photo I do not see the loop. I hope as you said before it is connected.

[Arran]

These sets, as well as all other Philco AC/DC or transformerless power supply designs, have the common negative isolated from the chassis, they are NOT hot chassis sets. They chained all of the B- points together with a bus wire and then coupled the chassis to the B- with a capacitor-choke assembly and a resistor. It does not make it 100% safe but still much better then having the power line soldered directly to the chassis.
I've seen the polarized plug idea circulating for a few years and believe that it gives a false sense of security. For one thing how do you know that the outlet is connected correctly? For another even with the polarized plug that will only work if the set if on, if it's off you will find that it still gives a tingle if you rub your knuckle on the chassis.
The shock hazard was not unknown even when these were new, there were warnings with all of the literature about connecting a ground, and steps were taken to prevent someone from touching the chassis itself such as having a back and plastic knobs. In fact some Philco Transitone sets originally had rubber covers to insulate the chassis screws.
There are two ways to make an AC/DC sets 100% safe, treat it with respect, or operate it through a GFI outlet or an isolation transformer.
Regards
Arran

[mikeyhitchfan]

So if I ignore the pictures and look at the schematic...A5 goes to pin 4 & A6 goes to pin 6 (of the 7A8 tube), right? Now, in the photo it shows A5 as the one with the ground lead connected to chassis, and it shows A6 as the other side, right? Well, this is why I'm confused. The schematic is the opposite if the way it's wired. The 47mmf cap (#15) comes from A6 side (not A5) connects to the osc coil then to the #15 cap then to pin 4. So, is it possible that the schematic has A5 & A6 labeling reversed in error? This is why this radio is proving difficult to diagnose. A sig gen would be most helpful.

[morzh]

Mikey

I cannot honestly figure out the photo. If you did several prosectives or red-arrowed the parts you referred to....

But the sch shows correct arrangement: the feedback coil 33 goes to the 1st and 2nd grids which is the oscilator arrangement with pentagrids and octodes, and antenna (in other radios - antenna transformer or coil) goes to pin 6 which is the control grid of the amplifying portion.

And, yes, a sig gen is a must for anyone who is half serios about fixing old radios.
And it s cheap.