[Welder]

We tried the oscillator test and the unit failed to make any sound at all.  I tried with another tube radio and it made the IF squealing sounds you spoke of.  I guess we need a new oscillator to solve the problem.


Welder

[morzh]

Well.
you touched it and it stopped working.
Short of you physically damaging the coil or cracking a mica cap, your components are likely ok.

Look for signs of your activity and try to retrace the steps. There's no such thing as new oscillator short of you replacing every single component in it, which to me is a bit excessive.

[Welder]

Morzh:

Tried to send Pic. but it didn't work. It's right next to the 35 Z and tuner cap. ?

[morzh]

6A8 tube is at the back of the chassis (close to you and away from the front panel) between the tu ing cap and the 1sr IF can.
The T3 oscillator transformer and C9 cap are at the bottom of the chassis, mounted at the side by the tuning shaft.

[morzh]

Well....I took over.

The sch seems to be the same as 46-250. Same tubes and seens to be same everything else.

So. Tonight I triedto inject the IF through.
I shorted the points where the loop antenna is connected.
The IF is tuned to.....625kHz. not 455kHz. Hence the problems. Oh....and the gain is low.
So I'll have to figure out why it is.


Rich,
When you said the IF passed through, what frequency was it? You said 455kHz but it does not react to it.

[Welder]

Well....I took over.

The sch seems to be the same as 46-250. Same tubes and seens to be same everything else.

So. Tonight I triedto inject the IF through.
I shorted the points where the loop antenna is connected.
The IF is tuned to.....625kHz. not 455kHz. Hence the problems. Oh....and the gain is low.
So I'll have to figure out why it is.


Rich,
When you said the IF passed through, what frequency was it? You said 455kHz but it does not react to it.

Mike:

I just played with the trimmer on the IF can but I had the signal generator tuned around 455 Khz.
I could also hear talking in the background but very, very weak. I could be way off.

Rich

[morzh]

Well... it's working now.
What you did was you bypassed the filament of the 7A8, soldering in and out wires to the same pin.
What confused you (and me, for a couple of hours) was that the IF did get through, which it did due to the parasitic coupling the inside the tube.
What exascerbated the confusion was that the tubes whose heaters were visible did glow, and so did the pilot lamp, so we did not think there was anything wrong as typically with series connected filaments nothing glows or everything blows up.

So....it receives now. Has distortion, don't know if it is alignment or speaker, but voice is ok, music when loud is distorted, but I let you figure that one out, if it needs be.
But the amp and oscillator did not work. So when all wires were correct but I did not hear the oscillator in the second week radio, and traced the filament, it was not heating.

[Welder]

Mike: Thanks so much for your help with this unit. Let me know when it's convenient to pick it up. No hurry here but I'd like to sit down with you for a few minutes and go over my mistakes.

Gratefully,
Rich

[morzh]

Rich

I think tomorrow, if all is ok, and I don't take another day off due to the inclement weather, you could come to my work and pick it up.
Do give me a call at my cell before you come.
If you don't have it, tell me, I'll call you from it so you have it.

[Welder]

Mike:

Just want to make sure the unit will be available tomorrow afternoon (Tues). Is that convenient?

Thanks,
Rich

[morzh]

Yes, it should be. Hopefully I do not forget to pick it up. I'll try not to.
Like I said, call me before you come here, just in case.

[Welder]

Thanks so much, Mike!

[jcassity]

i was taking notes,,,

so these IF's are 625kc?

[morzh]

No, 455kHz.

It was badly out of alignment.

[jcassity]

oh, so you fiddled with the generator till you heard somthin then thats where 625kc came from?