[RodB]

Looks like the IF is 130kHZ. One IF transformer with 2 trimmers.

[morzh]

Rod

Yes, it is. However in the alignment procedure for H-2 chassis (exists in the same volume) they recommend triming 2nd IF and the 2nd Detector trimmers, and NOT touching 1st IF trimmer unless the oscillation is unstable. In my case there is only one IF trimmer so, if it be considered 1st IF, then only 2nd Detector could be touched.

This said, my local station is RIGHT on the money, 1160 kC on the dial.
And the IF frequency gets through only when set at 130kHz.

Which tells me that the alignment is still not too far off (which was the case with my 808A).

I also found out I need to re-solder the speaker plug (I do not see ourtight shorts but something happens when I wiggle it) so I need to do it before I proceed with touching the trimmers and padders.

However, I'd really like to have some alignment write-up for 82 chassis. It would make it so much easier. I do not like to use my brain unless reeeeally necessary.

[RodB]

I'm with you on that, there may be some order to follow. Otherwise you may get worse results. I'm just looking at the docs for the AK L1. It may have been the last AK TRF, 1930. Looks like the PT is shot. Can't even get out of the gate with this one.

[morzh]

Well, I aligned it as best I could, using this thread I found.
I am sure this is not a complete alignment but the radio was not that bad out of it anyway.

When adjusting the IF stage padders I had to fashion out the shield instead of the one that covers the filter. Thing is, the can does not have holes for the padders access.
And if aligned without the shield, the frequency gies up after replacing it by about 2kHz or so.

So I did this


   

Out of fishpaper for sturdiness and aluminum foil around it, which I them grounded with a wire.

After that the frequency did not move much after I put the shield back.



----------



Question: does anyone know, is the tuning knob supposed to rotate the gang and the pointer in reverse? When I rotate it CW, the gang and the pointer move CCW. And vice versa.

PS. I got an answer on Facebook in AK group: yes, it seems it is popular in AK - reverse rotation of the knob vs dial.

[morzh]

I put it back together one more time, and thought I'd be done.

However the sound is not very good. And there is some hum from the speaker, which I think is responsible for the quality of sound. It is a low grade hum, not corelating with the volume. And it even exists, to a smaller but comparable degree, when the audio tube is yanked. I think it is the ripple through the field coil. And I am not sure the speaker has the humbucking coil.

The capacitors are good; the 1st one is 8uF Solen film, the second is a good grade 10uF electrolytic. I tried to bump up the second cap's value by paralleling a 20uF very good cap, to no change whatsoever.

I am starting to think this might be a norm.

The problem with a low grade hum is, it gets amplified by the cabinet; I had the same problem with my Philco 87. It can be barely heard with the speaker on the bench, but put it in the cabinet, and voila!


PS. Found this thread on ARF

https://antiqueradios.com/forums/viewtop...5#p3547115


Confirms my suspicions.

[morzh]

Radiola Dave on Facebook confirmed his 84 also has a similar problem. Not very strong (nor is mine) but noticeable when the radio is not playing.

Oh...forgot to say, I think there is no humbucker in the speaker, but just in case there was, I plugged the speaker plug from inside the chassis. This reverses the field coil. While the humbucker, if it was there (which I think it isn't) would not change the direction, so some change would be noticed.
Well, as expected, no change whatsoever.

So, tomorrow I will put it back together one last time, to be taken apart only in case of something going bad and in need of repair.

[RodB]

Hey Mike, have you thought about using DC on the heaters?

[morzh]

Rod

No. That is yes, I know this technique, but there are cons:

1. If I were to use DC on all tubes, we haved 6 tubes at 1.75A each. This makes it about 10A RMS. This said, I will need a bridge rectifier as the winding is not centertapped double voltage. 4 diodes, each dissipating roughly half that current times Vf which (Schottky could be used as the voltage is low) is about 0.4 - 0.6V. Lots of heat.
2. The voltage will be dropped by 2xVf. That is about 1V. Considering the filament voltage is 2.5V it is too much.
3. Yes I could bring DC to 47 tube only. Less current, but still a lot of reduction of the Filament voltage.
4. In either case a decent size capacitor is needed to filter the DC as the current is large.
5. Last but most important: I try to stick to original circuitry, except for cases where there is little choice, like dropping the voltage in AC/DC radios and using a capacitor to do that instead of huge resistors or curtain-burnere cords.

All in all, even though possible in theory, the early radios with low voltage / large current filament tubes are not the easiest to use DC for filaments.

[RodB]

I was thinking more in the line of troubleshooting, not as a permanent solution. So you must use it as a room heater in the winter?

[morzh]

Well, yeah.....most power goes to heaters. And it is 35W (2.5V @ 6x1.75A + 5Vx2A).
And then most of the rest of teh power (80W) also goes to heat, because the output acoustic power in these radios is 2 to 3 Watts.

So it is more or less an 80W heater.

Yes, to try to power the 47 from a separate DC source might work. Need to find this source. 2.5V, 2A. But even if it works, then in the end I will go back to AC to keep it original.

[morzh]

   
   
   


Well, here it is. Put together and playing.

I have a video but since a few years ago I cancelled my account on Youtube, I can't share it right now.

Took me a couple of months, yeah.....but I was working very, very slow.

I am happy with the cabinet, I do not think it needs any restoration; maybe some furniture rejuvenator at best, but even that is not necessary.
I will take a break, then off to.....16? That one has a good cabinet but needs some veneer regluing. But...it will be then. Not now. Then.

[GarySP]

Looks great, Mike. As far as how long it took, who ever said it was a race? Take care and BE HEALTHY! Gary

[morzh]

Gary, thanks!

If I were to count pure time spent......15-16 hrs.

https://www.facebook.com/groups/11174558...&ref=notif

I dunno if you can use the link to listen to it playing.

[tbone]

That radio sounds and looks great! Nice job!

[PhilcoJohn]

Mike the radio came out great. What a great pickup at Kutztown. I like that radio very much. It's a keeper for sure. good luck with it!