[OZ4]

I finally found a radio to work on. I rescued it from some garage sale. You can see it's a had a tough life. It's been wet and missing most of the fluted molding on the base. And is will need new grill cloth. Oh and I paid a whole five dollars for it.

[OZ4]

You can see the chassis is typical condition with some rust.

[OZ4]

He it is stripped down ready for navel jelly. No surprises so far. I did cover all the holes with foil tape and small ones with hot glue so the all that goop would not get underneath.

[OZ4]

And here she is all slathered up. This stuff works wonders on rust. It just takes a little time.

[OZ4]

Oh and of course the tube shields.

[OZ4]

And here is is after some scrubbing with fine steel wool and wiping down with damp paper towels. I did cheat and ran some water on the tight spots to rinse and used the air hose to dry. Afterwards only some minor pitting at the front top of chassis. I also found that navel jelly cleans up brass pretty well.

[OZ4]

Something I forgot to mention is that before disassembly I took lots of pictures with my new Galaxy tablet for reference. It will focus nice and close up.

Now to attack the underside. I made up the little stand so as to not crush the tubes and such while working on the circuit.

After reassembling all the trimmers , grid cap wires, replacing some bad resistors along with the power filter caps I did some rough alignement. I used a signel generator a 456k for the IF. It tuned up pretty well but I found it made some miner poping and cracking noises when powering up. Also the audio sounded a little garbled. So after some capacator replacement all around the detector tube it work much better. I am disapointed that it has no automatic vol contol.

[OZ4]

Here it is in it's latest incarnation. I stuck little labels to most of the components to help find my way around. I find these radios a real test of patience. I also numbered all the rf xformers leads on the schematic and made diagrams to match. It really helps me when troubleshooting. You can see the new filter caps and some others. Oh and the voltages are a little high. It seems to like 110 volts better that 125.

To date I think I may have 40 hours into it.

Next is the cabinet.

[OZ4]

I do have a question for anyone that knows. Is there a tracking cap for alignment of the oscillator on this one? If so which one is it?
See
http://www.nostalgiaair.org/PagesByModel...003296.pdf
Thanks
Chris

[Radioroslyn]

Good job Chris!!! Chassis looks so much better! I've gotten into the habit of saving old caps just for the cardboard tubes. So when I come across a bunch of those Sealedtite job I have something to rebuild.
Terry

[OZ4]

Thanks. I did forget to mention that is sealed the bare metal after cleaning with semigloss polyurethane.

I don't know what Sealedtite caps are. Though I do have a box of old parts but it's not very big yet.
Chris

[Arran]

The Sealedtite capacitors or those molded wax ones with the blue label that says "Solar" on them. They don't actually use a cardboard shell like a typical old capacitor, they were made out of molded wax with a thin paper label. They are not original to the radio though, most of the ones I have seen were used new in radios and TVs of the 1940s and 50s, and as replacements, the older Solar brand caps did use the more normal cardboard shells. Unlike most old paper caps they are one of the few that still tests good most of the time, well sort of good in that a 600 vdc cap will work up to 400 vdc, but you still don't want to trust them.
Regards
Arran

P.S I don't think that headset jack belongs there.

[OZ4]

That headphone jack appears to be an input jack and it does show on the schematic. Though I am not real impressed with it.
http://www.nostalgiaair.org/PagesByModel...003296.pdf
I would much rather use a small am transmitter.

As for the caps I think I will leave them for now. There are no more strange noises and it seems to be working fine. The only thing left I would like to do is align the oscillator to track the dial.

Thanks for the help. I will post more on the cabinet later I am waiting for some toner spray.
Chris

[jerryhawthorne]

Very nice job on that chassis 0Z4.
Jerry

[morzh]

The Chassis looks great.

I would re-stuff the tubular caps with the new ones, but that is a choice of taste.

Just to make sure (cannot see on pictures) - you did not use the center pole of the old electrolytic to solder the new ones? I can see the old in place but the new lytics are out, so just making sure....