[EdHolland]

I just remembered, I have some hi temp silicone rubber material which could do the trick. Or a piece of FR4 laminate. The other idea I had was to fold several layers of alumin(i)um foil and attach it with Kapton tape. That would be a safe and effective heat shield.

[Arran]

Ed;
One material that I have seen, but never tried for this was material for making exhaust gaskets, it's similar to asbestos but is not of course, some auto parts stores like NAPA sells it.
Regards
Arran

[radiorich]

hello Ed,
how about that special tape used for ducting it's like foil or how about thin piece of
aluminum roof flashing and use really good double back tape.

Sincerely Richard

[EdHolland]

Good ideas, thank you Arrange and Rich. I have the adhesive aluminum foil already and can try that immediately.

More later.

[EdHolland]

I completed the insulation on the cabinet interior (Al foil and hi temp silicone rubber), and reglued the speaker gasket.

FM front end alignment completed, chassis bottom cover back in place, tidied up the flying lead that is used to couple the line cord to the FM antenna I had everything back in the case.

Time for a test - all sounding great on FM, dial alignment is pretty good, ditto on AM. And then the trouble started.. loud crackles and crashes again on AM. Almost certainly SMD again So I shall be going in to clean the micas in the remaining AM cans. Not unexpected, I suppose but not something I really wanted to be getting into at this stage.

[Paul Philco322]

That's a bummer but get them now. Paul B

[EdHolland]

Yes - better it happened on the repair bench than returning to the owner.

The other question is - do I also dissect and clean the remaining FM IFs as well? That's would make a total of five cans to work on...

(I'll get the AM side sorted first, then decide)

[radiorich]

Hello Ed,
yes, I like letting projects run for few days to make sure they don't start acting up .
Sincerely Richard

[EdHolland]

I got into the first AM IF can today, and found its mica was cracked. Amazing that it was still working. This one makes up three capacitor sections 120 pF, 120 pF and 240 pF. The last two share a common plate.  Fortunately, I had suitable silver mica caps on the shelf. I cut some sections of insulating sheet to replace the original mica, so the contacts don't short out, and reassembled with the new capacitors concealed in the can. I find there are three or four stages of note taking beginning with the basic chassis wiring and orientation of the can, then recording to which tags the wires of each coil are attached, and lastly the arrangement of contacts to pads on the mica sheet, orientation of the mica etc., quite time consuming.

Figuring what should go where for cap substitution was tricky, and reference was made to the schematic, and the original mica's silver pads to get the configuration correct. Thankfully after getting it back together, the radio was still receiving AM, and IFT1 peaked up cleanly on the signal generator.

Of course, it still crackles and crashes because the problem is in IFT2

But at least I didn't end up in a worse situation than I started - there was some fear that I'd mix up connections or miss something, and end up with a dead radio.

I see that the last remaining AM IFT has three coils and three capacitor sections, so more delicate surgery lies ahead.  . One thing I figured out was a good way to hold the parts while resoldering wires and caps into the can.