After more than 6 years away from restoring antique TV sets, due to personal issues, I am BACK IN THE SADDLE AGAIN!
My poor condition Ariline 94GSE-3018A has been sitting on the shelf waiting for about 15 years. Here is a photo of the one at ETF
http://www.earlytelevision.org/airline_94gse.html
Stored in a wet basement the cabinet was falling appart with much of the plywood badly de-laminated. I have the cabinet fully restored and is in very nice condition now.
The unit consists of 3 chassis. Crt chassis with High Voltage and sweep ckts, Main chassis with power supply, tuner and RF and video ckts, and the 3rd chassis which has an AM/FM radio tuner.
The main chassis with the power supply, tuning and video circuits evidently had a fire underneath at one point. A very bad amateur job of repair was done. (I hate working on other people's botched sloppy work) and after fixing all the bad work and re-capping the entirety of all 3 chassies, I have the TV set working fairly well with a somewhat usable 7JP4. It produces a nice picture in a dimly lit room.
NOW FOR THE MAIN PROBLEM, with hopes that someone a lot more knowledgable than I, might be able to help me figure this out.
The AM and FM radio section is totally dead. Not even a hint of receiving anything. I have check and rechecked for any circuitry errors and have found NOTHING. I spoke to John Folsom, and he suggested that I might be dealing with silver mica disease. There are 3 IF transformers in the set, and indeed, the schematic shows that the 3 if transformers have an internal capacitor paralleled with each coil segment. Unfortunately, there are no values for the caps in the transformers. The IF transformers look to be rather specialized. They appear to have an FM and AM set of coils in each transformer.
I took the aluminum can cover off of one of the transformers. The questionable caps appear to be sandwiched between 2 layers of phenolic material that forms the base of the transformer to which the terminal lugs are attached. The 2 layers of phenolic are riveted together. Delicate surgery could be performed to remove the silver mica caps. But without knowing what the values for replacements should be, what does one do?
Would there be a way of pumping test signals through to find out where or if the if transformers have faulty caps?
My test equipment is fairly limited to using meters and a scope. Signal generators and alignment is pretty much out of my abilities.
I don't even know where to begin. I am hoping that I can get some guidance on how to proceed. Or perhaps someone with more advanced abilities than mine, might be willing to step in and give me a hand to trouble shoot this issue.
This link will take you tot he schematic at the ETF site
http://www.earlytelevision.org/pdf/a...sams_93q-2.pdf
The AM/FM chassis schematic is on page 4.
Thanks in advance for your help, and I hope to see you at the ETF convention this year.
Bob Galanter