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Couple of questions on a 60
05-30-2019, 08:44 AM
>Course all it's doing is motorboating.
As long as it does not sail too far. People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing. 
05-30-2019, 04:41 PM
Ha, Ha, he
 Its good to have a sense of humor. Complex methods of testing require a LOT of patience and understanding. I am a bit lost in the last few responses, The B+ is now O.K? If so, testing and correcting for motor-boating can be easy, (take a guess and try something) or get "scientific" again  Here is a "list" of things in increasing obscurity. The wiring has been re-routed plate and grid circuits are adjacent. Wrong value component installed or left out. Another short.. Shield missing usually the IF tube, flaky tube, try replacing all. Critical alignment adjustment or re-alignment because RF wiring disturbed or a critical component (usually a mica cap) has been replaced. An OLD mica cap in the RF/IF/OSC has drifted off. The rectifier may be shot if the B+ is still low... Go from there... I'll jump back in when your about to chuck the radio out the window...  +1 on the VTVM, I have used one or another for many many years. Only occasionally using the DVM just because I could not wait for the VTVM to warm-up and settle. I used to leave the VTVM on 24/7 but after 6 mo the tube(s) get out of balance and has to be re-calibrated... Then the battery goes flat. GL Chas Pliny the younger “nihil novum nihil varium nihil quod non semel spectasse sufficiat” 
05-31-2019, 06:17 AM
I always wondered how it was determined that a wire should be shielded, as most radios do have at least one wire with a shield. It seems to vary with different radios. How is this determined?
05-31-2019, 08:53 AM
Simple. If a radio has interference and a wire is determined to be a suspect, and the shielding eliminates the problem - it is shielded.
People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
05-31-2019, 09:52 AM
So the manufacturer would make a "prototype", test it, determine if there are any problems and what the solutions are, makes the corrections, retest it, then sends it to production? And they would have to do this with EVERY model change? You'd think that with experience, they would know in advance what the problem areas would be and work around them without having a mock-up.
05-31-2019, 01:27 PM
Everything in engineering starts with a prototype. It gets studied, goes through certifications etc.
You don't build a final product from the first try. People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.
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