R390 70j-3 BFO has an interesting issue- one I have not seen before. Z502
tunes from 463 to 479 kc, stable and good signal per spectrum analyzer.
checked all external parts- all withing spec, opened unit, all parts
present ( someone has opened it the past seal was broken). "Things" look ok.
moving core appears to be intact does not appear to have been tampered.
Before I go any further anyone with thoughts?
- any known loss of permeability of the core? possibly due to temp?
caps internally go "bad" 1600pf, 50pf NPO, 50pf N600.......there is not
much in there as per schematics...simple hartely osc.
the core does not go completely to the end of the form, maybe couple mm
from end. but does cover the coil length.
How do get the core out for inspection? I saw where someone else had
epoxied one back together.....but no notes on full disassembly.
So....If it is non repairable...anyone have a 70j-1 or a -3 available?
Renée, K6FSB
______________________________________________________________
R-390 mailing list
Home: http://mailman.qth.net/mailman/listinfo/r-390
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:R-390@mailman.qth.net
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
