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BINGO! Fixed: insufficient vertical height. F321221WNNO1 (CTC169 chassis)

J

Jason D.

Jan 1, 1970
0
That is TOUGH DOG. Set sat for weeks, I've been at it on and off.

CR4501 tests ok on diode test but fails on ohm check, leaks like 26K
ohm both ways. Scope did not catch that, except voltages with dmm on
pin 2 and 3 of this LM113 were low.

That diode is jellybean 1N4148.

Cheers,

Wizard
 
R

RonKZ650

Jan 1, 1970
0
CTC169 with vertical troubles is always a "tough dog". The only reliable way to
check this diode would be to check the DC voltage on both ends of it. If you're
dropping more than the normal 0.6v of a good diode, the diode is open, and yes,
they will always check good on a diode checker.
Ron
 
J

JURB6006

Jan 1, 1970
0
Heck, that ain't shit, how about "no color" intermittently, 164589 130V
rectifier, super high speed. Tried one ECG580 and it lasted 10 seconds. Had at
least ½ dozen of those when the chassis was newer. Later the 15V rectifiers
started going.

Being a ½ way smart muthaf......nevermind, I've reasoned that these diodes must
be built in two cells, a high speed section with lower specs and a higher
current section that takes over after the beginning of the conducted pulse.

This is the only way I can see for a diode to lose it's high speed switching
characteristic and yet be able to function and test normally at lower
frequencies.

Any otrher ideas ? Anybody care ?

Is there an official explanation ?

JURB
 
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