Re: 1986 Fisher television B+ Low
i tested the SOT23 Transistor and zener diode and seem okay. the problem is the thin film resistors on it. the manual doesn't specify the resistance.
i have a tv shop looking for one.
thanks
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Re: 1986 Fisher television B+ Low
it is the JU0161 Error detect module. i substituted some zener's and resistors and the B+ came up to 111volts and the picture is perfect.
now if i can only find one of the replacement modules.
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Re: 1986 Fisher television B+ Low
i did replace the optocoupler with a tlp621 that i had on hand with no change.
attached the power supply schematic....Last edited by drunkendwarf; 04-27-2023, 01:37 PM.
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Re: 1986 Fisher television B+ Low
on the error drive i got the following on what i measured.
Error Drive Measured. Schematic
Pin13 0.650v 0.70v
Pin12 18.22v 23v
Pin8 19.80v 19v
Pin6 1.286v 1.6v
Pin4 -1.401v -1.7v
Pin3 1.294v 2.1v
Pin2 0.612v 0.3v
on the Error Detect.
Measured Schematic
Pin10 88.9v 111v
Pin9 88.9v 111v
Pin 7 7.17v 6.0v
Pin 1 33.3v 40v
on the switching...
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Re: 1986 Fisher television B+ Low
Yes, I apologize. I forgot to mention I replaced all the electrolytic caps....
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1986 Fisher television B+ Low
Hi guys, i have a 1986 Fisher PC420 television. Chassis #A7R-42000
it works but has no picture width and some barrel distortion. i narrowed it down to low B+ 89volts. service manual says it should be 111volts.
it uses these Sanyo hybrid IC chips for error detection and drive that are discontinued and i cannot find anywhere. i found one post regarding a Sanyo TV with same symptoms and the resolution was the error detect module.
Part # JU0161 and JU0148
i'm now looking at bypassing that error detect to the optocoupler circuit somehow...
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