Fisher/Sanyo TV Tuner

Don't have the model number handy, but the set was made by Sanyo and sold by Fisher, dated 1996. It wouldn't tune in any channels, the voltages (5 and

9VDC) were present on the tuner and injecting a signal into the IF stage produced a normal picture. I had every reason to suspect a bad tuner, but once replaced (with a rebuilt one) I got the exact same result. Apart from checking the supply voltages, and injecting an IF signal past the tuner, I don't know how to troubleshoot it any further. I checked around for bad capacitors but couldn't find any. Is it possible the replacement tuner was bad too? Or is there something I'm missing? Thanks for any advice.
Reply to
Packrat
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I would look into the signal controlling the tuner. Is it a varying voltage, or is it a digital bus?

Reply to
James Sweet

Check to see if the controling signal to the tuner is working properly. You may have to give the set out to a JVC service center to have it properly verified. The fault can be from the uPC, EPROM, or some circuits in the path from the controling source.

Jerry G. ======

Reply to
Jerry G.

9v? shouldn't there be varying (33v or so) tuning voltage?

-B

Reply to
b

There is a 1 watt 33k or 39k resistor that is open that supplies the

33v to the tuner. It is located on the middle of the board from front to back and it is closer to the right hand side of the board than the left. (The position varies from chassis to chassis.) Chuck
Reply to
Chuck

On Nov 2, 4:15 am, b wrote: vice.

Sorry, part of that got swallowed. meant to say there should be a 33v feed to the tuner - is it present? then measure the voltages on the pins - will vary as the tuner searches for stations.

-B

Reply to
b

Reply to
Packrat

Nice to hear that the tip worked. I got out of the consumer electronics repair business 6 years ago, but back then this was the most common failure in Sanyo tvs. Your old tuner is ok. These resistors just open up under normal current draw. Chuck

Reply to
Chuck

Yes, everyone should send their Fisher/Sanyo TVs to JVC for service. That will really confuse them! ;-)

Reply to
Jumpster Jiver

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