[TechAssist] Re: Old Sharp VCR VC-489U Anyone have a scrapper unit?

Gary,
Send me the FCC number off the back and I'll check in the dark and damp 
basement tomorrow.
Jeff
--
Intrepid Video TV/VCR Repair
263 S Front St, Steelton PA 17113
717-939-7708; (F) 717-564-4952
www.intrepid-video.com  www.tech-repair.net
----- Original Message ----- 
From: "Gary McCartney" <gary@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Thursday, September 16, 2004 1:09 AM
Subject: [TechAssist] Old Sharp VCR VC-489U Anyone have a scrapper unit?


I have an old Sharp HI-FI VCR in the shop that belongs to a good friend 
of mine. This was a high-end unit and it is still in very good shape, 
other than it won't tune in any channels. This machine was from 1985 and 
it has the electrically powered drawer on the front panel that opens up 
to reveal the remote control and function buttons. If it belonged to 
anyone else, I'd say to forget it but I would like to solve the problem 
in this case.

The VCR tuning circuitry is not functioning. Just snow on the screen. I 
replaced the tuner without improvement.
I believe the problem is in the frequency synthesizer circuit. Some of 
the voltages around the PLL IC 1401 are wrong. On the tuner, the VT pin 
  is zero volts and the B2 terminal should have 11V but it is zero. I 
injected my own voltages to these pins and was able to tune in a 
channel. I have replaced the band switching IC 1503 (IX0260CEZZ or 
LA7910) and tested transistor voltages and the 4.5Mhz crystal is at 
correct frequency.

I am hoping that someone has one of these units sitting on a shelf 
waiting to be sold at a reasonable price for parts. I'd especially like 
to get the synthesizer, tuner, and timer boards.

Thanks for any help.
-- 




Gary McCartney

McCartney Electronics
Guelph Ontario Canada
Est. 1984
email: gary (at) number63.ca







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