![]() |
|
#1
|
|||
|
|||
|
I have a SONY KV-8100 Trinitron 1982 bought new as a backup TV. It has very little use & has never been repaired. It has electronic tuning & 14 presets. It is currently set to all channels in this area & remembers it's settings. Everything works as new except when I checked the tuning function. The tuning lights come on however it's like the the 2 switches (up & down) are not making contact & also Channel clear acts like no contact. These switches have both a removeable cover & an external flip down cover.
The owner manual is currently MIA as I may not have looked at it since 82- it's here somewhere. I have the Sony schematic included w/ the TV. The Sony schematic shows these 3 switches NO to connect points on IC 002 CX 760C & a red (on schematic) wire to ground. Primarily I work on cars including modifications & the electrical. I can pretty much fix anything except electronics at the component level & have never fixed a TV. I have a VOM & soldering iron. Normally I would shoot some contact cleaner into the 3 switches. So do you think it just needs the 3 switches cleaned? Evidently you guys are very good & fixing many TVs w/o the Service manuals. While a Service manual would have limited if any help for me, would it be worthwhile to buy a Service manual for it though probably not needed for this issue? |
|
#2
|
|||
|
|||
|
...
Last edited by andy; 12-06-2021 at 12:05 PM. |
|
#3
|
|||
|
|||
|
Andy
The switches in question are as you described- evidently bad. So what's your recommended replacement procedure? Thanks Bill |
|
#4
|
|||
|
|||
|
...
Last edited by andy; 12-06-2021 at 12:05 PM. |
|
#5
|
||||
|
||||
|
I had to replace simliar switches on a Sears (Sanyo) beta vcr. (about the same age as this tv) I found some that were similiar in stock at Radio Shack (!) The only difference is the tab stuck up too high on the new ones; I was able to cut them down and they worked fine. Not too hard to solder them in.
__________________
Bryan |
| Audiokarma |
|
#6
|
|||
|
|||
|
Since I only need to tune in 1 preset to Channel 3 or 4, is there some way a probe be used to make the contact?
|
|
#7
|
|||
|
|||
|
Pic. of switches. The two ovals at left bottom tune down & up. Over to right past a pin is the round Channel Clear.
|
|
#8
|
||||
|
||||
|
I heard that the switches are long gone out of production, but you could probably make something by cutting up the rubber keypad from a late model remote hand unit. They have the exact same concept, and I bet it can be done!
Charles
__________________
Collecting & restoring TVs in Los Angeles since age 10 |
|
#9
|
|||
|
|||
|
Andy asked on the 15th for a pic. of the switches & mentioned one thing to watch out for to avoid electrical shock. Does a smaller TV like this Sony 8" AC/DC have less shock hazard voltage/amps than a larger tv like a typical 19"?
I jumped the switches to verify tuning would work fine if the switches were replaced. Later removed the center part of the switch which is snapped in & can be pulled to jump the switch w/ a probe. The antenna connection is a 1/8" plug. The included adapter, 2 screws to 1/8" plug, was disassembled revealing a direct connection (no electronics). A UHF 300 ohm bowtie antenna was connected which improves UHF to excellent while VHF remains excellent. Later the schematic was pulled from the Sony box which shows a 75 ohm antenna connection. Any explanation on the 300 ohm vs. 75 ohm antenna connection? |
![]() |
|
|