VCR control button problems

[lnx64]

I am having some serious problems with the control panel buttons on my Sony SLV-795HF VCR.

For example, when I press the stop button, it sometimes stops.. Sometimes if I press hard enough, it goes into record mode.

I accidentally erased one of my fathers old concert tapes because of this VCR (and he not remembering many many MANY years ago, to pull the freakin tab off the tape). I pressed stop, it looked like it stopped, so I walked away.. Little did I know, it didn't stop, it went to record and started recording live TV (hence it looked like it stopped).

What could be causing this? From the remote it works just fine. It's only from the front panel button.. I thought bad solder joint, but it looks and appears fine, all soldering is ok.

[Ed in Tx]

Electrically noisy switches. Sometimes a little drop of Deoxit into each momentary contact switch will fix it right up.

[Ed in Tx]

BTW any of those old tapes you don't want accidentally erased, break out the record safety tab. That should prevent the machine from going into record, even with flaky switches.

[lnx64]

Yea I'm aware about the tab. As I had mentioned, many years ago my Dad forgot to remove the tab and I assumed it was already removed.

A noisy button will cause the VCR to think a "different" button was pressed? That is so odd.

[Ed in Tx]

Some Sonys used resistor voltage divider type function switching, where different push switches would make circuit with different value resistors, or direct to ground, and the microprocessor decodes the different voltage levels as stop, play, record etc. Noise and poor contact in the switches can trick it into misbehaving.

Lilewise with the rotary FF-REW search control if yours has that, and the rotary encoder on the bottom of the deck can get noisy and cause problems too.

[lnx64]

Ouch, that sounds like a dumb design. Ok I'll give that a shot. And yes, mine has the rotary jog wheel.

[Ed in Tx]

That resistor voltage divider switching was used on several brands.

If that rotary FF-REW control is the variable type, what I do is pull the knobs off, stand unit on its back, put a tiny amount of Deoxit down into the rotary switch, work it a few times, put it back together. Always fixes intermittent FF-REW mode switching for me.

[Labrat]

The resistive voltage divider was used for the front panel push buttons on at least one Sharp V.C.R. model in Australia.
The National Panasonic model NV300A (A for Australia) used this control method for the wired remote control. This usually failed in the long lead becoming damaged.