Sony PVM-8040

[LADR]

Got a Sony PVM-8040 at a hamfest the other day. It produces a great picture, but, none of the front controls and power LED indicator are not working at all, like the board is dead. All the correct voltages are there. Thoughts? This is way newer than anything I’m used to working on.

[zeno]

Is that the one with backlit membrane buttons ?
What they may be doing is putting the button commands into a small IC
then sending one line to the micro. Also check the TAC switches for
being closed & locking out all of them. Look for rust, water stains
& damaged membrane.
I did quite a few PVM's but the only problem on most was a 'litic in
the vert.

73 Zeno
LFOD !

[freakaftr8]

Are all voltages coming off the rails of the stand alone power supply? Check solder joints at the ribbon connectors going to the button board. They are known for moisture contamination also.

[LADR]

Originally Posted by zeno

Is that the one with backlit membrane buttons ?
What they may be doing is putting the button commands into a small IC
then sending one line to the micro. Also check the TAC switches for
being closed & locking out all of them. Look for rust, water stains
& damaged membrane.
I did quite a few PVM's but the only problem on most was a 'litic in
the vert.

73 Zeno
LFOD !

It’s not the one with backlit buttons. It’s just potentiometers.

[MadMan]

If my Sony tv is any indication - cracked solder joints. Everywhere!

I was actually just thinking about it earlier... I wonder if it was an early attempt at lead-free solder?