Sony PVM-8020 Worked until I messed with it :(

[enzoleet]

Hi All,
I picked up a Sony PVM-8020 at the flea market over the weekend.
The picture and color was flickering and the knobs on the front seemed to be very finicky.
I took our the HA Board to clean the contacts and knobs and a capacitor came out with it.
Now the TV doesnt power on. Can anyone point me to where this cap came from so I can solder it back on?
Pictures attached.

I have the manual here
https://ia803406.us.archive.org/17/items/pvm-8020-sm-sony-en_202104/PVM8020_SM_SONY_EN.pdf
But I dont know how to read a schematic.

If anyone can help point me to where this cap should go it would be greatly appreciated.

[Runco990]

That capacitor should have come from around the flyback somewhere.  They are usually on the sweep/hv board.

As to those pots....  good luck with them.  The wipers break off the plastic carrier inside.  I used to have to de-solder the pots, open them up, do some surgery and re-assemble.  They commonly go bad and contact cleaner usually does NOT help.

[macboy]

225 is 2200000 pF or 2.2 uF (microFarad)
K indicates 10% tolerance
2E is 250 V rating.

So look in the parts list for a capacitor marked 2.2 250V, probably with 10% tolerance, but it may show something higher (a tighter tolerance part might have been used). Annoyingly, they use "MF" for "microFarad" in the parts list, a terrible convention, but it is what it is. At quick glance, I see only one, on the degauss (DC) board, C892.

[enzoleet]

Thanks macboy that was it!  It's powered on now. 

Still have tremendous problems with the pots knobs on the front like the other poster said no amount of contact cleaner helped.  Any ideas how to fix or replace them?

[Runco990]

Replacing the ORIGINAL pots isn't an option.  They were discontinued ages ago.

I used to de-solder them, cut the little rivets that hold them together, take apart, figure out how to re-attach the metal wiper to the plastic disk that held it...  (2 little plastic welds break off) then re-assemble and I just used wire to tie the pots back together.

This worked well.  PITA to do, but.... what choice do you have OTHER than finding and making a suitable replacement.

Some engineer should be shot for designing those pots.

[enzoleet]

Thanks Runco. So I pulled a working pot out for the vsync and tested with a multimeter and it sweeps back and forth fine. I just wanted to see a working one.
Next I pulled out the Sharp pot and tested it. Nada. So I decided to open it up and take a look. Here are some pictures. it looks like the little finger on the knob is fine so im not sure what is not functioning here. Any ideas?

[Runco990]

Your pics don't show how the wiper is attached.  Look closer.

[enzoleet]

Yea I'm an idiot and have no experience with Pots. I opened it up further and inspected and wiper.  It's so so so tiny.  I cleaned and put back together but it's faulty.... I checked aliexpress and found some that look like they might work but without the push lock feature.

In case anyone is interested in the resistance ratings
10k rv507 vsync
1k rv501 sharp
20k rv505 hue
1k rv504 color
20k rv503 bright
Dual 20k/1k  rv502 contrast
10k rv506 volume

After these come in I'll update everyone if they fit

[enzoleet]

Great News!
The RK097 Pots I ordered from AliExpress fit! They lack the push to lock feature but they fit right on the board.
There was a tricky little hurdle and I figured I would share the information in case anyone else ever heads down this path.
On the HA Board, RV502 is a 6 pin dual Pot. 20k in the front and 1k in the back.... They dont make them like this so I ordered extra dual 1k's and 20k's.  I took both apart and reassembled them to make a 20k/1k pot.  Superglued them back together.  The rest soldered in nicely and when reconnected to the PVM everything works and looks lovely.

The only drawback is the knobs are very recessed now so much so that I have to add a screwdriver slot to each knob.  Check out the pics!


Thanks for your help guys!

[Runco990]

That's awesome!  These are pretty good little monitors.  In general, you set the controls and left them alone, so it's not a problem using a screwdriver now.

I repaired and color corrected thousands of the PVM series back in the SD broadcast days.
The BVM's are King, but their complexity is causing repair challenges today. 
I keep a 9" PVM on my bench, perfectly calibrated.   

[enzoleet]

Thanks for all your help Runco. This was my first crt repair and I'm kind of addicted now.  Lol. Keeping my eyes open at flea markets for another pvm.

One question.  I can't seem to find any alignment settings.  The image could use a little shifting to the right.  Is there anything I can do or just enjoy it for what it is?

[Runco990]

Oh man... it's been ages since I did these....  There ARE alignment pots.  But do NOT touch the magnets around the CRT.  Those do purity and convergence.  That can be a nightmare if you don't do setups for a living.  I used to replace CRT's and do it in my sleep, but it took time to get good at it. 

Edit:  Found the manual.  It's all there.   

https://ia903403.us.archive.org/20/items/pvm-8020-sm-sony-en/PVM8020_SM_SONY_EN.pdf