Problems with Sony PVM-2130QM Cube

naujoks

Active member

Donor 7 years: 2019-2025
Joined
Dec 24, 2018
Messages
343
Reaction score
60
Location
Berlin, Germany
Today I received a PVM-2130QM.
It has two problems.
The more serious is that after some 20 or 30 minutes of operation, I can hear arcing, apparently coming from the red HV divider block.
I can smell ozone, but in darkess I cannot see the arcing. It does not influence the picture yet. It remains undistorted.
When I switch off the monitor for a few minutes I can then use it again for 20 minutes or so without arcing.
I'm expecting this problem to get worse and eventually killing the monitor. Is there anything I can do to fix this?

The second problem concerns geometry, which experiences rather sever pin cushioning, but predominantly on the left hand side.
How can I fix this? I see many little pots on the main PCB, but they seem to be inaccessible without removing the board, unless there's trick?
Might caps be an issue? I didn't spot any leaked or buldging caps.
 
Look up Pat on eBay. He's the expert on these PVM'S

View attachment 859975
Just a note for anyone who goes down this route, he works based on a fee for a full service. It's very expensive...just so everyone is aware. He is also in his late 80s...so responses may be slow. Unless you live close to him and can lug your CRT to his garage workshop, it is worth considering alternative repair options.
 
I would still reach out to him. He's very knowledgeable and can at least steer you in the right direction.
 
Pat said that the HV block needs to be replaced. A replacement can only be obtained by harvesting one from another monitor. I don't another one, of course.
However, I've been using the monitor for an hour or so, and again 30-45 minutes on further occasions, and the arcing did not occur again. Maybe it sorted itself out. After all, I'm sure the monitor hadn't been used in many years.
As for the geometry issue: there are pots on the D board, which can be accessed with a very thin flat head screwdriver.
I'm now pretty happy with the image quality. Arcade boards (DK, DK Jr, Tetris etc) look great on it.
Guess I'll see how much time this monitor has left.
 
The divider is for x-ray protection (from 26KV or so it gets a 10-20V sample) and can be bypassed (and tossed) so the anode voltage is sent directly to the tube. A new x-ray protection voltage can be obtained from a secondary output of the flyback, typically the same output as the heater voltage. And that's it, not difficult at all for someone with average monitor skills.
 
That is interesting.
So the reason why the arcing in the HV block doesn't negatively effect the picture is that the circuitry in which the arcing occurs is not responsible for the image creation?
What would happen if that part fails, say it goes completely open?
You solution to this problem does not seem to be widely known. I have not seen any forum post on this, nor any Youtuber doing this.
I think it would help a lot of people if you could work out detailed instructions of how to do this.
 
The low voltage sample of the anode voltage doesn't make the monitor work or work better. It's just for protection. You could unplug it from the chassis and nothing would change but of course it's better to have it in case the flyback outputs higher than normal secondary voltages (one of which is the anode voltage).

What I suggested above is pretty simple. You disconnect the anode lead coming from the flyback and going to the red block (requires a push and twist action). The lead is terminated with this contact:
DSCN3235.jpg
You take a spare anode lead with suction cup and put at the other end a crocodile clip big enough to "bite" the above contact (e.g. Hirschmann AK2S):
DSCN3232.JPG
You put a PVC tube of adequate diameter/length/thickness around the connection so it doesn't arc and the monitor will work just fine.

As for the new protection voltage obtained from the heater output of the flyback, there are plenty of examples in TVs and monitors as that's the method used by most manufacturers, e.g. Wells Gardner K7400/U5000 (FBT pin 5 rectified by D711), Neotec NT-2515 (FBT pin 9 rectified by D409) or this JVC TV (FBT pin 4 rectified by D525):

https://www.manualslib.com/manual/839744/Jvc-Av-27d502-R.html
 
Last edited:
Back
Top Bottom