Spark on frame when turned off/on

Laserolame

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Hi all,

I have some sparks between the monitor frame and the metal of the cabinet when i turn the monitor off and on.
There are plastic spacers between the cabinet stand and the monitor frame, form the factory.
Actually i did the following but nothing solved my issue:
- Tried another chassis,
- Isolated the chassis from the frame,
- Cleaned the pins on the tube (neckboard),
- Re-soldered the black cable turning around the monitor,
All options (lamp, psu, etc..) where disconnected. Actually the monitor is plugged directly to the AC outlet.

Once, i got no spark but he picture on the tube went very bright, quite completely white.

The video of the problem is here

Thanks a lot for your help and suggestions!
 
I would have guessed that was a leak from your anode cup or the HV wire that feeds it leaking but you said you tried another chassis?

The degauss wire should only be energized on power up so not sure how that could be involved.
 
Thanks Bobbyb13. I tried unplugging the degauss, and no effect. It still sparks.
 
Thanks for your answers.
This is a Nanao MS8-18B with the matching tube.
The flyback are genuine on both chassis I tried.
Both chassis were freshly recapped.
I don't use isolation transformer and I never seen some setup with it on this tube.
I noticed that the ground wire turning around the tube was maintained around each corner by simple rope. Whereas on other tubes there is continuity because it is attached with a metallic wire. I put some wire on each corners and now the problem is gone.

I experience now another issue because, as I mentioned previously, the brightness varies alone from low to excessive.
I had this issue once when the ground wire wasn't connected to the corners, so it's maybe another issue?
I will try to clean the potentiometer of "brightness" and "screen" to see wether the issue comes from the chassis or the tube.
But I'm a little bit worried I fried some component on the chassis. When I had sparks, the video out cable touched the frame, and there was a spark between them. As a result, my Recalbox RGB Jamma video amp fried. Also, I lost the sync of my source. I tried then with PCB and it was working fine except the sparks when turning off.

 
Last edited:
Thanks for your answers.
This is a Nanao MS8-18B with the matching tube.
The flyback are genuine on both chassis I tried.
Both chassis were freshly recapped.
I don't use isolation transformer and I never seen some setup with it on this tube.
I noticed that the ground wire turning around the tube was maintained around each corner by simple rope. Whereas on other tubes there is continuity because it is attached with a metallic wire. I put some wire on each corners and now the problem is gone.

I experience now another issue because, as I mentioned previously, the brightness varies alone from low to excessive.
I had this issue once when the ground wire wasn't connected to the corners, so it's maybe another issue?
I will try to clean the potentiometer of "brightness" and "screen" to see wether the issue comes from the chassis or the tube.
But I'm a little bit worried I fried some component on the chassis. When I had sparks, the video out cable touched the frame, and there was a spark between them. As a result, my Recalbox RGB Jamma video amp fried. Also, I lost the sync of my source. I tried then with PCB and it was working fine except the sparks when turning off.

I had to check, the MS8 apparently doesn't need an isolation transformer. but I'm certain they're supposed to be run at 100V, if anyone knows more about this I'm interested.

I can never keep MS8 and MS9 straight, I just know I've needed to cap them for people in the past.
 
I had to check, the MS8 apparently doesn't need an isolation transformer. but I'm certain they're supposed to be run at 100V, if anyone knows more about this I'm interested.

I can never keep MS8 and MS9 straight, I just know I've needed to cap them for people in the past.
I am willing to be slapped down by the experts on this also, but generally I have found that chassis with 3 prongs for power have built in iso and don't need transformer. Not sure it's across the board but that's what I've noticed.
 
I am willing to be slapped down by the experts on this also, but generally I have found that chassis with 3 prongs for power have built in iso and don't need transformer. Not sure it's across the board but that's what I've noticed.
also being Japanese I'm certain these are supposed to be run off 100V mains supply. there should be some red labels somewhere indicating such. lol
 
It's a 100v chassis. It's written on the tube. I use a 220v->100v transformer.
 
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