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29" Makvision monitor shutdown and leaking capacitors?

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mamenewb100:
So I feel a little depressed and stupid for possibly damaging more components on my monitor than I should have. Hoping I didn't make it irreparable.

From the beginning... Even being 'Brand New' I've always noticed some issues with my Makvision 29 inch SVGA arcade monitor. And I was aware from the beginning that many people reported issues and warned it was cheaply made yadada. I still took the chance 4-5 years ago because I wanted a true arcade monitor that wasn't already used.

Games displayed fine and looked fairly nice for the most part. Especially after finding out I could double the refresh rate of 15kHz resolutions to achieve scanlines even on a 31khz monitor. Unfortunately there always seemed to be random issues with some resolutions or frequencies not displaying properly. They could often times be fixed by changing some settings but then cause other resolutions to exhibit the same problems. Like pincushioning, warped image, vertical rollover, etc.

Well to make a long story shorter: A few days ago I started noticing the pincushion effect getting worse but was able to correct it to some degree by adjusting pot's on the monitor. Then as I was testing different resolutions and switching between them, it appeared to get stuck trying to change it. Made an unsettling noise (probably component shorting out) and the image onscreen suddenly looked washed out and getting increasingly whiter while starting to fade away. I unplugged the monitor and let it discharge itself for a few minutes. When I turned the monitor back on there used to be a NO SIGNAL message bouncing around the screen but NOTHING shows up. No Onscreen Display at all either. Just a whitish blank screen warped at the sides of the screen that I left on stupidly for about 5 minutes while I documented what was happening and took some pictures.

Well, shortly after that the display turned itself off and I immediately unplugged the outlet. There was a burnt smell coming from the monitor. I took apart my arcade cabinet to get to the back of the monitor and noticed what looks APPEARS to be several capacitors leaking. I had read it was common for Electrolytic capacitors to fail on Makvisions. It could be yellowish glue used to bond the capacitors. Hard to tell exactly, since I don't know what to look for. Nothing Black or burnt looking. And this could of been happening for quite sometime and I didn't pay close attention until now.

Did a lot of reading and came across an interesting read  https://www.gammaelectronics.xyz/trcswos2e_7.html

It goes over many things I think I experienced. Listing the Horizontal Output Transistor and Flyback failures which can trigger shutdowns of the monitor for safety reasons. Their appear to be many variables.

There is literally one CRT repair place I know of about (possibly one of the last left in the USA) an hour from where I live that could possibly repair it. If it's as simple as replacing all the capacitors, that would obviously be the best case scenario. I would feel nervous doing this myself and honestly Don't even feel safe plugging the monitor back in at this point as it could do further damage.

Anyway if anyone else could chime in with their experience or even suggestions on the best route to go, that would be greatly appreciated. Sucks that CRTs are going extinct and repairing them will soon be impossible due to inexperience or even parts being available to fix it. :'(

mamenewb100:
Tried plugging in the monitor again. You can hear the degaussing sound, main board has power with a green LED. However the screen does not turn on at all with no static or anything. It appears the yellow around the capacitors is probably just adhesive glue. Can't really get a good look at the board without moving the whole machine. It's possible some capacitors lifted but I don't see any obvious bulges or burn marks.

I've heard solder joints could have come undone too. I did use a small 4" inch subwoofer in the cabinet below the monitor which may have shook something loose. Lots of variables. Probably just have to have someone look at it.  :embarassed:

mamenewb100:
And now I learned the Flyback is whats responsible for supplying voltage to the screen. So clearly that must have gone bad at the very least. And yes I keep replying to my own posts. At least I'm making an effort to learn this stuff.  ;)

grantspain:
i have only worked on a few of these chassis, its unlikely your electrolytic caps are causing this but it is possibility and indeed that is glue you can see
I would be looking at either a hv cap failure or flyback as the extreme pincushion prior to failure would point towards these, its also possible the HOT has failed as a result
These chassis have safety resistors on all critical voltages, when i get chassis like these for repair the first I do after inspection for the obvious is to dummy load the collector of HOT and check all the chassis voltages, 24v vertical deflection, b+, 12v and 5v ( chassis dependant of course and using a schematic for reference)
I do not think this is a job you can do unless your soldering skills and equipment are of a good level but if you were to try then i would suggest reading the HOT with a meter on diode test collector to emitter first to check for dead short and take it from there

mamenewb100:

--- Quote from: grantspain on April 25, 2021, 02:45:58 am ---i have only worked on a few of these chassis, its unlikely your electrolytic caps are causing this but it is possibility and indeed that is glue you can see
I would be looking at either a hv cap failure or flyback as the extreme pincushion prior to failure would point towards these, its also possible the HOT has failed as a result
These chassis have safety resistors on all critical voltages, when i get chassis like these for repair the first I do after inspection for the obvious is to dummy load the collector of HOT and check all the chassis voltages, 24v vertical deflection, b+, 12v and 5v ( chassis dependant of course and using a schematic for reference)
I do not think this is a job you can do unless your soldering skills and equipment are of a good level but if you were to try then i would suggest reading the HOT with a meter on diode test collector to emitter first to check for dead short and take it from there

--- End quote ---

Thank You. By HV Cap, you mean High Voltage right? Makes sense that a component getting to hot, would trigger a safety shutdown. Or just flat out failing due to the stress. So it is possible the Flyback didn't get harmed. Although maybe not a rare part or expensive to replace anyway. Any input will help narrow down the problem and help the repair guy narrow down what the problems are. I'm hoping to have him replace the critical components causing the issue. Then I'd happily spend extra money to replace all the capacitors since they were probably cheap in the first place and do a yoke adjustment.

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