KTMF Chassis monitor issue

Gonzo

Twinkle Star Sprite
Hey guys, I picked up a converted Cab with a 4-slot MVS that had been stored for a bit. The chassis says 25” RCA KTMF 2641M. When I plugged it in image was bad and would only read 1st slot and none of the other 3. Gave the carts a decent clean along with the MVS. Image look way better and able to choose all 4 slots. I still noticed colors aren’t perfect and certain scenes get a glitch on a game and sometimes it looks like the image gets smaller the bigger a bit but mostly depends on which carts is playing. Magical Drop 2 seems the worst at the white high score screen, glitches and screen gets bigger/smaller. This is my first CRT cab so this is unfamiliar territory. I was told to check B+ but not exactly sure where to do it at and what voltage it’s supposed to read? Am I correct thinking it’s the monitor part or would it have something to do with the 4-slot? Any help would be great.
 

lachlan

drunk downunder!, aka. Muff Diver.,
You need to start at the cabinet's wiring and power supply first and make sure they are to spec / good working order.

Next you need a known working PCB to test and use that to adjust anything on the monitor that needs attention.

Pictures are a must if you want accurate guidance here.

Going straight to checking the monitors B+ voltage when you have no experience with CRT's is getting ahead of yourself. Start at the base, check the cabinet, the wiring, the pcb first.
 

Gonzo

Twinkle Star Sprite
It’s been a while since I posted and forgot how to upload pics and videos, I did upload on Facebook but not sure if I can post a link here. Am trying to learn how to troubleshoot myself if possible but not sure what exactly to check or what numbers I should be getting. Am going off the number on the chassis but haven’t had much luck getting info.
 

lachlan

drunk downunder!, aka. Muff Diver.,
The chassis PCB should have a row of adjustable pots for various things. Try those but please use a plastic tool.
 

Gonzo

Twinkle Star Sprite
Definitely. Am go to look into buying some plastic TV tube tools. In the meantime am going to see if I can upload some pics that way I can get better help.
 

Gonzo

Twinkle Star Sprite
Here’s where the screen starts shrinking and glitching then gets normal for a second or so and does it again. It does it multiple times till the scene changes.
 

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Gonzo

Twinkle Star Sprite
I was doing research and decided to check the 5V power at the PCB connector plug and was reading at 6.1X! I went ahead and started to adjust the power level and it immediately dropped to 0.62V. I didn’t hear no sound. Wasn’t sure what happened since I didn’t get to turn it and just gave it some pressure. I unplugged it and replugged and started back up. I tried adjusting again and this time turned a bit and started dropping then went down to under 1V once again. I repeated the process a few more time and the las one was about 5.30V and was able to turn without any issues till I got it to 5.12V and left it there. Is it possible to clean or repair the power supply or better off purchasing a new one? It’s a big brick looking one with a fan on top (don’t know exact name). Image looks a lot better along with colors but still get a slight glitch. At least seems am going in the right direction. Going to keep researching and reading.
 

Gonzo

Twinkle Star Sprite
Yes. On the back side of the plug connected to the PCB while turned ON. Top side number 3 and 4 spot.
 

Gonzo

Twinkle Star Sprite
You might've fried something running 6.1V into the 4 slot.
I don’t think it’s the board, I tried my 2- slot on it and it did the same thing but when I install into my LCD converted Cab I have no issues.

wondering if am better off finding a good shop to have them check out the chassis board.
 
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