Help me understand this piece of matuSHITa

mjansma

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Donor 3 years: 2023-2025
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My recently acquired Centipede cocktail unfortunately has the 14" Matsushita in it. I'm learning very quickly why a lot of people don't like this monitor. I've been reading, testing, and trying just about everything and I'm about ready to throw in the towel. I have two questions that hopefully someone can help me with…

First, why does it look amazing when I have the TPG hooked up to it, But then looks horrible and only has faint red when a tested/good board is hooked up to it? I have all of the bias and drive knobs turned up.

Second, what is my best and easiest option for replacing this monitor when I decide to throw it off of a bridge sometime in the very near future? 13" K7000?

I need a beer.
 

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Harness issue?
I thought it could be. I'll have to dig around and see if I still have some edge connector pins around. I think I do. Maybe my next move is to re-pin red, blue, and green? I am getting some red, just very faint.
 
Yeah, what Charlie said. This doesn't feel like a monitor issue, it smells of something else. Broken video ground between the game board and monitor, maybe? All signals are weak, which suggests something common to all of them (like a ground).

Don't start repinning things. Get your DMM out and start testing connections, and visually inspecting things. Whatever the issue is here, it's findable with basic tools. Measure first, find problems second, and replace parts third.

Look inside all of the video/monitor connectors (shine a light to help see), and see if any contacts are bent inside the housings, and maybe aren't making contact with the monitor header pins.
 
If for some reason you decide to throw in the towel on this monitor, I would be interested in the chassis. I have been unsuccessfully looking for a replacement flyback for months for a 14in Matsushita monitor, at this point I would go for a whole chassis so I have backup parts.
 
If for some reason you decide to throw in the towel on this monitor, I would be interested in the chassis. I have been unsuccessfully looking for a replacement flyback for months for a 14in Matsushita monitor, at this point I would go for a whole chassis so I have backup parts.


There's no reason to trash or part out this monitor. It's basically working, and there's a simple issue.

If you need a flyback, post a wanted thread looking for a spare chassis. Or find someone with a complete monitor with a dead or highly burned tube, who can pull the chassis.
 
There's no reason to trash or part out this monitor. It's basically working, and there's a simple issue.

If you need a flyback, post a wanted thread looking for a spare chassis. Or find someone with a complete monitor with a dead or highly burned tube, who can pull the chassis.
Andy, I did that back in Feb. No luck.
 
Andy, I did that back in Feb. No luck.

I'll give you a tip. The trick to finding (as well as selling) stuff here is to make a thread, and bump it once a week or so. Vary the day, as well as the time of day that you bump.

There are a lot of people registered here, but only 100-150 online at any given time. And it's not always the same people. Some people only read threads in the morning, some only on weekends, some once a week, etc. So anytime you post a thread, MOST people will not see it. If you want to reach all of the eyeballs here, it just takes a bit of patience and persistence. Slow pressure over time.

(And I already bumped your thread for you.) :)
 
I'll give you a tip. The trick to finding (as well as selling) stuff here is to make a thread, and bump it once a week or so. Vary the day, as well as the time of day that you bump.

There are a lot of people registered here, but only 100-150 online at any given time. And it's not always the same people. Some people only read threads in the morning, some only on weekends, some once a week, etc. So anytime you post a thread, MOST people will not see it. If you want to reach all of the eyeballs here, it just takes a bit of patience and persistence. Slow pressure over time.

(And I already bumped your thread for you.) :)
Thanks Andy! We gotta get together again at some point! It was great seeing you at Jeffs and Funspot!

Jason
 
I'm starting back at the brick again, P5, and measuring everything, which I'm going to document here. The voltages appear to check out and look to be within tolerance. The monitor connections look fine upon a quick initial inspection. I'm pretty busy the next few hours but will have some more time this afternoon/evening to look a little closer.

1- 13.30 VDC
2- 13.33 VDC
3- 13.35 VDC
6 to 7- 37.13 VAC
8 to 9- 6.89 VAC
12- 107.7 VAC (100V pin measured to pin 10/Com)
14- 131.1 VAC (120 V pin measured to pin 10/Com)

P5 100V pin 12 to P26 monitor connection- 107.3 VAC
 
That all looks ok. This is a video problem, not a power problem.

Focus on the video wires from the game board to the monitor. The ground in particular. Inspect the wires at both ends (monitor and game board). Look for bent contacts, and frays at the crimps. Trace each wire from the monitor back to the game board. Look inside the edge connector to make sure no pins are bent.
 
This is a real head scratcher. There's only 5 wires going from the connector to the monitor. The pin for video return was mangled pretty bad inside the housing. Almost like someone had a screwdriver in there trying to band it and went too far. I popped it out and crimped a new one, but there was no change. I also checked resistance on all 5 wires but they were all fine.
IMG_8208.jpeg
 
From the black edge connector pin to the molex that connects to the monitor.

I probably should have gone all the way to the chassis connection, right?
 
Yeah, sorry I should have given more detail in my last post.

I would test continuity from a spot on the trace on the game board (ideally near the edge connector is easiest), to the corresponding trace on the monitor. (Or a component that the trace connects to, since it might be tricky if the trace is under the board. But look at the schematics to see the first component that trace connects to.) Do that for all 5 wires.

There might be a problem with the header, or solder joint, or a broken trace at the joint, etc. Testing trace-to-trace will verify everything in the path in one shot.
 
I finally got to it this morning. I tested from the the pcb trace for each pin as close to the edge connector as possible all the way to their respective locations on the monitor. Everything still looks fine.

Red- 0.6
Green- 0.2
Blue- 0.3
Yellow/comp sync- 0.4
Black/video return- 0.3
 
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