Hantarex MTC9110 - Have neck glow, but no picture

richiewoo

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Hi,

I have a Hantarex M9110. It powers up, monitor charges, then nothing. Neck glow stays, and there's static on the screen if I put my hand up to it.

It was like that when I got it, so I:

Capped it
Reflowed headers for power and video input and output to the neckboard.
Verified that I was getting power past the fuses.
Checked B+ at the big resistor (R105) and it's good.
Replaced the flyback with a new one, then with one from a working chassis.
Tested the HOT (test ok).
Lifted one side of D10 to see if it would come on, but it didn't.

It seems fine, except there's no picture. The fan spins, and like I said I have neck glow and it seems to be charging up.

Anyone seen this? I had a power issue with it, in that it was totally dead at one point, and I had to replace ZD1. So, now I'm back to where I started.

Let me know if you might have seen this and of course, what it was! I hate to blindly replace parts, but I have a working MTC9000 (19 inch) that I can scavenge if I need to. I hate to take a working monitor down, but this is kicking my ass, and I'd like to get it resolved.

Thanks in advance.
 
No.

I was manipulating that trying to get something and nothing.

I have to pull the HOT and VR to test. I'm gonna swap them with the ones from the other chassis I have. If that doesn't solve the issue, then at least I'll know.

It seems to be working well, but just no picture...
 
Ok, I have an update, but it's not much!

I worked on this for an extensive period of time. I went through the circuit and verified that things were where they should be per the schematic. I'm not an EE, so it's possible I missed something.

Anyway, I replaced the HOT even though it tested fine. Swapped in another working fly from an MTC9000 I have. Replaced C37 with the one from my working board.

I tested the B+ at TP10 and it's 131V. Neck glows. I hear static when it powers up. It doesn't appear to be in shutdown. The game plays fine (the video output is good) with other monitors.

I have a 19-inch MTC9000 that I might try this board in to verify that it's not a tube problem. Would that be a problem? WHen I got it, it was playing blind. Plugged it in when I got home and it played for a few minutes and then faded out, and never came back (that's when I capped it and did the fly).

ANyone got anything? I guess I could bypass the fan and temp circuit by plugging the yoke directly into the chassis, just to ensure that it's not there. Yeah, maybe I'll do that.

Thanks!
 
Update...

I bypassed the fan/thermostat and plugged the yoke directly into the board. I also verified the 24V on TP14.

It flashes up, but no pic still. If I power off the game and power it on, there's a flash on the screen, then nothing. Since the B+ is good, I don't think that it's in shutdown and I lifted one side of D10 to verify, and still got the same result. The symptoms are like a monitor in shutdown though.

I tested the B+ on TP10, it's good.

I thoroughly went over the power circuit. Something else I can check?
 
I have a 19 inch MTC9000

I had heard that they were almost identical. Can I drop the 19"chassis into the frame?

I was going to test the 25"chassis in the 19" frame, just to see if it would come on, but if I'm still having issues, maybe I can just do that?

What you think?
 
Update

I turned the input pot all the way up and got something.

By the input pot, I mean the one in the lower left corner that adjusts the video input signal. I got a pic, though faint.

It's like there's almost no brightness. I would think flyback, but I've tried three in this, one being new, all with the same result. There are a couple resistors that point to brightness on the schematic, but they test ok. (R90, R126, R89).

I'm so damn close, but I can't seem to get the right one. So, it's behaving like it should, it's not in shutdown, but I still have shit for a pic.

Any ideas?
 
I had one that gave no picture, although i could turn the brightness up a bit and see some diagonal lines that were NOT raster. Turned out to be a broken trace under the cap on the neckboard. Once that was fixed, the pic was back and perfect...
 
I actually have a pic

It's just faint. I'll go over the neckboard again though, as I'm getting to the point where I;d like to smash it with a hammer!

I have it hooked up to my Police Trainer, which is serving well as a test lab at the moment. I got screen, though the sync is poop. No brightness from the fly though. The pic I got was from turning up the input pot all the way.
 
Man, still the same

After a lot more testing, I still have the same result.

This is what I've done additionally:

Tested the voltage at D15 - 197 at the cathode. The anode side was 0v. I replaced it just to see, and it tested the same

Tested the voltage at TP14 - 185.

Tested the voltage at TP10 again, and at R90 - (B+) 130V. The other side of R90 had .5V. I replaced that too for the heck of it.

Went to the neckboard and replaced C206, again, just to see and got the same result. Also checked R217 and R218, both test good.

If I turn the screen pot on the fly all the way up, and the contrast pot, I get a weak picture. It's like the brightness is missing.

I still think that the flyback is good because it came from a working game, and the new fly as well as the original all give the same result.

I'll keep digging tonight and post my results. I am gonna find this problem if it kills me!

Of course, if you have any ideas, I'd be happy to hear them.
 
Update - Fixed!!

I found that mofo!

It was the factory brightness adjustment pot.

RV7 - a 220K pot for factory adjustment. Pulled it and took a measurement, though it seemed good, I gave it a thorough twisting and put it back in.

Monitor works now!

Thanks for the help and I'm happy to move onto other things!

~Wooooo
 
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