New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

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Josh128
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New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by Josh128 »

So guys full disclosure Im a jackass-- took a literally brand new unit that had some not so good convergence on on the right side low center of the screen and tried to adjust convergence rings to help. When I would get the problem area converged well, the rest of the screen was off. Tried with convergence strips, turns out the strips were only able to create more separation, ie "belly-out" the area having troubles. The problem follows the movement of the yoke, so Im quite sure its a yoke issue and not a tube issue, so I decided to remove the yoke to inspect.

Sure enough, inside the yoke there were 10-12 very small mag strips taped to the coils in strategic locations, and it appeared that the tape holding some of them had come loose and some were dangling out of place. After carefully inspecting, I was pretty confident I was able to re-secure them about where they were before due to the tell-tale sticky tape residue on the coils. Once I did this, I re-installed the yoke and THOUGHT I had everything plugged in correctly, only to find I had a single vertical line of the game I was displaying. I quickly pulled power and found that I had not fully seated the H/V deflection coils connector on the board-- Im thinking the vertical coil was connected but not the horizontal.

Upon re-seating the connector properly, I re-powered the monitor and didnt get any static sound of it coming on or any picture at all for that matter-- only a light "click" sound every second or two. Is it possible that not having the deflection yoke fully connected caused something to blow in the chassis board? I came across the post below with a user having the same issue and he was able to replace a bad diode to fix it.

viewtopic.php?f=4&t=32612

For CRT experts out there, is it a common problem to blow a chassis by powering up with the deflection yoke not connected? It only stayed like this a few seconds before I powered down. Can anyone provide some insight?
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by grantspain »

read the horizontal output transistor
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by Josh128 »

Thank you Grant, will do. It was an accident, but is powering up a chassis with no yoke connection a common cause for trouble with the HOT?
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by grantspain »

diiferent chassis behave in different ways, most chassis would just not run and would be fine. These weiya type are very sensitive
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by PascalP »

Josh128 wrote: September 13th, 2020, 8:31 pm
Upon re-seating the connector properly, I re-powered the monitor and didnt get any static sound of it coming on or any picture at all for that matter-- only a light "click" sound every second or two. Is it possible that not having the deflection yoke fully connected caused something to blow in the chassis board? I came across the post below with a user having the same issue and he was able to replace a bad diode to fix it.

viewtopic.php?f=4&t=32612
He there, thanks for quoting my (old) post ;)
Yeah the issue I had back then was a shorted diode, not sure if all the Photobucket links and Youtube vids in my old thread are still working though.
But for me it was very clearly visible the diode was shorted, every 2 seconds when it 'clicked' and I dimmed the lights in my room I could clearly see a small 'flash' from the diode.

Let me know if this is the same for you and I might have some spare diodes of the exact type in my stash as I had to order 10x and only needed 1x :)
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by Josh128 »

Hey Pascal, thanks for the offer! I actually did do the "dark room" check as you described in your thread but I didnt see any arcing or flashing-- no neck glow either. Definitely not getting high voltage at the anode. I have a friend coming over with a thermal imaging camera to look at what if anything is getting hot on the chassis- something is, because if I leave it on, even with no source RGB connected, after 30 seconds or so I can smell something getting hot. Hopefully we can see something on the IR before I blow something else. I will definitely let you know if I need one of those diodes though. Hows your Tri-sync btw? Are you still using it? I have heard that a fan blowing across the yoke / neckboard and chassis can extend life and I see why-- Im not sure about the chassis and neckboard, but the yoke gets pretty darn hot under operation (until you blow the chassis, anyway :wtf: ). That may be normal for most CRTs, not sure, but I could see how a little moving air wouldnt hurt.

I plan to update this thread with progress. I have a scope, DMM, non-contact tester, etc. Whats the best way to check the HOT? Ive read that sometimes it has some internal resistance and wont read with a diode check like a normal transistor. This actually is a brand new unit, got it Friday before last, so Im definitely going to do what it takes to repair it, and if I fail, Im going to have to bite the bullet and order a chassis. Im already upside down bad on this unit because I purchased another one about a month ago that came with a detached shadow mask that would bloom ugly colors on bright colored screens. It would shimmer when knocking on the screen so Im 100% sure it was the mask. I had to send it back and eat the shipping both ways. Other than the blooming on bright / white screens, it had pretty good convergence-- I just cant seem to win.

Just for informative purposes, below are some brief YT videos I made showing the shadow mask blooming issues I had on the first unit. Its interesting to see how the problem gradually comes and goes when going from bright to dark, allowing the mask time to shrink from cooling and bow from heating, but so sad to see on a (yet another) brand new CRT with an otherwise beautiful picture.



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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by PascalP »

Hope you get it resolved man!
Was some time ago I used it (2016 IIRC) and since then I switched back to the original MS9 chassis in my Cyberlead and run striclty 15KHz games, for 31KHz games I have a Sega NNC with the Tosh PF tube so I'm all set :D
Sold the Weiya on some bloke here on the forum and schipped it to New Zealand I think.

A buddy of mine also bought a new Weiya 3129 together when I bought it and that one arrived DOA, never got that running either.
I know he still has that in storage somewhere so might be fun to have a go again at some point.
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by Josh128 »

Wonder if your buddy would be interested in parting it out? If I ever get this fixed I still have the original problem of bad convergence on the right center (that I blew up my unit trying to fix :oops: ). I really do suspect the yoke and would be interested in a spare. Of course if I could get my own yoke issue resolved that would be ideal. But run it by him and see if hes possibly interested in parting it out.

If not, I have seen chassis available online for about $200. If he cant fix it perhaps throwing a bit more $$$ at it might fix him up, lol.
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by PascalP »

Send my buddy the link to this thread.
Sure if he wants to part with it he will let you know ;)
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by Josh128 »

Havent had time to really troubleshoot just yet, but I managed to take some thermal images with a thermal camera of the chassis while the chirping is going on. There is a component, looks like some sort of coil/inductor, that is getting hot QUICK. I dont leave it on for more than 30 seconds or so because you can start to smell the hot/beginnings of burning insulation. I noticed this the day it crapped out and it may just be because there is no load on the power supply, but not sure. I will post the thermals hopefully this evening here.
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by Josh128 »

Pics from the top of the chassis.
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by PascalP »

Wow, that is pretty sweet, hope you can isolate the culprit with this!
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by PrincessPrinPrin »

That's probably the PTC. It's normal that it gets very hot.
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by nem »

PrincessPrinPrin wrote: September 22nd, 2020, 8:02 amThat's probably the PTC. It's normal that it gets very hot.
It's not the PTC. In the last pic (20180209-183127.jpg) you can see the wiring for the degauss coil. The PTC is to the right of the degauss coil connector. The PTC does show up in the thermal image, but as green, not red.


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The component that's glowing red definitely looks like the 2420A-1 coil.
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by PrincessPrinPrin »

That's the AC filter. I don't think it's bad, maybe a shorted diode bridge could get it hot but in that case the power supply wouldn't work at all.
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Re: New Wei-Ya / Makvision Tri-sync M3129DS-LG 1 Sec Click of Death...

Post by Josh128 »

2420A

Yeah the visible and IR cameras are offset a bit and the images dont exactly line up especially when looking at something close up, but if you look at the IR only you get a perfectly accurate indication of where the hotspot is, just takes a bit of figuring by whats around it.

I think its the 2420A thats getting that hot. And Im pretty sure its because of something else that shorted or blew, could well be diodes or still maybe the HOT. Theres definitely either no voltage coming out of the flyback to the anode.
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