PVM-20M2U Vertical shake -Sync? Vhold? Oscillator? AFC? IC?

[deezdrama]

Edit..... Man this series of pvm's are problematic. I have two of them with various issues. Ive had to change the title 3 times now because after fixing one thing another issue pops up.


Original post......

Had this pvm-20m2u that was dead/red tally light.
The power board was outputting all the correct voltages but when it was plugged into the chassis board the 15v rail would drop to around 12v and the board was going into a failure or protection mode and wouldnt put out HV.

I installed the 17 capacitors that savon pat sells as a kit for fixing common issues with this model.
Included are some capacitor value changes over the factory specs.
I also replaced a handfull of capacitors directly around the flyback, and caps on neckboard.

It now fires up, I hear the degauss, the HV whine, a loud snap which I hope is just the anode cap needing cleaned again..... And I get a raster with the " no sync" message.
I hooked up a snes to svideo but it seems none of the front panel buttons are working. I cant change source, go into menu, nothing. None of the button lights turn on when I press them.

Ive read a user preset could disable front buttons but if a preset was set then remote light should be on which it is not.

Any ideas?









UPDATE#######
So I have a 14m2u I havnt tested yet. It fired up and has a wavy raster so im sure the same cap set I put in the 20m2u would fix the 14m2u but the buttons and menu works on the 14 so plan to try to swap them.





UPDATE #2

So looking at this I dreaded getting the front panel H board out but it wasnt that bad, I just had to remove the bottom tray that the chassis board sits on.
Theres literally nothing to this front panel board. Some buttons, resistors and pots. The board looks pristine.
Not sure if its even worth swapping out. Dont know what the problem could be at this point, the H board looks great and connections were firmly connected.

[tongshadow]

Not looking good, at this point it might be an issue on IC101, it's the one that reads the keyboard's commands. Maybe check the electrolytics around it?

[deezdrama]

Not looking good, at this point it might be an issue on IC101, it's the one that reads the keyboard's commands. Maybe check the electrolytics around it?

So I went ahead and swapped the front H board with the one in my 14m2u. It wasnt as bad as I thought, only had to remove the bottom tray to access the H board.

This one works!


Now I have a new problem. I set my phone to record while I fired it up to see if I could pinpoint the loud arcing pop when first firing the set on. It looks like the grounding fingers that contact the aquadag are shooting arcs.
Now I know the HV going into the tube has to leave it through the tubes aquadag and chassis grounding.... This startup arcing only happens for a split second on startup so not sure if its a shorting degauss coil or the tube grounding fingers are oxidized and not making a good connection to the aquadag on the tube.
Never seen this before. I guess Ill try to clean the contact points.
Anyone seen this before? Maybe that arcing is what killed the first H board?



Anyway.... The faulty H board...... I cant see how it would of failed since its only pots, buttons, and a few resistors.
Guess ill test the resistors..... All the solder joints looked fine.

[deezdrama]

Cleaned the fingers with a swab and 91 iso alcohol. Got rid of the problem about 80-90%. Just a small static discharge spark now.
Swab accidentaly rubbed off some aquadag so need to find a suitable aquadag type product to brush on under those grounding fingers.

The 20m2u pvm is alive and well otherwise

[deezdrama]

So I cleaned the tube grounding fingers and directly soldered a chassis ground cable to the 2 fingers.... This got rid of the discharge arcing.



Hooked up my mister via rgbs and began calibrating geometry,brightness and, contrast, was starting to look sweet.



After this above image i noticed things were a little blurry so set the focus and got everything looking really good.

Started playing some games and after about 30 min i noticed the lower portion of the screens geometey got worse, then the whole screen started slightly shifting up and down, this soon developed into a vertical roll almost like i lost sync but the menu and other sources do it as well.

This is after the deflection recap and the set warms up. I would think its a bad vertical deflectiion cap but i just replaced those .... Arrrrggggg

Heres the menu with no signal

https://youtube.com/shorts/q2MeM-XQCUc?feature=share

Heres the rolling vertical image now

https://youtu.be/qzyXlMsnjnw



So frustrating. If I search "pvm rolling" or "pvm image jumping" theres a ton of results with similar issues and almost all of them are with a 20m2u,14m2u,20m4u,14m4u or medical variants.... All based off the same chassis and power boards.
Man this pvm is becoming a pain. What could it be now?
I would say deflection caps but I just put new ones in and it worked great untill the set warmed up.
Should I dump another $50-70 into recapping the power board?
Reflow vertical ic?
I just dont know at this point.
Messed with vhold in service menu and it slows the rolling but my geometry is bad now and vertically unstable.
Any ideas?
Was starting to look really good. Crazy... I have a ton of older 40 series pvms that are rock solid after recaps, these seem finicky as hell.

[jd213]

Shot in the dark, but I had deflection problems with an Olympus OEV 143 (OEM version of the M2 series) that turned out to be a bad film cap (specifically C2510), so you might want to check some of those.

[deezdrama]

Shot in the dark, but I had deflection problems with an Olympus OEV 143 (OEM version of the M2 series) that turned out to be a bad film cap (specifically C2510), so you might want to check some of those.

Thanks, all shots in the dark are welcome at this point. Ill check that and surrounding caps out. Did that specific film cap cause a similar issue in yours?

[jd213]

In this PVM the horizontal control was borked and none of the controls could fix it (vertical could still be controlled though):
https://postimg.cc/gallery/wxv9WZd

So not too similar an issue, but it at least taught me that film caps can go bad. This particular OEV 143 was manufactured in 2005, too.

[tongshadow]

Man, cant catch a break huh. This PVM is cursed!

[deezdrama]

Man, cant catch a break huh. This PVM is cursed!

Yeah and I get to work on its little brother the 14m2u after I figure this one out ugggg lol

[Dochartaigh]

Just in case any of this is related to the parts which make the tally light error/fault code turn on, here's a document on that fault on this series (14", but super similar to 20"):

https://archive.org/download/pvmrepairg ... 0Light.pdf

I always found it super weird that the tally light comes on to show there's a problem of some sort, like it's a built-in feature, but there is ZERO documentation of that in all the service manuals... and that fault is the most common problem I've had with the 14/195X and 14/20M2 series (still only 3 out of 30 so still not bad for how old these are though).

[deezdrama]

Just in case any of this is related to the parts which make the tally light error/fault code turn on, here's a document on that fault on this series (14", but super similar to 20"):

https://archive.org/download/pvmrepairg ... 0Light.pdf

I always found it super weird that the tally light comes on to show there's a problem of some sort, like it's a built-in feature, but there is ZERO documentation of that in all the service manuals... and that fault is the most common problem I've had with the 14/195X and 14/20M2 series (still only 3 out of 30 so still not bad for how old these are though).

Yeah, i seen this document and so had some 5v voltage regulators on hand but the board is outputting close to 5v so im stumped. Will try to swap it out with another power board and see if that changes anything, if not I guess ill poke around in vertical deflection circuit.

[deezdrama]

Well its definitely not the power board. Swapped in another one and the same issue persists.

It worked great for 30min after the deflection recap then over a 3 min period i watched bottom geometry get stretchy and then the whole image would vibrate up and down a little until it got worse and worse and started rolling.

Its like i watched a cap or a component fail.
Only cap im concerned with is c584 it was a factory 1uF 160v high ripple rated cap. The one single orange cap from the factory.
Sonys service bulletin called to replace it with a 2.2uF 160v. Ive read suggestions to get high ripple but didnt read that until after I replaced it already.

I used a nichicon low impedance 2.2uF 200v 105c with 25mA ripple rating.
You would think it would be fine. I think that cap just controls the menu anyway.

I guess its possible one of the caps I replaced was faulty from the factory.
The issue looked like I watched a cap fail before my eyes. Good calibration and geometry went to crap before my eyes then the rolling. I replaced almost all caps on deflection side of the board.
So frustrating.

Guess ill pull it all back apart and throw esr meter on caps. Dont know what else it could be

[deezdrama]

I dont know if the sync controller can be blamed for what I witnessed ( lower geometry stretch then the vertical jitters then rolling) but went ahead and ordered a new NEC upc1377c sync controller and will try replacing it and see if that helps.



While im at it i will replace a handfull of small caps in the same general area that I didnt replace originally.

Actually ill probably go ahead and make sure that whole half of the board is recapped.

I really want to save this pvm. For the 30 minutes it was working it looked really great.
Tube appeared nice and vibrant and should have alot of life left if I can just figure this issue out.

Any other ideas are welcomed.

I can swap parts all day long and do some basic troubleshooting but schematic reading is not my strong point.
Also i felt like this models particular service manual was lacking info unless you are a hotshot with a scope and can read waveforms. Maybe its just me..... Read sentence above the last one lmao


Oh..... The big metal pot on the chassis board.....rv501....... This same pot was on my 40 series pvms and always used it to tweek one of the screen positions.... I did tweek it a hair a few minutes before things went south.
Can anyone confirm what this pot is. The one big pot right on the A board above the HOT(below it in this image) I couldnt find any reference to it in the serv manual.

[tongshadow]

That's the H.Center potentiometer.

[deezdrama]

That's the H.Center potentiometer.

Cool, wanted to make sure.
Still havnt made any headway on the rolling issue
I ordered a new sync controller chip but not sure if thats it and looks like a bitc# to pull old one because so many nearby surface mount components

[tongshadow]

You definitely should get one of these to test for capacitors in circuit (and out of them too).
https://i.imgur.com/jJHCVYa.jpeg
Not sure if there's an updated model now, but this has been a lifesaver for me.

[deezdrama]

You definitely should get one of these to test for capacitors in circuit (and out of them too).
https://i.imgur.com/jJHCVYa.jpeg
Not sure if there's an updated model now, but this has been a lifesaver for me.

To test capacitors or transistors?

I have 2 peak atlas esr70 plus meters, a GME esr meter, and an m328 which is a multi component identifier/checker that looks like a cheap version of the meter you posted. I read the peak was the most accurate in circuit when I researched a year or so ago but i like the GME for ease of use. My peak had an issue with the leads so they sent me a new one and i plan to replace the croc clips and lead on the faulty one with tweezer probe.
But yeah, im covered for in circuit cap testing unless that one can isolate decoupling caps in circuit or something these other meters cant do?

[deezdrama]

So ive seen a couple mentions and got a reply on reddit... All about the sync seperator IC which I already have a new one on hand but was calling it a sync controller a few posts up.

Anyway... I thought about swapping that IC out and replacing a few small caps that surround it that didnt get replaced when I did the initial cap kit savon pat suggests but dont want to just be shotgunning parts in the dark.

I wish I knew how to use a scope I would buy one but is there anything i can test for voltage wise on the sync seperator IC?

Im still new to schematic reading but does it appear I should be getting 12v at pins 21 and 11?

[tongshadow]

So you do have the tools, time to poke the capacitors and find the ones that have high/unreadable ESR. I dont think ICs are a common point of failure on these monitors, they were built for heavy duty use and the weakest link will always be the capacitors.

[deezdrama]

So you do have the tools, time to poke the capacitors and find the ones that have high/unreadable ESR. I dont think ICs are a common point of failure on these monitors, they were built for heavy duty use and the weakest link will always be the capacitors.

Yeah, ive already replaced most of deflection side of the board, around the flyback, and the neckboard.

Rechecked all the caps i replaced and a couple of the new caps have borderline high esr but I think the nichicons are like that new. I need to compare esr value against some new ones I ordered to recap the 14" m2u.

Theres a handfull of small 10ohm 50v caps around the sync ic i think im going to swap out, then reflow solder on everything in the vertical circuit after sync ic.... Then retest. If that doesnt work then ill swap the sync ic and the 2 vertical ic's.
I guess its time i invest in a scope and learn to use it. I hate blindly throwing parts on a board.

I do feel like a cap went bad over a couple minutes time as geometry and sync slowly went bad infront of my eyes unless this behavior could also be indicative of a sync or vertical ic going bad but not sure if those just fail instantly or can progressivly go bad like i witnessed.

[deezdrama]

A non eventfull update....

This morning I pulled out a jewelers loop and examined the vertical circuit untill my eyes crossed.
Was happy as hell when I thought I found a cap leg I forgot to solder.
After work I rushed home to reflow it and the vertical ic's and sync chip.... Put her back together and ........ Same ol sh##


I think the cap leg I thought I missed was just probably one of those vias that sucks in the solder and leaves a concave solder joint. Damnit.... I thought it was going to be an easy fix.

Back to the drawing board. Will probably end up shotgunning the entire vertical circuit from sync sep onward

[deezdrama]

Made a video of the process...

https://youtu.be/cUFdCbEcRZQ

[deezdrama]

Update....

This is a followup to the last video on the 20m2u, After fixing no power/protection state, faulty front panel board, and an arcing tube I lost vertical sync.... Ive had the sync seperator IC chip in hand for a while but wasnt confident that was the issue untill reading about sync seperator chip being faulty could cause horizontal distortion along with rolling.....both issues I was experiencing so went ahead and replaced the sync chip along with surrounding capacitors. so now the whole deflection side of the board has new caps.

Still didnt correct the issue. OSD bounces and still have horizontal distortion and vertical rolling.

back to the drawing board. Guess ill try vertical IC's next. Probably just a film cap or something stupid that I have no idea how to find. Maybe its time to get a scope.

https://youtu.be/0EEp3wBwioc

[jd213]

A scope might not be required, when I had horz deflection problems with my OEV 143, MKL was able to help me find the bad film cap by measuring resistance from ground to anodes/cathodes and other points on the board: viewtopic.php?p=1482563#p1482563

Not sure if that will be applicable in your case, or how exactly one determines which points to measure, though... Tried searching for guides that show similar techniques but didn't find anything.

[deezdrama]

A scope might not be required, when I had horz deflection problems with my OEV 143, MKL was able to help me find the bad film cap by measuring resistance from ground to anodes/cathodes and other points on the board: viewtopic.php?p=1482563#p1482563

Not sure if that will be applicable in your case, or how exactly one determines which points to measure, though... Tried searching for guides that show similar techniques but didn't find anything.

Thats awesome that he was able to guide you through that. So it ended up being a film cap in the pincushion circuit or what circuits film cap was the issue?
I tried throwing my esr meter on a few film caps the other day but they gave really high esr/ohm readings in circuit.
I wonder if I could use the esr meter to find a faulty film cap by looking for one with really low esr in circuit.

[tongshadow]

I would look for low capacitance, always lift one leg from the circuit board if you get weird readings.

[jd213]

A scope might not be required, when I had horz deflection problems with my OEV 143, MKL was able to help me find the bad film cap by measuring resistance from ground to anodes/cathodes and other points on the board: viewtopic.php?p=1482563#p1482563

Not sure if that will be applicable in your case, or how exactly one determines which points to measure, though... Tried searching for guides that show similar techniques but didn't find anything.

Thats awesome that he was able to guide you through that. So it ended up being a film cap in the pincushion circuit or what circuits film cap was the issue?

I can't find it in the circuit diagrams on the PVM-M2MD_Service_Manual, but it's in section D9 on the A board. Perhaps not coincidentally, it's one of the few components that is marked as "critical for safety" on the parts list.

[deezdrama]

A scope might not be required, when I had horz deflection problems with my OEV 143, MKL was able to help me find the bad film cap by measuring resistance from ground to anodes/cathodes and other points on the board: viewtopic.php?p=1482563#p1482563

Not sure if that will be applicable in your case, or how exactly one determines which points to measure, though... Tried searching for guides that show similar techniques but didn't find anything.

Thats awesome that he was able to guide you through that. So it ended up being a film cap in the pincushion circuit or what circuits film cap was the issue?

I can't find it in the circuit diagrams on the PVM-M2MD_Service_Manual, but it's in section D9 on the A board. Perhaps not coincidentally, it's one of the few components that is marked as "critical for safety" on the parts list.

And your monitor was the medical 14m2 variant? Your image stretched horizontally?
Mine stretched right before it started rolling. Probably not the same thing but guess I could check.

[jd213]

It's an OEV 143, but the parts/boards seem to match those in the PVM-M2MD_Service_Manual more closely than any other manual. AFAIK there isn't a service manual specific to the OEV 143/203 on the net.