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The PVM-2730QM thread (H-STAT issue, colour bleed, convergence and more!)


buttersoft

Question

This thread started about a single issue, but is devolving into a more general thread about PVM-2730's, so I changed the title. These are basically the same as the KX27HG1 and KX27HG2 sets (powersupplies are swappable but may not be identical) along with the Japanese Profeel sets that look the same. They are close cousins of the US PVM-2530's and possibly the PVM-2550's. Different revisions have S-Video, and the US versions have a DB25 plug instead of SCART. The Japanese sets may use JP21. The service manual for the 2530 shows it to be a bit different inside, with a ton of tiny extra circuit boards and different layout. Still a lot of commonalities though, but it will pay to note these differences and check the schematics before touching anything.

 

Hi all,

 

I have a KX27HG1 (same thing as a PVM-2730) with a CRT fault. It powers up when cold, and then after twenty minutes, or even longer if it's freezing in the garage, there's a click (normally) and the screen shuts down. The picture folds in like the screen has been powered down, but the rest of the set still works - indicator lights, sound, etc. If I power-cycle, the tube powers up again for maybe a second, and then goes down. If I wait 10-20 seconds and power up again, the picture comes up for a few seconds, but the colours are bleeding sideways, particularly red. Then the CRT loses power again.

 

There's definitely a buzzing sound the whole time the picture is up, and it's not as stable as it should be at 240p, and the brightness flickers slightly. There's a click sometimes as it powers down that might be coming from the HVT/flyback, or might be something nearby.

 

Also, the "Screen" adjustment, on the neckboard of this set, doesn't seem to do a lot, mostly just messes with colour gain, but no huge brightness adjust or retrace lines appearing.

 

I just recapped the electroyltics in the power supply, and the same thing still happens. Any ideas where to go next? I've found replacement flybacks online, I think, but I'm not 100% on that being the problem.

 

Help greatly appreciated!

Edited by buttersoft
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Hi,

 

I'm having a problem with my 2730QM when playing Gamecube games.

On some elements on the screen i'm getting a kind of ghosting effect (see attached picture).

 

This seems only to happen in 480i content like the Gamecube (50Hz and 60Hz).

When my SNES is plugged in, I don't see this problem.

 

I already changed all capacitors of the D1-,D2- and C-board.

 

Does someone have a clue, what i could try to fix this problem?

 

IMG_2890.jpg

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@Pahnda i'm not sure i can see any ghosting - can you post a better pic? Unless you'referring to the colour misalignment in the white border of Kirby's pic - the horizontal separation of R/G/B - that would be a convergence issue. The convergence setup is described in the service manual for these sets, but as they age the adjustments might not go quite far enough. Try the H-stat first, and make sure to take photos of the position of any pots on the D2 convergence board before you start fiddling!

 

Most of all, remember that you need to know how to be safe when playing with a live CRT!

 

Otherwise, a better pic might help, but ghosting isn't always a simple issue to sort out.

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I'm trying to do a better picture later today. I'm speaking about the eyes and the left contour of kirby. You can see a kind of shade of the eyes of kirby very lightly right next to the real eyes. The same happend with the left contour of kirbys body. This effekt is more present in the left side of the screen. I will post some more pictures to show the effect a bit better.
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Ahhh, yup, ok. Hmmm, it's definitely signal reflection, but after telling you to check your cables, it's not easy to diagnose. If you're on a pal GC, using RGB, where did the cables come from, and do they match the required spec perfectly? Do other consoles show the same symptoms at 480i or 240p? An even longer shot is going to be whether the 75R terminations are in place on the SCART socket - which they will be, but it won't hurt to check.
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I also have a Sony PVM 2130qm here, with this PVM I got no problems at all using the same pal GC with the same cable. I only hooked up my SNES and PS1 and didn't noticed a signal reflection. I think i will test my ps2 which should also do 480i if I'm right. Are the 75R terminations sitting in the female SCART socket in the TV or on the input board of the PVM?
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I also have a Sony PVM 2130qm here, with this PVM I got no problems at all using the same pal GC with the same cable. I only hooked up my SNES and PS1 and didn't noticed a signal reflection. I think i will test my ps2 which should also do 480i if I'm right. Are the 75R terminations sitting in the female SCART socket in the TV or on the input board of the PVM?

 

The 75R terminations are the first components inside the PVM for the R, G & B lines - at least according to the service manual. If other consoles are working fine and don't get reflection whether at 240p or 480i, the terminations will be fine. Assuming other consoles at 480i are fine...

 

 

TBH i think it's going to be the PVM-2730 aging. If you really want to you can try fiddling with the cable though. If you look at the gamecube SCART cable in Viletim's schematics (linked in my previous post) there's an extra termination resistor for the composite video/sync line, placed before the 220uF cap. The termination in the TV comes after that. Any chance you could open your SCART cable head and see if that resistor is there? If it is, try removing it (as long as you're confident you can reconnect without damaging the cable.). If it's not there, try adding it.

 

Even better, add a 200R pot and dial it around. Probably won't do much, but you never know.

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I just remembered that i have a original GC-Scart kable in my basement. So i hooked it up and no more signal reflection, perfect picture. I opened the other scart cable and there is no 22uF cap nor a 75R resistor. It's kinda wierd that i have no problems on my smaller 2130qm however. Well i will fix my cable now and check if the 75R terminations are fine in the PVM, the next time i open it.

Thank you very much for your help =)!

I might come up with other problems with my PVM 2730 :D

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It is slightly weird that the 2130 doesn't show reflection when it's meant to take 75R video. High quality arcade monitors don't normally care, but the PVM should.

 

Still, I'm glad I was wrong and it was the cable :)

Edited by buttersoft
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I soldered the 220uF cap and the 75R resistor into the syncline of the GC cable. It works finde now, thanks again for you help!

 

However I still have a problem with my PVM 2730QM.

The problem is:

 

When the PVM is cold and I start it up, everything is fine, I can adjust V-SIZE that the picture fits the screen and even overscan the image.

In the first 1-5 minutes, I notice some flickering in the horizontal size and vertical size, like someone is playing a bit with the V-SIZE and H-SIZE potis.

This effect becomes becomes less the longe the PVM runs.

However, the longe the PVM runs, the smaller the vertical size of the picture gets. In the first 10 minutes, you can easily adjust this effect with the V-SIZE poti.

But there is a point, when the picture kinda rolls up in the upper section of the screen, when you adjust the V-SIZE too much (see picture 1).

PICTURE1: IMG_2967.jpg

After about 20 minutes, I need to shrink the image verticaly using V-SIZE, so that on the upper an lower end is about a 2cm black bar. If i would adjust the V-SIZE too much, the image would roll up again.

This means, that i can't fit the whole screen vertically anymore without rolling up the image.

In this state however, i can use the PVM all day long. When i power it off and let it cool down a few hours, everything starts from beginning.

The mentioned syntoms above, happen with 240p PAL signals and 240p NTSC signals.

 

When I send a 240p NTSC signal to the PVM, the longer the PVM runs the more the very upper end of the image begins to warp to the right (see picture 2).

IMG_2968.jpg

I think this effect is somehow connected to the other problem with the vertical size, as it is also depending on how long the PVM runs.

When I send in 480i NTSC signal, in the upper end of the image the picture kinda gets split up. Seems like that every second drawn image is warped (see picture 3).

480i PAL signal is perfect without any issues.

IMG_2973.jpg

 

So to some it up, i think there is some problem in the vertical deflection circuit. As it is getting worse over time when the PVM gets warmer, I think there might be a faulty part which is teperature depending (maybe a transistor).

What i already did:

1. Change all elec caps on the D,D2 and neckboard.

2. Changed all transistors in the V-SIZE circuit.

 

I didn't touched the power supply board yet, but i measured the voltage inputs on the D and D2 board.

The low voltage (12V and 16V is fine) but the higher voltages are a bit low, on 40V i get 36V and on 140V i get 130V.

I'm about to test now if the voltage drops over time.

 

Could faulty caps on the power supply produce such symptomps?

Or maybe the transistors on the power supply?

Has anyone an advice, where to look or what to check regarding this problem?

Thank you very much.

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b+ needs to be spot on and when it is the other voltages from the PSU will also be correct but there are probably other things. This monitor is quite old now and needs a full revision.
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Thank you very much for the advice with the b+, i set it exactly to 140V and problem 1 is gone now (picture1). There is no more rolling up of the picture.

However the problem (picture 2 and 3) still persist.

Any advice where to check for the NTSC problem? I geometry adjustings for NTSC won't help with this.

I got a better picture showing the problem with 240p NTSC signals.

IMG_2981.jpg

Edited by Pahnda
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There's a distortion correct pot on the D-board accessible from the back, which will probably affect this. That and the H-sync pot are the ones to try first. Be aware that adjusting for one image at NSTC 480i will affect how 288p PAL images display, perhaps negatively. You can always wind the pots back, of course. Just don't presume if you fix it for one image the rest will be ok.

 

To me, these sets really feel like they were designed with PAL resolutions in mind. For one, I find that a 480i PC image has the same number of physical lines as a 240p one, or very close to. Some lines would seem to be drawing right on top of others, and there's big 240p-sized gaps. Switch to 576@50i and the gaps between lines are gone, the detail all comes back and the image is absolutely incredible. I realise there are more lines each frame or field in a 576@50i image than a 480@60i one, and that's not what i'm seeing. I like running anything 3D in 800x600i for that reason.

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There's a distortion correct pot on the D-board accessible from the back, which will probably affect this. That and the H-sync pot are the ones to try first. Be aware that adjusting for one image at NSTC 480i will affect how 288p PAL images display, perhaps negatively. You can always wind the pots back, of course. Just don't presume if you fix it for one image the rest will be ok.

 

To me, these sets really feel like they were designed with PAL resolutions in mind. For one, I find that a 480i PC image has the same number of physical lines as a 240p one, or very close to. Some lines would seem to be drawing right on top of others, and there's big 240p-sized gaps. Switch to 576@50i and the gaps between lines are gone, the detail all comes back and the image is absolutely incredible. I realise there are more lines each frame or field in a 576@50i image than a 480@60i one, and that's not what i'm seeing. I like running anything 3D in 800x600i for that reason.

 

Hello again,

thank you so much for your help! The Potis for H frequence did it! I found a sweet spot at which PAL and NTSC is fine. However I think it is impossible to get a perfect geometry on PAl and NTSC. Finally i got a fully working 2730 😁👍. I think i need to find a new PVM i can tinker with.

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Hi,

it‘s me again with another problem on a PVM 2730.

So i now have 2x 2730s. I recapped one last year and the other one today. After the recap i noticed on both, that when I adjust the Hsize potentiometer, the Pinamp also changes.

See the short video on youtube:

https://youtu.be/_IyDTqBp3N4

 

Last year I thought it was normal and lived with it as I normaly only adjust the Hsize once.

However when the same happend to my other 2730 after recapping, something I thought it could be right. Unfortunately I could quite remember if this also happened before the recap... but I don‘t think so.

 

I would be really thankful if someone could tell me if this is normal. And if it‘s not, where to look for.

I changed each Cap on the D D2 D3 and C board one by one and always checked the capacity and voltage. I sometimes used higher voltage ratings in the hope that the caps last longer, but capacity was always like the old caps.

 

I think I need to look between the Hsize poti and the connection between D3 and D. But I‘m not quite sure what to loom for or what to meassure. I don‘t know how a part could get broken during the recap... and also why does it happen on both of my 2730. Might be a mistake I made twice, but I really don‘t know what could have gone wrong.

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hello everyone, it's amazing but I'm in the same situation as buttersoft exactly at the beginning of his adventure! If I had found this discussion before, I would certainly have saved a lot of time even if I still had doubts. In practice I have two 2730qm units one of these suddenly loses the video signal while the monitor remains on sometimes it returns with phase shifted colors in particular the red wich bleed to the right exchanging the deflection boards I then isolated the two-component problem The flyback or rather the resistor assy or that damned red box, I had serious difficulties in detaching the anode cup because totally different from the one common so I risked damaging the tube itself! The tripler or H stat or resistor assy does not seem damaged externally I wonder if is possible to repair it because there is no spare part on the market :( the rest thanks to buttersoft I can fix it!

 

 

 

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I would guess it will not be possible to repair the H-Stat (red block/resistor assembly). It's cast into resin. How do you know it's damaged? Assuming your PVM-2730 has the same problems as mine, like you can read in this thread, if the H-stat is failing, you should be getting shutdown due to HV protection. The colour bleed does not seem to be related to the H-stat but to that failing resistor on the neckboard.

 

If the H-Stat is faulty or leaking HV, the one thing you might try is to run the set in the dark, with the back cover off, and see if you can see any corona around the H-Stat. It shouldn't be a spark, but maybe a faint glow as the H-stat leaks HV into the shielding over the back of the tube. If this is occurring, see if you can narrow down exactly where from, and try to cover the H-Stat block in HVR silicone, perhaps.

 

If this doesn't work, and you need a new H-Stat, you might try calling down Soyl's attention. Type an "@" symbol in front of his name and he'll get a message. He's a CRT guru who lives in Italy, I believe. Sony parts 1-230-712-21, 1-230-712-22 or 1-230-712-23 are suitable H-stats for this set.

 

And sorry to @Pahnda because i don't know the answer to that problem. But no, it's doesn't happen on mine. The pimamp does not noticeably change when i change H-size.

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Ok really thank you for the clarifications and your valuable advice I go ahead with the replacement r702 that I have already tested and it is out of specification and I hope to solve in the meantime I replace the electrolytics on the neck board. I have one last question, swapping the pieces between a monitor and the other now I find one with Corona under the anode cap problem that was not present before, I checked there is no loss of high voltage outside but there is something which fries under the anode cup and yet I cleaned the whole area well before inserting it. I noticed that at some point you also had this problem, may I know how you solved it? may I know even if there is a correct way to extract the anode cap without risk of damaging anything?

 

Finally do you think it would be possible to replace the rubber suction cup together with the "shatter hook" inside it with something more conventional? I have often done on some flybacks of the Aero city nanao chassis and everything went perfectly but here the situation seems different ... I must say that the tubes of these monitors seem indestructible mine are in perfect condition have a contrast and a white level absolutely impeccable despite age a real shame that many spare parts are no longer on the market.

 

 

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You must not replace the rubber cup and shatter hook! This set uses a coax HV lead between the H-stat and the anode button, and if you take a look at the hook assembly itself you will see there's a tiny pad right in the middle that connects to the delicate little spring in the middle of the anode button. This anode button has two connections - one to the main ring around the outside (the two main hooks) and one to that spring that feeds back into the potentiometer in the H-stat - it's shown in the service manual. This feedback is linked to how the set controls horizontal static convergence, so it's really important.

 

I would first try cleaning the anode cup again, using something like isopropyl alcohol, but also cleaning the tube around the anode button and the button itself (be careful of the little spring in the anode button!)

 

If this doesn't work perfectly, try obtaining some high-dielectric silicone grease (most online electronics retailers will stock some, or you can use spark-plug grease from any auto parts store) and coating the rim under the the rubber anode cup (but not the anode button itself, obviously).

 

Hopefully this post helps?

 

And yes, the tubes in these do seem to last well :)

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I'm in the same situation as buttersoft exactly at the beginning of his adventure! [...] In practice I have two 2730qm units one of these suddenly loses the video signal while the monitor remains on sometimes it returns with phase shifted colors in particular the red wich bleed to the right

 

Is it really the same problem? From a quick read the issue in the beginning of this thread is high voltage shut down (caused not by an actually excessive EHT but by a defective voltage divider in the red box that was sending out a reference voltage high enough to trigger the x-ray protection in the uPC1377C). Your description ("loses video signal while the monitor remains on") doesn't clarify if the EHT was lost or not.

 

exchanging the deflection boards I then isolated the two-component problem The flyback or rather the resistor assy or that damned red box

 

Did you swap only the boards or also the flybacks and/or the red boxes? If you only swapped the boards I don't see how you can say the issue is caused by the flyback or the red box. If the issue wasn't cleared by only swapping the red box i don't see how you can say that you have isolated the problem to the red box. And when I read your next post it seems to me that the problem has not been isolated at all:

 

I go ahead with the replacement r702 that I have already tested and it is out of specification and I hope to solve in the meantime I replace the electrolytics on the neck board.

 

Again, unless the issue was cleared by swapping the red box assembly, you may be barking at the wrong tree.

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Yes, i totally forgot to write down that it almost sounded like a faulty connection or cold solder joint somewhere, in regard to losing signal while the monitor is staying on. Though if resistor R702 is failing open intermittently that wont help.
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I can only say thanks for all the infos and expecially to you Buttersoft, the monitor is fixed no more loose the signal (black screen) and returning with no convergence. This is what i have done:

disassembled the power board and rebuilded lots of solder joints, most of them were 100% dried out! found two caps 2200uf 25V leaking then replaced all big caps eccept the big filter one, replaced r702 (this resistor fixed 100% the convergence issues), now the monitor stay on for hours without any issue eccept the top right corner wich have a little discoloration issue and I want try to fix with magnet strips. I have also replaced the Flyback with one different sony code: 1-439-339-12 uselessly, although I found out that this works as well as the original, I have then reinstalled the original one.

 

Edited again... I forgot the most important I have replaced on both set two caps all with esr fully out of spec (on the first monitor) those are both on the neck board one 22uf 250v (this one 100% out of spec in capacitance and esr) and another one 220uf 16v

 

The second 2730qm set was arching just under the anode cup no HV release outside so I got some ringing artifact at start up (like snowy interfer) and this was from I have swapped the h.stat boxes between the two sets, I cleaned all again apply some shinetsu dielectric greese and placed the anode cap in another position no more arching but believe me I am afraid only to think of having to remove and put back this type of shatter hook and not for the high tension but because I think it is very delicate if you do not know the right method to "unhook" you can easily ruin the h stat or even the tube button and I still am not sure I can do it correctly nor have I understood the meaning of the hieroglyph printed on the anode cap.

By the way this set is absolutely awesome , sharp and vibrant colors plus perfect geometry! on this one I have not replaced a single cap (eccetp the two on neck board) but I want inspect the power board and clean well all inside. I'm sure that the anode cap was just not fully in place, it has never happened to me before with other monitors!

[TABLE=class: vi-centerclass, width: 0]

[TR]

[TD] [/TD]

[/TR]

[/TABLE]

 

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