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 Post subject: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Tue Oct 02, 2018 5:36 am 



Joined: 04 Nov 2013
Posts: 41
Noticed this when I ran a game, which only runs at 60Hz with my MSX2+. Some games let the bios set the refresh rate, but this dioes not. As a result the picture is very sharp, but it "wobbles" a bit on the lower side of the screen. This is clearly due to the game being at 60Hz. Games, that either run or let themselves being run on 50Hz are wobble free. I have tested with both RGBs and RGB as both are available as separate inputs on the Sony (BKM-25P). Same result.

As my unit is the "e"-model, it's sold in Europe region originally (50Hz psu). I've understood that RGB is "international" in the way, that it works everywhere. Is there a reason/way to fix the wobbling? :/

Sorry, I'm no technician here :(


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Tue Oct 02, 2018 10:16 pm 



Joined: 30 Jul 2017
Posts: 83
Location: UK
My 20F1E also had bad vertical shaking. I recapped the deflection board and no change, then I recapped the video module and there is now no shaking or wobble whatsoever.


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Tue Oct 02, 2018 10:23 pm 


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Joined: 18 Oct 2015
Posts: 786
Sefirosu789 wrote:
My 20F1E also had bad vertical shaking. I recapped the deflection board and no change, then I recapped the video module and there is now no shaking or wobble whatsoever.

by video module, I assume you mean the card with the RGB inputs?


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Wed Oct 03, 2018 7:15 am 



Joined: 04 Nov 2013
Posts: 41
Quote:
My 20F1E also had bad vertical shaking. I recapped the deflection board and no change, then I recapped the video module and there is now no shaking or wobble whatsoever.


Ok, thanks for this :) My unit only has this with 60Hz sources... 50Hz is perfect. Also the wobbling with 60hz in on two different input cards/modules (BKM-25P and the default BKM-28X). Does this mean anything? I really cannot recap the unit myself, so I'd need really exact info what to recap (if any) :/

*edit*

I may have forgotten an important factor here... The problematic MSX2+ is hooked to the Sony via Sync Strike (LMM1881 sync stripper), which obviously cleans the sync signal. I just realised I have no clue if the Sync Strike accepts 60hz? thereason for the MSX2+ to be connected via SS is that the sync level (CSYNC) of the Philips is too high (has been originally also...). Without the SS the Sony goes mental :D

I'll do some more testing.


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Wed Oct 03, 2018 12:45 pm 



Joined: 30 Jul 2017
Posts: 83
Location: UK
AndehX wrote:
by video module, I assume you mean the card with the RGB inputs?


Correct. The video/BK board which I believe has "analog" written on it when you look from the back of the monitor.

emuola wrote:
Ok, thanks for this :) My unit only has this with 60Hz sources... 50Hz is perfect. Also the wobbling with 60hz in on two different input cards/modules (BKM-25P and the default BKM-28X). Does this mean anything? I really cannot recap the unit myself, so I'd need really exact info what to recap (if any) :/

*edit*

I may have forgotten an important factor here... The problematic MSX2+ is hooked to the Sony via Sync Strike (LMM1881 sync stripper), which obviously cleans the sync signal. I just realised I have no clue if the Sync Strike accepts 60hz? thereason for the MSX2+ to be connected via SS is that the sync level (CSYNC) of the Philips is too high (has been originally also...). Without the SS the Sony goes mental :D

I'll do some more testing.


Just because it also happens with the 25P and 28X doesn't mean that it isn't the BK board. The BK board is the "master video board" and affects all the others. edit for clarification: BK board = video module

Is it only happening with that console at 60hz, or all?

Here's mine before and after:
Hopefully these are viewable
Both were 240p. After the re-cap there was next to no shaking, even before calibration. This monitor also has high amount of hours at 90,000 and now it's just as good as 4000-6000 hour monitors I've owned
.
https://imgur.com/JO4PUkV
https://imgur.com/AAWJasU


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Wed Oct 03, 2018 5:21 pm 



Joined: 04 Nov 2013
Posts: 41
Thanks for the info, I really appreciate it :) Here's my best shot (literally...) on the problem. The wobbling can only be seen, if you record it at 60Hz. Tried with a Olympus pro camera on a tripod at 30fps -> no go. This was shot with iPhone 6 at 60Hz holding the phone on the tripod. The wobbling isn't quite as evident as in real life, but it's there.

https://drive.google.com/open?id=0B5aJT ... 03NmprSGMw

Tested with Core Grafx (Japan) that runs at 60Hz, same story... So, it has something to do with the refresh rate. All 50Hz sources are really good. I have to remind you and me also, that in EU our psu:s are 50Hz. Can this difference be the reason for this?

Sorry, I'm no pro here regarding electronics.

All the best,

-Olli


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Fri Jan 18, 2019 6:49 am 



Joined: 04 Nov 2013
Posts: 41
*UPDATE*

Now both the deflection board and the video module have been recapped. Unfortunately 60Hz still has the slight wobble while 50Hz is perfect :/

Can it be something I've overlooked? I'm still wondering the psu (50Hz vs. 60Hz). Like I said I'm not a pro regarding electronics so I'm just trying to hit something in the dark.


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Fri Jan 18, 2019 6:17 pm 



Joined: 30 Jul 2017
Posts: 83
Location: UK
emuola wrote:
*UPDATE*

Now both the deflection board and the video module have been recapped. Unfortunately 60Hz still has the slight wobble while 50Hz is perfect :/

Can it be something I've overlooked? I'm still wondering the psu (50Hz vs. 60Hz). Like I said I'm not a pro regarding electronics so I'm just trying to hit something in the dark.


Recapping the video module fixed it for me entirely.

It could be the power board or a power problem. You could try and recap that, I guess.


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Sun Nov 15, 2020 3:59 pm 



Joined: 01 Apr 2020
Posts: 4
Has anybody been able to come to a conclusion on the exact root cause of this wobbling ?


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Sun Jun 06, 2021 8:34 am 


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Joined: 04 Oct 2020
Posts: 22
Location: London
Had this issue on a PVM 20L4. I recapped the whole monitor entirely and it reduced the wobble only a little.
I noticed that turning the "contrast" down a bit (it was maxed out) helped massively.


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Tue Jun 08, 2021 6:16 am 



Joined: 08 Jun 2021
Posts: 1
Steps to consider when facing issue in which 4K resolutions (either 4096x2160 or 3840x2160) are only possible at 30hz refresh rate rather than 60hz.


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Sat Jun 12, 2021 10:15 pm 


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Joined: 04 Oct 2020
Posts: 22
Location: London
Have you checked in the maintenance menu for the E board, there should be a few settings related to AFC (automatic frequency control). It might be worth tweaking them to see if it helps?


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Sun Jun 13, 2021 3:13 am 



Joined: 01 Apr 2020
Posts: 4
Thanks for the suggestion. It does not appear that the maintenance menu offers more than the standard menu, the only option available is « AFC TIME » which can be either set to slow or fast.
None of these two settings seem to affect the very light wobble I can observe on test patterns.
Is there another setting related to AFC I overlooked?


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 Post subject: Re: BVM20F1E and RGB with 60Hz: slight wobble
PostPosted: Sun Jun 13, 2021 6:28 am 


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Joined: 04 May 2015
Posts: 34
Location: Japan
This could be completely unrelated, but when I moved to Tokyo (50Hz mains), I brought my 120V 60Hz North American CRT with me and noticed some wobble when used here. I suspected it was because of the mains frequency which proved to be right as when I removed the de-guass coil it all went away. Of course I wanted the de-guass coil so I bought a 12v meanwell PSU and wired that into a North American DC-AC inverter which then produced 60Hz AC. Problem solved after that. Try removing the de-guass coil and see if it goes away.


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