Pioneer Kuro PDP-LX5090 buzzing and crackling

[tn245]

Hi there. I'm working on a PDP-LX5090. It's otherwise working perfectly but while on and displaying anything on screen it makes a fairly loud buzz, louder than the normal plasma buzz, and quite audible from viewing distance while watching. When just turned on it also makes a slight crackling sound like static electricity I think coming from around the edges of the panel.

The buzz sound itself seems to come from the power supply or at least in that region of the panel. It is more audible from the back of the TV.

A video of the sound:
https://photos.app.goo.gl/Hw67z0S0MmPgRR9U2

I have another working PDP-LX5090 and I have tried swapping the PSUs and the buzz remains in the original panel and does not transfer with the PSU.

I have also tried turning down VOL_SUS and ABL as mentioned by tom66 in another thread on a KRP-500 that was making zapping noises but this only had a slight effect on the noise.

Any suggestions or thoughts?

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

I've tried to narrow down the source of the buzz. It seems to be mainly around L701/T702 which appear to supply vsus. Vsus voltage is 212V which is almost the same as the other 5090 I have open. The other TV has the same buzz but just not as aggressive and no crackling sounds. I also tried swapping X drive and Y drive boards as well as mentioned the PSU between them with no change.

[zomi]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Have you had it dormant for a while then used ?
I saw this in a set where it hadnt been used for a year and it showed this crackling
But once its been on for a few mins its gone, also had a slightly louder buzz too..

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

You're right. It has been dormant for a while. That might explain the crackling I guess (although the one I'm comparing it to has also been sitting about the same amount of time). The previous owner got rid of it because he complained the buzzing had got too noisy and thought there must be a fault with it.

Interestingly this morning when I went back to it I noticed something strange. I've got the two TVs side by side and suddenly the previously good one was the noisier one now and the other one was quieter. I must have not been paying close enough attention after yesterday's board swapping, but after further testing the X drive board seems to be the culprit. Swapping the X drives around does indeed move the buzz between the TVs, although the crackling stays with the original noisy one.

[zomi]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

The crackling only lasts first few mins its turned on ?
then it works fine ?

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

That's right. I'm not too worried about the crackling sound - just thought it might be related but now I'm thinking it isn't. Going to check out the caps on the x drive next.

[tom66]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Crackling is caused by VSUS being set too high - check service menu setting. Max voltage around 215V.

Buzzing is a problem on the normal mode, but Energy Save Mode 2 seems to reduce it.

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Thanks Tom. Vsus is 212V. VOL_SUS is 128 in service menu setting. It was already set on Mode 2 energy save. Interestingly the quieter TV had energy save set to off.

Any idea why swapping the xdrive board would affect the buzz?

[tom66]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Could be due to the resonance adjustment being off. I've had a Kuro that had a pink tint due to resonance issues. You can adjust these settings in the service menu (in fact, there's very little you can't adjust.)

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Could be due to the resonance adjustment being off. I've had a Kuro that had a pink tint due to resonance issues. You can adjust these settings in the service menu (in fact, there's very little you can't adjust.)

Wouldn't service menu settings be stored on the main board though? So it wouldn't travel with the xdrive board when swapped between TVs.

There are some adjustment pots on the xdrive board for VKOFS1_ADJ, VKOFS2_ADJ and SUS_B_ADJ. Could these be out? There are test points for VKOFS1 and 2 but not sure where to measure for SUS_B.

[tom66]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

It's stored in the control board - but different X-mains could have differing resonant parameters, it's determined by the value/quantity of inductors and capacitors in a certain position of the circuit.

Do not adjust the pots on any of the boards, you need to do all of the adjustment through the service menu.

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

It's stored in the control board - but different X-mains could have differing resonant parameters, it's determined by the value/quantity of inductors and capacitors in a certain position of the circuit.

Do not adjust the pots on any of the boards, you need to do all of the adjustment through the service menu.

That makes sense. I will stick to tweaking in the service menu to see if I can reduce the noise. Thanks so much for your help. Hopefully last thing: would you mind saying which of the settings are for resonance adjustment? I have adjusted for pink tint on another Kuro by adjusting VOL RST P and VOL YKNOFS settings but I'm not sure which would be for the resonance adjustments you mention.

[tom66]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

That makes sense. I will stick to tweaking in the service menu to see if I can reduce the noise. Thanks so much for your help. Hopefully last thing: would you mind saying which of the settings are for resonance adjustment? I have adjusted for pink tint on another Kuro by adjusting VOL RST P and VOL YKNOFS settings but I'm not sure which would be for the resonance adjustments you mention.

I can't remember exactly what settings it was, do you have a list of the settings? I think it was something like XRES and YRES but I can't be sure.

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

There's a list of settings here:
https://www.avforums.com/threads/pio...tings.1753414/

Panel-1 ADJ

VOL SUS =
VOL OFFSET =
VOL RST P =
VOL XPOFS1 =
VOL XPOFS2 =
VOL YKNOFS1D =
VOL YKNOFS3D =
VOL YKNOFS4D =
VOL YKNOFSAD =

RESET1ST_KSB =
RESET2ND_KSB =
YSTIL_1SF_KSB =
YSTIL_1SF_HZ =
XSUS_1ST_B =
XSUS_2ND_B =
XSUS_3RD_B =
YSUS_B =
XSUS_B =
YSTL_KSB =
YSTL_HZ =
YSTL_2SF_KSB =
YSTL_2SF_HZ =
YSTL_FMR_KSB =
SCAN ADR SADJ =
SUS FREQ =

Panel-2 ADJ

R-HIGH =
G-HIGH =
B-HIGH =
R-LOW =
G-LOW =
B-LOW =

ABL =

Panel Function

R-LEVEL =
G-LEVEL =
B-LEVEL =

Address L1 =
Address L2 =
Address L3 =
Address L4 =
Address U1 =
Address U2 =
Address U3 =
Address U4 =

STK Mode =
FULL BLACK =

Panel RX =
Panel RY =
Panel GX =
Panel GY =
Panel BX =
Panel BY =

CLS R =
CLS G =
CLS B =

[zomi]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Whats the easiest way to access service menu on the 5090 ?

[Relayer]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Hello tn245,
It is possible that what you may be hearing is transformer lamination buzz.
In my CRT TV repair days, I came across several sets that had their switching transformers buzzing. I fixed them by soaking the tranny into a can of clear varnish for a day, ensuring total submersion. Removed it and allowed it to dry solid. Re-installed it and the buzz was totally gone.
I used to get the same problems with deflection yokes as well, but that's another story.
Regards,
Relayer

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Whats the easiest way to access service menu on the 5090 ?

I'm using a usb to RS232 adapter connected to the service port and sending the command FAY to get into service menu.

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

Hello tn245,
It is possible that what you may be hearing is transformer lamination buzz.
In my CRT TV repair days, I came across several sets that had their switching transformers buzzing. I fixed them by soaking the tranny into a can of clear varnish for a day, ensuring total submersion. Removed it and allowed it to dry solid. Re-installed it and the buzz was totally gone.
I used to get the same problems with deflection yokes as well, but that's another story.
Regards,
Relayer

Thanks Relayer. I was considering this but as I mentioned I swapped the psu board around from another same model but quiet TV and the noise stayed with the TV and did not transfer to the other TV with the psu board. My conclusion is something else is putting more demand on the psu making it buzz louder.

[tn245]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

I just found this on another forum:

Tip:
if you have problems with buzzing/Screaming transistors on a Full white field
try to change Y/XSUS_B a few steps up or down.
even if the field is clean you can have them wrong set.
you should get no buzzing or high pitch rattling noise when you have set them perfectly.

Although it says buzzing transistors rather than transformers interestingly. Anyway, I guess these are the settings you were talking about tom66. I will give this a go.

[tom66]

Re: Pioneer Kuro PDP-LX5090 buzzing and crackling

It's the inductors that buzz and yes it's the YSUS_B and XSUS_B that I adjusted. Let us know. Make sure to adjust slowly.