Viewsonic VA2010wb (High Pitch Squeal At Power On)

[RetroComputingGrotto]

I've got a monitor on my workbench at the moment that makes a high pitch squeal (that I cant hear as my ears are too old) when you power it on and lasts a couple of seconds before quitening and apparently it can be heard at regular intervals whilst on.

On opening up the monitor and looking at the PCB the usual suspects showed their heads so I have already replaced all the electrolytic capacitors.

The other issue that was reported with this monitor was the fact it took ages to start displaying anything after pressing the power button.



What component(s) might be causing the squealing noise then?

[momaka]

What component(s) might be causing the squealing noise then?

Just to make sure we are on the same page: are the squealing noise and slow picture startup issues still present after recapping the power supply?
Usually, it's bad caps like this in the PSU that would cause the high-pitched squealing noise (and also slow turn-on, as the PSU power-cycles until the caps heat up enough for their ESR to lower and then the PSU become stable.)

So if you haven't recapped the power supply already, then go ahead and do that first. Make sure to use good quality Japanese electrolytc capacitors, though. I've dealt with a similar FSP-built power supply like this in a "no name" 19" LCD monitor by the brand of "Wise Wing", and all I can tell you that it's not a very well-designed PSU. Mainly, it's how the output caps are put right above the secondary heatsink, which gets quite hot (65C with 25C Ta room) and slow-roasts the caps. Most LCD monitors also have terrible ventilation on the metal back cover for whatever reason, which adds to the problem.

Also, the caps on the main/video board could be going bad too, especially after being fed with bad power from the failed caps in the PSU. So give those a checkup too... or just simple replace them if they are know to be problematic brands/series.

For reference, below you'll find links to two monitors I recapped with similar FSP PSU boards. Actually, the Hanns-G HC194d uses the same exact PSU model as yours shown above, if I'm not mistaken.
https://www.badcaps.net/forum/troubl...monitor-repair
https://www.badcaps.net/forum/troubl...nitor-recapped

[RetroComputingGrotto]

Just to make sure we are on the same page: are the squealing noise and slow picture startup issues still present after recapping the power supply?
Usually, it's bad caps like this in the PSU that would cause the high-pitched squealing noise (and also slow turn-on, as the PSU power-cycles until the caps heat up enough for their ESR to lower and then the PSU become stable.)

So if you haven't recapped the power supply already, then go ahead and do that first. Make sure to use good quality Japanese electrolytc capacitors, though. I've dealt with a similar FSP-built power supply like this in a "no name" 19" LCD monitor by the brand of "Wise Wing", and all I can tell you that it's not a very well-designed PSU. Mainly, it's how the output caps are put right above the secondary heatsink, which gets quite hot (65C with 25C Ta room) and slow-roasts the caps. Most LCD monitors also have terrible ventilation on the metal back cover for whatever reason, which adds to the problem.

Also, the caps on the main/video board could be going bad too, especially after being fed with bad power from the failed caps in the PSU. So give those a checkup too... or just simple replace them if they are know to be problematic brands/series.

For reference, below you'll find links to two monitors I recapped with similar FSP PSU boards. Actually, the Hanns-G HC194d uses the same exact PSU model as yours shown above, if I'm not mistaken.
https://www.badcaps.net/forum/troubl...monitor-repair
https://www.badcaps.net/forum/troubl...nitor-recapped

In the past, replacing all the caps has got rid of any squealing noises like this, problem is my old ears couldnt hear it to begin with so I just assumed it had gone until 2 of my colleagues came in and heard it when I powered it on!

With regards to the slow picture startup, I've not actually seen this fault in action, every time I have turned the monitor on the picture has come up in what I would say is a normal amount of time, less than a second.

I'll check the daughter board with the VGA connector on it for caps and take it from there.

Thanks.

[RetroComputingGrotto]

Also, the caps on the main/video board could be going bad too, especially after being fed with bad power from the failed caps in the PSU. So give those a checkup too... or just simple replace them if they are know to be problematic brands/series.

Unlike other monitors I've seen that use this same power board, there arent any electrolytic caps I can check/replace on the video board:

[RetroComputingGrotto]

I've justd realised I've missed a tiny capacitor but it doesnt have a value on it:

C123 simply says TAICON 0643 (M) on it.

[RetroComputingGrotto]

I've had a look in my Spares and Repairs box and I had a duplicate power board so I have swapped them over and the squeal has gone so it must be the caps I used from CPC/RS Components not being good enough.

It's been on test for nearly 24 hours now and I've not heard/seen any issues so all good for now, just a shame I didnt manage to fix the original board.

[momaka]

I've justd realised I've missed a tiny capacitor but it doesnt have a value on it:

C123 simply says TAICON 0643 (M) on it.

It should have a value printed on it. Probably just hard to see.
Perhaps you should have read through my thread about the Hanns-G HC194d LCD monitor, I put the value of that cap there.
C123 = 50V, 22 uF.
This is the PSU's "startup" cap. It going bad can also cause a slow startup and the PSU to squeal. So always make sure to replace that one in PSUs.
Replace it on your "bad" PSU board, and see if that changes anything. If not, what cap brands and series did you end up using on your PSU board and where did you get them from?

Unlike other monitors I've seen that use this same power board, there arent any electrolytic caps I can check/replace on the video board:

Ah, but I see that there ARE caps on the video board.
The last picture you show in post #4 is of the T-con board. That's *not* the same as what people commonly refer to as the video/logic board. The video/logic board is the one that has the VGA connector on it. And I can just see a glimpse of it in the upper right corner of the 2nd picture in post #4.
All those small caps on the video/logic board can fail too, and sometimes that can also cause a no power or a slow-startup issue... or in rare cases, weird/erratic behavior of the monitor, including noisy and/or pixalated signal.

[Capacitorial]

Could it be the transformer on the PSU? I had one CCFL TFT that had a bad transforer that was way too damaged to function properly and the monitor backlight went off after a few seconds. The transformer was sqeeking too.

[RetroComputingGrotto]

Since changing the PSU board over for another one it's been working fine, we've been using it for around 8 hours a day for our pro-active network monitoring system and so far no issues with it.

Up until recently I've only had access to RS Components and CPC for ordering parts from but we've recently opened an account with Mouser UK so I can now buy from there too so hopefully now able to get the best brand of capacitors to rule out a component quality issue causing me issues.

The brands of capacitors I used in this repair were as follows:

Panasonic
Rubycon

The one that made the squeeling happen a lot less was this one: https://cpc.farnell.com/panasonic/ec...300?st=ca07300



I didnt have a 50V version in my stock so used this just to see if it fixed it or not.

It could well be the transformer but I dont have another one to swap it out with to find out.


Mouser seems to be a very widely used/trusted site that I see a lot of people ordering from, what brand(s) from there should I be buying?

[momaka]

The brands of capacitors I used in this repair were as follows:

Panasonic
Rubycon

Those are excellent brands - two of the top four Japanese brands. The other two are Nichicon and United Chemicon.
Of course, picking a good brand is only about 1/2 of the process. The other 1/2 is to pick a series based on the need/function of the circuit and make sure the caps can fit too. In the case of switchmode PSUs, you need low-ESR caps... so that generally leaves 85C-rated caps out of consideration, since these are only meant for low-frequency circuits. Of course, if you have nothing better, even 85C general purpose caps are better than any cap that's failed or failing.

The one that made the squeeling happen a lot less was this one: https://cpc.farnell.com/panasonic/ec...300?st=ca07300

I didnt have a 50V version in my stock so used this just to see if it fixed it or not.

Right, well, that's not a bad attempt. Even though Panasonic ECA is an 85C-rated general purpose series (and only rated for 2000 hours at that temperature), at least you used a higher-voltage -rated cap... which means the cap was physically bigger... which means it will have lower ESR and higher ripple current capability compared to a 50V cap with the same capacitance from the same (ECA) series. So that might have fixed the PSU if the original one was failed.

Mouser seems to be a very widely used/trusted site that I see a lot of people ordering from, what brand(s) from there should I be buying?

Same as always, anywhere : Rubycon, Panasonic, Nichicon, United Chemicon.
In the case of getting polymer caps, Kemet and Wurth should be OK too.

Could it be the transformer on the PSU? I had one CCFL TFT that had a bad transforer that was way too damaged to function properly and the monitor backlight went off after a few seconds. The transformer was sqeeking too.

The inverter transformers can indeed go bad occasionally. Typically, their secondary windings get shorted or open turns. The primary windings are relatively short piece of relatively thick wire, so the primary is extremely unlikely to go bad.
Now, as for the main transformer of the PSU - that one is also very unlikely to go bad, again, due to having very thick and short piece of wire for windings.