ViewSonic VP201b

[SteveVK]

Re: ViewSonic VP201b

Hi Guys

I need some help please. I have a VP201 that has (mostly) stopped working.

The fault is as following. There is no output on the screen with any input mode aside from about 1 second post power on. In the one second the monitor is fine, the back light is even, colours are correct and the OSD works. And I clearly have a green power LED on the front.

Here is what I have done so far.

About one year ago the large cap in the switchmode was replaced as it was smelling and sounding dead.

Since the new fault has occured. I have retested the output of the PSU and it is okay both in and out of curcuit. I have fed 18V from an external power supply also. I think the PSU is okay.

I have tested the the fuses on the inverter board and they are both okay. I have also replaced the two electros on the the inverter board, one was 220uF and the other 200uF, both in spec.

Any ideas where to look next?

Many thanks
Steve

[Bobdee]

Re: ViewSonic VP201b

You seemed to have left out testing CCFLs, I know you said the B/light was even but dont be fooled by that, best to check them

[SteveVK]

Re: ViewSonic VP201b

Okay, what is the best way to test them please? And will they all be "out"

Thanks

Steve

[Bobdee]

Re: ViewSonic VP201b

Hello
It only takes one failing tube for the Inverter to be shut down

Several ways to check them, one is open up screen and visibly inspect and test (NOT recommended)
Connect another panel with B/lights known to be working
Some members use a comp case mod kit that can test CCFLs with inverter and test inverter with CCFLs (2 at a time)
And one or two have used spare working tubes
I think the best would be the mod kit

Doubt very much that they are all failing,probably one or a pair

[lucky13]

Re: ViewSonic VP201b

VP201 is not known to have bad lamp.

Most of the time is the inverter board. YMMV.

Do what Bobdee suggest and swap in known good lamp(s).

I keep a good lamp (pair) ripped out from a cracked panel for testing. I swap in one light at a time to eliminate lamp problem quickly.

[SteveVK]

Re: ViewSonic VP201b

When I look at the board (inverter) I have six transformers (chokes) forming six outputs. Is there a pair of ccfl per output?

Steve

[Bobdee]

Re: ViewSonic VP201b

Steve
It will be 6 tubes in there not 6 pairs
Hold my hands up, never been in one with 6 tubes so I dont know how they are set out in there or paired off on the inverter (come back in lucky13 please)

[SteveVK]

Re: ViewSonic VP201b

Thanks Bobdee and Lucky13

I dont have a old panel to take ccfls from nor do I have another working VP201 to use to test. So I guess I am faced with a "mod kit" or buying a couple of replacement ccfls for my monitor.

What would you recommend at this stage.. the mod kit? If it is this option, what do I look for when I am purchasing, is there any voltage/current ranges etc?

Many thanks yet again!

Steve

[Bobdee]

Re: ViewSonic VP201b

Hello Steve
I personally have not owned one, like lucky13 I have access to spare tubes and screens
This is the type of mod kit that they use there are plenty more on ebay
http://cgi.ebay.co.uk/Akasa-Red-Cold...d=p3286.c0.m14
Not 100% sure this is suitable but maybe another member can recommend one to you
ANY HELP OUT THERE ON MOD KITS FOR STEVE PLEASE

[EGuevarae]

Re: ViewSonic VP201b

Hello Steve
I personally have not owned one, like lucky13 I have access to spare tubes and screens
This is the type of mod kit that they use there are plenty more on ebay
http://cgi.ebay.co.uk/Akasa-Red-Cold...d=p3286.c0.m14
Not 100% sure this is suitable but maybe another member can recommend one to you
ANY HELP OUT THERE ON MOD KITS FOR STEVE PLEASE

That's almost like the one i use. I just replaced the output connectors with ones from a dead 700P monitor.

[SteveVK]

Re: ViewSonic VP201b

I have ordered one, with luck it will be with me on Monday.

I will keep you posted, thank you!

S

[EGuevarae]

Re: ViewSonic VP201b

I have ordered one, with luck it will be with me on Monday.

I will keep you posted, thank you!

S

Check this thread for a sample of the use of the kit I mentioned.

[SteveVK]

Re: ViewSonic VP201b

Hi guys

Well I have now got two ccfl tubes and an inverter to test with. I have tested a working new tube once for each of the outputs on the inverter board and have found no change. Am I now assume the inverter board is faulty or do I need to test each tube in the monitor with the inverter from the case light kit I purchased. I guess what I am asking is it often that two tubes could be faulty?

Thanks loads.
Steve

[EGuevarae]

Re: ViewSonic VP201b

Hi guys

Well I have now got two ccfl tubes and an inverter to test with. I have tested a working new tube once for each of the outputs on the inverter board and have found no change. Am I now assume the inverter board is faulty or do I need to test each tube in the monitor with the inverter from the case light kit I purchased. I guess what I am asking is it often that two tubes could be faulty?

Thanks loads.
Steve

Test each tube with the inverter you have. A single tube in a set of 4 (or in your case, six) can shut down an inverter. If the tubes are shot, I might have a screen (broken) with good CCFLs. Let me see around here ......

[SteveVK]

Re: ViewSonic VP201b

Hi Guys

Well i have fianlly had 15 mins to test this. Two CCFL tubes are "down" my invert board is okay. Good news I think.

I am going to be in the US for a few weeks for work, any suggestions on where to buy the replacements?

Huge thanks for the all the help.
Steve

[PolishPaul]

Re: ViewSonic VP201b

Welp, a bit late but... I finally got around to posting the pictures of my repair job when replacing the fuse. Its not the prettiest thing but it works. The pics don't show the electric tape which secures the wire wick.

The pics may not be in order... but should be able to help out someone trying to disassemble this thing

[Bobdee]

Re: ViewSonic VP201b

Hello PolishPaul
In the last picture of the top row it looks as if there is clearly 2 domed caps on the p/supply board
You will need to put up a top down picture of that board for better help
As for the fuse I not saying nothing LOL

[PolishPaul]

Re: ViewSonic VP201b

what makes you say they're doomed? I'm nowhere near that monitor now so i won't be posting any new pics - the thing works fine however.

As for the fuse... I had no other choice (no decent merchants) and I only had about a week or so before going overseas. Hey.. it works Using the wick for the surface solder worked better than i though.

[Bobdee]

Re: ViewSonic VP201b

what makes you say they're doomed? I'm nowhere near that monitor now so i won't be posting any new pics - the thing works fine however.

As for the fuse... I had no other choice (no decent merchants) and I only had about a week or so before going overseas. Hey.. it works Using the wick for the surface solder worked better than i though.

Domed not Doomed (not flat on top) a sign of failed or failing caps
As for fuse I cetainly never meant any offence

[Bobdee]

Re: ViewSonic VP201b

sorry double post