ViewSonic VP201b

[jankro]

Re: ViewSonic VP201b

It seems that after a few days of working fine, the original fault has returned and it seems to come and go.
Here's some video of it in action:
http://www.youtube.com/watch?v=azFRo8uhad0

After I filmed this, it returned to normal and has been working fine for a couple of hours now.

-Jan

[jankro]

Re: ViewSonic VP201b

Hello to everyone, since this is my first post on this forum!

I just received a malfunctioning VP201b and the original owner claimed that the picture rolled from top to bottom.
However, when I unpacked it, it functioned perfectly, hmm...
Since I have been reading a lot about the bad caps in Viewsonics, I decided to take a look inside.
It looked like someone had been there before me, but I removed the power supply to measure the ESR on caps. I found that they were fine, BUT the main 400v cap was totally broken off from is soldering on + side and same thing on one of the legs on a power transistor, other that these probs, it seem to function perfectly.

-Jan

[EGuevarae]

Re: ViewSonic VP201b

Exactly!!

PlainBill

[PlainBill]

Re: ViewSonic VP201b

You read my mind ...

Exactly!!

PlainBill

[EGuevarae]

Re: ViewSonic VP201b

Go into the menu and select D-Sub as your default input?

PlainBill

You read my mind ...

[PlainBill]

Re: ViewSonic VP201b

I Also Repaired Inverter Replacing A Fuse, But I Must Press Button 2 Down On The Screen So That It Gets The D-sub Signal. Everytime I Turn It Off It Starts Checking For Dvi-d, Like It Doesn´t Detects Signal, It Goes To Standby Or Orange Led State(it Goes To Sleep). So I Press The 2 Button And It Detects The Vga Signal And The Image Appears. Does Someone Knows How To Solve This Issue?

Go into the menu and select D-Sub as your default input?

PlainBill

[dcast11]

Re: ViewSonic VP201b

I Also Repaired Inverter Replacing A Fuse, But I Must Press Button 2 Down On The Screen So That It Gets The D-sub Signal. Everytime I Turn It Off It Starts Checking For Dvi-d, Like It Doesn´t Detects Signal, It Goes To Standby Or Orange Led State(it Goes To Sleep). So I Press The 2 Button And It Detects The Vga Signal And The Image Appears. Does Someone Knows How To Solve This Issue?

[EGuevarae]

Re: ViewSonic VP201b

can't seem to edit my post.. but, i was able to buy a mini ceramic 2A fuse at Radioshack part # 270-0005.

I used the wick as a wire (don't have any braided wire) wrapped around the fuse ends, the other end grabbed the board surface really nicely, isolated with electric tape and off i go!

Pics?

[PolishPaul]

Re: ViewSonic VP201b

can't seem to edit my post.. but, i was able to buy a mini ceramic 2A fuse at Radioshack part # 270-0005.

I used the wick as a wire (don't have any braided wire) wrapped around the fuse ends, the other end grabbed the board surface really nicely, isolated with electric tape and off i go!

[PolishPaul]

Re: ViewSonic VP201b

i saw the part #, but how did you decipher what it is? I'm trying to figure out how to obtain such info when fixing consumer electronics.

[EGuevarae]

Re: ViewSonic VP201b

Excellent thread!

My Viewsonic vp201b went dark one night. I love this monitor, its very nice so i had to save it. What was rough is taking it apart - besides the screws, all you need to do is pry the edge with your (long) nails.

Long story short, my left fuse on the inverter was bad. I just unsoldered/popped it off and jumped it with a sliver of 'soldering wick'. Which BTW you can use to unsolder things - get it at your local Radioshack.

Anyhow, put it together and bam it works. This thread showed me the fuses and it was right on. Thanks so much! I'll probably do the 'external' fuse solution some how. Important thing is that it works!

QUESTION however... How do you know the component number? Where can one get schematics for these things? I'm not expert, but I'm sure i can follow a schematic...

Oh and any advice on a surface solder? The used wick sliver grabbed the surface really nice.. how would you do a good surface connection?

See post #16 for part number. And normally you can't get schematics (for most of the units). Oh, and welcome to the forums.

[PolishPaul]

Re: ViewSonic VP201b

Excellent thread!

My Viewsonic vp201b went dark one night. I love this monitor, its very nice so i had to save it. What was rough is taking it apart - besides the screws, all you need to do is pry the edge with your (long) nails.

Long story short, my left fuse on the inverter was bad. I just unsoldered/popped it off and jumped it with a sliver of 'soldering wick'. Which BTW you can use to unsolder things - get it at your local Radioshack.

Anyhow, put it together and bam it works. This thread showed me the fuses and it was right on. Thanks so much! I'll probably do the 'external' fuse solution some how. Important thing is that it works!

QUESTION however... How do you know the component number? Where can one get schematics for these things? I'm not expert, but I'm sure i can follow a schematic...

Oh and any advice on a surface solder? The used wick sliver grabbed the surface really nice.. how would you do a good surface connection?

[dantm]

Re: ViewSonic VP201b

Now that you guys have had great success with these fixes, can you advise a poor man (me! :-) at:

https://www.badcaps.net/forum/showthread.php?t=7038

Thank you!

[EGuevarae]

Re: ViewSonic VP201b

suspended on red wires. I never said it was pretty...but it works!

[Thornapple]

Re: ViewSonic VP201b

Thought I'd come back to post my VP201b success story.

I got some solderable fuses and replacement caps. I chickened out of replacing the caps as the new ones were quite a bit bigger than the existing caps. I soldered the one fuse that was definitely faulty. It's the thing weirdly suspended on red wires. I never said it was pretty...

https://www.badcaps.net/forum/attach...id=10099&stc=1

...but it works!

https://www.badcaps.net/forum/attach...id=10100&stc=1

This LCD screen cost me about £550 three and a bit years ago, whatever that is or was in US Dollars. I'm not sure what is most gratifying, the £550 or the raspberry to Viewsonic who have failed to coerce me into buying another screen.

Thanks everyone for this moral victory!

[EGuevarae]

Re: ViewSonic VP201b

c. They are the same. I would form the leads so you can solder the Picofuse to the ends of the original fuse. It doesn't meet Mil-Spec, so you'll never be able to use the monitor on a warship, but I doubt you will lose any sleep over that.

[Thornapple]

Re: ViewSonic VP201b

Thanks Plainbill, I will certainly change the capacitors. Unfortunately I don't think Chip Quik is available over here so I'll have to do without it.

TC

[PlainBill]

Re: ViewSonic VP201b

I was almost ready to give up on my VP201b, but then I found Badcaps and this thread!

The display on my VP201b blanked suddenly leaving just the green LED lit. Following this thread, I have found that one of the tiny fuses on the inverter has blown. Other diagnostics:
i) the power supply board is outputting 18V so I think the PSU is OK.
ii) I have tested the two electrolytics on the inverter ('Rubycon', 220uF 35V). One is OK, the other is over 10 times the expected value (2.6mF). That's tested in-circuit though.

So it might just be a question of changing the blown fuse. The one mentioned in the thread (576-0429002.wrm) is only available from USA (Mouser) and I will have to pay £12 postage (UK pounds). That's OK, but I'd like to be as sure as possible I won't need any other parts; if I have to go back to Mouser a second time that's another £12 (plus what Customs & Excise slaps on). So are there any other basic tests I can do? In particular, could someone explain Eguevarae's test in non-technical terms; I mean 'Check also if voltage is reaching the inverter (from ground to a fuse you should get a V reading)'. I'm not sure what is 'ground' and which side of the fuse he means.

A few more questions:

a) Do these tiny fuses snap out like domestic fuses or are they soldered in?
b) If the latter, can I just solder the new one on top of the old one (unsoldering things is horrible)
c) One of the posts mentions 'picofuses'. Are these the same as 'Pico Fuses' available over here, i.e. fuses with axial leads? Would these need to be soldered in? Would I have to drill holes through the PCB??
d) I think I might have some 2A 20mm glass fuses, maybe even quick blow. To test if the fuse is the only problem I might be able to connect one of these across the blown fuse using small croc clips and switch on...or would this be suicidal?

TC

In less technical terms, measure the voltage from the negative output of the power supply or any of the screws used to hold a board in place to each side of the fuse (or fuses) in question. If you read the same voltage as the power supply output (18 Volts in this case) to each side of the fuse, the fuse is good. If you don't read 18 volts to either side, the problem is elsewhere. If you read it to only one side, the fuse is bad. I STRONGLY urge you to replace both capacitors on the inverter board. One is certainly bad, the other may follow.

Answers to other questions:

a. Soldered in

b. Yes. But at some time check out a product called Chip-Quik. It makes desoldering easier.

c. They are the same. I would form the leads so you can solder the Picofuse to the ends of the original fuse. It doesn't meet Mil-Spec, so you'll never be able to use the monitor on a warship, but I doubt you will lose any sleep over that.

d. That is a valid way of testing.

PlainBill

[Thornapple]

Re: ViewSonic VP201b

I was almost ready to give up on my VP201b, but then I found Badcaps and this thread!

The display on my VP201b blanked suddenly leaving just the green LED lit. Following this thread, I have found that one of the tiny fuses on the inverter has blown. Other diagnostics:
i) the power supply board is outputting 18V so I think the PSU is OK.
ii) I have tested the two electrolytics on the inverter ('Rubycon', 220uF 35V). One is OK, the other is over 10 times the expected value (2.6mF). That's tested in-circuit though.

So it might just be a question of changing the blown fuse. The one mentioned in the thread (576-0429002.wrm) is only available from USA (Mouser) and I will have to pay £12 postage (UK pounds). That's OK, but I'd like to be as sure as possible I won't need any other parts; if I have to go back to Mouser a second time that's another £12 (plus what Customs & Excise slaps on). So are there any other basic tests I can do? In particular, could someone explain Eguevarae's test in non-technical terms; I mean 'Check also if voltage is reaching the inverter (from ground to a fuse you should get a V reading)'. I'm not sure what is 'ground' and which side of the fuse he means.

A few more questions:

a) Do these tiny fuses snap out like domestic fuses or are they soldered in?
b) If the latter, can I just solder the new one on top of the old one (unsoldering things is horrible)
c) One of the posts mentions 'picofuses'. Are these the same as 'Pico Fuses' available over here, i.e. fuses with axial leads? Would these need to be soldered in? Would I have to drill holes through the PCB??
d) I think I might have some 2A 20mm glass fuses, maybe even quick blow. To test if the fuse is the only problem I might be able to connect one of these across the blown fuse using small croc clips and switch on...or would this be suicidal?

TC

[olenac]

Re: ViewSonic VP201b

Hi Guys:

Thanks for the feedback. I test the board again and found that diode in position D602 in the bottom of the video board was shorted. I replaced that with a spare board I have but still the same problem. I have a voltage in this diode of 2.43 which is the input for IC601 and IC603. There is some output voltage from this 2 Ic`s but I don't know if they are ok. If any one knows the value of this diode in order to buy a replacement please advice. I notice that this board is making some noise near to IC401 but is very difficult to find from were exactly. Attached some pictures of this video board.

I will appreciate all the help you can bring in order to fix this LCD.