Re: ViewSonic VP201b
lol.. dOmed... I don't believe they were... And no offense taken whatsoever
lol.. dOmed... I don't believe they were... And no offense taken whatsoever
-
-
Re: ViewSonic VP201b
Good evening gents... my USB ports aren't supplying power. I suspect a fuse is out for the hub. My computer is recognizing the monitor when I plug it in... but it is not sending juice to the 4 USB ports. Is this fuse easily replaceable... I searched through the images in this thread and it didn't stand out.
Also, I found a service manual online for anyone that is interested:
Comment
-
Re: ViewSonic VP201b
Check IC955; that appears to be the voltage regulator for the USB section.Originally posted by pixelvisions
PlainBillFor a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.
Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.Comment
-
Re: ViewSonic VP201b
Nice find. Thanks for sharing. This one does have schematics for the p/s too!Originally posted by pixelvisions
You should check that 6-wire connector to see if your 5v is there to the USB board or not.Comment
-
Re: ViewSonic VP201b
If you back up a little bit on that FTP address, there are many other service manuals for other Viewsonics too:
http://ftpkuban.com/FTP/Manual/ViewSonic/
-JanComment
-
Re: ViewSonic VP201b
I got another VP201b to play around with. It had some problems when picture was very bright it starts to flicker.
I checked the power and inverter caps, they were file, then I started to check the main board SMD caps and some were 2-10 times the ESR what they are supposed to be.
Has anyone replaced these main board caps?
-JanComment
-
Re: ViewSonic VP201b
I am probably showing my ignorance here, but is it possible to get an accurate reading of one smd cap still on the board?
Al.Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!
Comment
-
Re: ViewSonic VP201b
That is a very good question. I was wondering that too. I know that "normal" electrolytics can be measured reliably while in ircuit, but I'm not sure about SMD's.
Well the second VP201b had a bad inverter (fuses and caps fine). Backlight flashed briefly at startup so I replaced the inverter and it seems to be fine now. Ihad a spare inverter from my first VP201 from which I borrowed the panel to fix a vertical striped Dell 2001FP (the vertical stripe is caused by defective panel).
-JanLast edited by jankro; 07-07-2010, 09:46 AM.Comment
-
Re: ViewSonic VP201b
Initial things to check on that bad inverter board are the transistors or the transformers...Comment
-
Re: ViewSonic VP201b
Just wanted to thank you all on this thread for your assistance diagnosing & fixing my problem.
My display cut out suddenly one evening - green LED, but no display. If I was lucky, on power on I'd get a slight flicker in the display.
I followed the service manual instructions for this, leading to an inverter failure diagnosis.
Testing inverter fuses, I found one had blown, which I replaced with a glass fuse and holder from Maplin (UK electronics store):
10x 20mm 2A Quick Blow glass fuses: GG26D
1x PCB fuse holder with cover: KU29G
Attached photo is of new fuse holder & fuse. At this point, I had progress; I'd get a display for about 1s on power on, then the display would cut out as before.
Though they looked absolutely fine, I replaced both 220uF capacitors on the inverter board, again with kit from Maplin:
2x 220uF 35V 105C radial capacitors: N86KF
The solder holding the old caps onto the board wouldn't melt with my 40W iron, so I clipped off the old caps and joined the new cap leads onto the old cap leads (and thus the PCB). No photos of this I'm afraid.
This fixed it - happy days.
All in all, about £5 to fix a £600 monitor. Thanks again.
Service manuals:
Revision 1b: http://dl.dropbox.com/u/845142/Manua...b_%5BET%5D.pdf
Revision 1d: http://dl.dropbox.com/u/845142/Manua...1b-1_SM_1d.pdfAttached Filesif you find these attachements useful please consider making a small donation to the site
Comment
-
-
Re: ViewSonic VP201b
*** Second attempt ***
Four years since I visited this thread. I'm glad it's still here because I still have the VP201b but it has developed a problem. It flickers for 10 minutes before the lighting becomes even and even then it is prone to start flickering again at intervals.
I've taken some pictures of the innards and based on what I have read in this thread I have a notion what the problem is, but would like confirmation.
First, the inverter board:
The pic doesn't show the cap ends but they are flat [the monstrosity on red wires is a DIY fuse].
The centre board:
I can't see anything wrong there.
Finally, the power board:
Of the six caps visible four have flat ends, but the two at the top right (680uF 25V) appear to be bulging:
Closer up:
I would grateful if someone would cast an eye on those pics, especially the last two, and say what they think.Attached Filesif you find these attachements useful please consider making a small donation to the site
Comment
-
-
Re: ViewSonic VP201b
*** images not working on previous post....retrying......***Comment
-
Re: ViewSonic VP201b
Nice. They used Rubycons YXG capacitors, albeit the lower range for low ESR type. Kinda extremely rare to see quality capacitors on LCD monitors nowadays...
Those bulging and leaking Ltec capacitors has to be replaced. Looking at the proximity of the heatsinks, its not surprising to see those capacitors go bad easily. Try replacing them first.
Last edited by lexwalker; 06-07-2013, 11:04 AM.Comment
-
Re: ViewSonic VP201b
Thanks for the confirmation Lexwalker.
My next question is...how do I remove that board to change those two capacitors? I can see six disconnections that must be made, shown by the two yellow arrows:
The white plug is no problem. The five connections to the mains input socket are hopefully spade connectors and will come out with persuasion. But I can see a problem with the inflexible metal lugs (green arrows) holding the board down, and much worse, the curious tag thing marked by the red arrow. When I undo that screw I can't see any way I will be able to lift the board without cutting a slot in it to let the tag through. I can't even pivot the board upright (lifting the left hand side) because the mains socket will knock against the metal lugs immediately above and keep it down.Attached Filesif you find these attachements useful please consider making a small donation to the site
Comment
-
-
Re: ViewSonic VP201b
Do check the capacitor size when ordering, note the dimensions of the original capacitors (diameter x height x lead pitch). I used Panasonic FMs a lot (till ran out of stock in hand recently) but quite often due to space constraints on the board (since Panasonic FMs are much bigger) I revert to using Panasonic FR, Panasonic FK and Nichicon PS due to their smaller size.
Recommended capacitors...
- Panasonic FM, FR, FK, FC series
- Nichicon HE, PW, PS series
- Rubycon ZL, YX series
Those in bold are the ones I've used most often. Rarely used Rubycon though...
Last edited by lexwalker; 06-08-2013, 03:34 AM.Comment
-
Re: ViewSonic VP201b
Oops...spotted this just after sending the order. The place I've ordered from doesn't give dimensions, make or any picture. The only info is the temperature rating (105C). I'll have to wait and see what turns up. If they're no good I'll look elsewhere...not that we have much choice in UK.Do check the capacitor size when ordering, note the dimensions of the original capacitors (diameter x height x lead pitch). I used Panasonic FMs a lot (till ran out of stock in hand recently) but quite often due to space constraints on the board (since Panasonic FMs are much bigger) I revert to using Panasonic FR, Panasonic FK and Nichicon PS due to their smaller size.
Recommended capacitors...
- Panasonic FM, FR, FK, FC series
- Nichicon HE, PW, PS series
- Rubycon ZL, YX series
Those in bold are the ones I've used most often. Rarely used Rubycon though...Comment
-
Re: ViewSonic VP201b
Reporting back
The replacement caps may have been unbranded...
...and the soldering job may have lacked finesse....
...but it worked!
Thanks everyone
Attached Filesif you find these attachements useful please consider making a small donation to the site
Comment
-
-
--- begin sig file ---
If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.
We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.
Please do not post inline and offsite as they slow down the loading of pages.
--- end sig file ---Comment
-
Hello, I came here after finding some similar questions asked on other monitors and hope someone here can help me get an ancient Viewsonic VP230mp (23" 4:3 LCD) back to working condition.
First a little background, I have a background in computer and electrical engineering, and I'm smart enough to know I know nothing about LCD displays and how they work. For this topic I'm as green as they come.
When the display is turned on the viewsonic logo displays in the uppper left for 2 seconds then the screen goes black, the power LED is green (on) and when a computer is connected... -
My cheap crappy 1KW grid tie inverter (GTI) seems to keep blowing IGBTs. When I first got it, it had two failed IGBTs. It used four 60N100's (TO264). I bought 5 from a dubious source (fleabay) and replaced just the two that were dead. The GTI worked for almost two years but recently one of the two that I replaced failed. Since I had three spares, I replaced the dead one. Then a few weeks later it failed again. Weird. Well since I bought dubious China-sourced IGBTs from fleabay it could very well just be a mixture of fakes. I replaced it, but then a day later it failed again! I put in the last...Today, 12:34 PM
-
I just got this tv today and it appeared to have no backlight on. After taking off the rear cover and checking again in the dark I can see that MAYBE one quadrant is lit.. But still it's quite dim. I was going to check the LEDs with my tester, and I found LED 1 and LED 2 + pins on the wire from the inverter, but I couldn't identify a ground. Nonetheless I tried using a mounting screw on the inverter board and also the chassis as ground but regardless my tester reads 300 which is what it reads when there is no voltage draw.
I don't know how exactly to test the inverter itself. Is it... -
I have a tripp-lite aspint 3636vr inverter charger which blow some of mosfet transistors. I replaced them repaired also the driver circuit and tested but the mosfets burn again.
It work very well as inverter and also as charger if I let the rear switch in auto mode (inverter) and charger only(charging) but in auto when I connect the feed line 220V AC first time it pass ok to line and start charging the batteries but when I remove the feed line it pass to inverter mode and if I do it again the second time when passing from charging to inverter the Main transformer start making a...03-06-2023, 07:07 AM -
For some reason I'm just not going to let this 19" TV defeat me. I guess because I have a schematic to work from I feel like I'm oh so close.
History- while adding a turn-on circuit I let a small screw roll under the power board. Worked through all of that circuitry, probably replacing a MOSFET and PWM controller that were not bad but I was following the service manual. Finally figured out that the power supply is in working order when the inverter section (for the backlights) is disconnected. When the +12 supply to the inverter is disconnected the +12 and +5 will come up...
Comment