Moved-Viewsonic VG2021m Blue flashing PLED no image

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

I finally found the schematics...I have seen some references to eprom reset
for other models but not for 2021.

Your submission could not be processed because a security token was missing.

could not upload them!

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Converted from PDF tp JPG

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Hi Folks,

Well i tried every concievable combo of button pushing and holding with the power unplugged then holding and plugging etc etc...no change..not surprised, if it were that easy I would have contemplated shooting myself in the foot...

[PlainBill]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Hi Folks,

Well i tried every concievable combo of button pushing and holding with the power unplugged then holding and plugging etc etc...no change..not surprised, if it were that easy I would have contemplated shooting myself in the foot...

If you have good SMT desoldering skills (or ChipQuik), remove U7. That SHOULD be the chip that stores the settings data. If the monitor works, you have isolated the problem.

PlainBill

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Hmmmm
Well I could go that route however a few reasons will keep me from that.

1. I can jumper pin 1 and pin 4 (Ill have to verify which pin(s))
and clear it. I really dont think its that simple of a problem.

2. I have now invested 35$ in a new invt/power board, 15$ in caps,
13$ in a new chipquick set up, and couple of bucks for regulators.
The new signal board only cost 30 bucks and its local.
My fault as I started shotgunning before I came here but I really was
convinced this was a power board problem and with the buldging caps
as evidence I was confident that it was damaged.

3 If i had ANYTHING that showed life in this rig I would be happy.
I have a PLED that is on immediatly.
I don't need to even touch the power button.
That to me sounds like a short.
Also As I have stated U4 on the sig board is over heating and voltages are once again becoming irratic,
that too sounds like a short.
The inver/pwr board won't even give me backlights for even a second.
That sounds to me like it is not recieving the proper signal voltage for power up.
I am trying to figure out which pin of the 16 (or where ever)
is the one where this signal is supposed to be.
My schematic reading is crappy,
I'm blind in one eye and can't see out the of the other..Ha!
and this was always my sore spot during my illustrious career in the service.

Anywho if I could be sure this is only a vid signal PCB problem I would just go and get it,
but I dont want to throw any more major parts at it
unless I can be 'reasonably' sure thats what the problem is.
I am having fun diagnosing and conversing with knowledgable people
and getting the ole brain matter stimulated, however I would like to get back to my art/video work soon.
As are many folks I'm so broke I can barely pay attention
so buying a new lcd is not possible.(not till tax refund time anyway)

so if you folks can enlighten me as to which pin and the voltage the inv/pwr
pcb is looking for I would appreciate it...
or if you think I am way off target and could point me in a better direction
that too would be appreciated.

Good evening to ya

Joe

[PlainBill]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

OK, good luck.

PlainBill

[alexanna]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Like you suggest I think you have a short causing the U4 to heat up and causing unstable voltages,The new logic/signal board would probably be your best bet.
On the 16 pin connector bottom row the ENA pin voltage will go high when back lights are requested,You had called it EVA.
Do you have any schematics of the inverter/PS supply?It may tell us what voltage to expect to see.

[PlainBill]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Like you suggest I think you have a short causing the U4 to heat up and causing unstable voltages,The new logic/signal board would probably be your best bet.
On the 16 pin connector bottom row the ENA pin voltage will go high when back lights are requested,You had called it EVA.
Do you have any schematics of the inverter/PS supply?It may tell us what voltage to expect to see.

It's on the first page of the schematic Medlock provided. CN4, pin 15 on the signal card is the inverter On/Off control line. It's pulled high through a 10K resistor tied to the 3.3V rail on the signal card, and pulled to ground by a FET, Q2. Brightness has a similar arrangement.

PlainBill

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Morning everyone

ok today I briefly jumped U6's 3.2 volts to the EVA (thats the actual letters) pin and tada BACKLIGHTS!

So I am going to go ahead and get the board. I traced the short to the main chip on the signal PCB. I think I lost the PCB to the power annomaly we had recently, where we didn't lose power completely but we had a low voltage situation for about 2 hours. I had run around the house turning off all he surge protectors but forgot that the monitor was on a separate one all to itself.

I will return to update and to hopefully close out this thread. Thank you all for your help and I will be sure to come back if I need any help with other things. Also I will spread the word to others.

I have a samsung 46" LCD TV that went kuput last month. This model like many others from samsung was on a recall for....bad caps. Fixed for free. If this is something that you all were not aware of, I'll start a thread with the makes and models involved.

Thanks again and I will type ya soon.

Joe

PS i have a new 12m033 power inverter for sale ....LOL!

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Hiya Gang

a quick question while I wait for my board, due here today.

While working with the other power board and old signal board, (still trying to narrow down the short), I blew (or it blew) the 5 volt rail fuse on the pwr/invr pcb. I followed Alexannas link for the regulators and tried like heck to search that fuse package. I could not find it. Can you give some data on that SMD please. Its the one right off the 5v rail at the 16 pin connector marked with a 'W'.

Thanks

PS would like to add the PDF service manuals here but I keep getting a Security Token error.

[Rtech]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

A 'W' signifys 4Amp.

[alexanna]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Check this one out. don't pay attention to the F in the illustration.
http://search.digikey.com/scripts/Dk...206F400-2CT-ND

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Thanks for that info I ordered a few of them just to be sure.

So the video board arrived and the monitor is back in service.
However if by chance anyone who reads this and decides to order a signal
board, make sure you check all reference numbers not just the PCB hash
numbers.

For instance:
A190A2-A02-H-S1 Fits many different LCD models but not yours in particular.
There are other reference numbers on the board which will I dentify your
model. THis one is on a sticker that has a barcode on it with the numbers
19A2LSH000 this number identifys your particular model number.

This is important when dealing with plug n play type LCD's. It can send the
wrong info to the video adapter. Such as refresh and resolution maximums.
Also the Model number to a lesser extent.

Beats me to why they would use the same exact part numbers on the PCB's
Makes more sense to have individual numbers per model. Gets confusing when
the description of the part says it fits many more models than shown.
The prices vary also, thats where I got caught. One was 29$ and the other 35$. So of course I ordered the cheaper. BURNED myself. The guys where I
purchased it were cool about it and are going to exchange it for me.
However many places won't do that for a 'tinkerer' and not a legitimit service
tech.

All in all it was educational and will be sure to check Caps and check here for
info as other things come my way.

PS still cant upload the entire service manual in PDF form.

End Thread------

[PlainBill]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Think about it. Some firm buys 'unstuffed' pc boards that will be 'stuffed' with components to make signal cards. They supply signal cards that can be used to make monitors with anywhere from a 3 x 4 17" LCD panel to a 9 x 16 23" panel. An audio amplifier is optional. VGA is standard, a DVI connector is an extra cost option. They can support a wide range of LCD panels with varying resolutions.

Why on earth would they want to stock dozens of raw boards when they can stock only one? In particular, support of different panels and resolutions is handled in firmware. It may even be possible to load a base firmware on all finished boards and handle the customization at test!

PlainBill

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Right I get that part, but why not use the 'sticker' part number when selling these boards rather than the PCB part number alone and then just refer in the description what monitors they may fit.

Or in this case list just one monitor with a note that it may work on many others. Thier Catalog showed upteen listings of the same PCB part number
with the same picture and different prices.

In the manufactoring of it, what your saying makes perfect sense, but at the resale level, it leads to confusion. No where was there a reference to
the barcode number, just a list or a single reference to a model number.
It may well have been just this particular reseller that catalogs this way, I
made mention of the fact they don't list a version or barcode number
anywhere in the description. Also the OSD buttons were not working correctly. Number one was 2 and up and down were reversed etc etc,

Anyway it worked out, a learning experience all the way to the end.

Have a good evening

[PlainBill]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Right I get that part, but why not use the 'sticker' part number when selling these boards rather than the PCB part number alone and then just refer in the description what monitors they may fit.

Or in this case list just one monitor with a note that it may work on many others. Thier Catalog showed upteen listings of the same PCB part number
with the same picture and different prices.

In the manufactoring of it, what your saying makes perfect sense, but at the resale level, it leads to confusion. No where was there a reference to
the barcode number, just a list or a single reference to a model number.
It may well have been just this particular reseller that catalogs this way, I
made mention of the fact they don't list a version or barcode number
anywhere in the description. Also the OSD buttons were not working correctly. Number one was 2 and up and down were reversed etc etc,

Anyway it worked out, a learning experience all the way to the end.

Have a good evening

Welcome to the real world. I have worked for a number of companies, and I swear they go out of their way to make the numbering systems chaotic.

Perhaps the most outrageous was IBM. Of course, every PC board had the part number of the bare board. There was also an assembly number. And there was a FRU number - which in theory was a number which was used to order a replacement board - which might have completely different numbers than the failed board. To further drive everyone insane, in development each product was assigned a name. For example, a particular SCSI controller was a 'Spock'. But it wasn't used in the 'Enterprise' family of computers.

PlainBill

There is one primary reason the resellers use the board number - you can be sure all boards will have that number.

[Medlock]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

I guess this will be my final post.
Its been a few days and the monitor is working flawlessly.
I really like viewsonic products and before this one gave me
trouble it was well into its lifespan. I would have gotten away
with just the cap repair and the signal board. I ended up with a 'new'
power/inverter. I went with my repaired Pwr/invtr because it has the
superior components. Its output at the 12 and 5v rails were stronger
than the new. 11.87 / 4.93 vs 11.98 / 5.04, not allot, but if I had to
just look at the stats....
Anyway thanks for the help, it was well worth the money and time spent.

[commanderkeen]

Re: Moved-Viewsonic VG2021m Blue flashing PLED no image

Have you tried to download these schematics at http://www.eserviceinfo.com/download...c_VG2021m.html
ive found the first 2 files work but the last one was corrupt.