Need help DCLCD 19" LCD Monitor - I already replaced caps

[Tayninh55]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Hello, I was having problems with this same board. I had the 2 seconds to black problem. Followed the threads until they came to a "screeching halt"! I then decided to check out my board. I was trying to check the voltage at the filter capacitor,,,,when I slipped,,,and shorted something out. I saw a "puff of smoke come up between the two disc capacitors and the transformer beside the filter capacitor. Couldn't visually see any problem with either of the components but evidently there is. Everything went black, instead of 2 seconds to black,,,,,it's all black. No power light at all. Got new caps to replace the filter cap, and the starter cap, put them in,,,,,,and still nothing at all. Tried to find a voltage (165v) at filter cap,,,,but nothing there. The disc caps don't look burned, and can't see anything "melted" on the transformer, but not sure how to check them.

[Tayninh55]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Hi, I followed this post all the way thru,,,,,hoping that someone came up with the answer. I thought that surely, DJM_PHX, would let us know what happened after all of his testing,,,,,,,,,,then,,,,,,,,,,,,nothing???????

[TPettenati]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Just joined and wanted to say thanks for the great info. My DCLCD DCL9A+ recently failed to power on. I have the same power supply board as shown in post #172. Replaced all 10 caps as listed by Don P in post #179. Up and running again. This is an excellent fix for under 10 bucks!

TP

[petesvilla]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Hi again, sorry for the delayed response.
It turns out after more testing that the inverter is working OK and so are all the tubes. I think it's reasonable to assume then that either the logic board or LCD screen itself has a fault.
Iwas given the monitor for spares anyway and so I 'think I'll put it on the junk pile in the garage!
Many thanks for the help though.

Next job is to try to find an EDID file for a Viewsonic VP930.....................

Regards,

Pete

[alexanna]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

If this is the power supply I think it is it is notorious for having some very small transistors short, causing a very fast flash of the backlights and the display being very dim.
Pictures?? top and bottom of the power supply

[petesvilla]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Thanks for the swift reply
The monitor is a Gericom S1902D which uses the LM004 PSU. It had the usual short flash / blinking green light problem.
I did a full recap of the board (except for the audio coupling caps) and it duly burst into life and worked fine for about 20 minutes. Then the screen became a bit darker over a large part of but not all of its area. I rechecked the PSU and to my horror I'd fitted the 10uf 10v cap in the wrong way round
(This is what happens when you're tired but want to finish the job befoere going to bed)
I noticed on another thread that there should probably be some 12v going to the logic board but I can't find any on the connector. I suppose a circuit diagram would be the best thing to have but can't find one anywhere on the net.
Any ideas please?

Pete

[alexanna]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Unless you are lucky enough for someone finishing up a repair on one of these, you might be waiting awhile.
I have had my fair share of these apart, and the majority were able to be repaired, but I did not record any voltages.
It may help if you would describe the type of problems you are experiencing with your monitor, as there are some fairly common failures.
It's always good to have detailed photos of what you are working on. When you post photos, the managed attachments feature is preferred by several members that actively try to help in the monitor forum

[petesvilla]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Hi folks, I just found this forum so hope I'm posting in the right place!

Regarding the LM004 rev3 power supply, could some kind soul possibly give me a list of the voltages found on the connector from the psu to the logic board please? (on a correctly working model)

Cheers,

Pete

[Don P]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Ok, I am pleased to report that my parts did come in this afternoon, and that I now have a functional monitor again!!!!!!!!!

Thank You to Everyone that helped !!!!!!!!!!!!!!!!!!!!!

[PlainBill]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Excellent, although the having the right spacing between the leads will make it a bit easier. at this point, I would guess it's ok to place the order?

Thanks Again..

Yes. One final point on ordering from DigiKey - specify USPS First Class Mail shipping. Postage for your order will run under $3.00 and it will typically arrive in two days.

PlainBill

[Don P]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Excellent, although the having the right spacing between the leads will make it a bit easier. at this point, I would guess it's ok to place the order?

Thanks Again..

[PlainBill]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

One point that should be made - it's not necessary the replacements match the original dimensions. The only criteria is they must fit in the available space.

If originals were 15 mm in diameter and 20 mm high, 12.5mm x 25mm would be acceptable IF you had enough height.

PlainBill

[Don P]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Yikes !!!!!!!!!!!!!! Thank You !!!!!!!!!! I had the wrong stuff.. my 10 & 220 uF were ok, but you hit the caps right on the head!!!!!!! my 1000 & 470 were both the wrong size....10x20 on both sets...

Now my updated order list looks like this....

5 220uF/25V P12383-ND EEU-FM1E221
2 470uF/35V P12415-ND EEU-FM1V471
2 1000uF/16V P12366-ND EEU-FM1C102
1 10uF/50V P11250-ND EEU-FC1H100


Nice catch... I once again bow to the geniuses...

[alexanna]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Could you also measure the capacitor sizes, along with the volt and UF values?

The diameter and height of the capacitors are a critical measurements,They need to fit where you want them to go.
Example #7 and #8 look to be 12.5MMx20MM.Or 10mmx20mm?
#9 looks like 10mmx20MM.

[Don P]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

As requested, I removed the caps and have them listed for verification. Ok, here's what I have for info. I'm posting a new picture, with number labels above each cap. first number is picture label, second is ps board part# third is capacitance fourth is voltage....

1 C33 220uF 25V
2 C72 220uF 25V
3 C14 220uF 25V
4 C13 470uF 35V
5 C11 470uF 35V
6 C33 220uF 25V
7 C12 1000uF 16V
8 C12 1000uF 16V
9 C33 220uF 25V
10 C7 10uF 50V

First column is quantity, 2nd is capacitance/voltage third is digilink part # fourth is panasonic #

5 220uF/25V P12383-ND EEU-FM1E221
2 470uF/35V P14440-ND EEU-FR1V471L
2 1000uF/16V P14398-ND EEU-FR1C102
1 10uF/50V P11250-ND EEU-FC1H100

Once again, Thank You for your time, consideration, and great technical advice!

Don

[PlainBill]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Thank You both for your input on this... guess it's time to break out the soldering iron and see what I need... and where to find them... I think I saw a link somewhere here that recommended a good place to find them. I can solder, but to be truthful, I'm really appreciating your knowledge, especially in the area of good/marginal caps...

I agree with everything alexanna said.

I FINALLY took a look at your profile, and learned you are in the USA. My preferred supplier is DigiKey. Here is a link to a procedure for locating suitable caps.

I suggest selecting suitable replacements, then posting the list here BEFORE you place the order. Someone here will verify your selections seem to be correct.

PlainBill

[Don P]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Thank You both for your input on this... guess it's time to break out the soldering iron and see what I need... and where to find them... I think I saw a link somewhere here that recommended a good place to find them. I can solder, but to be truthful, I'm really appreciating your knowledge, especially in the area of good/marginal caps...

[PlainBill]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Sorry about that.... here are 2 pictures. One of the signal board, the other is the bottom of the power supply board. I don't know why it won't let me load the third one, I'll post the top of the power supply in the next post...

Sometimes the site is just obnoxious. I'll give you a C+ on the pictures - grading on the curve, of course. A couple of things are apparent.

1. You have at least two bad caps. One has obviously vented.

2. The monitor was built with Capxon caps.

Capxon caps aren't the worst possible caps, but they aren't far from it. I suggest replacing all 10 of the electrolytic caps (with the exception of the large one) with Panasonic FM or FR series caps. There is a good chance that is all it will take to repair the monitor. You may be able to dig the values from this thread. Double check that against the actual capacitors in your monitor.

PlainBill

[alexanna]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

You power supply looks like it's of a newer design.
You have some budging capacitors just above the large transformer with the yellow tape on it.
Replace all the capacitors with the exception of the really big on.
I have to warn you there is the possibility of damage to the logic or signal board from low voltage, but it's worth a shot to replace the capacitors.

[Don P]

Re: Need help DCLCD 19" LCD Monitor - I already replaced caps

Here is the top of the power supply board...