Two Samsung Monitors with same model # same caps that pop there top

[sam_sam_sam]

My boss ask me to look at two monitor with same model with the same power boards and video control board the same four caps that pop there tops

The blue LED power light was the only thing that would work or come on

So I open them up to see what had happen to them and this is what I found .....>

Two caps in the inverter part of the board
Two caps in the power supply part of the board

I ordered the caps to recap the board except the main power cap

The pic fuse that powers the inverter part of the board are blowen

All parts for both Monitors from Digikey $14.00 plus $5.80 for shipping

1000 uf @ 16 volts * pop top
820 uf @ 25 volts * pop top
330 uf @ 16 volts
47 uf @ 50 volts
10 uf @ 50 volts

I will post some photo later with model #

[tama4tama]

Re: Two Samsung Monitors with same model # same caps that pop there top

Go ahead and changer all the bad caps and the fuse and let us know the out came.
Good lucky.

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

I recap these two boards.......>

With the fuse for the inverter in place NO blue LED Light
With the fuse removed the blue LED lights on both boards
later to day or in next few days I post some photo of this board

[PlainBill]

Re: Two Samsung Monitors with same model # same caps that pop there top

I recap these two boards.......>

With the fuse for the inverter in place NO blue LED Light
With the fuse removed the blue LED lights on both boards
later to day or in next few days I post some photo of this board

There are shorted drivers (transistors, ICs) in the inverter.

PlainBill

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

Here are some photo of this board


The two small sim chip

Has a part # of STM8309

Where the two cap are for the inverter across both cap I have a short which trace back to the output of the STM8309 which is a dual mosfet

I found ten of the on Ebay for $18.00 and free shipping but from Hong Kong which will take about a month

PlainBill

Thanks for the info

I did not have time at work to check any thing else after changing the four caps
My boss told me to take them home and see what I could with them because a new one would cost $150.00 for this size

[Scenic]

Re: Two Samsung Monitors with same model # same caps that pop there top

Just curious.. What model monitor is it?
Might also help others to find this thread..

Also:
http://www.ebay.com/itm/320846018196
http://www.ebay.com/itm/390166221090

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

I put the model later on

Here is where I found 10@ $18.00

http://www.ebay.com/itm/150658624891...84.m1423.l2649


One note I did fix the two not so good soldiering joint that did not look so good

[Scenic]

Re: Two Samsung Monitors with same model # same caps that pop there top

Oops.. I forgot you had 2 monitors.. ignore the ebay links I posted

[mockingbird]

Re: Two Samsung Monitors with same model # same caps that pop there top

That looks like it came out of a Samsung 2053BW...

I just repaired one of those PSUs for like $5. That's not your PSU right? Someone already put Panasonic caps on that one. Mine had all Samwha. None of them were bloated, but after changing the caps, the screen worked perfectly (The symptom was that it was saying no input signal when connected).

[PlainBill]

Re: Two Samsung Monitors with same model # same caps that pop there top

The equivalent part is available from Digi-Key as either their part number SP8M5TBCT-ND ($1.30 ea) or SH8M5TB1CT-ND ($1.77 ea). They have different package designations, I'm not clear on the difference. I suspect either would work, but suggest calling Digi-Key to get an expert opinion. Specify USPS First class shipping. And both should be replaced on each monitor.

One other point - your communications skills leave a little to be desired, but your troubleshooting skills were first rate.

PlainBill

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

PlainBill

I try to use the same part # if I can and I am not in any hurry any way

On your ...> "One other point" I have never been a very good speller or writer

I just do the best I can

I have been trouble shooting many different type equipment for many year

Thanks for the complement

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

That looks like it came out of a Samsung 2053BW...

I just repaired one of those PSUs for like $5. That's not your PSU right? Someone already put Panasonic caps on that one.

I put the Panasonic caps on this board and a new fuse

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

That looks like it came out of a Samsung 2053BW...

No it is Samsung 2253BW

Note I order the STM8309 from that EBay seller that I post the link to I should get them the first part of March these parts are coming from Hong Kong

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

Up-Date

Samsung 2253BW


Well the parts came in today I put them in both board

The bad new is one of the board has the 2 second ON then OFF

When I first got these monitors they where for the most part DEAD except for the blue power LED light so I open both of them up found four pop the top cap so I recap both board and both the power LED would not come ON

Then I remove one lead of the fuse to the inverter part of the board then the Blue power came back on so I check for short starting at the two caps next to the tiny mosfet chip and found both of them shorted

So today I replaced the tiny mosfets on both boards this was real fun now I have the 2 second ON then OFF

So I check the connector that goes from one board to the other board

There is one mark 3.3 volts this one reads 3.4 volts when back light is ON the same when OFF
There is one mark 5.0 volts this one reads 5.5 volts when back lights ON the same when OFF

There is one mark 13.0 volts this one reads 13.5 volts when back light is ON BUT when back light is OFF it reads 14.99 to 15.05 this seem not to be right

When the back light come ON it only lights up 3/4 of it from right to left the left side is a lot darker than the the right side
I know that the CFL tube are good on both monitor because other board will work both monitor

What should I check next

[budm]

Re: Two Samsung Monitors with same model # same caps that pop there top

So far 14 down the thread and you still did not give us the model number to look up for more info. Any reason why?

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

They are both a Samsung 2253BW

I put it in post 13

[budm]

Re: Two Samsung Monitors with same model # same caps that pop there top

Sorry, I thought it said no it is not 2253w.
OK when the lamps are not fully lit, it can be caused by not enough high output voltage from the transformers due to 1) low power supply DC voltage, but you are getting about 13vdc which is about right since the two caps in the inverter are rated at 25vdc. 2) The inverter out put circuits is setup as a bridge type (4 MOSFET's 2 in each IC), the center output is connected to the primary winding of the transformers which are connected in series and another end of the winding is connected to the two coupling capacitors to ground, so check those two caps. 3) leaky small ballast caps (small blue caps on the output side of the transformers, more likely to be about 10~18pf 10kV, check them out.
Luckily you have two identical monitors to look at and can compare some reading. The green fuse read less than one Ohm?

[sam_sam_sam]

Re: Two Samsung Monitors with same model # same caps that pop there top

budm

Thanks for your reply

UpDate

The problem was that I must have over heated one of the mosfet or it was bad to being with

I now have both monitor working now they have been running for 60 minutes now and they both look very nice

Two more monitor that did not end up in the land fill

I want to thank ever one that reply to this post

I have learn alot fix these two monitor

[budm]

Re: Two Samsung Monitors with same model # same caps that pop there top

Great two less monitors to the land fill. Thanks for the feedback also.