Samsung SyncMaster LD220HD HDTV/Monitor - no power on

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

I'm not sure why I thought that either!

[selldoor]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

Is this L78M05ABDT-TR a suitable replacement, do you think?

Not sure why you would think that - are you looking at the datasheets

the 09 in the 78M09A iindicates it is 9v fixed output
the 05 in the L78M05ABDT-TR indicates it is 5v fixed output

We dont of course know that it is faulty maybe just not getting voltage in.
the 0 0 0 test result suggests that might be the case.

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

Is this L78M05ABDT-TR a suitable replacement, do you think?

[selldoor]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

Hmm - Im slipping!!

The first one IS a 78M09A dont know how I didnt find it.

Here is the data sheet

http://www.alldatasheet.net/datashee.../L78M09AB.html

Should be 9Volts !! Will have to think about that.

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

There's not a lot of daylight here [foggy], but here's some more pics...

I just noticed that there's also "J66" in the centre circle of IC 78M09A at IC1001.

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

OK, will have a try in daylight, tomorrow, but my camera's not brilliant.

Edit. Message from previous owner...

"the monitor was working fine and suddenly one day it just stopped working and would not turn on at all."

Maybe it was struck by lightening!

[selldoor]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

I've not found any datasheets yet.

Details of the ICs are in post#42

3 on the top and 1 underneath.

Yes I have been looking at that post

The one with 78 M0 9A KW 9A has me puzzled can you do a close up pic of it

The other two are 1117 s and with no other numbers are usually adjustable
with a minimum output of 1.25v so they are not right BUT they could be ok and something else affecting them. Can you do a closer pic of the board
perhaps in 4 shots. Its not looking good and I have been looking to see if
I could find another board but they are like hens teeth!!

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

I've not found any datasheets yet.

Details of the ICs are in post#42

3 on the top and 1 underneath.

[selldoor]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

I Have been reading back through- whilst one regulator was pointed out as being a problem I think the others need looking at.
Which one did you replace. ic???? Also there are only 3 so one of the other IC
is not a voltage regulator. Did you find any datasheets for them?
EDIt
Just sspotted it was ic1009 that was replaced

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

The lamps don't really light up. I'm just getting a bit of white flickering now and again.

The caps that I removed were Rubycon ZLH 1000uf 10v. I've now got an ESR meter and have tested them, and they seem OK.

972uf/ESR.10
963uf/ESR.09

Replaced with SD C288H

They test at over 1000uf and ESR ~.06

No history, I'm afraid. The monitor was given to me and was DOA. I might be able to find out, though.

[selldoor]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

With F301 re-soldered, I've tested with the lamps with the 3v battery, and I get a little bit of flickering, but that's all.

Hi - sorry- do you mean the lamps light well but flicker a bit or
lamps barely light at all


EDIT also v early on you said you replaced two caps
-did you use low esr ones? what make/series

EDIT2 also what was the original problem/symptom
if the set was yours what led up to that.

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

With F301 re-soldered, I've tested with the lamps with the 3v battery, and I get a little bit of flickering, but that's all.

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

Yes, just found some CR2032s in the drawer. I'll have a go, tomorrow.

[selldoor]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

2 x 1.5 or even rechargeable 2x1.2 might do or a cr2016 cr2032 watch
/ cmos battery

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

I've not got a suitable resistor to try that.

I'll have a look, but I don't think I've got a 3v battery, either.

You're right. It would be nice to see something working...

[selldoor]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

OK dont know if you have tried this

re solder F301 if not already done so connect it all up except the main board.

Have you got a 3v battery? or something that will give you 3vdc.
or if you got a big resistor to drain the caps.
Either connect the 3v neg to ground and pos to on/off then switch on and see if the backlights come on OR use the resistor and connect the 5v on the connector to the on/off on the connector using the resistor and switch on.
If nothing else it shows that if it gets fixed the lamps work and its a bit
encouraging to see.

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

It does test steady on some things. The big cap tested at a steady 336v today.

[selldoor]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

As all your voltages appear unstable I wonder if your meter is ok.
Perhaps test it on a few things battery - car battery mains (carefully)

whilst being careful Test the big cap again - is that steady

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

I've now replaced IC1009 with the LM1117DT-3.3 from CPC.

The readings are...

pin 1. = 0.000
pin 2. = 3.1 to 3.3
pin 3. = 4.1 to 4.9

...which looks better than in post#42. The readings are still jumping around, and still no power on light.

The other 3 ICs remain the same.

The voltages across the the connector pins are now...

1 [B-DIM] 0.0
2 [15V] 13.2 to 14.2 unstable
3 GND
4 GND
5 GND
6 [5.2V] 4.2 to 4.9 unstable
7 [5.2V] 4.2 to 4.9 unstable
8 [DCR] 3.8 to 4.2 unstable
9 [ON/OFF] 0.0

[oddbodd]

Re: Samsung SyncMaster LD220HD HDTV/Monitor - no power on

I think so. It was stuck fast to the board, and when I finally got some movement, I had to lever it off of the tab side.

I'll add a dab of solder to the tab.