Samsung SyncMaster 204b

[john98103]

Re: Samsung SyncMaster 204b

Voltages are as follows
CN2
#1:PWN-Dim - 0-volts
#2,3 & 4 - ground - 0-volts
#5,6 &7 - 13V - 13.11 – volts
#8 - Dim - 0 –volts
#9 -on/off -0 –volts

CN3 through CN6 all measure zero volts.

[PlainBill]

Re: Samsung SyncMaster 204b

Voltages are as follows
CN2
#1:PWN-Dim - 0-volts
#2,3 & 4 - ground - 0-volts
#5,6 &7 - 13V - 13.11 – volts
#8 - Dim - 0 –volts
#9 -on/off -0 –volts

CN3 through CN6 all measure zero volts.

You've got a problem on the signal card. The pictures supplied in post #1 aren't good enough to provide much troubleshooting assistance. I can identify a voltage regulator, but not much else.

I would suggest you take a good, clear picture of the signal card and attach it to your next post using 'Manage Attachments' (below the text entry area). We're looking for something like 2000 x 2000 pixel resolution.

PlainBill

[john98103]

Re: Samsung SyncMaster 204b

I took these voltages from the power supply when it was separated from the monitor; should I have tested while all boards were attached?

[PlainBill]

Re: Samsung SyncMaster 204b

I took these voltages from the power supply when it was separated from the monitor; should I have tested while all boards were attached?

Well, that WOULD help verify the nature of the problem. Ordinarily if no signal is present the power LED goes from blue (or green) to amber within a few seconds. It is very unusual for it to go blank.

PlainBill

[john98103]

Re: Samsung SyncMaster 204b

with power supply connected to monitor Voltages are as follows
CN2
#1:PWN-Dim - 0.05-volts
#2,3 & 4 - ground - 0-volts
#5,6 &7 - 13V - 13.11 – volts
#8 - Dim - 0.05 –volts
#9 -on/off -0.01 –volts

CN3 through CN6 all measure zero volts. (grounded at the nearest PS hold down screw and pushing pin through wires)

[PlainBill]

Re: Samsung SyncMaster 204b

with power supply connected to monitor Voltages are as follows
CN2
#1:PWN-Dim - 0.05-volts
#2,3 & 4 - ground - 0-volts
#5,6 &7 - 13V - 13.11 – volts
#8 - Dim - 0.05 –volts
#9 -on/off -0.01 –volts

CN3 through CN6 all measure zero volts. (grounded at the nearest PS hold down screw and pushing pin through wires)

ARGHH!!! We still aren't communicating. Let's do this properly. Part of the problem is I'm not familiar with this monitor. Some configurations make troubleshooting very difficult. Others allow you to hook all parts of the monitor together and still measure voltages.

Setup: Power supply / inverter (PS/I) connected to signal card. Computer with desktop showing connected to signal card. Monitor front panel connected to signal card. It is preferred the CCFLs from the LCD panel be connected to the power supply / inverter. If the design permits it, LCD panel connected to signal card.

Apply power to PS/I. Power LED should come on, if it doesn't, press the power button. CCFLs should light. Measure the voltages on CN2. If the design permitted it, you should see the desktop on the lcd panel. If the CCFLs are not connected do NOT try to measure the voltage on CN3-CN6. There is a very good chance you will destroy your DMM.

If the power LED goes off, changes to amber, etc, report it.

PlainBill

[john98103]

Re: Samsung SyncMaster 204b

I'm able to connect all components while monitor is disassembled. I've followed the above directions.

LED lights blue for one second then turns off. CCFL's don't light up, not even momentarily.

Voltages remain as reported previously and are as follows
CN2
#1:PWN-Dim - 0.05-volts
#2,3 & 4 - ground - 0-volts
#5,6 &7 - 13V - 13.11 – volts
#8 - Dim - 0.05 –volts
#9 -on/off -0.01 –volts

CN3 through CN6 all measure zero volts. (grounded at the nearest PS hold down screw and pushing pin through wires)

[retiredcaps]

Re: Samsung SyncMaster 204b

I would suggest you take a good, clear picture of the signal card and attach it to your next post using 'Manage Attachments' (below the text entry area). We're looking for something like 2000 x 2000 pixel resolution.

john98103, we are still waiting for these pics.

[PlainBill]

Re: Samsung SyncMaster 204b

It's time to direct your attention to the signal card. The power LED turning off is definitely unusual. A good picture of YOUR card would be very helpful.

PlainBill

[john98103]

Re: Samsung SyncMaster 204b

Boards for SyncMaster 204b

Power Supply IP-45130A
Video Board BN41-00620E

[PlainBill]

Re: Samsung SyncMaster 204b

Boards for SyncMaster 204b

Power Supply IP-45130A
Video Board BN41-00620E

Good pictures, thanks. In the upper left corner of the signal card is an IC marked 1501-33. The is a voltage regulator. Pin 1 has a triangle next to it, pin 3 and the tab are both ground. What are the voltages on the other pins (try to get measurements with both power LED on and after the power LED turns off.

PlainBill

[john98103]

Re: Samsung SyncMaster 204b

first of all; thanks for all the help.

there is an IC just below CN501 (ribbon from CN2) marked IC405 (9933B / W58A). is this the IC I should get voltages from?

[retiredcaps]

Re: Samsung SyncMaster 204b

PlainBill wants the voltages from the yellow circled component.

[john98103]

Re: Samsung SyncMaster 204b

Pin 1 = 13.11V
Pin 2 = 3.64V
Pin 3 = 0
Pin 4 = 3.37V
Pin 5 = 0

The LED no longer lights on; previously I would have to have the power off for a short while to get the LED to turn off momentarily, now it won't light up after being powered off for 5 min.

[PlainBill]

Re: Samsung SyncMaster 204b

Pin 1 = 13.11V
Pin 2 = 3.64V
Pin 3 = 0
Pin 4 = 3.37V
Pin 5 = 0

The LED no longer lights on; previously I would have to have the power off for a short while to get the LED to turn off momentarily, now it won't light up after being powered off for 5 min.

That voltage is essentially correct - it's a 3.3 volt regulator. I've identified a few more ICs on the picture (attached). What are their part numbers?

PlainBill

[john98103]

Re: Samsung SyncMaster 204b

On the left of board, top down:
IC405 9933B / W58A
IC304 17-16 / 05481L (very hard to see)
IC203 MP1583DN / 57975819 / MPS541

On the right side of board, left to right:
IC301 LF25 / 6K1DT546
IC604 CCRB / LM / 393M

also

I've had the power off to the monitor for 6 hours. I get no momentary blue led light any more when first switching on.

[PlainBill]

Re: Samsung SyncMaster 204b

On the left of board, top down:
IC405 9933B / W58A
IC304 17-16 / 05481L (very hard to see)
IC203 MP1583DN / 57975819 / MPS541

On the right side of board, left to right:
IC301 LF25 / 6K1DT546
IC604 CCRB / LM / 393M

also

I've had the power off to the monitor for 6 hours. I get no momentary blue led light any more when first switching on.

IC405 9933B is a SI9938BDY dual P-channel mosfet.
IC304 17-16 / 05481L (very hard to see) No match
IC203 MP1583DN / 57975819 / MPS541 No match
IC301 LF25 / 6K1DT546 is a LF25 2.5 volt regulator
IC604 CCRB / LM / 393M is a LM393M dual comparator

Well, I'd hoped to do better. 3 parts out of 5 ID'd, only one of the three is of interest.

On IC301, the tab and the stub pin are Gnd. What are the voltages on the other two pins?

On IC 304, what are the voltages on each of the pins?

PlainBill

[john98103]

Re: Samsung SyncMaster 204b

with the tab facing up:
left pin = 3.23V
right pin = 2.49V

[PlainBill]

Re: Samsung SyncMaster 204b

with the tab facing up:
left pin = 3.23V
right pin = 2.49V

That would make sense, assuming it's a 2.5 volt regulator.

PlainBill

[john98103]

Re: Samsung SyncMaster 204b

IC 304 with tab at top:

tab = 1.81V
left pin = 0V
stub = 1.81V
right pin = 3.23V