Samsung 215TW 1 sec on then off analog only

[PineCreek]

All modes work except analog where each time power cycled or Windows changes state display comes on for 1 second, then off. No bulging caps I could find. Could not see display with flashlight at angle. I've tried with two different cables and on at least 6 different computers. I've loaded Samsung drivers multiple times on multiple computers.

[Rtech]

Re: Samsung 215TW 1 sec on then off analog only

Fault then is going to be on the Logic Board..and would think you need a replacement,as trying to find and rectify the fault,is probably a no-no.

[bonney]

Re: Samsung 215TW 1 sec on then off analog only

What about eeprom gone faulty

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

I was afraid that was the answer. So.....looks like a new logic board is about $55. Refurbished unit is around $280. Probably not a bad trade if the probability is high of fixing the problem. Can you suggest any way to narrow the probability?

I have the service manual so I've got block diagrams and full schematics.

[Rtech]

Re: Samsung 215TW 1 sec on then off analog only

I think you are stuck with the $55 route.

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

I'm with you, but one more doublecheck before I spend the bucks: I just read the thread titled "Samsung 215tw cuts out" started by almoodie. Very similar symptoms except there is no mention of what input they are working with so no clue on isolating problem to logic board. However, it appears most failures discussed in that and other threads end up with CCFL failures. Think I should eliminate that before spending $?

[PlainBill]

Re: Samsung 215TW 1 sec on then off analog only

I'm with you, but one more doublecheck before I spend the bucks: I just read the thread titled "Samsung 215tw cuts out" started by almoodie. Very similar symptoms except there is no mention of what input they are working with so no clue on isolating problem to logic board. However, it appears most failures discussed in that and other threads end up with CCFL failures. Think I should eliminate that before spending $?

It's a trivial test. If the 'backlight on' signal from the logic card to the inverter stays on while the backlights go off, it's an inverter problem. If the backlights are switched off, it's a logic card problem.

PlainBill

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

I could not find a signal identified as 'backlight on' but I the schematics I have identified a signal call BL_EN_ on pin 9 of CN501 on logic board. This pin is connected to the pin opposite the ADJ(Red) pin on the Inverter board and there is lettering that appears to real o/f close by. this pin reads 3+ volts when the power button is pushed and remains at 3+ volts when the screen goes blank. Am I correct to take this to mean the problem is on the inverter board and/or the display?

[PlainBill]

Re: Samsung 215TW 1 sec on then off analog only

I could not find a signal identified as 'backlight on' but I the schematics I have identified a signal call BL_EN_ on pin 9 of CN501 on logic board. This pin is connected to the pin opposite the ADJ(Red) pin on the Inverter board and there is lettering that appears to real o/f close by. this pin reads 3+ volts when the power button is pushed and remains at 3+ volts when the screen goes blank. Am I correct to take this to mean the problem is on the inverter board and/or the display?

Got it in one. You get the blue ribbon for today.

PlainBill

[Rtech]

Re: Samsung 215TW 1 sec on then off analog only

The title says the fault is only on the Analogue side,and ALL MODES work except analogue !!!!OR does it mean the Monitor only has an Analogue Input ???Is it me,or is this confusing ???The BL_EN is Backlight Enable,and unless there are 2 of them,and therefore dual circuits on the PSU/Inverter,one for an Analogue signal,and one for a Digital Signal,and IF the latter works fine,as indicated by the all modes bit, then surely it has to be the Logic board.If as described the EN voltage stays on,and B/L's go off then it must be PSU/Inverter.

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

Good point. that contradiction is what's hung me up all along. I'll find an S-video or component source I can take to the shop and see what the EN signal does in the other modes, but I'm not sure what that will tell us. I would bet it will stay on and that doesn't prove anything.

It seems like what we're looking for is something from the inverter board forward that is only active during analog mode. I haven't been able to read the schematics well enough to find such a thing. Any idea of a setting like some type of power savings that would fit that set of symptoms?

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

Check operation in S-Video. BL_EN is on and at the same voltage (3 V) in S-video and in this case the backlights are on. Same signal is same voltage in Analog mode but backlights are off. I tried to check all the signals going from logic to ip board to see if any of them are different. I don't think I found any, but need to try one more time.

[bonney]

Re: Samsung 215TW 1 sec on then off analog only

what voltage goes to your panel (screen)?
have you schematics of the logic board you can post

[Rtech]

Re: Samsung 215TW 1 sec on then off analog only

On the same connector as the BL_EN is on, there should be one for Dim or Adj,woiuld be interesting,to see if that voltage changes with the signals you used for S-Video and Analogue !!

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

In process of recording all voltages during different parts of analog and S-video modes. I'll post all tomorrow. From memory, BL_EN is 3.3 v during S-video and as I recall it stayed 3.3 in analog even when panel went blank. That was what lead several folks to condemn the inverter board.

ADJ was .9v in S-video and I think but not sure it was 3.3 v in analog.

I will post schematics I have tomorrow. I did find another interesting signal shown on schematic called Panel_EN. I found two points on schematic where it was identified. Neither show it going to any connectors off-board. I haven't measured it yet to see how it reacts to different modes.

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

I tried to upload schematics three times. No joy. File is .pdf 2.6mb. suggestions?

[Rtech]

Re: Samsung 215TW 1 sec on then off analog only

Cannot help you with uploading the schematics,sorry.Normally on ADJ, and anyone correct me if I am wrong !!,minimum or no voltage is Max brightness,and much higher potentials eg your analogue 3.3v(you think)may cause the opposite ??

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

You were right that the ADJ pin is some kind of inverse function of brightness. I couldn't prove how it coupled with Analog vs S-Video because while I was setting up to measure ADJ in various states, I tried to gain control of the ADJ function by using a button on the panel they have called "MagicBright" which is supposed to automatically adapt to various environments. It did react, but not as expected. However, while I was trying to figure out what it was doing, the Analog function began working. I have not been able to break it yet. (ADJ is well under 1 volt). I've shut the system down for the night to see if it works cold. If it does, I'll put it back together and scratch it off as "Magic".

I'll let you-all know tomorrow.

[PineCreek]

Re: Samsung 215TW 1 sec on then off analog only

Back together and working in Analog. I haven't tested other modes. I can make unit fail by putting the "MagicBright" function in any mode but Custom. I'm guessing that's not the way it should work so probably do have some type of corruption in program on logic board and I just lucked into a mode that avoids it. At this point, I plan to use it as is for awhile.

A huge thanks to all who helped me. It was a tortured trail to the "solution" and I appreciate the patience and good input from everyone.