Hi
its about SDM-E76D
The picture is shown for only half second and then gone away. Have replaced all the CE on the motherboard.
A friend told me Inverter or CCFL.

thanx

 

faulty CCFL.

 

A flashing of the display is usually a faulty CCFL. The CCFL string must be powered to detect a fault, so the ones still good will light for a brief period, thus giving you the flash.

 

So...

https://flic.kr/s/aHskPVGpvE

I see that one is even broken. That maybe it`s from my disassembly maybe not.

How to purchase new? Are they only for this model Sony or?

What do you think - will I find it in Bulgaria local store?

 

get one with same diameter and length and you will be good.

 

i think i understood.

Yesterday have purchased this stuff from china
CCFL Lamp Inverter Tester For LCD TV Laptop Screen Backlight Repair Test 12V NEW

I wrote on one Aliexpress seller about the product CCFL because he sell these.

https://www.aliexpress.com/item/Uni...sc&btsid=4a3180ea-1478-47c5-9564-719453be9df6

i see only retail package/the ccfls/. Should i save something from the old pieces taken from the display or should i purchase something new and what?

Thanks in advance

 

Part2

I see(exactly hear) another problem except the CCFL which really are gone/i tested them before minutes/

I hear noise like "click click click click" from the power board. Maybe from some transformer. What do you think?

Can we say if yes from which? What measurement can i do to help you answer me?

 

click from PSU could mean a shorted component from the secondary side

 

Need some time...!

 

Hi
its about SDM-E76D
The picture is shown for only half second and then gone away. Have replaced all the CE on the motherboard.
A friend told me Inverter or CCFL.
I dont see in manual what voltage to look for on the pins of this ic. I looked the pdf of the ic but still dont find.

thanx

Hello unnamed user. The inverter board powers the ccfl lamps and has a voltage and current monitor circuit that detects when the lamps expire

 

When an inverter starts up it will output a high voltage high frequency burst to ionize the gas and start the florescent lamps. It compares the current and if all lamps are within spec and balanced, then the voltage drops to a run voltage to keep them on.
If there is a problem, either one lamp is weak (usually a dark end will be noticed), broken, or the inverter circuit, then it will turn OFF and stay off until it is restarted. If you attempt too many times with a broken lamp you can destroy a working inverted. The high voltage is too high without some load, and these step-up transformers are not made to withstand these voltages.
There are ways to monitor the output pulse and get an idea of where the problem is. Place a o-scope probe next to the transformers during startup. The high voltage AC will induce a waveform. Compare the different transformers (hold the scope probe in the same location to compare apples to apples) and if the waveforms are clean, but one is higher than the rest, then suspect that lamp to be open (burned up). If you don't see this waveform on one of the stages during startup, then suspect that stage of the inverter.
Another way to see if the the inverter is working is to put a neon lamp next to the output section of the step-up transformers in the inverter section. If one lights it brighter then suspect that lamp. If it doesn't light then suspect that stage of the inverter.

 

When an inverter starts up it will output a high voltage high frequency burst to ionize the gas and start the florescent lamps. It compares the current and if all lamps are within spec and balanced, then the voltage drops to a run voltage to keep them on.
If there is a problem, either one lamp is weak (usually a dark end will be noticed), broken, or the inverter circuit, then it will turn OFF and stay off until it is restarted. If you attempt too many times with a broken lamp you can destroy a working inverted. The high voltage is too high without some load, and these step-up transformers are not made to withstand these voltages.
There are ways to monitor the output pulse and get an idea of where the problem is. Place a o-scope probe next to the transformers during startup. The high voltage AC will induce a waveform. Compare the different transformers (hold the scope probe in the same location to compare apples to apples) and if the waveforms are clean, but one is higher than the rest, then suspect that lamp to be open (burned up). If you don't see this waveform on one of the stages during startup, then suspect that stage of the inverter.
Another way to see if the the inverter is working is to put a neon lamp next to the output section of the step-up transformers in the inverter section. If one lights it brighter then suspect that lamp. If it doesn't light then suspect that stage of the inverter.

Be careful with the high voltage output if it is unloaded due to a broken lamp it can arc a two inch long arc and shock the piss out of you stay away from the output I know this because I repair Tvs for a living. As far as measuring voltages from the monitor circuits on the inverter, the factory does not provide service information to be able to tell how far its out of tolerance. Replacing all the ccfl lamps with the right kind should resolve the problem. Keep neon test lamps away from the output in the event it is unloaded

 

Hi.
It`s me again. I have broken one transistor leg and trashed it(that was before times). The new pcs are here - maybe 10.

I am sure that the CCFLs are gone and they are in Recycle Bin since a lot of time

The CCFLs are gone. ALL ce are replaced with new. The transistor/new/ is not on the board still. How to proceed now?

If i watch the lines on the board primary part is that with Entry Capacitor, fuse, Thermo resistance and other. So the secondary should be "the other one".

On the front side of the board in 2nd i see a few elements:

One "RAK" element.
I will desolder and check the two doubled Diods
The coils
Some blue capacitors
Resistance near the Transformer 1 and 2
Power Transformer 1 and 2
and that`s that;

P.S i still dont have osciloscope

 

Hi.
It`s me again. I have broken one transistor leg and trashed it(that was before times). The new pcs are here - maybe 10.

I didn`t understand that for the arc. I am sure that the CCFLs are gone and they are in Recycle Bin since a lot of time

If i make measurements with Cable in the wall where TO NOT put the probes about that arc?
A friend of mine told me that it`s best when measure high voltage to solder wires where i want to measure and plug them into my digital multimeter.

The CCFLs are gone. ALL ce are replaced with new. The transistor/new/ is not on the board still. How to proceed now?

If i watch the lines on the board primary part is that with Entry Capacitor, fuse, Thermo resistance and other. So the secondary should be "the other one".

On the front side of the board in 2nd i see a few elements:

One "RAK" element. I dont see electric parts in replacement lists in the manual of the monitor. I will desolder it and then will think how to analyze it.
I will desolder and check the two doubled Diods
The coils
Some blue capacitors
Resistance near the Transformer 1 and 2
Power Transformer 1 and 2
and that`s that;

P.S i still dont have osciloscope

 

You broke a transistor leg on the inverter board? Uh oh. I wonder how much a reclaimed board is from shopjimmy.com

 

I dont know that site and cannot understand the joke ... really.

You have not ever broke something? I did not remember the conditions but the leg was broken and i preffered to purchase new pieces not to put a wire(Resistance Leg for example) to complete the leg.

No joke there really is a website named shopjimmy.com that sells tv parts

 

I have one question...

If we look this
could you tell me what to expect on the pins of this IC? What normal should i have on them if i have powered only board/
715G1899-1-GP/and there are no connected CCFLs.

voltage feedback pin
Current sense pin
OUT Gate drive output to drive the external MOSFET
Supply voltage pin
HV

thanks

 

I have one question...

If we look this
could you tell me what to expect on the pins of this IC? What normal should i have on them if i have powered only board/
715G1899-1-GP/and there are no connected CCFLs.

voltage feedback pin
Current sense pin
OUT Gate drive output to drive the external MOSFET
Supply voltage pin
HV

thanks

There are no more service manuals for TVs anymore throw it in the garbage or buy a board

 

I have one question...

If we look this
could you tell me what to expect on the pins of this IC? What normal should i have on them if i have powered only board/
715G1899-1-GP/and there are no connected CCFLs.

voltage feedback pin
Current sense pin
OUT Gate drive output to drive the external MOSFET
Supply voltage pin
HV

thanks

Find the service manual.