DAC-19M009 dead?

[papagoose]

Re: DAC-19M009 dead?

Interesting, since the max VCC for this chip is 20VDC. Are you placing your probes across pins 1 and 2 ?

I checked the datasheet but I wasn't sure how to determine the orientation of the chip. I've marked which pins I measured as 1 and 2

[jetadm123]

Re: DAC-19M009 dead?

That was a good idea- when I removed F200 I still have the same problem (LED flashes once, no voltage on the connector pins to the logic board) so I guess that means its not the inverter?



With the logic board disconnected and no CCFLs, the voltage is about 10.5V and fluctuates a little (say +-0.2V). With the logic board connected and the CCFLs disconnected, the voltage is about 31V and steady the whole time

Interesting, since the max VCC for this chip is 20VDC. Are you placing your probes across pins 1 and 2 ?

[papagoose]

Re: DAC-19M009 dead?

A little Monday morning quarterbacking.
If I understand you correctly, with the logic board disconnected the power supply stays alive?
One more thing that should be checked is a problem with the inverter causing the power supply to shut down. Remove F200 it's the glass fuse in the center of the board,with that removed and the logic board installed recheck the voltages.

That was a good idea- when I removed F200 I still have the same problem (LED flashes once, no voltage on the connector pins to the logic board) so I guess that means its not the inverter?

The quick and easy test on the TEA1532 is to measure the voltage from pin 1 (Vcc) to pin 2 (Gnd) (DON'T use chassis ground). If the voltage is steady below 8 volts the chip is bad. If it's pulsing, the startup cap is bad, an output diode is shorted, or you have an excessive load on an output of the power supply. If it's in the 12-20 volt range the chip seems to be working properly.

This IC has the rectified mains voltage applied to pin 8, and is prone to failure.

With the logic board disconnected and no CCFLs, the voltage is about 10.5V and fluctuates a little (say +-0.2V). With the logic board connected and the CCFLs disconnected, the voltage is about 31V and steady the whole time

[PlainBill]

Re: DAC-19M009 dead?

Yes, that one.

However, wait 24 hours before ordering to see if PlainBill has anything to add to this discussion.

The quick and easy test on the TEA1532 is to measure the voltage from pin 1 (Vcc) to pin 2 (Gnd) (DON'T use chassis ground). If the voltage is steady below 8 volts the chip is bad. If it's pulsing, the startup cap is bad, an output diode is shorted, or you have an excessive load on an output of the power supply. If it's in the 12-20 volt range the chip seems to be working properly.

This IC has the rectified mains voltage applied to pin 8, and is prone to failure.

PlainBill

[alexanna]

Re: DAC-19M009 dead?

A little Monday morning quarterbacking.
If I understand you correctly, with the logic board disconnected the power supply stays alive?
One more thing that should be checked is a problem with the inverter causing the power supply to shut down. Remove F200 it's the glass fuse in the center of the board,with that removed and the logic board installed recheck the voltages.

[retiredcaps]

Re: DAC-19M009 dead?

This is the one, yes?

http://www.ebay.com.au/itm/IC-TEA153...#ht_1973wt_882

If thats correct, I'll order it

Yes, that one.

However, wait 24 hours before ordering to see if PlainBill has anything to add to this discussion.

[papagoose]

Re: DAC-19M009 dead?

ebay.com has selection with either free or reasonable shipping

Search ebay for ea1532

I see quantity = 2 for $1.20 with $4 for shipping to Canada.

Hahhah I was just looking at eBay when I saw your post! This is the one, yes?

http://www.ebay.com.au/itm/IC-TEA153...#ht_1973wt_882

If thats correct, I'll order it

[retiredcaps]

Re: DAC-19M009 dead?

I'll have to look around for where to get a replacement, shipping to Australia comes out at over $30.

ebay.com has selection with either free or reasonable shipping

Search ebay for ea1532

I see quantity = 2 for $1.20 with $4 for shipping to Canada.

[papagoose]

Re: DAC-19M009 dead?

1) This SMPS chip has been bad in other lcd cases posted here. Since all the caps have been replaced including the startup cap, this chip could be bad.

2) Digikey sells a replacement for $1.14 at (which I believe is the correct part)

http://search.digikey.com/scripts/Dk...=568-3316-1-ND

3) PlainBill is the real expert on concluding if this chip is bad or not by taking voltage measurements at the various pins.

edit: He gives a good explanation at

https://www.badcaps.net/forum/showpo...7&postcount=20

4) If you have not done smd soldering, see

http://www.youtube.com/watch?v=3NN7UGWYmBY

Hmmm thanks for all the help I'll have to look around for where to get a replacement, shipping to Australia comes out at over $30. At the very least, I'll have spare parts for the other Chimei monitors I have

[retiredcaps]

Re: DAC-19M009 dead?

EA1532A

1) This SMPS chip has been bad in other lcd cases posted here. Since all the caps have been replaced including the startup cap, this chip could be bad. That is my best guess at what is causing the voltage to drop.

2) Digikey sells a replacement for $1.14 at (which I believe is the correct part)

http://search.digikey.com/scripts/Dk...=568-3316-1-ND

3) PlainBill is the real expert on concluding if this chip is bad or not by taking voltage measurements at the various pins.

edit: He gives a good explanation at

https://www.badcaps.net/forum/showpo...7&postcount=20

4) If you have not done smd soldering, see

http://www.youtube.com/watch?v=3NN7UGWYmBY

[papagoose]

Re: DAC-19M009 dead?

What is part number red circled component (on the backside)?

It has written on it:

EA1532A
6E1E607
Hn66291

I'm going to take some better photos of the board, should post them soon

[retiredcaps]

Re: DAC-19M009 dead?

What is part number red circled component (on the backside)?

[papagoose]

Re: DAC-19M009 dead?

Wasn't able to get alligator clips, I ended up just doing it

When I turn it on, the voltage is about 340V, it does jitter a little for the first couple of seconds but I think that is just lag on my multimeter (it doesn't drop to zero instantly when I remove the probes). The voltage sits at 340 the whole time (I'm in Australia)

[retiredcaps]

Re: DAC-19M009 dead?

There is still an electrical buzz from the big cap area, it is there the whole time (even after the LED turns off)

Okay, it sounds like the power supply is failing under load.

If you have aligator clips, use them to attach to the big cap to take DC voltage readings (since you are not comfortable with live voltages).

Clip the aligator leads (red to positive, black to negative). Turn on the lcd and watch the DC voltage. It should be around 160 to 165V DC. See if this voltage drops or fluctuates. Make sure to note the voltage in the first 3 seconds and afterwards.

Aligator clips allow you to take readings hands free can be purchased pretty much anywhere and look like

[papagoose]

Re: DAC-19M009 dead?

I know your logic board is good, but I'm curious about the voltages on the 2 circled voltage regulators (red and yellow).

Put your black probe on the ground screw and red on each pin (not the tab). Report

a) part number of each
b) DC voltage of each pin

When measuring these DC voltages, is the power LED on or off? The logic board controls this power LED.

Okay, so I've replaced the small 22uF cap and that hasn't changed anything either. I did check the voltage regulators but I found something more interesting afterwards

Both the regulators have written on them

EH16A
621J15

Now when I turn the power on, the middle regulator's lowest pin reads 5V, the big pin about 3.6V, and the others are I think zero. However, 3 seconds later the LED blinks on, and then everything drops to zero. That would probably explain the LED turning off. So I thought I should check the connector pins from the inverter board going into the logic board.

When disconnected, the top two pins read 13.6V and 5V respectively, and they did that as long as the power was on (from my previous measurement). Now, when I turn the power on, they read 14V and 5V. Pretty much exactly 3s later, there is a quiet clicking sound, and both of these drop to zero. The voltage drop is gradual, and I bet if I recorded it, the result would be something resembling an exponential (so it drops to say 1V very quickly, and then slows). The clicking sound just about coincides with the LED lighting up. So right after the LED flashes on, there is no power going into the logic board!

There is still an electrical buzz from the big cap area, it is there the whole time (even after the LED turns off)

[retiredcaps]

Re: DAC-19M009 dead?

I know your logic board is good, but I'm curious about the voltages on the 2 circled voltage regulators (red and yellow).

Put your black probe on the ground screw and red on each pin (not the tab). Report

a) part number of each
b) DC voltage of each pin

When measuring these DC voltages, is the power LED on or off? The logic board controls this power LED.

[retiredcaps]

Re: DAC-19M009 dead?

if I can't find a low ESR one, is there anything else that would be better than general purpose?

The start cap is usually "entry level" low ESR like a Panasonic FC. You should replace even though the secondary voltages (13.8V and 5V DC) are present.

[papagoose]

Re: DAC-19M009 dead?

Let's try this. Hookup all the boards without the ccfls plugged in (disconnect all ccfls). Does the power LED stay on now?

No luck. I have the inverter connected to the logic board and none of the CCFLs plugged in, but the light still flashes on once and then stays off. As with before, the board doesn't make the sound that I uploaded, it only does that when it is disconnected from everything else.

[retiredcaps]

Re: DAC-19M009 dead?

When I plug it in and turn on the power, after a couple of seconds the green power LED flashes once, and then nothing else happens.

The rest of the system is fine, I tested it with a known good DAC-19M009 and it powered on OK (at least, it was when I started!

Let's try this. Hookup all the boards without the ccfls plugged in (disconnect all ccfls). Does the power LED stay on now?

[papagoose]

Re: DAC-19M009 dead?

1) See attachment for pin numbering.

Any reading under 30 ohms suggest the mosfet is shorted and potentially bad.

Thanks for the attachment, none of the readings are below 30 ohms

2) Did you measure that smd fuse in post #9? Your photo is too blurry for me to know where it is.

I spent ages looking for F104 before realising I'd misread the original post! I think F102 is fine, I measured 0.5 ohms. I've attached an update of the back showing where F102 is for future reference