Chimei DAC-19M009 Power Supply problems

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

Maybe.

This is actually second time I fix this monitor. First time I only needed to change caps. A week later it stopped working again and I have not fixed it yet.

But now, when I removed P605 from circuit and tested them, I saw that one of them had S2 shorted with drains.
The strange thing is that when I tested it now, it did not show any shortage :S

[Amraks]

Re: Chimei DAC-19M009 Power Supply problems

Should I touch wood on this psu and hope to god mine don't fail too.

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

It doesn´t show any sign of being shorted but I will try removing anyway. Maybe it has some effect.

[jh20]

Re: Chimei DAC-19M009 Power Supply problems

hey boss, any luck with your monitor yet? if you refer to my last post of this thread:

https://www.badcaps.net/forum/showth...?t=8349&page=2

you'll see that i'd just fixed mine a few days ago. but it actually died on me the next day with the clicking noise problem!

i'd just found the problem to my psu today and thought i might share it with you incase yours is the same fault. the 2 driver fet, part number p605, which drives the inverter transformer, one of them had shorted pins between the source and the gate.

try measuring between pin 1 and 2, then pin 3 and 4, of the 2 driver ic's and see if they're shorted.

edit: i do not have a replacement ic so i don't know if it will fix my problem completely but the clicking noise stopped after i removed the shorted ic. and the green light was coming on when i tried to switch it on.

[Amraks]

Re: Chimei DAC-19M009 Power Supply problems

hope this helps anyone for later.

A guide capacitor map.

The_boss wanted to know the values of the capacitors.

So I done a diagram.

Thanks to all that helped me yet again.

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

I sent you a personal message.
Would be nice if you could test that out but if you don´t want to, I have no problem with that.

[Amraks]

Re: Chimei DAC-19M009 Power Supply problems

what did you want me to test?

i just resembled the monitor to run it for a few hours.

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

Okay, I did some magic which made me realize that mainboard is faulty.

I connected a computer PSU and buttonboard with the mainboard. It still had the flickering lights. This shows that LCD PSU had nothing to do with the clicking sound and flickering LED-s.

Now the question is - Is the PSU faulty too or just the mainboard?

http://www.ebay.com/itm/Main-Board-A...item3cc4b1c6c2 I was planning to buy this if it turns out to be faulty.

Now I will trouble Amraks a little so he could test something for me

[selldoor]

Re: Chimei DAC-19M009 Power Supply problems

Wheww!!! I think we got there and its good news ( well as far as the transformers are concerned. In your picture the secondaries are S3 to S7 358ohms and S6 to S8 366ohms - They are within 3 % of each other so they are good. I will have to think of something else!! Thanks for helping amraks, hopefully we can get you both fixed.

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

Updated my post with some more accurate information.

[selldoor]

Re: Chimei DAC-19M009 Power Supply problems

Ok perhaps i see - You still need to look at each transformer as an individual.
I think the other secondary pin may be the pin at the right hand end of the row of 6 as in your pic - The two are connected so measuring across the two blues will be approx double the value so can you test S1 to pin 6 on one transformer and S3 to pin6 on the other.

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

So I took a picture of it..

Pins in red are only connected with the transformator. They lead nowhere else.

S7-S8 725 ohms
S1-S2 1 ohm
S4-S5 1 ohm
S4/S5-S6 546 ohms
S1/S2-S3 546 ohms
S7-S3 358 ohms
S8-S6 366 ohms

[selldoor]

Re: Chimei DAC-19M009 Power Supply problems

Each transformer has two pins which should read ( probably as you say around 725 ohms) I just guessed which pins and was wrong.
To find out you need to number the pins in your head then test 1 to2 1 to 3 1 to4 1 to 5
and so on then 2 to3 2 to4 2 to 5 :: 3 to 4 3 to 5 3 to6 and so on until you find which are the secondary pins on one transformer then just check those pins on the other.

As one of the pins I marked that measures 725 ohms use that as pin 1 and test it against other pins on the same transformer and let us know.

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

The Boss
Ok - how about testing the inverter transformers - see here
https://www.badcaps.net/forum/showpo...68&postcount=6

Is your board the same ( I am not certain those are the secondaries but try there first.

Transformer pins marked S2 and S4 in your picture are not connected with anything

725 ohm between S1 and S3 if that might be important to know.

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

this was what mine was doing.

Haven't fixed it as I am stuck with getting that cap 220uf 50v cap the trace was lifted. having trouble finding where its meant to go on the negative side.

pretty sure positive lead traces to above zener diode.

I am not sure if the picture helps so I tested it instead.

Positive side is connected with D109 and R133, negative side is connected with C121 and R144.

Positive side rail should go underneath a diode also.

[selldoor]

Re: Chimei DAC-19M009 Power Supply problems

The Boss
As you see Amraks has a problem -If your board is the same any chance you could take a detailed picture of the yellow box area in the picture in this post
https://www.badcaps.net/forum/showpo...0&postcount=39

[selldoor]

Re: Chimei DAC-19M009 Power Supply problems

The Boss
Ok - how about testing the inverter transformers - see here
https://www.badcaps.net/forum/showpo...68&postcount=6

Is your board the same ( I am not certain those are the secondaries but try there first.

[Amraks]

Re: Chimei DAC-19M009 Power Supply problems

this was what mine was doing.

Haven't fixed it as I am stuck with getting that cap 220uf 50v cap the trace was lifted. having trouble finding where its meant to go on the negative side.

pretty sure positive lead traces to above zener diode.

[RethoricalCheese]

Re: Chimei DAC-19M009 Power Supply problems

Just tried jump starting. The lights turn on for half a second and go back off.

The lamps I used are taken from another monitor and are in 100% working condition.

[selldoor]

Re: Chimei DAC-19M009 Power Supply problems

Ok - did you try jump starting - Can you find a pin labelled pson or blon or on/off on the main board connector. with the main board disconnected but with the lamps plugged in,
get a 500ohm resistor and jump the 5v pin to the pson or blon pin Switch on the mains power and see if the lamps come on ( may also need a resistor jumper to Blon.)