Re: Samsung Syncmaster 245BW
Report 1: today recevied TDA4863G to replace ICP801S, now I can read 350V. Now I am waiting 24V SMPS IC ICM801 (MC33067)....
sky007
Member
Last Activity: 11-16-2023, 09:46 PM
Joined: 10-29-2012
Location: zhuhai
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Re: Samsung Syncmaster 245BW
I get little progress. I put back QB801, and open JB805 which feed M_vcc to IC801S (SMPS IC), break the connect J808 which feed M_Vcc to ICM801, then between the primary ground and the QB801 Emitter read 7.2k Ohm, the voltage on Emitter is 17.56V now.
If one of jumpers connect, I would not get 17.56V on QB801.
Is it possible the IC801S and ICM801 both blow out?Last edited by sky007; 09-11-2014, 12:56 AM.Leave a comment:
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Re: Samsung Syncmaster 245BW
Shorting transistor E and C, voltage on E show 0.18V, main Cap still only get 170V.
Something wrong.
Maybe we can say the transistor QB801 is good. The loads of M_Vcc get problem.Leave a comment:
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Re: Samsung Syncmaster 245BW
Between the primary ground and the Emitter only 24.7Ohm.
Shorting transistor E and C, so the PW_ON would not need, and transistor E will be fed by AUX directly (17.56V), am I right?...Leave a comment:
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Re: Samsung Syncmaster 245BW
Sorry, it is 3.3k Ohms. I indeed have 3v on PS_ON. The PC802S is On, otherwise I should not have voltage reading on one end of RB815 which connect to QB801 base.
I just do not understand why the transistor off board testing is good, but on board shows bad. Is any other component failure could cause trouble?...Last edited by sky007; 09-10-2014, 11:15 PM.Leave a comment:
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Re: Samsung Syncmaster 245BW
Yes, I have that document. It help me understand how it work. I find some different, but mostly part are same.
Yes, using a 330k resistor connect Sb and PW_On, so I do have PSON 3V signal.
With QB801 on board, Base 0.55-0.88v, Collector 0.7 - 1.4V, Emitter 0.6-0.9V.
Without QB801, base 15.61V, Collector 17.56V, Emitter 0V.
But test QB801 individually by multimeter, switch multimeter to diode test, read B-E 577, B-C 577, E-B 1, C-B 1, E-C and C-E both get 1. It looks good.
Anyway, I will...Last edited by sky007; 09-10-2014, 10:21 PM.Leave a comment:
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Re: Samsung Syncmaster 245BW
I think QB801 is bad. I take it out from board, and get reading from base 15.61V, Collector 17.56V, Emitter 0V.
But strange thing is, test QB801 off board, switch multimeter to diode test, read B-E 577, B-C 577, E-B 1, C-B 1, E-C and C-E both get 1. It looks good.
Can't find exact mode on ebay, but I find TIP41C 6A 100V NPN Transistor. Is it good as replacement?Last edited by sky007; 09-10-2014, 09:47 PM.Leave a comment:
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Re: Samsung Syncmaster 245BW
I will do tomorrow and let you know. Thanks....Leave a comment:
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Re: Samsung Syncmaster 245BW
If I take out QB801, am I able to get aux output voltage on Cb809?...Leave a comment:
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Re: Samsung Syncmaster 245BW
On the Collector, read 0.7 - 1.4V, Emitter 0.6-0.9V....Leave a comment:
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Re: Samsung Syncmaster 245BW
Sorry, my mistake. You are right, SMPS IC ICM801 Vcc is same as ICP801S (PFC IC) Vcc, 1V only. I got 14V on ICB801S Vcc pin....Last edited by sky007; 09-09-2014, 10:55 PM.Leave a comment:
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Re: Samsung Syncmaster 245BW
Just checked resistor/diode network between the Gate drive output pin and the Gate of the PFC MOSFET, they looks good.
Using a 330k resistor connect Sb and PW_On, so I have PSON 3V single. It switch on QB851, so PC801S and PC802S on.
I ahve trouble now, the ICP801S (PFC IC) Vcc is 1V only which should above 15V. And the Vcc on IC801S (SMPS IC) is 14V.
Checked around components, look good. My question is, if PFC IC is damaged, will it cause Vcc pin low voltage?
Thanks....Leave a comment:
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Re: Samsung Syncmaster 245BW
I was suspect the same thing. Either no VCC for PFCIC which is M_Vcc power by QB801, or boost circle problem. Can you tell M_Vcc reading when power on?
Also I test all components around ICP801S, looks like something wrong with DP803. Using multimeter, switch to diode, get the same reading on both side. Does it suppose one side no read?
Sorry my bad English....Leave a comment:
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Re: Samsung Syncmaster 245BW
Correct, my is 195A....Leave a comment:
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Re: Samsung Syncmaster 245BW
Need help here.
Got a monitor from my friend. Power supply is BN44-00195A. It gets 2 fuse blown, NT801S blown as well. After some work, cleared up all bad glue, found QP801S blown as well, replaced QP801S. I do not know what NT801S is, just found one NTC thermistors from a old computer power supply. Now connect all the boards together, I can see the blue power LED blinking, but I can't turn it on. Measure the main board connect, only SB give the 5.2V. Checked PFC, it is 155V only.
What else should I check? Thanks.Leave a comment:
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Re: Samsung 24" power supply BN44-00195A first stage voltage?
Need help here.
Got a monitor from my friend. Power supply is BN44-00195A. It gets 2 fuse blown, NT801S blown as well. After some work, cleared up all bad glue, found QP801S blown as well, replaced QP801S. I do not know what NT801S is, just found one NTC thermistors from a old computer power supply. Now connect all the boards together, I can see the blue power LED blinking, but I can't turn it on. Measure the main board connect, only SB give the 5.2V. Checked PFC, it is 155V only.
What...Last edited by sky007; 09-03-2014, 11:41 AM.Leave a comment:
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Weird problem: Dell 2005fpw noisy OSD menu
The monitor works well. But the weird problem happened.
Whenever I call OSD menu, the OSD menu always show lots noisy dots in the menu, not on the other part of screen, only in OSD menu area.
There is no visible failure CAPs on power and logic boards. Anyway, I replaced c637 and C635 on logic board. Symptom remains.
Any idea to fix it?
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