Re: Samsung Syncmaster 204B repair
Right. Sending 0 volts for inverter on CN2
sermulis
Member
Last Activity: 06-24-2021, 12:14 PM
Joined: 07-23-2013
Location: Riga
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Re: Samsung Syncmaster 204B repair
shorted 5&6 pins on EEPROM A81SC. (if arrow indicates first pin) didn't help.
also, it seems that i was too fast - saying that power/inverter part is working. i see no backlights (or logic board prevent them to start)...Leave a comment:
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Re: Samsung Syncmaster 204B repair
no! sorry, if i confused you. power/inverted part seems to be ok now.Leave a comment:
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Re: Samsung Syncmaster 204B repair
what you suggest me to check now?
also, i've placed bulked 82uF 450V instead of 150uF 450V in primary, although i am getting 13V (which is OK) on CN2Leave a comment:
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Re: Samsung Syncmaster 204B repair
replacing diode bridge solved short circuit in primary.
now after power on i see blue diode light, but nothing on the screen and it's not possible to switch it on or off - just blue lightLeave a comment:
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Re: Samsung Syncmaster 204B repair
S1toD1 and S2toD2 are not shorted for all. S2toD1 are shorted for all.
readings showed about 1,1MOhm when tested 1to8 pin.
You still think that it is mosfet failure although i powered the board without the fuse for the inverter section and it blowed fuse in primary circuit?Leave a comment:
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Re: Samsung Syncmaster 204B repair
unfortunately i was not able to read P/N from U202 and U203.
Board is 204B-VE REV0.1.
I guessed that pins 3&4 are for source and drain, because pins 5&6 and 7&8 are shorted (G1 and G2 pins)
On 3&4 I am receiving 24kOhm (in the circuit) on U202 and U203
I have replaced F101 one more time (had some spare ones). Removed inverter section to check if short is caused w/o inverter added by removing F301 fuse. Received short circuit one more time. So it seems short circuit is caused in...Leave a comment:
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Re: Samsung Syncmaster 204B repair
i've checked these both mosfets for shorts from source to drain and received no short circuits.. i should check resistance for these mosfets out of circuit?Leave a comment:
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Re: Samsung Syncmaster 204B repair
Hi,
OK, i found and installed caps from spare boards.
C110, C111 - 1000uF 25VC
C112, C113 -> 470uF 25V
C304, C305 -> 470uF 25V
C105 -> 82uF 450V (bulked a little bit)
Found out that fuse F101 was dead (as i received it) - replaced the fuse.
Powered board on and received short -> Fuse F101 dead.
What do you suggest me to check ? What might be the cause for short in primary ?...Leave a comment:
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Re: Fujitsu SCENICVIEW P15-1A power board repair
after replacing C906 monitor came back to life
Last edited by sermulis; 09-15-2013, 01:35 PM.Leave a comment:
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Re: Fujitsu SCENICVIEW P15-1A power board repair
hmm. but why than I am receiving variable voltage on C906? I will replace this cap and post here results
Leave a comment:
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Re: Fujitsu SCENICVIEW P15-1A power board repair
hi,
what readings should I get for good diodes? should I test them out of circuit?
transistors can be checked in circuit for shorts in source to drain pins?
thanks!Leave a comment:
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Fujitsu SCENICVIEW P15-1A power board repair
Hi,
Fujitsu SCENICVIEW P15-1A monitor was not showing any led activity.
After opening it - one cap was bulked C922, which was replaced. After than i Was able to switch monitor on two times between not able to switch it on about 20 times.
Checking the power board i came to conclusion, that i'm not receiving power in secondary circuit - (caps C922-C925 0V DC).
I am receiving variable DC readings on C906 and IC901 (1 to 7 pin) from 11 to 15 Volts. Also, I am hearing ticking component in primary circuit (guessing that IC901 is not able to start)... -
Re: HP 1955 Monitor Repair Guide
Alright. Finally dealt with this monitor. After re soldering bad joints, and fixing cable to logic board, monitor came to life.Leave a comment:
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Re: HP 1955 Monitor Repair Guide
After all came to conclusion that my Power supply board IS OK.
Cut and repaired old sleeve from logic board to control buttons.
Connected all cables back. Now i am not able to see any diode indicator lights on control menu (diodes are OK). Pressing power on button seems doesn't work (silent dead monitor state).
May be someone can provide Logic board chema for this HP 1955 ?Leave a comment:
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Re: HP 1955 Monitor Repair Guide
if i understood you right.. than
V1 - 3.3V
V2 - 4.97V (pin to GND)
V3 - 5.07V (pin to GND)
V4 - from left to right - 3.13V, 0.02V, 0.02V (each pin to GND)...Leave a comment:
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Re: HP 1955 Monitor Repair Guide
hmm. maybe i am doing smth absolutely wrong or problem is behind the power board? pinout differs on actual board versus schema. measurements was taken without logic board and lcd panel connected....Leave a comment:
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Re: HP 1955 Monitor Repair Guide
on D602 i've got 10.9V
Sorry for measleading info. I measured standard diodes not zener ones.
Find proper ones
[B]ZD601 - 10.2 V
ZD602 - 10.6 V[/B]Re: HP 1955 Monitor Repair Guide
on D602 i've got 10.9V
Sorry for measleading info. I measured standard diodes not zener ones.
Find proper ones
[B]ZD601 - 10.2 V
ZD602 - 10.6 V[/B]Last edited by sermulis; 09-06-2013, 04:21 AM.Leave a comment:
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Re: HP 1955 Monitor Repair Guide
I see.. is it wise idea replacing zener diode without going any further? may be mosfets Q602, Q603 are shortd too, as well as zener diode ZD602.
p.s. sorry for spamming into forum. I am totally new in electric diagrams and repairs greater than simple cap replacingLeave a comment:
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