metropical
Member
Last Activity: 11-13-2024, 12:08 PM
Joined: 01-19-2017
Location: NYS
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little bump -
Hi RJ. If you have a minute to advise. Thanks, FritzLeave a comment:
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finally got to it.
Had 5.76v at p1 of Main 1.
p3&4, nothing.
p7&8, 10v
p11&12, 12.76v
there is a red LED on inside the cage on the left as you face the back of the TV.Leave a comment:
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Can this all be done without the Main 1 & 2 (PD) plugs connected?
Could J7914 be used for 5v and J7918 be used for PS_ON?
Don't have the dinkiest gator clips....Leave a comment:
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is there no way to check those voltages without the resistor? My days of having parts around are long gone.
If it is likely a main board problem, at the price of new TVs now, I'll probably bring it to ecycle.
It is so old that shopjimmy wasn't interested in my shipping the pcb's.Leave a comment:
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standby 5V is good. I have the schematic.
In that thread, you refer to Q7902/Vc 23v, which appears to be in a cage.
Is there a test point I can check with the PS still in and powered?
Are VCC & VCC_ON 5v?Leave a comment:
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fuse has continuity.
Found the attached pin outs for the 3 PS board connectors.
I'll check the BU5V but what is the legend clip at the Main board?...Leave a comment:
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Sharp lc32d42u seems dead
plugged in after being off for quite some time. No OPC lights. Tried flashlight test for backlight check, nada.
Pulled the PS and checked all diodes including the 5w(?) D7908 that was the issue last time. All diodes check OK in circuit with DVM diode test.
No caps look unhappy. It is 17 years old. Was gonna fix and give to my brother.
But is there anything else to try or is it likely met its match.?... -
Re: sharp lc32d42u power supply - DPS-178APA
"Since all the other voltages are being supplied by the power supply, and you say the rest of the tv is working and the fault is on THIS power supply. Simply forcing on Q7926 will not be an issue and the tv will work because you tested proved it with the other power supply correct?
Correct.
Can I assume that this resistor test can be done without the "load" of the rest of the TV?
If so, I'd bring it to my friends shop week after next and do it there.
If not I'll get a couple 1ks...Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
"Shorting Q7907 collector to ground will force the PNL5V ON. "
Something has changed here. The blue power LED upfront no longer lights.
I just shorted the C of Q7907 to gnd. PNL POW (P4 of PD) OV.
P3/4 of PE at 0V.
Perhaps Q7907 was failing or am I coming to the wrong conclusion?
Other Voltages are all still correct.Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
PE
pin1=UR6V - 5.77
pin2=gnd
pin3=PNL5V - 0
pin4=PNL5V - 0
pin5=gnd
pin6=gnd
pin7=UR10V - 10
pin8=UR10V - 10
pin9=gnd
pin10=gnd
pin11=UR13V - 12
pin12=UR13V - 12
PD
pin1=PS-ON - 3.02
pin2=AC_DET - 3.07
pin3=gnd
pin4=PNL POW - 0
pin5=BU5V - 5
pin6=gnd
LA
pin1~5=24V yes
pin6~10=gnd
when I short Q7907 collector to ground, the red LED annunciators on...Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
Since I'm sure the PS is the problem, as when I swapped supplies with another of the same TV, it works.
Isn't there some point to source the problem on the power board?Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
trying to figure out the location.
Is there any indication in the SM pcb drawings that would indicate this heat sink. The ref point might help localize the chip.
[ATTACH]206651[/ATTACH]
Or remove it that I might have a look at whats hidden.Re: sharp lc32d42u power supply - DPS-178APA
trying to figure out the location.
Is there any indication in the SM pcb drawings that would indicate this heat sink. The ref point might help localize the chip.
[ATTACH]206651[/ATTACH]
Or remove...Last edited by metropical; 02-05-2020, 05:35 PM.Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
IC2007, R2004 and C2024 seem to be on the B-side (trace).
Are there test points on top I can access?Last edited by metropical; 02-05-2020, 01:33 PM.Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
zero volts on J7915 with plug PE restored and the lvds unplugged.Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
Hi R_J. I realize you're prolly have other things going, but when you get a chance.
Thanks,
FritzLeave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
both sides behind the cage.
Ov.Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
which is the LDVS cable? The 2 ribbons at the top of the board or those at the bottom behind the cage.?
Also, not familiar with those connectors. How do they separate?...Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
Took some doing but there is always a piece of sacrificial Cat 5.
I took a piece of wire from ground to the Q7907 collector.
With TV on or off, 5v.
So Q7926 is good?Last edited by metropical; 01-30-2020, 10:27 PM.Leave a comment:
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Re: sharp lc32d42u power supply - DPS-178APA
I'll have to find me some better gator clips. It's pretty tiny on that Q.
But, unplug PE on the power supply and with the tv on, check the voltage on J7915. It is 0 volts.
This might take me a few days to find leads out here in the boonies.
Prolly pick some up in the city next week.
I'll be in touch.
Thanks very.Leave a comment:
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