Re: TV Sharp LC 37D42U (DPS 178AP)
UPDATE!
I found the problem! it seems like the board got bend during shipping!. checking a circuit (i was checking values and continuity of all components) i found that i was getting a problem with IC76002, so i found out it didn't have continuity between its anode and the resistor R7629
I check real close the board and finally see that it was a little (minimal) bend, so keep checking and found were the conductive track were broken, now i just made a little soldering and test again the board! and BUMM it finally worked!!...
jdnation
Member
Last Activity: 05-30-2020, 05:27 PM
Joined: 05-28-2020
Location: Maracaibo, Zulia
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Re: TV Sharp LC 37D42U (DPS 178AP)
Here are the measure of the PD socket
1.- Measurements doing the VolUP-CHdown thing
GND = 0 Vdc
BU5V = 5.09 Vdc
PNL POW = 1.1 mVdc
GND = 0 Vdc
AC_DET = 3.09 Vdc
PS-ON = 3.02 Vdc
2.-Measurement when the TV is doing LED flashing thing
GND = 0 Vdc
BU5V = 5.09 Vdc
PNL POW = 0 Vdc
GND = 0 Vdc
AC_DET = 3.09 Vdc
PS-ON = 0 Vdc...Leave a comment:
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Re: TV Sharp LC 37D42U (DPS 178AP)
I just made the test and nop, the tv still doing the led flashing thing...Leave a comment:
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Re: TV Sharp LC 37D42U (DPS 178AP)
Ok ok i understand that, so what should i do?, how can i test the inverter board?...Leave a comment:
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Re: TV Sharp LC 37D42U (DPS 178AP)
Yes that's right!
but the optocoupler have 0.615V on the anode, i measure D7301 and its voltages are = C: 0.615Vdc, A:0.777Vdc
Then i measure R7306 and its voltages are 4.92Vdc and 0.777Vdc.
I think the problem is in the circuit that controls the gate of Q7304. But i really don't understand that circuit....Last edited by jdnation; 05-28-2020, 07:17 PM.Leave a comment:
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Re: TV Sharp LC 37D42U (DPS 178AP)
About Q7602 and Q7603 those were shorted in the old board, i get another one. This one seems find and the mosfet in this one are okey but i think this one have some other problem
Sorry i couldn't find that transistor (Q7900), i found Q7901 and Q7902
Q7901:
Ve= 0.535Vdc (VCC-ON)
Vb= 0.535Vdc
Vc= 0.00 Vdc
Q7902:
Ve= 0.535Vdc (VCC)
Vb= 0.835Vdc
Vc= 22.7 Vdc
Thanks for the help!...Last edited by jdnation; 05-28-2020, 06:53 PM.Leave a comment:
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Re: TV Sharp LC 37D42U (DPS 178AP)
Update:
Searching the internet i found the squematic diagram (Page 25 of the attachemnt) of the PSU. i've been studying it but can figure out what going on...Leave a comment:
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Re: TV Sharp LC 37D42U (DPS 178AP)
I did that, and the voltage appears but only for a second, then ti goes down to zero...Leave a comment:
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TV Sharp LC 37D42U (DPS 178AP)
Hi every one! i have a tv Sharp Model: LC 37D42U, witch have a DELTA power supply DPS 178AP
At first i had a bad power supply and the tv didn't have standby power (BUS 5Vdc) checking the board i realized that the two main MOSFET P16NS25 were shorted.
So i buy another one, it wasn't brand new so i trust the guy who sell it to me that it was good. Now i just connect the new board and i have stand by power (Bus 5Vdc), but now i have the power and opc led flashing one time and then only the power led flashing on time.
I've been investigating and the service... -
Re: New Members - please post your introductions here
Hello everyone!... I'm in this page cause i need some help with a SHAP TV. Model LC-37D43U.
I have read some of the post that talk about problems with these tv, but still can't figure out what is worng.
More about myself!. I'm From Venezuela, i'm an electrical engineer with way to basic basic knowledge about electronic, but with the proper guidance i know i can resolve some problems!.
Thanks! best regardsLeave a comment:
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