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Search: Posts Made By: R_J
Forum: Troubleshooting TVs and Video Sources Yesterday, 06:14 PM
Replies: 72
Views: 8,003
Posted By R_J
Re: Toshiba 26AV600A

I don't believe the optocoupler is the problem
The datasheet says that pin 4 provides a 2v reference voltage which should show up on one end of R932, This voltage is from the ic itself so I suspect...
Forum: Troubleshooting TVs and Video Sources Yesterday, 05:54 PM
Replies: 10
Views: 120
Posted By R_J
Re: Samsung UA46C8000 Vertical lines

I would bet money someone cleaned the screen and liquid ran down and damaged the board that connects the lcd itself, Remove the front bezel and inspect that board, but it is likley not repairable
Forum: Troubleshooting TVs and Video Sources Yesterday, 05:48 PM
Replies: 1
Views: 56
Posted By R_J
Re: Vizio Main bord Question

Maybe the eeprom is not the problem?
Forum: Troubleshooting TVs and Video Sources Yesterday, 10:31 AM
Replies: 33
Views: 617
Posted By R_J
Re: Vizeo E500i AO dead with led on

What ac voltage are you talking about that is doubling? The ac from the line is rectified to 160VDC, Then when the power supply is turnd on, the PFC circuit starts and using high frequency switching,...
Forum: Troubleshooting TVs and Video Sources 05-28-2020, 09:27 PM
Replies: 72
Views: 8,003
Posted By R_J
Re: Toshiba 26AV600A

It would seem the ic is in standby, pin 5 needs to be above 50mv. Check the two resistors, R932 (3.9k) and R992 (100Ω) if they are ok, check that the optocoupler is not bad and that C991 is not...
Forum: Troubleshooting TVs and Video Sources 05-28-2020, 07:51 PM
Replies: 16
Views: 179
Posted By R_J
Re: TV Sharp LC 37D42U (DPS 178AP)

That was just an example, you could have a high load on one of the other supplies, You could try unpluging the inverter board and see if the tv turns on without backlight.
Forum: Troubleshooting Computer Displays 05-28-2020, 07:45 PM
Replies: 9
Views: 89
Posted By R_J
Re: Samsung 245BW BN44-0019A

It is likely easiest to unsolder the transformer secondaries from the board to check the smd components
Forum: Troubleshooting TVs and Video Sources 05-28-2020, 07:24 PM
Replies: 16
Views: 179
Posted By R_J
Re: TV Sharp LC 37D42U (DPS 178AP)

That looks like an over voltage/over current protection circuit, if any of the voltages are too high such as UR6V, then D7315 conducts and turns on the Q7304 SCR. The SCR turns ON shorting out ic7902...
Forum: Troubleshooting Computer Displays 05-28-2020, 07:12 PM
Replies: 9
Views: 89
Posted By R_J
Re: Samsung 245BW BN44-0019A

the 473 should read 47k but if you look at the circuit you will see they are basically in parallel with the transformer and the RM811/RM813 resistor. so it would seem, either the resistor or the...
Forum: Troubleshooting TVs and Video Sources 05-28-2020, 07:04 PM
Replies: 16
Views: 179
Posted By R_J
Re: TV Sharp LC 37D42U (DPS 178AP)

I was looking at the poor schematic, so it would be Q7902. Q7902 has 23v on the collector which is ok, to get the 15 volts on the emitter, the base needs to be turned on by the optocoupler IC7902,...
Forum: General Electronics Technical Discussion 05-28-2020, 06:43 PM
Replies: 28
Views: 3,837
Posted By R_J
Re: component identification

Glad to here its up and working again.
Forum: Troubleshooting Computer Displays 05-28-2020, 06:40 PM
Replies: 9
Views: 89
Posted By R_J
Re: Samsung 245BW BN44-0019A

Yes those are the components, the resistors look ok in your picture but check them anyway, also check the transformer to make sure the two secondary windings are not open.
The diodes are likely...
Forum: Troubleshooting TVs and Video Sources 05-28-2020, 06:28 PM
Replies: 16
Views: 179
Posted By R_J
Re: TV Sharp LC 37D42U (DPS 178AP)

Since you have standby BU5V, also check if you have voltage on Q7900 collector (18~25vdc) Then with the power supply turned ON, check if you have VCC & VCC_ON
If Q7602 & Q7603 were shorted, check...
Forum: Troubleshooting Computer Displays 05-28-2020, 05:58 PM
Replies: 9
Views: 89
Posted By R_J
Re: Samsung 245BW BN44-0019A

You can operate the board without RM801. This power supply is in 3 sections, the standby supply, the PFC supply and then the main supply. The pfc ic and mosfet are ICP801s and QP801s
Forum: Troubleshooting Computer Displays 05-28-2020, 05:45 PM
Replies: 9
Views: 89
Posted By R_J
Re: Samsung 245BW BN44-0019A

Are these component numbers from the board or the schematic? If they arefrom the schematic, RB802 is 47Ω not 100k. with RM801 removed and the board turned OFF, what is the voltage across the main cap...
Forum: Troubleshooting Power Supplies and Power Supply Design 05-28-2020, 02:50 PM
Replies: 12
Views: 185
Posted By R_J
Re: Dead ATX power supply, please help.

If the coil was open circuit, you can just use a short piece of wire to replace it for now, If you want to rewind the coil, use the same gauge wire that was on it, or something close. The coil is...
Forum: Troubleshooting Power Supplies and Power Supply Design 05-28-2020, 10:35 AM
Replies: 12
Views: 185
Posted By R_J
Re: Dead ATX power supply, please help.

Check that the bridge rectifier is not shorted, and also check if the main switching mosfets are not shorted.

If the coil was still making connection in the circuit the power supply should have...
Forum: Troubleshooting Power Supplies and Power Supply Design 05-28-2020, 10:27 AM
Replies: 12
Views: 185
Posted By R_J
Re: Dead ATX power supply, please help.

You can just rewind it, You must use coated wire not bare copper wire. The paint color is only to indicate the core material etc.
If you do replace the coil, place some insulated material between...
Forum: Troubleshooting TVs and Video Sources 05-28-2020, 10:14 AM
Replies: 72
Views: 8,003
Posted By R_J
Re: Toshiba 26AV600A

The 13 volts is ok for the ic's vcc, Check the voltage on ic970, pin 7, and pin 5 (look at the schematic and locate a nearby component to check the voltage to avoid shorting the ic pins (IE: pin5 use...
Forum: Troubleshooting TVs and Video Sources 05-27-2020, 07:47 PM
Replies: 33
Views: 617
Posted By R_J
Re: Vizeo E500i AO dead with led on

What about the other diode? it might be D120? I don't have a schematic so without the ic numbers I don't know what else to check.
If you can't make out the ic numbers you might need to clean them...
Forum: Troubleshooting Power Supplies and Power Supply Design 05-27-2020, 01:55 PM
Replies: 12
Views: 185
Posted By R_J
Re: Dead ATX power supply, please help.

It is not critical, you can install a wire in place of the coil if you like. Or find some coated wire and rewind the coil.
Forum: Troubleshooting TVs and Video Sources 05-27-2020, 12:20 PM
Replies: 11
Views: 125
Posted By R_J
Re: sharp aquos lc-60le640u Backlight

No, the 3, 70" strips together are longer, then the 2, 60" strips. they go from one side to the other of the lcd panel and very likely light the edge of the light guide plate.
Forum: Troubleshooting Computer Displays 05-27-2020, 12:06 PM
Replies: 1
Views: 47
Posted By R_J
Re: LG W1946 buttons / schematics

You could GOOGLE search for the manual
Forum: Troubleshooting TVs and Video Sources 05-27-2020, 11:17 AM
Replies: 72
Views: 8,003
Posted By R_J
Re: Toshiba 26AV600A

The resistors are ok, so the fets are likely ok, Now check the voltages
Forum: Troubleshooting Power Supplies and Power Supply Design 05-27-2020, 10:48 AM
Replies: 12
Views: 185
Posted By R_J
Re: Dead ATX power supply, please help.

Is the coil connected where the a/c line comes in? if it is it is not that critical and you could find some similar coated wire and rewind it, or find a similar coil from another power supply. If it...
Showing results 1 to 25 of 500

 
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