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Search: Posts Made By: R_J
Forum: Troubleshooting TVs and Video Sources Today, 09:45 PM
Replies: 27
Views: 227
Posted By R_J
Re: Sony KDL-55EX620 stand-by present, no stand-by light, AC_OFF_DET @.47V

It may not be that easy on this power supply because of ic6151, Disconnect CN6101 from the main. try placing a 1k resistor from STBY3.3v to POWER_ON, and you may also need a 1k from STBY3.3v to...
Forum: Troubleshooting Power Supplies and Power Supply Design Today, 07:09 PM
Replies: 1
Views: 12
Posted By R_J
Re: Mean Well PT-65-R13VAI with a short.

Start by checking the resistance across the + & - of BD1 bridge rectifier, then check each of the 4 diodes in the bridge, then check Q1 mosfet for shorts, if it is shorted, I suspect the drive ic u1...
Forum: Troubleshooting TVs and Video Sources Today, 06:44 PM
Replies: 27
Views: 227
Posted By R_J
Re: Sony KDL-55EX620 stand-by present, no stand-by light, AC_OFF_DET @.47V

Then you should never connect the power supply to the main board because it supplies 3.3 volts to the ac detect line and you are saying that it will damage the board
Nothing is going to get TOOSTED...
Forum: Troubleshooting TVs and Video Sources Today, 05:14 PM
Replies: 27
Views: 227
Posted By R_J
Re: Sony KDL-55EX620 stand-by present, no stand-by light, AC_OFF_DET @.47V

My sugestion was to fake the ac detect line to the main board, that was in case the fault WAS caused by the missing ac detect voltage from the power supply. If the fault was caused by a missing ac...
Forum: Troubleshooting TVs and Video Sources Today, 04:24 PM
Replies: 27
Views: 227
Posted By R_J
Re: Sony KDL-55EX620 stand-by present, no stand-by light, AC_OFF_DET @.47V

There are a bunch of small fuses on both sides of that main board, it might be worth checking them, you never know, I see at SJ there is an update to do after replacing the main board
Forum: Troubleshooting TVs and Video Sources Today, 04:13 PM
Replies: 14
Views: 163
Posted By R_J
Re: troubleshooting bn44-00598a

You can can test the fets inside the ic to see if they are shorted, If one is shorted then you know you found the problem.
Forum: Troubleshooting TVs and Video Sources Today, 03:57 PM
Replies: 6
Views: 37
Posted By R_J
Re: Samsung UE55JU6872UXXH - Lower third darker

My guess would be bad led's (shopjimmy is out of them) Looking at the power supply board, there are two seperate strings for the backlights and there are LED Test points marked on the board near the...
Forum: Troubleshooting Laptops, Portable, and Mobile Devices Today, 03:31 PM
Replies: 2
Views: 30
Posted By R_J
Re: ripped IC tripping USB OVERCURRENT

Post a picture of the ic if you can, It could be a SPN7002D or MTDN7002ZHS6R dual mosfet or maybe ADG702dual cmos low voltage spdt switch
Forum: Troubleshooting TVs and Video Sources Today, 03:17 PM
Replies: 3
Views: 82
Posted By R_J
Re: Philips 47PFL8404 H / 12, chassis Q548.1ELA

How did you check the ccfl lamps in the panel? You may have a bad inverter transformer, there are two, check the resistance of the secondaries and compare them to each other.
Forum: Troubleshooting Computer Displays Today, 02:17 PM
Replies: 1
Views: 16
Posted By R_J
Re: Blink EVSE touchscreen intermittent problem.

It looks similar to this http://www.urt.com.tw/products_show.php?show=215 But might be custom
It is either resistive or capacitive, I would guess capacitive
Forum: Troubleshooting TVs and Video Sources Today, 01:58 PM
Replies: 11
Views: 7,215
Posted By R_J
Re: Panasonic TX-L42B6B LED Single Blink

I blame the consumer, You all wanted large, cheap, flat panel tv's and you got them.
Forum: Troubleshooting TVs and Video Sources Today, 09:49 AM
Replies: 14
Views: 163
Posted By R_J
Re: troubleshooting bn44-00598a

Use something like alcohol to clean the top of the ic, you might see the number, if not I will try and find it

When the fets short are all three pins shorted together?
The ic Might be a BD8693 ...
Forum: Troubleshooting TVs and Video Sources Today, 09:17 AM
Replies: 6
Views: 87
Posted By R_J
Re: CRT TV:What causes this kind of geometry issue?

Why not post the model number so we know what we are dealing with. An actual picture of screen with the fault might help also.

Check when there is a large white area is there bleading of a...
Forum: Troubleshooting TVs and Video Sources Today, 09:06 AM
Replies: 14
Views: 163
Posted By R_J
Re: troubleshooting bn44-00598a

The proble could be with the drive to the fets, check the gate resistors (if they have them) and it could be that the gate drive ic's are bad. When the fet shorts, it can supply high voltage back to...
Forum: Troubleshooting TVs and Video Sources Yesterday, 09:17 PM
Replies: 6
Views: 87
Posted By R_J
Re: CRT TV:What causes this kind of geometry issue?

could be a bad one of these, scope the vertical circuit
Forum: Troubleshooting TVs and Video Sources Yesterday, 08:22 PM
Replies: 14
Views: 163
Posted By R_J
Re: troubleshooting bn44-00598a

If you have Vs voltage and you have Va voltage, that part of the power supply is ok

You may have a fault with the SVT_XOUT voltage circuit
The SVT_XOUT voltage comes from the Vs voltage and is...
Forum: Troubleshooting Game Consoles & Other Weird Devices Yesterday, 07:50 PM
Replies: 9
Views: 96
Posted By R_J
Re: Repairing digital scales (readout not stablizing)

If that to220 is a regulator ic, it's caps could be bad and its output noisy, the processor might be seeing that noise and changing the reading.
Forum: Troubleshooting TVs and Video Sources Yesterday, 07:07 PM
Replies: 8
Views: 106
Posted By R_J
Re: chip orientation

This tells me nothing.
Forum: Troubleshooting TVs and Video Sources Yesterday, 06:32 PM
Replies: 8
Views: 106
Posted By R_J
Re: chip orientation

Which ic are you talking about? What mosfet are you refering to?
the ic in post #1 has nothing to do with the ic pictured in post #5
What number are you replacing IC7903 with? IC 7903 is the...
Forum: Troubleshooting TVs and Video Sources Yesterday, 05:21 PM
Replies: 14
Views: 163
Posted By R_J
Re: troubleshooting bn44-00598a

The Va voltage goes to the plug CN4006. There are likely shorted fets for the Z-sus part of the board (on the back of the board)
What are the locations of the fets that keep shorting?
Forum: Troubleshooting TVs and Video Sources Yesterday, 02:55 PM
Replies: 3
Views: 44
Posted By R_J
Re: Grundig 49 VLE 6620 BP Led *Backlight blinking

I suspect the ac voltages listed are high frequency as the come from the switching power supply, (20-50khz) most meters won't measure them
If you can, turn down the backlight (or sometimes...
Forum: Troubleshooting Power Supplies and Power Supply Design Yesterday, 01:50 PM
Replies: 27
Views: 187
Posted By R_J
Re: Voltage Regulators and Heat Issues

without putting any caps on that regulator it will oscillate, and when it does it will run hot.
Forum: Troubleshooting Power Supplies and Power Supply Design Yesterday, 09:37 AM
Replies: 27
Views: 187
Posted By R_J
Re: Voltage Regulators and Heat Issues

Something like this is what I was thinking of, there are other types also https://www.aliexpress.com/item/1PCS-Mini-DC-DC-12-24V-To-5V-3A-Step-Down-Power-Supply-Module-Voltage-Buck/32806176585.html...
Forum: Troubleshooting Power Supplies and Power Supply Design Yesterday, 09:18 AM
Replies: 27
Views: 187
Posted By R_J
Re: Voltage Regulators and Heat Issues

I would agree, 24 volts is near the input limt for a 7805, I would at least put a 7812 between the 24 volts ant the 7805 input, also make sure you have good filtering on the input and output, and its...
Forum: Troubleshooting TVs and Video Sources 03-19-2019, 09:54 PM
Replies: 3
Views: 51
Posted By R_J
Re: Panasonic TC-P50GT50, Won't turn on.

The standby circuit usually is fed by 160 volts, There is no need to run the pfc circuit to operate the standby, it would be a waste of energy.
The a/c runs through the resistor because in standby...
Showing results 1 to 25 of 500

 
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