Friday, February 23, 2024

Power Supply Repair Book

Ultimate Power Supply Repair Guide is launching soon. This book focuses on component level repair of switching power converters found in consumer electronics devices like LCD/LED Tvs, monitors, device chargers and more. 

John has also put together a 3 day course on power supply repair and is now available for power supply repair consultation as well. For more information vist preherservices.com



Wednesday, March 26, 2014

Samsung HPS4253 no power, PSPF391A01A / BN96-03252A power supply repair

Repair service for Samsung PSPF391A01A / BN96-03252A power supply which is used in the following Samsung Models,

     HPR4272X/XAA, HPS4233X/XAA, HPS4233X/XAC SD03, HPS4233X/XAC SG04, HPS4233X/XAC SD01, HPS4233X/XAC SG02, HPS4253X/XAA, HPS4253X/XAC SD01, HPS4253X/XAC 0001, HPS4253X/XAC SD03, HPS4253X/XAC SG02, HPS4253X/XAC SG04, HPS4273X/XAA and SPS4243X/XAA


Typical failure symptoms that indicate power supply failure: No power. Totally dead, no standby LED and does not respond to buttons being pressed. TV shuts down immediately after being turned on. TV makes a clicking sound.


If you are interested in having a PSPF391A01A / BN96-03252A power supply or any other power supply repaired professionally contact johnpreher@gmail.com



Thank you for visiting our blog and remember to also visit www.preherservices.com

Monday, February 24, 2014

Sony BRAVIA KDL40EX600, no power, APS-272(CH) power supply repair

Sony BRAVIA KDL-40EX600

Failure symptom: No power

Upon diagnosis of the power supply I found that  power MOSFETs Q6101 and Q6102 were shorted between source,drain and gate and fusible resistor R6536 was open. Power MOSFETs Q6101 and Q6102 were 2SK4096 , 8 amp, 500 volt, N channel MOSFETs and were replaced with substitutes, FQPF9N50CF 9 amp, 500 volt MOSFETs. Resistor R6536 was a 1/2 watt 0.47 ohm fusible resistor.



After replacing the faulty components and installing the power supply the TV turned on and was completely functional.

 KDL-55EX500, APS-272(CH) Professional Repair:
If you are interested in having an APS-272(CH) or any other power supply repaired professionally then contact johnpreher@gmail.com



Thank you for visiting our blog and remember to also visit www.preherservices.com

Sony BRAVIA KDL-55EX500, no power, APS-256(CH) power supply repair

Sony BRAVIA KDL-55EX500

Failure symptom: No power

Upon diagnosis of the power supply I found that  power MOSFETs Q6304 and Q6305 were shorted between source and drain and fusible resistor R6350 was open. Power MOSFETs Q6304 and Q6305 were 2SK4096 , 8 amp, 500 volt, N channel MOSFETs and were replaced with substitutes, FQPF9N50CF 9 amp, 500 volt MOSFETs. Resistor R6350 was a 1/2 watt 0.47 ohm fusible resistor.


After replacing the faulty components and installing the power supply the TV turned on and was completely functional.

 KDL-55EX500, APS-256(CH) Professional Repair:
If you are interested in having an APS-256(CH) or any other power supply repaired professionally contact johnpreher@gmail.com



Thank you for visiting our blog and remember to also visit www.preherservices.com


Tuesday, October 2, 2012

Samsung power supply repair

HPT4254X/XAA, BN44-00161A Professional Repair:
If you are interested in having a BN44-00161A, BN44-00162A or any other power supply repaired professionally visit preherservices.com




Preher Services offers mail in repair service on power supplies for the following Samsung models,


Samsung HPT42
Samsung HPT4234X/XAA
Samsung HPT4234X/XAC
Samsung HPT4254
Samsung HPT4254W
Samsung HPT4254X
Samsung HPT4254X/XAA
Samsung HPT4254X/XAC
Samsung HPT4254X/XAP
Samsung HPT4264X/XAA
Samsung HPT4264X/XAC
Samsung PL42C71HDPX/XAX
Samsung PL42C71HPX/XAX
Samsung PL42C91HPX/RCL
Samsung PL42C91HPX/STR
Samsung PL42C91HPX/XAP
Samsung PL42C91HPX/XAX
Samsung PL42Q91HDPX/XAX
Samsung PL42Q91HPX/XAO
Samsung HPT5034X/XAA
Samsung HPT5034X/XAC
Samsung HPT5044
Samsung HPT5044X
Samsung HPT5044X/XAA
Samsung HPT5054X/XAA
Samsung HPT5064X/XAA

If sending your power supply, TV should have one of the following failure symptoms:

-Clicking
-shuts down
-goes on/off by itself
-No power-won't come on-dead

Sunday, July 24, 2011

Viewsonic VG1930WM no power, repaired

I just finished repairing a Viewsonic VG1930WM that had no power, no standby LED, completely dead. I opened up the monitor and checked the output voltages from the power supply and both were present and stable. I verified that the 5V was still present at the main board. Next I checked the output from the 3.3V and 1.8V linear voltage regulator ICs on the main board and the 3.3V regulator's output was considerably low around 2.2V, the output from the 1.8V regulator was also very low but it gets its input from the 3.3V regulator so it makes sense that the 1.8V regulators voltage was low. I replaced the 3.3V regulator after verifying it was faulty and the monitor was still dead when I plugged it in to check voltages again, the 3.3V regulator's output was now within tolerance so I again checked the output from the 1.8V regulator and it was still low about 1.2V, so I then replaced the 1.8V regulator and when I plugged the monitor in to check the output from the 1.8V regulator I saw the standby light turn on, the voltage output from the 1.8V regulator was now within tolerance and the monitor turned on and functioned flawlessly.




Also don't forget to visit www.preherservices.com

Viewsonic VX910 no power, repaired

I recently did a repair on a Viewsonic VX910 that had no power. Upon opening the monitor I could see that someone had already replaced all the electrolytic capacitors on the power supply secondary side. I plugged the monitor in and attempted to power on to check for any output voltages from the PSU and I could here a faint chirping coming from the power supply, this is always a good indication of a shorted output diode or faulty components in the feedback circuitry, the power supply is continually trying to start up and then shutting down,over and over. As I suspected there was no output from the power supply. I removed the power supply and the first thing I checked was the dual schotttky diode D660 and one of the diodes in the dual package was shorted. The original diode was a MBR10100CT dual schottky diode, I replaced it with a B20100G dual schottky diode. After replacing the dual diode the monitor powered on and worked once again.








Learn how to repair any power supply...

Also don't forget to visit www.preherservices.com

Ask about our 3 day power supply repair course.

Monday, June 20, 2011

Philips 37MF321D/37, 37MF331D/37, 715T2056-1 Power Supply Repair



We have been receiving quite a few 715T2056-1 power supplies for repair from Philips 37MF321D/37 and 37MF331D/37 LCD TVs. The failure symptom is typically that the green standby/power indicator led blinks constantly and the TV will not turn on. The most common reason this particular power suppy fails is the 2200uF 25V capacitor at location 2074 has puffed and vented or has a significantly high ESR, some of the other electrolytic filter capacitors on the secondary side of the power supply may have a high ESR as well. The 9.1V 0.5W zener diode(BZX79C9V1 is used for replacement) at location 6079 is commonly shorted, but may also be open as well. The SMD 2.2 ohm 0.125W resistor at location 3045 has opened and is usually burned often damaging the copper trace on the bottom of the PCB. Parts are available from http://www.mouser.com/.











Remember to visit www.preherservices.com

Wednesday, June 8, 2011

Samsung HPT5044 (HPT5044X/XAA) BN44-00162A power supply repaired.



To learn how I repaired this power supply email johnpreher@gmail.com

HPT4254X/XAA, BN44-00162A Professional Repair:

If you are interested in having a BN44-00161A, BN44-00162A or any other power supply repaired professionally visit http://www.preherservices.com.