Citizen C27604HD TV No Power

I was able to find a service manual for a Viewsonic N2751W which appears to have the same hardware.  It can be downloaded from here.  A better power supply schematic can be found here.

The usual suspect for power issues are bad electrolytic caps.  It took me a while to get the back cover off since it was being help in place by clips.  I had to push in the sides of the back cover to release it.

Inspecting the power supply board, I found four bulged capacitors.  2 x 1500uF/16V, 220uF/25V and 220uF/35V.  These were all capxon brand.  I replaced the non-bulging capxons as well which were 2 x 1000uF/25V and 220uF/16V.

When I reinstalled the board, I still had no power so I googled the board part number FSP 212-3F01 (3BS0118510GP).  This board is used in several TV’s including Hanspree JT01-32U1-000G and Viewsonic models N2635W, N2751W, N2752W, N3235W, N3250W, N3251W and N3252W.

Q7 and ZD4 are usual suspects with no power since these parts provide 5V DC standby.  Checking Q7 with a multimeter showed it was shorted base to collector.  A good BJT transistor should have a diode drop between base to emitter and base to collector.  You do have to be careful working with the power supply board when it is plugged in since the majority of it is hot and you can get a shock even from touching the ground.  ZD4 should have 15V DC across it.

I replaced Q7 – MMBT4401 (Digikey #MMBT4401LT1GOSCT-ND) and ZD4 (Digikey #1727-4962-1-ND).  I also decided to replace all the remaining smaller capxon caps 33uF/35V (3), 2.2uF/50V,  10uF/50V and the two remaining Taicon 1000uF/35V caps.

Once power was back up, I had some issues with the remote control not working.  I was able to get it working by performing a factory reset.  With the TV on, press the power button in the front,  and up and enter keys on the top at the same time (all three together) to bring up the service menu.  Select EEPROM Init to perform the reset.

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