Dead tv unit is dead.Further cheking finds Dp027 shorted.Nothing else was shorted.Replasing the diode and reapplying power again shorts dp027 again.

If the tv appears dead with no standby light, try this: I have come across several units with this problem. The issue is a shorted diode. It will be one of the top ones fanning out from the transformer on the upper right of the board. Typically the top one at an angle just below the blue capacitor. It will cost just over a dollar at mouser.com. The diode is a FR154-b 1.5A 400v rectifier diode. This will fix you up! Use a multi meter to test for short. The Zener diode above this one may read as shorted but is is probably not. The other one is linked to it

Hi,

Here are some basic steps that will help you fixing the problem.

I'm assuming that your unit is dead set without an standby LED light and your outlet is live.1.Power cord - check the cord it might be opened (no continuity).This is due to frequent bending,pulling. 2. Power switch - check for dry joints, open contact. 3.Check the internal fuse- sometimes the fuse fail because of the power surge, replacing with new one will cure the problem, If this is the case I would advice you to use surge protector/AVR (Automatic Voltage Regulator). However if the fuse blew again this is an indication that you have a shorted parts in the power supply, you may visit the linkhttp://www.fixya.com/support/r8053361-fuse_keeps_blowing for more info. If no reaction and still the unit didn't power up then you have an open parts on the power supply.

4.If you see that the fuse is intact , don't attempt to touch anything because there some fatalcomponents stored electricity enough to hurt you with a simple mistake only. I would advice you to look for a professional to troubleshoot the power supply. If you want to repair it yourself make sure that you have necessary tools and test instrument. First check bad solder joints(re-solder all cold solder), leaky electrolytic capacitor(sometimes it has bulged at the top but not all, you better have a capacitor checker), open/shorted regulator transistor/IC(mounted in heat sink), open fusible resistor (caused by shorted regulator Transistor/IC), shorted zener diode.

You may also replace the entire power supply board, click this LINK.

Hope I helped you.

Thanks for using fixya.

Jdvillanueva

that problem is in the power supply..

try to open the cover then look for the power supply if you see the power supply try to see inside then look for the fuse if busted?if it is busted check all the possible caused like power transistor called regulator.diode,transistor check if it is shorted..and also look for the leak capacitor and open resistor when you find defective parts replace it and finally try to test it again

please rate my answer if it is helpful thank you

Hello
You haven't specified anything about your Sony Tv. No model number or anything to compare. Although I hereby giving you a general trouble shooting method, first adopted by technicians like me. You have stated that the fude has blown out. Fuse will not burn out without any reason. it is a protective device used in every telivisions,as if any internal components inside it gets shorted, especially in power supply section, the fuse will get burned and protect the other components from further distruction. Therefore you have to trace the reason for the failure of fuse first.
You must beging it from power supply regulator section itself. Chech the resistance accross the main filter capacitor first. Set the multimeter in Ohms range, and the resistance must be above 250Ohms in one direction, and upto infinite in the other direction. If both readings comes below 20Ohms or so, suspect the power regulator Ic; usually sony sets udes STR type regulated power supply, and this STR will get shorted. As you haven't specified your sets model, I can't make sure whether it is circuted with STR or a switching transistor. As both cases, this regulator has a chance to get shorted. Desolder it out and check for short. if it finds shorted, check the rlated components also, such as zener diodes and resistors, for open and short,as they also will get damaged due to this main switching transistor, or STR; whatever may be.
Check the degaussing posistor for short. Check the rectifier stack for short. Check the mains filter capacitor for short. Check each and every diode for short. you must measure the forward reisistance of diodes with multimeter set in 100KOhms range. There shouldn't be any slight leak with this test. If it shows a slight leak, replace it. You just do these and inform me the result through Fixya. I'm ready to assist you furthermore. When you reply to me; please include the model number of your Sony Tv. Ok.

Hello
Check the input fuse first. If it is blown, there will be some short inside the power regulator circuit. Usually Sony sets uses STR regulated power supply. You can see this STR, and Ic, screwed onto a heatsink. Replace it with a same type and number. Before replacing the STR, check the diodes used in that section for damage, mainlu zener diodes. They might get shorted along the blowing of the STR. Check that section throughly before resoldering the new STR.
If any further assistance you needs, get me through Fixya. Ok.

it sounds like the compressor has shorted out the best way to find out is use a multi meter and text the terminals on the compressor to ground if the multi meter sounds off in the diode setting then the compressor has a dead short hope this helps good luck

Repaired dead Polaroid TDA-03211C

I fixed a dead Polaroid TDA-03211C for my friends. When it failed it had just been turned on and then it went totally dead. This unit is a little over a year old and out of warranty. When I inspected the power supply it was continuously trying to start up but could not. With a Fluke meter you could see some of the DC output voltages rapidly rising and falling, but never getting to normal levels. I pulled the power supply thinking some of the capacitors were bad. Once I had the power supply out I used the Ohmmeter to check for any open or shorted diodes and/or transistors. To my surprise I found a shorted diode! I figured it would be the capacitors (typical failure in switchers), however they looked OK (not leaking goo or puffed out) and the TV is not that old. The failed diode (sorry I forgot to get the circuit designation) is a HER-304 (near the middle of the board with the cathode lead soldered to a small silver colored heatsink). The HER-304 is a 300 Volt, 3.0 Amp High Efficiency Rectifier in a DO-27 package. The DO-27 package is cylinder shaped with axial leads, 0.375" (9.5mm) long and 0.197" (5mm) in diameter. This diode is for the 20 volt source and is connected to one of the secondaries of the transformer. On eBay I found a vendor selling five (5) HER-305 (400 Volt units, better than the original) for $1.25 plus $7.95 shipping. Also I checked most of the Capacitors with a Sencor Z-meter, all that were check were OK. If a Cap. had another in parallel with it I did not check the other. I removed (un-soldered) the heatsink from the board and then the diode from the heatsink. I put it all back together and Yes, under $10.00 in parts (actually a $0.25 part) and a little time and the TV works again! 24 July 2009.

WARNING!!! WARNING!!! WARNING!!! Switch mode power supplies such as this use and generate voltages at current levels that can be LETHAL!!! If you DO NOT know what you are doing, find someone that does or buy a new TV, it is not worth dying for!!!

next to the fuse that blows is 4 large black diodes.one of those is common to short out. the bad one would give you areading of zero ohms when checked with a meter. or just replace all 4.most likely its location D603. hope this helps

Check Zener Diode ZD2 on the board to see if it's shorted.
If it's shorted replace it.

The problem is most likely in the vertical circuit, possibly the vertical IC itself or one of the feeder caps in that circuit. Could be possible poor solder connections on the IC also. Is the problem intermittent? There are a number of common problems with this unit effecting the following parts: Dp027 (27v Zener) P/N 244835 Tp022 (Bc648) P/N 198743 Tp025 (Bc558) Ip001 P/N 257786 Ip050 Ic Voltage Regulator , Zener Diode With 3 Legs Looks Like Diode. Ip030 263567 Dp057 232662 Tp052 198743 Tp020 (2sk2842) P/N 263692 Tp023 (2sc8550) P/N 257827 Dp025 244870 This is an ITC008 chassis built in mexico and the problem you're describing should be an inexpensive repair - but my downside opinion is that with this particular unit you could expect the next problem in about one to two years. Being a certified technician there are few TV's that I would tell a customer to walk away from if they were considering a purchase - but this is one of them. I'm sorry for such a negative review, please don't take it out on my rating for this solution. But if you have it repaired take it in yourself and save a few bucks - and ask the shop to save all the old parts for you. Good Luck Bill