Entertainment Center: TVs, Stereos, VCRs and DVDs - Sony TV won't stay on

I have a Sony KV34XBR800 TV and it won't stay on. I could hear the relay "click" to power up, sound is heard, but before the picture comes on, relay "clicks" and powers down. The first time I noticed anything wrong was about a week ago, when the TV shut itself off after about 20 minutes.

There is a small "Standby" light that flashes 6 times repeatedly when it powers down. Sometimes it flashes 7 times. Might this be a fault code to the problem?

Thanks

Here's the info straight from Sony.


Shutdown 6 blinks Low HV shutdown, Low B+ protection.

Symptoms / Customer Description
Shutdown 6 blinks
[Primary Symptom Code: 2111 ]

Solution

Low HV Shutdown:

On the D Board.

Check IC8004/pin 7 should be 7.4v.

Check IC8006/pin 2 should be 2.5v if lower will trigger shutdown by causing pin 1 to turn on.

Check IC8006/pin 3 reference voltage 2.2v.

IC8006/pin 1 normally at 0v. If high
turns D5007 ON which turns the latch circuit Q6532,

Q6530, and Q6527 ON and turns the AC relay RY6501 OFF.



NOTE: 6 blinks also can be Low B+ protection.



Unregulated 7.5 v from the power supply to 5v reg IC504 on the A Board. 5v to M Board Q2314


to CPU IC2300/pin 43. If 5v missing set will shutdown with 6 blinks.

Do you have a meter?

Thanks craftsman_50 for the quick reply.

I do have a meter. I take it that I should be able to measure these voltages while the unit is in the standby mode?

I have not removed the back cover yet. Will the boards and components be identified? Or will I need diagrams to find these parts?

The boards are usually marked and the ic locations are definitly marked. You should check the volts in both stanby and power on.It might check ok in standby,but when it loads up it might crap out.

The TV set is working again. So whatever is causing the set to turn off is intermittent. It could work for hours without shutting down. What I've noticed a few times is that when the set is about to shut down, the picture fades slowly(about 1-2 seconds), then the sound goes.

Anyway, until the TV fails permanently, or a least more often, my wife won't let me near the set to check the voltages. I will post my findings at a future date. Thanks

Since it started working again that narrows the problem to a bad solder connection or a capacitor going bad.Good news is it will be a cheap fix.:thumbup:

Craftsman_50,

I opened the back of the TV and found Boards D and A. When looking at the unit from the back, Board D is on the bottom left and Board A is on the bottom right. But I was unable to find the IC's you described(IC8004 & IC8006).

On Board D, there are IC6501 and IC8002. Both have identical IC's: Shindengen MCZ3001D 05325.

On board A, I found an IC903.

My Sony chassis is DA4.

Regarding bad solder joint and capacitor, how would you go about locating them?

The unit was quite dusty so I vacuumed everything off. It is still unplugged from the wall.

My latest observation is the picture will get real big and dim, then goes black, all in 1-2 seconds, and the sound quits afterwards. I sometimes see 4 blinks, then 6 blinks afterwards. On some occasion, instead of 6 blinks, it will be 7 blinks. But mostly, it is 6 blinks.

If the picture is changing in size ,that says its a voltage regulation problem.So since it intermitten I would suspect a capacitor.They normally are blue,black ,red or yellow, mounted with both component leads coming out of the bottom.The wraping on them will have the size printed on it,IE 100 mf,50 volt.Look for ones that have the wrap shrunk down exposing more of the top of the cap than the other ones do.Also look at the top of them to see if it seems to have expanded at the top.They will not look flat on top as compared with the others.A bad one can have one or both of these symptoms.
Remember if it was easy everyone could do it and I'd be out a job..lol:thumbup:

I'm about ready to pull Board "D" out and get a closer look at the capacitors. All of the connectors have been disconnected except for the wires running up to the board that plugs into the CRT. I just unplugged that board with the wires attached. They go back to the high voltage of Board "D"..

Also, the high voltage wire going up to the top of the CRT is still connected. I can't figure how to disconnect it. What's the trick? I peeked under the big rubber boot and could see the clip. The TV has been unplugged for 2 days. Is there still a charge on that wire?

Thanks

Ok, finally got the high voltage wire disconnected from the CRT. Touched the wire to the ground around the CRT to discharge, but no zap. Anyway, will give the circuit board a careful look-over and hope to find something that jumps out at me. Any other thoughts while the board is out?

Make sure you check the A board while your at it.Most bad solder connections will have small cracks in the solder,not smooth and flowing around the connection.They may even be discolored some.It's possible to have a lot of them that are suspect.To err on the righ side I would resolder every connection that looks suspect.They also happen on the pins of the ics.Any ic mounted on a heatsink check the solder on the pins.They run hot and the hot and cool down is what cracks the solder.
Good luck:thumbup:

All of the solder joints looked good on the D Board. But I did find one capacitor on the D Board that looked different than the others. The top wasn't quite as flat as the others. It was a 33uf 250v electrolytic. Couldn't find one rated at 250v, so I replaced it with a 300v one. They both behaved the same way when tested with a DVM. So I'm not sure there was anything wrong with it. It was cheap enough, costing less than $1.

Anyway, plugged it back in and it worked for a whole day. Turned it on and off many times. Then the next day, it was on the 6 & 7 blinkin routine.

Will try to get at the A Board next. Looks like this will be a little more challenging as there are other boards plugged into it.

Aside from doing a visual inspection, should I try to measure voltages?