View Full Version : Sony KV-32XBR450 shutting off


Spinning Head
07-20-2017, 11:18 PM
I've got a Sony KV-32XBR450 that I curb picked 5 years ago and is the newest set in the house (no flat panels here). Decent set, but lately has been been shutting off shortly after power on. I'm guessing this is the two power supply chip issue that's been discussed in other threads. But would like confirmation.

Electronic M
07-20-2017, 11:26 PM
Any blink codes when it fails? You can search those online and in the service manual for a fix.

IIRC the PS chip issue results in a dead set normally, so that probably is not it...Yet.

Findm-Keepm
07-21-2017, 12:10 AM
On the 32-inchers, a common intermittent problem is on the A (main board) - the connectors on the board develop bad solder joints - the heat/cool cycle affects them greater because the mass of the pins is greater than the typical component lead. The connectors will all have a "CN" prefix.

I stealthily fixed one in my ex-in-laws timeshare. We had a service call in, but there had to be someone there to "host" the tech - yeah, right. So I got help, manhandled it over to the table, pulled the back, and went to work re-soldering with a butane powered iron at first, and then a RadioShack iron second. About 20 or so really obvious bad connections repaired, and it was fixed. Dora the Explorer for the kiddo...

Take a good look at all the chip connections to - the uP resonator and the microprocessor IC itself (big chip, center of board with 56 or 64 pins..) - they can cause all kinds of problems. Don't flex the board looking for bad connections - you can corrupt the EEPROM and start a whole new set of problems (DAMHIK) - use a good quality magnifier/loupe to inspect the A board connections.

The only other intermittent shutdown I'm aware of in the XBRs is the audio chip TA82XX (not sure of the suffix...) will start into overcurrent/overheating and shut down a set. You can run it at low volume for hours, no shutdown. Raise the volume to room volume, and wait a minute or two, and bam - shutdown. Sony also advised replacing the diode feeding it B+, and we did change a few of them as a precaution.

Spinning Head
07-21-2017, 10:21 PM
Ok, I counted the blinks and downloaded a service manual. 5 blinks = white balance failure. Seems like some problem on the CRT board with cathode current. Is this a common failure mode? Could it be leaky or high ESR electrolytic caps. Thanks for any advice.

Findm-Keepm
07-22-2017, 12:17 PM
Has your set ever arced? Sony had a bulletin for sets that had CRT base arcing, as sometimes the arcing would trigger a shutdown.

I'd post it here, but the fourm limits the size of PDF files. Essentially, you remove the CRT socket, remove (very carefully) the index key cap on the base of the CRT, and then remove the RTV at the base of the CRT. The RTV they used didn't have a high enough dielectric strength when cured to avoid a flashover. They specify a Sony-part numbered RTV, but RTV3145 will also work.

Good news - the bulletin is here:

http://ebaman.com/index.php/component/remository/Home-Electronics/Sony/Sony-tv-bulletins-repair-modifications-note/orderby,6/page,25/?Itemid=0

TVP0557.pdf

Findm-Keepm
07-22-2017, 12:23 PM
...and Scribd has the training manual, good, because my paper copy is MIA:

https://www.scribd.com/document/27936264/CTV32-Training-Manual

See the section on AKB troubleshooting - it may be weak CRT, mis-adjusted G2 (gotta crank it up as the CRT weakens with age..) or a component failure.

Findm-Keepm
07-22-2017, 12:31 PM
Oh, and if it is one of the driver chips that has failed, it will usually flash that color, or lose that color right before shutdown.

I may have a NOS driver chip - TDA6180 or something close to that, IIRC. I've seen one with a bad chip, but it came on with one color "full on" so the problem was pretty obvious. Still the troubleshooting for a 5-flash/AKB fail mentions them, so...

TV Engineer
08-18-2017, 08:52 AM
Ok, I counted the blinks and downloaded a service manual. 5 blinks = white balance failure. Seems like some problem on the CRT board with cathode current. Is this a common failure mode? Could it be leaky or high ESR electrolytic caps. Thanks for any advice.

Your CRT is defective. You may be able to rejuvenate it, but the guns are no longer balanced, so the set blanks the video.