Entertainment Center: TVs, Stereos, VCRs and DVDs - Troubleshooting Sony KV-27XBR60

My TV has been giving me some video breakup lately so I have attempted to troubleshoot this but have not come up with the solution. Briefly, this is what I did:

- Checked all connections - OK
- Used a cold spray to find cold solder joints - no breakup when applied
- tapped on boards and saw breakup (resinates thru out)
- removed audio/video board (U) to ensure that it is not the problem.
- still saw breakup as I tapped after removing that board (U).
- Looked at the solder joints on the main board - No indication that I could see if there were any cold joints.
- Wiggled all wired connections - no breakup.

All indications to me results in a cold solder joint but I can't seem to see or locate it with cold spray. Tapping just resinates thru out.

If you have any other ideas, please let me know.

Thanks.... rbwest

I agree that the issue is related to a cold solder joint. First, though, don't just wiggle the connectors. Pull them and reseat them. (Except the flyback and anode cap -- high voltages are present.)

Instead of tapping the parts, use a small wooden dowel to touch & move each part. I'll bet one of them shows itself, or at least gets you closer to the problem area.

Don't forget the input connections. Wear & tear on RF and RCA connectors can loosen them over time.

Thanks Rick for your help. I did finally narrow it down. I re-soldered a couple of voltage regulators as well as a resistor that looked suspicious on the main board. My guess is that of the voltage regulators as they produce a lot of heat.

Again, Thanks....

rbwest