Static issue with older TV

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- Tim R.
  
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posted
15 years ago

Fri, Jun 13, 2008 3:02 AM

I have an old Zenith A1920W TV from 1984 that works great except for one small problem.

When I first turn it on, I will get nothing but static on all channels, and then it will suddenly clear up and work fine. It will alternate between working and static for a little while and eventually work normally. After that I can watch for hours with no issues.

Is it an overheating component? Or something expanding/contracting and making intermittent contact? If anyone can point me in the right direction I'd appreciate it.

Tim

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- PaPaPeng
  
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posted
15 years ago

Fri, Jun 13, 2008 3:54 AM

It is most likely a cold solder joint that is affected by heat. A good slap on the cabinet usually restores the video. Open up the cover and use a long wood dowel to move the cables around with the TV switched on. You might get lucky and the problem will appear. From there it is easy enough to trace the cable to where the cold solder joint is. Otherwise just reflow the solder on the pin connectors on the motherboard. This is faster and easier than trying to troubleshoot.

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- hrhofmann
  
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posted
15 years ago

Sat, Jun 14, 2008 9:35 PM

Trouble is, it may not be a cold solder joint to a connector, but ANY component that is soldered. Probing the entire board quickly when first turned on may find the problem area, but the OP will need to probe everything, not just in the vicinity of connectors..

Bob Hofmann

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- Chuck
  
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posted
15 years ago

Mon, Jun 16, 2008 2:42 PM

The tuner in this set usually will have broken solder connections, particularly at the sockets where the wire bundles run back to the main board.. The shield on the tuner will need to be removed. I think it needs to be desoldered, resolder all socket pins, touch up poor ground connections and it should work ok. Chuck

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- Art
  
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posted
15 years ago

Tue, Jun 17, 2008 10:53 AM

Could be anything from the tuner through to the video processing, however having snow indicates that most of the circuitry is operational excepting the tuner. Suspect voltage sources to the tuner also, dried up electrolytic can cause a very slow rise, and poor regulations in power supply voltages. Suggest ESR the caps in the power supply and any circuits directly related to the supplies for the tuner.