On Mon, 01 Feb 2016 09:48:02 -0500, legg wrote:

On Mon, 01 Feb 2016 07:59:04 -0600, Chuck wrote:

There was an AOC tv in the mid 80s that had capacitance touch switches
on the front and the channel indicators were illuminated with NE2 neon
bulbs. An ic drove transistor switches that turned the bulbs on and
off. The sets would come in where the channel couldn't be changed.
The first one took me a few hours to repair. The soluton was to
change the NE2 bulb on the channel the set was stuck on. The faulty
bulbs still lit at the proper voltage. Anyone have an idea how the
bulb could cause this fault? At the time we were a high volume repair
service so I didn't have the time to ponder circuit anomalies. Thanks.
Chuck

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Neons emit random noise, dependent on individual breakdown
characteristics and current. At some amplitude level or frequency,
this could be overloading another section of the circuitry. This could
latch up a logic function in one state, if it resulted in positive
feedback.

You don't indicate if
....one channel was more problematic than others, in a wide range of
sets
... or whether it only occurred after some time period set on the
problematic channel
.... Cold or heat dependent
.....same sets returned more than once
etc.

Without a memory, either mechanical or electronic, this should have
been reset on recycling of power.

RL


It was channel independent, never intermittent and not hot or cold
dependent and the sets never returned for the same problem. By the
way Jur006 had the correct explanation. I had forgotten what it was
but his answer jarred my memory.

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