"Peter Bogiatzidis" wrote in message
b.com...
Hello,

A friend of mine has an old Radio Shack Cinego D1000 projector with a
built-in DVD player that has recently started shutting down after 5
minutes or so. We tried cleaning out any accumulated dust and also
verified that all three of the fans are working. The problem seems to be
intermittent one because when he first told me about this the projector
started working okay for a few weeks.

Does anyone here have any tips on what to check? I realize that it's an
old unit, but for the present time it's all he has available.

Thanks in advance to those who post a reply to the group.

Peter.


I would think that bad joints, and bad electrolytic caps are the two prime
suspects. You can check for bad joints visually (if it's older than say 5
years, it will almost certainly be constructed with leaded solder and bad
joints will be easily spot-able) as well as by using an insulated tapping
instrument such as a ball point pen, or the butt end of a screwdriver for
more stubborn cases. A can of freezer, and a hair dryer can also be useful
tools for locating this sort of problem. Look / test especially around
devices that run at elevated temperatures such as power resistors, and any
power semiconductors either free-mounted, or attached to heatsinks.

Bad electros may reveal themselves by having bulging tops, and / or shrunken
or discoloured sleeves, and / or evidence of electrolyte leakage around
their bottom edge. However, just as commonly, there can be no visible cues
for a faulty one at all, in which case, the most useful diagnostic
instrument is an ESR meter. If looking for bad caps, first suspect any that
are located close to sources of heat, such as power resistors, or heatsinks.

Arfa