In article , Ian Iveson
wrote:

"Jim Lesurf" wrote in message
...

Must admit I was less than impressed with the circuit at the time.
From this thread it does look like this resistor is prone to burning.
Although perhaps that is made worse by the risk of the motor being
stalled or loaded.

Perhaps? Certainly, surely?

No, I can't say for *sure* since I don't now know the rest of the circuit
details or the motor characteristics, fusing, etc. Lacking details I can
only say "perhaps" in the above.

Is it really likely, do you think, that the manufacturer would continue
to fit an inappropriate resistor for so long? It's not like resistor
power rating is complicated or arcane. Cost difference can't be that
significant, and there's no shortage of space.

Afraid I have no data to base a general value of what is "likely". I can
only note that:

1) I found that the resistor was burned out and seemed to me to be rather
small (hence probably low power rating) and replaced it with a higher rated
one.

2) That others here are commenting in a way that supports this idea.

It would be interesting to know how the winding resistance compares
with the impedance of an up-to-speed motor. If the difference is great
enough, it could be that all those burned-out resistors are a result of
stalled motors or increased drag, or even the fitting of heavy
platters. It's also possible that every burned-out resistor has saved a
motor winding, in which case a higher-rated resistor would be a
liability.

That is possible. All kinds of speculations might sometimes return "true".
:-) However in the case of the resistor I replaced the turntable seems to
have worked fine since. The owner seems quite happy with it some years
later.

However, joining you in speculation, the problem with fitting components
with (relatively) low power ratings is that the component tends to run hot
and this can shorten life or lead to other problems. Given the cost of the
turntable it might be better to use a better design for the PSU. Or even
use a fuse that is user-replacable without a soldering iron. Or ensure that
the system is rated to remain undamaged even with a prolonged stall.

I agree that low power resistors are cheap, though. :-)

Slainte,

Jim

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