enkephalin
Harmless
Posts: 7
Registered: 22-12-2005
Member Is Offline
Mood: No Mood
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Stirrer Problem
My new (but used) Bibby HB502 stirrer hotplate arrived fucked. The hotplate bit works fine, but the stirrer mechanism doesnt. It only works at high
speed, and even then seems to pulse on and off, which makes the stirbar unstable. At lower speed settings, the pulses seem longer apart, which makes
the vortex less intense, but the stirbar becomes uncoupled. It seems pretty hopeless.
Anyone have any ideas or know anything about stirrer electronics and what might be the problem?
Thanks for any help.
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madchem
Harmless
Posts: 7
Registered: 25-3-2006
Location: mtl
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Mood: harmfull AND NOT harmless (its a type-o)
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Il give yopu my 2 cents.
I dont know this bibby brand but if its like cornings and fisher plates iv had this problem.
It was on the fisher(go figure), anyways, there is a motor that turns and has a pretty strong magnet on it. It was some what offset and when i tool
it apart you could seee that it did not turn
perfictly in the center. So I bent some metal and got it to spin in the center. Now my corning started doing the same thing but not to the point that
i have to open it up, but you can the the motor that spins slightly off set. If you like taking stuff apart, go for it, but it might not be that xact
same prob as me. Never the less its reletivly easyand worth it. Other option is sending it back to the company and well.....thats a bitch. I say pull
out your tool and give it a wirl
just my 2cents
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Rosco Bodine
Banned
Posts: 6370
Registered: 29-9-2004
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Mood: analytical
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If there is a trim pot on the control board for
adjustment of the minimum speed setting you
could try adjusting that . It may also have a
second trimpot for a gain control for the speed
correction / speed regulation . If it has an encoder
wheel and a sensor , make sure they are clean
and everything is lined up properly and secured
in position firmly .
I have seen brand new equipment of this sort
which is pretty marginal and does not do the
job it should , frankly some of it is junk already
when it is brand new off the assembly line at the
factory , because it was poorly designed in the first
place . The motors and the magnets are inadequate
by a very long way from what they should be .
I have a project underway to custom build an instrument
to my own liking and will be posting some new
information about the progress of that effort which
so far seems to be tracking well with my original
ideas about going well beyond the usual commercial
product .
[Edited on 29-3-2006 by Rosco Bodine]
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