18 Aug
2009
18 Aug
'09
1:35 p.m.
Sort-of a tangent to the 'contact lubricant' thread...
I've just bought an HP9125 plotter for my 9100 :-). For those who don't
know this device (built entirely from discrete transistors from what I
can see), it's basically a calcualtor interface (4 boards of logic)
driving a pair of DACs, driving an analogue X-Y plotter. Anyway, the last
part has slidewires (essentially long sliding potentiometers) to detect
the pen position and provide a feedback signal to the servo circuits.
The HP service manual (OK, it's a boardswapper guide, but I read all the
information I can find...) says you have to clean said slidewires with
special cleaner and then coat them with special slidewire lubricant. Of
course I want to make my slidewires last as long as possible, getting
replacements is non-trivial :-)
Does anyone know what modern product I should use?
-tony
19 Aug
19 Aug
10:23 a.m.
On 18 Aug 2009 at 21:35, Tony Duell wrote:
Does anyone know what modern product I should use?
From the published MSDS, the cleaner was nothing more
than
Trichlorotrifluoroethane, which is probably on the "CFC banned"
list.
You should probably contact Nye to see if they made the HP slidewire
lubricant and what they would suggest. They make/made a wide variety
of products that HP used, including a variety of electrical and
optical greases.
In my experience with various chart recorders, cleaning was done with
a soft cloth and nothing more--and no lube at all. The customary
silver bead contact would be replaced periodically, but that's the
extent of slidewire maintenance that I'm familiar with.
--Chuck
3:27 p.m.
In my experience with various chart recorders,
cleaning was done with
a soft cloth and nothing more--and no lube at all. The customary
silver bead contact would be replaced periodically, but that's the
extent of slidewire maintenance that I'm familiar with.
Wouldn't this slidewire be made of nichrome?
Maybe it is time to take it out, measure the resistance of the entire
wire and in some distances, and compare to the same awg nichrome wire?
6:20 p.m.
Thqnks for all the replies so far. It looks like I can use propan-2-ol
for cleaning (which I would generally regard as safe on such things). I
suspect the lubricant is rather more important, though.
> In my experience with various chart recorders, cleaning was done with
> a soft cloth and nothing more--and no lube at all. The customary
HP specifically mention a lubricant. Now, I am not going to be running this
machine all that much, but equally replacement slidewires are
unobtainable so I want to keep wear down as much as possible. So I'd like
to put something on there.
> silver bead contact would be replaced
periodically, but that's the
> extent of slidewire maintenance that I'm familiar with.
According to the manual, the wiper contact is integral to part of the
carriage, and you change the assembly. Again, something I can't do (due
to lack of spares). I'd rather not have to make something up.
Wouldn't this slidewire be made of nichrome?
Quite likely. Resistance wire, anyway.
Maybe it is time to take it out, measure the resistance of the entire
wire and in some distances, and compare to the same awg nichrome wire?
I've not looked at it that carefully (it's got some grease on it, which I
don't want to clean off until I know what to replace it with), but it's
not unheard-of for this to be a helix of thin wire around an insulating
former, and not a simple straight wire. Which makes repairing it a lot
harder.
-tony
12:15 p.m.
For the cleaner, the MSDS for HP 5080-3605 says:
"This product no longer available from Hewlett-Packard as of 1/90 due
to CFC content. Replacement P/N is 92193N (pre-packaged isopropanol
wipes)."
http://www.hp.com/hpinfo/globalcitizenship/environment/pdf/5080-
3605.pdf
--Chuck
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