Simpson 360-2 DVM problem
Steve
I've had a Simpson 260 on my bench for years
and just picked up this 360-2, which is a DVM
in the same case as a 260.
The problem is its over range on all settings.
Probably the input circuit. Has anyone out there
had this problem? If so, what was the fix?
Steve
Jeff Liebermann
Manuals and schematics. Some troubleshooting info included:
<http://www.simpson260.com/downloads/downloads.htm>
--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
whit3rd
Inputs are usually protected by fuses, and overrange
readings might mean the fuse is bad. Meter failures
also result from dirty/broken switches, worth checking.
(always check the obvious things first).
The last time a meter failed on me, it was a speck of
something conductive shorting the selector switch.
Dave M
news:3sd315hnpbubprdj6...@4ax.com...
> On Mon, 18 May 2009 12:10:48 -0700, "Steve" <za...@sonic.net> wrote:
>
>>Does anyone here have experience with these?
>>I've had a Simpson 260 on my bench for years
>>and just picked up this 360-2, which is a DVM
>>in the same case as a 260.
>>
>>The problem is its over range on all settings.
>>Probably the input circuit. Has anyone out there
>>had this problem? If so, what was the fix?
>>
>> Steve
>
> Manuals and schematics. Some troubleshooting info included:
> <http://www.simpson260.com/downloads/downloads.htm>
>
> --
> Jeff Liebermann je...@cruzio.com
First thing to check is the power supply voltages. If those are all OK,
then the next thing to suspect is the A-D converter, since it appears to be
the most obvious common component. From the parts list, it's a custom LSI
part. If it is a relabeled A-D chip, then it might be possible to locate a
replacement. You'll have to research the pin functions and try to identify a
standard part that matches. If it really is a custom Simpson part, then
Simpson is probably the only source. Don't know how long the 360-2 has been
out of production, but it's highly unlikely that the part is still
available.
Cheers!
--
Dave M
masondg44 at comcast dot net
One good thing about Alzheimer's; you get to meet new people every day.
Jeff Liebermann
wrote:
>On Mon, 18 May 2009 12:10:48 -0700, "Steve" <za...@sonic.net> wrote:
>
>>Does anyone here have experience with these?
>>I've had a Simpson 260 on my bench for years
>>and just picked up this 360-2, which is a DVM
>>in the same case as a 260.
>>
>>The problem is its over range on all settings.
>>Probably the input circuit. Has anyone out there
>>had this problem? If so, what was the fix?
>>
>> Steve
>
>Manuals and schematics. Some troubleshooting info included:
><http://www.simpson260.com/downloads/downloads.htm>
...and some details on the Simpson 360-2:
<http://www.simpson260.com/360/simpson_360-2-a.htm>
<http://simpson260.com/downloads/simpson_360-2_user_manual-1975.pdf>(4.5MB)
The manual has a schematic and parts list.
My rule-de-thumb for such old hardware is "if it moves, it breaks". As
suggested, check the power supply voltages. After that, clean the
slide and rotary switch contacts. My guess(tm) is that the output of
the input ampflifiers (IC101 and IC102 are pegged to one or other
rail, thus causing the over-range indication.
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 je...@comix.santa-cruz.ca.us
# http://802.11junk.com je...@cruzio.com
# http://www.LearnByDestroying.com AE6KS
Mark Zacharias
news:4a11b2bb$0$1631$742e...@news.sonic.net...
I'd certainly check the simple stuff first; the fuses and low value
resistors. Next comes power supply as someone else suggested. Anything too
much more than that is probably unecessary and unproductive - you can
replace your 360-2 with another from eBay. Prices vary but you can almost
always get one with it's power adaptor for under 50.00.
Mark Z.
Mark Z.
boxe...@gmail.com
Fred McKenzie
How much over range? Many old VTVMs had a resistor in its probe. If
you used a probe with no resistor, readings would be a bit high.
You might research the Simpson 360-2 to see if it happened to require a
similar probe.
Fred
K4DII