Simpson 260 sticky meter

[don87109]

I have a couple of old Simpson 260 multimeters that have sticky meter movements. Is there a way to free these movements? They seem to stick at the high end of the scale.

Somehow I aways reach for the 260 when I need a meter. The new-fangled digital meters just don't seem as good for general purpose work. Of course when I need precise measurements a digital meter is best.

Thanks,
Don

[Lenp]

First, I assume the meter is a D'Arsonval movement not a taut-band so here are some tips...
Here's a basic drawing. http://www.ece.osu.edu/~fiorentl/ECE205 ... lMeter.pdf

In the past I have found that the pointer may stick because it is dragging on the scale or glass, the pivot has friction, there is a coil obstruction or a tangled hairspring.
Caution!
The meter movement is a small, watch-like mechanism easily destroyed by carelessness. Any metal filings or chips attracted to the movement by its magnet spells disaster!
Pointer dragging:
Remove the meter bezel from the back of the meter front panel, 4 screws and try the meter. If it doesn't stick use the ohms function to set the pointer to the 'sticky' area and place the bezel back in position, watching to see if the glass presses on it. If the pointer drags on the scale or glass adjust the pointer gently to center it and retry.
Still sticks? Follow these
Pivot:
The pivots be tight or misaligned. There is usually a lock nut that can be slightly loosened and the pivot relaxed a little. Rarely the coil is not centered front to back on the magnet. This requires disassembly so the rear pivot can be adjusted with the front pivot to center the coil.
Obstruction:
A foreign body between the coil and magnet. With lots of care the pivot can be adjusted and a small strip of masking tape or small thin probe may retrieve the foreign object.
Coil:
Carefully untangle the coil, a toothpick is useful here!
Hope this helps,
Len

[don87109]

Lenp,

Thank you, very informative post. I don't think the pointer is touching the glass, but I'll double check and then proceed with your other ideas.

A couple of years ago I tried to fix a sticky meter and just managed to ruin it. They are pretty delicate mechanisms.

Thanks again,

Don

[Bob Scott]

A couple of years ago I tried to fix a sticky meter and just managed to ruin it. They are pretty delicate mechanisms.

Years ago as a hifi tech, I used to wear out one of those Radio Shack 22-204 analog multimeters every year or two. I went through 4 or 5 of them. When the meter gets sticky, they are worn out. I tried to fix a couple of them but like you, I failed and made it worse. I would not say that you or I ruined them. You can't ruin junk, but you did get a bit of education. They are just not repairable when they wear out, unless there is a replacement part for the meter movement.

I'll bet all experimenters can think back and cringe when they remember the stuff they ruined while they were still ignorant and learning. I remember a couple of "old radios" I butchered for parts. Similar models are now valuable antiques.

I still have the last RS analog meter I bought. I don't use it much since DVMs became available. I used to keep the analog one handy for checking semiconductor junctions in the Ohms scale, something the early DMMs could not do. Modern DMMs have a "junction" test position so I don't use the analog one at all anymore.

[MrAl]

[Note to Bob: His spam has now been deleted]

Hello,

I had a meter like that too and found that you can tighten or loosen the movement. I cant remember how i did it now because
it was so long ago, but somehow you can turn it and that makes the space between the shaft and cup bearing. Not sure if
they are all like this though.

[Dean Huster]

Here's a similar post that's going on concurrently with this one:

http://antiqueradios.com/forums/viewtopic.php?t=133272