Picked up a Simpson 260 6M at the local thrift store, I was initially disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully
deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
Picked up a Simpson 260 6M at the local thrift store, I was initially >disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully >deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
On Fri, 4 Apr 2025 11:36:40 -0400, bitrex <user@example.net> wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully
deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Leave this alone - it's normal for such meters. The 260 may need to
be calibrated.
Joe
Picked up a Simpson 260 6M at the local thrift store, I was initially >disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully >deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully >> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
On 4/4/2025 12:56 PM, Joe Gwinn wrote:
On Fri, 4 Apr 2025 11:36:40 -0400, bitrex <user@example.net> wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully >> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Leave this alone - it's normal for such meters. The 260 may need to
be calibrated.
Joe
Right. I've calibrated the DC voltage as best I can with what I have;
get the meter as close to full scale at 50 uA into it as I can with the parallel pot, then set voltage across the meter movement and its series
pot to 250 mV. On the higher voltage ranges (which is what I'd tend to
use it for anyway) it definitely seems good enough for rock & roll.
Anything further with analog meters I believe require specialized tools
which I ain't got.
On 4/4/2025 12:56 PM, Joe Gwinn wrote:
On Fri, 4 Apr 2025 11:36:40 -0400, bitrex <user@example.net> wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully >>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Leave this alone - it's normal for such meters. The 260 may need to
be calibrated.
Joe
Right. I've calibrated the DC voltage as best I can with what I have;
get the meter as close to full scale at 50 uA into it as I can with the >parallel pot, then set voltage across the meter movement and its series
pot to 250 mV. On the higher voltage ranges (which is what I'd tend to
use it for anyway) it definitely seems good enough for rock & roll.
Anything further with analog meters I believe require specialized tools
which I ain't got.
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully >>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
On 4/4/2025 1:01 PM, Cursitor Doom wrote:
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms >>>> vs the 1800 in the service manual. This causes the movement to not fully >>>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like >>>> 48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that >>>> can help in this situation? It seems a relative error of 3% is actually >>>> still barely within factory spec so probably best to just let it go and >>>> enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the
equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
After a "calibration" it still looks pretty good for rock & roll even
with the movement slightly out, at least far away from the extremes.
This is 25 volts at the terminals:
<https://imgur.com/a/GwoBz3f>
Also an excuse to check out my surplus 6177B whose output is still
pretty stable and meter bang on after all these years, even though the
meter doesn't go down anywhere near that far it's not hard to use the 10
turn pot to get a stable 50 uA out of it.
Pretty clean inside except for some dust:
<https://imgur.com/a/JTsPiVf>
Wait a minute, what the hell is this? That doesn't look factory :-|
<https://imgur.com/a/7pWwKnw>
On Fri, 4 Apr 2025 13:56:19 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 12:56 PM, Joe Gwinn wrote:
On Fri, 4 Apr 2025 11:36:40 -0400, bitrex <user@example.net> wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms >>>> vs the 1800 in the service manual. This causes the movement to not fully >>>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like >>>> 48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that >>>> can help in this situation? It seems a relative error of 3% is actually >>>> still barely within factory spec so probably best to just let it go and >>>> enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Leave this alone - it's normal for such meters. The 260 may need to
be calibrated.
Joe
Right. I've calibrated the DC voltage as best I can with what I have;
get the meter as close to full scale at 50 uA into it as I can with the >>parallel pot, then set voltage across the meter movement and its series
pot to 250 mV. On the higher voltage ranges (which is what I'd tend to
use it for anyway) it definitely seems good enough for rock & roll.
Anything further with analog meters I believe require specialized tools >>which I ain't got.
This ain't the National Bureau of Standards. Calibrate the 260
against a DMM.
On Fri, 4 Apr 2025 17:02:57 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 1:01 PM, Cursitor Doom wrote:
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially >>>>> disappointed to find it had a sticking meter but some gentle rocking >>>>> freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms >>>>> vs the 1800 in the service manual. This causes the movement to not fully >>>>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like >>>>> 48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that >>>>> can help in this situation? It seems a relative error of 3% is actually >>>>> still barely within factory spec so probably best to just let it go and >>>>> enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the
equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
After a "calibration" it still looks pretty good for rock & roll even
with the movement slightly out, at least far away from the extremes.
This is 25 volts at the terminals:
<https://imgur.com/a/GwoBz3f>
Also an excuse to check out my surplus 6177B whose output is still
pretty stable and meter bang on after all these years, even though the
meter doesn't go down anywhere near that far it's not hard to use the 10
turn pot to get a stable 50 uA out of it.
Pretty clean inside except for some dust:
<https://imgur.com/a/JTsPiVf>
Wait a minute, what the hell is this? That doesn't look factory :-|
<https://imgur.com/a/7pWwKnw>
I don't know how old this particular meter is, but you can't really be
too surprised when you encounter something like this in vintage
equipment. It doesn't look very elegant, but the important thing is:
does it impair functionality? Someone who really knew his onions
theory-wise may have done this and left the meter working perfectly.
Judging the efficacy of a repair by the quality of the workmanship
isn't a watertight approach. If the meter's accurate on all ranges I
wouldn't worry about it.
Picked up a Simpson 260 6M at the local thrift store, I was initially disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
In article <67effc27$6$2789$882e4bbb@reader.netnews.com>,
user@example.net says...
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully
deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
For a meter that is over 50 years old that is probably not too bad. I
have 2 of the meters and the book says the meter is 48 uA
the best I recall and that parallel pot sets it to 50 uA. So that
meter does not seem too bad. with digital meters getting much closer it
is hard to get it in ones head that those old meters were field
instruments and not super accurate. A 50 uA meter that has been banged >around for 50 plus years is luck to be that close.
Picked up a Simpson 260 6M at the local thrift store, I was initially >disappointed to find it had a sticking meter but some gentle rocking
freed it.
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully >>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
On Fri, 4 Apr 2025 11:36:40 -0400, bitrex <user@example.net> wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially >disappointed to find it had a sticking meter but some gentle rocking
freed it.
The Simpson 260 6M uses a taut band meter movement. It shouldn't stick.
Even though your gentle rocking "fixed" the sticking problem, you should
take a look around the meter movement for some remaining debris. You
might need a microscope: <https://www.learnbydestroying.com/jeffl/pics/microscopes/Olympus%20SZ30/S Z30-01.jpg> If you see something, try dislodging it with some dry low pressure compressed air.
Picked up a Simpson 260 6M at the local thrift store, I was initially disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
On Fri, 4 Apr 2025 11:36:40 -0400, bitrex <user@example.net> wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially >>disappointed to find it had a sticking meter but some gentle rocking
freed it.
The Simpson 260 6M uses a taut band meter movement. It shouldn't
stick. Even though your gentle rocking "fixed" the sticking problem,
you should take a look around the meter movement for some remaining
debris. You might need a microscope: ><https://www.learnbydestroying.com/jeffl/pics/microscopes/Olympus%20SZ30/SZ30-01.jpg>
If you see something, try dislodging it with some dry low pressure
compressed air. Don't use freeze spray or you will condense moisture
on meter movement. Use a dryer attached to an air compressor.
Something like this: ><https://www.amazon.com/Compressor-Separator-Regulator-Accessories-Air-Compressor/dp/B083XZ7THN>
I recently fixed my long forgotten Heathkit IM-105 VOM. It had a
sticky taut band meter movement. Snooping around inside, I found that
a tiny paper label inside the meter had fallen apart and jammed the
movement. Compressed air didn't work too well, so I switched to a 20
gauge needle and an improvised vacuum pump. The suction vacuumed out
the paper debris, which clogged the needle. That was acceptable
because the movement was now clear of debris and moving normally.
I don't know what to suggest for fixing the high resistance movement
problem. Good luck.
On 04/04/2025 18:01, Cursitor Doom wrote:
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms >>>> vs the 1800 in the service manual. This causes the movement to not fully >>>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like >>>> 48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that >>>> can help in this situation? It seems a relative error of 3% is actually >>>> still barely within factory spec so probably best to just let it go and >>>> enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the
equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
There's something very satisfying watching a perfectly-damped needle
move across the face of a meter and come to a steady halt. I was given
an Avo Multiminor almost 50 years ago and occasionally still use it.
Rather OT for this group I also have a couple of Post Office and British >Telecom meters (ex my F-i-L. He started working for them in the early
50s and retired in the early 90s):
<https://www.radiomuseum.org/r/gec_multimeter_4_gpo_g_469.html>
Unfortunately the shunts are missing. It's built like a tank (the case
is steel); the leather case is a bit battered but ok.
<https://www.ebay.co.uk/itm/166536768299>
The one I have is almost unused. Seems that an updated version is still >available:
<https://www.telenco.uk/tester-sa-9083>
I wonder how long it will be before it becomes fully redundant when the >change to FTTP is complete.
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms
vs the 1800 in the service manual. This causes the movement to not fully >>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like
48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that
can help in this situation? It seems a relative error of 3% is actually
still barely within factory spec so probably best to just let it go and
enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the >equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
On Fri, 04 Apr 2025 18:01:17 +0100, Cursitor Doom <cd@notformail.com>
wrote:
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially
disappointed to find it had a sticking meter but some gentle rocking
freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms >>>> vs the 1800 in the service manual. This causes the movement to not fully >>>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like >>>> 48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that >>>> can help in this situation? It seems a relative error of 3% is actually >>>> still barely within factory spec so probably best to just let it go and >>>> enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the
equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
Turned up trumps again today. Checking the DC tuning voltage to a VCO.
It was supposed to ramp up from 2.5V to 10V reset and repeat over a 3
second cycle continuously. A DVM failed to reveal this control voltage
was misbehaving badly, but it was *immediately* apparent with an
analog meter.
Sometimes, you just can't beat 'em.
On 4/9/2025 7:42 PM, Cursitor Doom wrote:
On Fri, 04 Apr 2025 18:01:17 +0100, Cursitor Doom <cd@notformail.com>
wrote:
On Fri, 4 Apr 2025 11:43:22 -0400, bitrex <user@example.net> wrote:
On 4/4/2025 11:36 AM, bitrex wrote:
Picked up a Simpson 260 6M at the local thrift store, I was initially >>>>> disappointed to find it had a sticking meter but some gentle rocking >>>>> freed it.
Unfortunately the movement resistance is a little high, about 1880 ohms >>>>> vs the 1800 in the service manual. This causes the movement to not fully >>>>> deflect when 50 uA (sourced from an HP 6177B, and monitored by a
recently lab-calibrated 3478A) is run through it, it goes to more like >>>>> 48.5 out of 50.
Is it correct that recharging the meter movement is the only thing that >>>>> can help in this situation? It seems a relative error of 3% is actually >>>>> still barely within factory spec so probably best to just let it go and >>>>> enjoy a meter that's nice enough for the 10 bucks I paid for it, lol
Oops, I meant to post this in sci.electronics.repair but here we are.
I did wonder! Simpsons are nice meters. Really nice and broadly the
equivalent of the UK AVO brand (still in business AFAIK). I really
like these old analogue meters. People say stuff like 'well, the
trouble with them is they load a circuit too much compared to modern
DVMS' but that *can* be desirable in many cases. Repairing vintage
radios you find that oftentimes the servicing instructions have
voltages printed on them which were read by meters with 20k ohms/volt
or less, so at high impedance parts of the circuit a modern DVM will
give completely wrong readings. Also I find it's much easier to peak
signals with a moving coil meter than a DVM. And another thing - you
want to monitor a voltage constantly over days and weeks (or a
current) you can do this with an analogue meter without having to
worry about the battery draining. And when reading high currents,
there's no time limit like you find with modern DVMs. You can leave it
hooked up to 10 or 12 amps for as long as you like.
I could go on, but there's just a few of the reasons I like these old
beasts.
Turned up trumps again today. Checking the DC tuning voltage to a VCO.
It was supposed to ramp up from 2.5V to 10V reset and repeat over a 3
second cycle continuously. A DVM failed to reveal this control voltage
was misbehaving badly, but it was *immediately* apparent with an
analog meter.
Sometimes, you just can't beat 'em.
Nice, I'm happy mine's working pretty well now.
I think I'll hold onto it to barter for a Cadillac with once Trump's
finished turning dollars to toilet paper..
I think I'll hold onto it to barter for a Cadillac with once Trump's
finished turning dollars to toilet paper..
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