Weston 862 VU (A type)

[voitto]

I recently purchased a couple of old, massive, Weston 862 VU indicators from Ebay.
I've hooked them up to the outputs of an old delta V1075 line driver to act as a buffer but not seeing any needle movement.

They measure 16k and 21k across the terminals.

Am I right in thinking the 862 have their own internal rectification and can simply be attached to the audio line with a 3.9k resistor in series on the positive terminal?

Is anyone familiar with the differences between the A and B types or have an idea what I might be doing wrong?

I've also tried hooking them up to my soundcard directly in the same configuration but still no movement.

They measure 16k and 21k across the terminals.

Thanks in advance.
Robin.

 

[mjrippe]

See attached file for specs.

"A" scale means that -20 to +3dB is on top of the arc and 0-100% modulation is on the bottom.  "B" scale is the reverse.

 

[gridcurrent]

Am I right in thinking the 862 have their own internal rectification and can simply be attached to the audio line with a 3.9k resistor in series on the positive terminal?
They measure 16k and 21k across the terminals.

1.  the series resistor is typically 3600 ohms, don't let a  LA-2a schematic mislead you.
2.  Weston VU meters have a very high incidence of open coils after decades of storage,
whether used or not.  Sad but true and I consider working examples the gold standard.
3.  test with a 1.5 VDC battery.
4.  with care, open the meter up and inspect.  some units I have examined have a resistor across the input to the copper oxide rectifier;
if the coil or perhaps the rectifier is open, that may be the resistance you are measuring.

 

[PRR]

I would suspect gridcurrent has a point. The ~~20K would be the back-leakage of the rectifier; not an exceptional value for old copper-oxide.

Yes, a 1.5V battery should nearly-pin the meter.

 

[voitto]

Thanks for the replies, I've opened up one of the meters and checked the coil with a battery as suggested, on the  but no movement. The two resistors inside measure 700 ohm on the positive side and 2.6k on the negative. Is there a way to check the rectifier is functioning?

 

[PRR]

> a way to check the rectifier is functioning?

See if it rectifies?

Put about 1 Volt AC into it, measure the DC V across the meter movement terminals.

 

[voitto]

Sorry, that was a dumb question...

Yes it seems the rectifier is working in both meters, with 1v AC across the terminals it measures 0.5v DC across the coil terminals. So I can conclude that the meter coil is open, Is this something that can be replaced or repaired or are they dead?

Thanks again for the advice.

 

[emrr]

They can be repaired.  One option:

http://www.metersales.com/

 

[Brian Roth]

I have never personally used these folks, but I've heard good reports.  They are an Olde-Tyme family biz.

http://www.larsonmetercraft.com/services.htm


Bri

 

[voitto]

Thanks for the links, I'm in Finland so I'll maybe try a few watchmakers locally and then send to one of these places in the US they're unwilling to try it.

I don't think my hand is steady enough to attempt it myself, I like my coffee too much 

 

[thakava]

See attached file for specs.

"A" scale means that -20 to +3dB is on top of the arc and 0-100% modulation is on the bottom. "B" scale is the reverse.

And C scale?

 

[mjrippe]

And C scale?

I can't say I've seen one. Perhaps Compression?

 

[thakava]

I can't say I've seen one. Perhaps Compression?

I have a Weston 862 C "A" scale... can't find any info on it

 

[mjrippe]

I have a Weston 862 C "A" scale... can't find any info on it

Oh, in that case the "C" may be a revision. No idea what it might mean. Does the meter work?

 

[thakava]

Oh, in that case the "C" may be a revision. No idea what it might mean. Does the meter work?

Sure does... Just wondering what the difference is between the revisions...