d'Arsonval Movement Repair

[mcp6453[_2_]]

One thing I do for fun is refurbish Dorrough Discriminate Audio
Processors. It's been a thing for me for years. Over that time, however,
I'm understandably seeing an increase in the number of VU meters that
are sticky. The one of the bench now has two meters that need to be
replaced or repaired. Replacements (Modutec) are not available, and
repairs are tough.

As an experiment, I connected my function generator to one of the sticky
meters are started hitting it with 2 Hz. As the movement seems to free
up, I increase the swing such that it eventually reaches full scale high
and low. The first meter I did this too seems to be working normally.
The second one is undergoing treatment at the moment.

Based on a previous recommendation here a long time ago, I got some
super fancy oil for the movements. At that time, I tried oiling a couple
of movements. It didn't help either one. Either I got the oil in the
wrong place, or oil wouldn't solve the problem.

My question is, if this conditioning process frees up the movement, how
likely is the movement likely to function before it starts freezing
again? Alternatively, does anyone repair meters any more?

[Fred McKenzie]

In article >,
mcp6453 > wrote:

> One thing I do for fun is refurbish Dorrough Discriminate Audio
> Processors. It's been a thing for me for years. Over that time, however,
> I'm understandably seeing an increase in the number of VU meters that
> are sticky. The one of the bench now has two meters that need to be
> replaced or repaired. Replacements (Modutec) are not available, and
> repairs are tough.
>
> As an experiment, I connected my function generator to one of the sticky
> meters are started hitting it with 2 Hz. As the movement seems to free
> up, I increase the swing such that it eventually reaches full scale high
> and low. The first meter I did this too seems to be working normally.
> The second one is undergoing treatment at the moment.
>
> Based on a previous recommendation here a long time ago, I got some
> super fancy oil for the movements. At that time, I tried oiling a couple
> of movements. It didn't help either one. Either I got the oil in the
> wrong place, or oil wouldn't solve the problem.
>
> My question is, if this conditioning process frees up the movement, how
> likely is the movement likely to function before it starts freezing
> again? Alternatively, does anyone repair meters any more?

MCP-

Meters I have come across, had dry "jeweled" movements. Something like
needle points riding in depressions or holes in jewels of some kind.

Your sticky movements may be due to use of lubricants that dried. You
might try using a solvent to unstick them.

Fred

[mcp6453[_2_]]

On 12/25/2019 12:44 PM, Fred McKenzie wrote:
> In article >,
> mcp6453 > wrote:
>
> MCP-
>
> Meters I have come across, had dry "jeweled" movements. Something like
> needle points riding in depressions or holes in jewels of some kind.
>
> Your sticky movements may be due to use of lubricants that dried. You
> might try using a solvent to unstick them.

What kind of solvent would you suggest, and how would I apply it? I
don't exactly know how these movements are put together. Where is the
pivot point?

[david gourley[_4_]]

mcp6453 > said...news:0pmdndP3if-hP57DnZ2dnUU7-
:

> On 12/25/2019 12:44 PM, Fred McKenzie wrote:
>> In article >,
>> mcp6453 > wrote:
>>
>> MCP-
>>
>> Meters I have come across, had dry "jeweled" movements. Something like
>> needle points riding in depressions or holes in jewels of some kind.
>>
>> Your sticky movements may be due to use of lubricants that dried. You
>> might try using a solvent to unstick them.
>
> What kind of solvent would you suggest, and how would I apply it? I
> don't exactly know how these movements are put together. Where is the
> pivot point?
>

If I didn't have anything else I"d probably just use some Air Flow Sensor
cleaner from the auto store. It's light, no residue, and doesn't attack
the plastic that holds the sensor.

david

[gray_wolf]

On 25/12/2019 11:44 am, Fred McKenzie wrote:
> In article >,
> mcp6453 > wrote:
>
>> One thing I do for fun is refurbish Dorrough Discriminate Audio
>> Processors. It's been a thing for me for years. Over that time, however,
>> I'm understandably seeing an increase in the number of VU meters that
>> are sticky. The one of the bench now has two meters that need to be
>> replaced or repaired. Replacements (Modutec) are not available, and
>> repairs are tough.
>>
>> As an experiment, I connected my function generator to one of the sticky
>> meters are started hitting it with 2 Hz. As the movement seems to free
>> up, I increase the swing such that it eventually reaches full scale high
>> and low. The first meter I did this too seems to be working normally.
>> The second one is undergoing treatment at the moment.
>>
>> Based on a previous recommendation here a long time ago, I got some
>> super fancy oil for the movements. At that time, I tried oiling a couple
>> of movements. It didn't help either one. Either I got the oil in the
>> wrong place, or oil wouldn't solve the problem.
>>
>> My question is, if this conditioning process frees up the movement, how
>> likely is the movement likely to function before it starts freezing
>> again? Alternatively, does anyone repair meters any more?
>
> MCP-
>
> Meters I have come across, had dry "jeweled" movements. Something like
> needle points riding in depressions or holes in jewels of some kind.
>
> Your sticky movements may be due to use of lubricants that dried. You
> might try using a solvent to unstick them.
>
> Fred
>

My dad repaired watches when I was a kid. A lot of them started working after
he flushed them out with naphtha. Seems they get gummed up after a while.

[Ty Ford[_2_]]

On Thursday, December 26, 2019 at 5:25:48 AM UTC-5, gray_wolf wrote:

> My dad repaired watches when I was a kid. A lot of them started working after
> he flushed them out with naphtha. Seems they get gummed up after a while.

Does that work on kidney stones too?

Regards,

Ty Ford

[John Williamson]

On 26/12/2019 15:40, Ty Ford wrote:

> Does that work on kidney stones too?
>
Nah, they need ultrasound. 18 to 20 kHz full scale with the output power
turned well up with some second and third harmonic distortion and a high
pass filter.

Just don't ask what speaker you need or where you have to put it.

--
Tciao for Now!

John.

[gray_wolf]

On 26/12/2019 9:40 am, Ty Ford wrote:
> On Thursday, December 26, 2019 at 5:25:48 AM UTC-5, gray_wolf wrote:
>
>> My dad repaired watches when I was a kid. A lot of them started working after
>> he flushed them out with naphtha. Seems they get gummed up after a while.
>
> Does that work on kidney stones too?
>
> Regards,
>
> Ty Ford
>

No. I don't think so. Ultrasonics may be the way to go. :-)

[Mike Rivers[_2_]]

On 12/25/2019 11:33 AM, mcp6453 wrote:
> does anyone repair meters any more?

That's questionable. There was a guy larsonmetercraft.com who repaired
meters - the name comes up on the Ampex List now and then. But when I
checked the web site to see if he was still in business, I got a starter
WordPress page. Maybe it's going to be a new web site, or maybe he
retired. A web search turns up a Google map page with a phone number
(619) 258-8990. Also, there's a web page:

https://www.hybridelectronics.com/manufacturer/larson-metercraft-inc-distributors


that has a link to Larson-Metercraft that gets back to that WordPress
page. Hybrid Electronics appears to be a general electronic parts
distributor on the other side of the country from the
larsonmetercraft.com map.

Very mysterious.

--
For a good time, call http://mikeriversaudio.wordpress.com

[Scott Dorsey]

mcp6453 > wrote:
>On 12/25/2019 12:44 PM, Fred McKenzie wrote:
>> In article >,
>> mcp6453 > wrote:
>>
>> MCP-
>>
>> Meters I have come across, had dry "jeweled" movements. Something like
>> needle points riding in depressions or holes in jewels of some kind.
>>
>> Your sticky movements may be due to use of lubricants that dried. You
>> might try using a solvent to unstick them.
>
>What kind of solvent would you suggest, and how would I apply it? I
>don't exactly know how these movements are put together. Where is the
>pivot point?

If you've got watch oil, put it on the point where that center axle that
goes through the needle touches the frame that holds it in place at the
ends (the pivot point). It will be enough of a solvent to dissolve whatever
old lube might be on there. Just flatten the edge of a toothpick and use
it as a brush to carry some oil over. It will not take much, maybe not
even enough to see.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."