sci.electronics.repair - 25 new messages in 8 topics - digest

sci.electronics.repair
http://groups.google.com/group/sci.electronics.repair?hl=en

sci.electronics.repair@googlegroups.com

Today's topics:

==============================================================================
TOPIC: Videorecorder problem - see pics
http://groups.google.com/group/sci.electronics.repair/t/6e566ea01f711ec0?hl=en
==============================================================================

== 1 of 6 ==
Date: Sun, Aug 1 2010 6:15 pm
From: "Arfa Daily"

"Mino" <nontelo@dico.no> wrote in message
news:4c55da25.347937@news.libero.it...
> Hi
>
> Frame taken from faulty VCR:
> http://i32.tinypic.com/29yqr6p.jpg
>
> Same frame captured from another recorder:
> http://i27.tinypic.com/16ge4ic.jpg
>
> What's wrong with the first VCR? Worn / dirty heads or anything else?

Likely worn heads, when there is black streaking from white fast transitions
like lettering edges.

Arfa

== 2 of 6 ==
Date: Mon, Aug 2 2010 9:04 am
From: Meat Plow

On Mon, 02 Aug 2010 02:15:34 +0100, Arfa Daily wrote:

> "Mino" <nontelo@dico.no> wrote in message
> news:4c55da25.347937@news.libero.it...
>> Hi
>>
>> Frame taken from faulty VCR:
>> http://i32.tinypic.com/29yqr6p.jpg
>>
>> Same frame captured from another recorder:
>> http://i27.tinypic.com/16ge4ic.jpg
>>
>> What's wrong with the first VCR? Worn / dirty heads or anything else?
>
> Likely worn heads, when there is black streaking from white fast
> transitions like lettering edges.
>
> Arfa

Those two links were pictures of a Yamaha multi-track recorder????????

== 3 of 6 ==
Date: Mon, Aug 2 2010 10:48 am
From: nontelo@dico.no (Mino)

Meat Plow <mhywatt@yahoo.com> wrote:

>Those two links were pictures of a Yamaha multi-track recorder????????

Yes they are and that recorder was used by a total incompetent.

== 4 of 6 ==
Date: Mon, Aug 2 2010 11:00 am
From: Meat Plow

On Mon, 02 Aug 2010 17:48:25 +0000, Mino wrote:

> Meat Plow <mhywatt@yahoo.com> wrote:
>
>>Those two links were pictures of a Yamaha multi-track recorder????????
>
> Yes they are and that recorder was used by a total incompetent.

Were those pictures captured from the VTR in question? If so I guess I
missed the point of the pictures.

== 5 of 6 ==
Date: Mon, Aug 2 2010 12:54 pm
From: nontelo@dico.no (Mino)

Meat Plow <mhywatt@yahoo.com> wrote:

>Were those pictures captured from the VTR in question? If so I guess I
>missed the point of the pictures.

The pictures are frames from a video, shot with a video-camera. That
video was copied to a normal-sized VHS cassette. I played the
videotape on 2 different VCRs and captured the exact same frame to
show how one of my VCR behaves, compared to a working one.

== 6 of 6 ==
Date: Mon, Aug 2 2010 6:41 pm
From: stratus46@yahoo.com

On Aug 2, 11:00 am, Meat Plow <mhyw...@yahoo.com> wrote:
> On Mon, 02 Aug 2010 17:48:25 +0000, Mino wrote:
> > Meat Plow <mhyw...@yahoo.com> wrote:
>
> >>Those two links were pictures of a Yamaha multi-track recorder????????
>
> > Yes they are and that recorder was used by a total incompetent.
>
> Were those pictures captured from the VTR in question? If so I guess I
> missed the point of the pictures.

Note the tearing in the time/date text from the VCR. The Yamaha is
just there to throw us off.

G²

==============================================================================
TOPIC: Isopropyl Alcohol for Cleaning Flux
http://groups.google.com/group/sci.electronics.repair/t/a7a3663fd81cf5bd?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Aug 2 2010 5:57 am
From: "Michael A. Terrell"

"Paul E. Schoen" wrote:
>
> "William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
> news:i32gbp$hnm$1@news.eternal-september.org...
> >> I remember having problems with leakage on a board that
> >> stored voltages in polystyrene capacitors using CMOS
> >> switches and op-amps, but the voltage would bleed off too
> >> quickly to be useful as a "memory". We tried all sorts of
> >> flux removers and it still didn't work well enough. But I had
> >> had an idea that it might be ionic contaminants such as
> >> salt, so I took a board into the mens room and scrubbed
> >> it with hand soap and flushed it with hot water. Then I dried
> >> it with a heat gun, and "voila" it worked like a champ rather
> >> than a chump.
> >
> > Interesting observation.
> >
> > Question... Wouldn't distilled water alone flush off ionic contaminants?
>
> Probably. But there may be some sort of oily residue that will be removed by
> the detergent. And hot water from the tap is much cheaper. It may be good to
> do a final rinse with distilled or deionized water. I have heard that some
> people stack their boards in a dishwasher. But my method works for me and is
> is very practical for small quantities.

We used a citrus based cleaner in a commercial board washing machine
at Microdyne. It was a modified stainless steel industrial dishwasher
with a separate solvent tank and fresh water wash. Then the boards went
into a board drying oven for 12 to 24 hours. This was for small runs of
boards stuffed and reflow soldered in house.

== 2 of 3 ==
Date: Mon, Aug 2 2010 7:03 am
From: zekfrivo@zekfrivolous.com (GregS)

In article <WtCdnar_6NJbXcvRnZ2dnUVZ_gadnZ2d@earthlink.com>, "Michael A. Terrell" <mike.terrell@earthlink.net> wrote:
>
>"Paul E. Schoen" wrote:
>>
>> "William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
>> news:i32gbp$hnm$1@news.eternal-september.org...
>> >> I remember having problems with leakage on a board that
>> >> stored voltages in polystyrene capacitors using CMOS
>> >> switches and op-amps, but the voltage would bleed off too
>> >> quickly to be useful as a "memory". We tried all sorts of
>> >> flux removers and it still didn't work well enough. But I had
>> >> had an idea that it might be ionic contaminants such as
>> >> salt, so I took a board into the mens room and scrubbed
>> >> it with hand soap and flushed it with hot water. Then I dried
>> >> it with a heat gun, and "voila" it worked like a champ rather
>> >> than a chump.
>> >
>> > Interesting observation.
>> >
>> > Question... Wouldn't distilled water alone flush off ionic contaminants?
>>
>> Probably. But there may be some sort of oily residue that will be removed by
>> the detergent. And hot water from the tap is much cheaper. It may be good to
>> do a final rinse with distilled or deionized water. I have heard that some
>> people stack their boards in a dishwasher. But my method works for me and is
>> is very practical for small quantities.
>
>
> We used a citrus based cleaner in a commercial board washing machine
>at Microdyne. It was a modified stainless steel industrial dishwasher
>with a separate solvent tank and fresh water wash. Then the boards went
>into a board drying oven for 12 to 24 hours. This was for small runs of
>boards stuffed and reflow soldered in house.

I noticed citrus based degreasers leave behind oil.
Thats a bad thing when you really want to paint something thinking
it will work. Bad for tape sticking also.

I think I allready mentioned mens room board cleaning.

greg

== 3 of 3 ==
Date: Mon, Aug 2 2010 10:08 am
From: "Michael A. Terrell"

GregS wrote:
>
> In article <WtCdnar_6NJbXcvRnZ2dnUVZ_gadnZ2d@earthlink.com>, "Michael A. Terrell" <mike.terrell@earthlink.net> wrote:
> >
> >"Paul E. Schoen" wrote:
> >>
> >> "William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
> >> news:i32gbp$hnm$1@news.eternal-september.org...
> >> >> I remember having problems with leakage on a board that
> >> >> stored voltages in polystyrene capacitors using CMOS
> >> >> switches and op-amps, but the voltage would bleed off too
> >> >> quickly to be useful as a "memory". We tried all sorts of
> >> >> flux removers and it still didn't work well enough. But I had
> >> >> had an idea that it might be ionic contaminants such as
> >> >> salt, so I took a board into the mens room and scrubbed
> >> >> it with hand soap and flushed it with hot water. Then I dried
> >> >> it with a heat gun, and "voila" it worked like a champ rather
> >> >> than a chump.
> >> >
> >> > Interesting observation.
> >> >
> >> > Question... Wouldn't distilled water alone flush off ionic contaminants?
> >>
> >> Probably. But there may be some sort of oily residue that will be removed by
> >> the detergent. And hot water from the tap is much cheaper. It may be good to
> >> do a final rinse with distilled or deionized water. I have heard that some
> >> people stack their boards in a dishwasher. But my method works for me and is
> >> is very practical for small quantities.
> >
> >
> > We used a citrus based cleaner in a commercial board washing machine
> >at Microdyne. It was a modified stainless steel industrial dishwasher
> >with a separate solvent tank and fresh water wash. Then the boards went
> >into a board drying oven for 12 to 24 hours. This was for small runs of
> >boards stuffed and reflow soldered in house.
>
> I noticed citrus based degreasers leave behind oil.
> Thats a bad thing when you really want to paint something thinking
> it will work. Bad for tape sticking also.
>
> I think I allready mentioned mens room board cleaning.

Mention whatever you want, but it was a NASA approved process. We
built telemetry equipment for the aerospace industry. NASA wouldn't
approve of your method. We built millions of dollars worth of equipment
per year.

==============================================================================
TOPIC: hissing sound coming from behind woofer on one side AR11
http://groups.google.com/group/sci.electronics.repair/t/3a9cce9766f809ce?hl=en
==============================================================================

== 1 of 8 ==
Date: Mon, Aug 2 2010 6:01 am
From: "Michael A. Terrell"

Amanda Ripanykhazov wrote:
>
> Thank you for your confidence everyone: If I wanted to wind everyone
> up, dont you think I would have found a funnier way of doing it than
> this?
>
> If someone can get me a way of posting a wav file to a NG, let me know
> and I will stick a microphone in front of the speaker and post
> whatever it records
>
> Meanwhile I will take the speaker out and report back if/when I have a
> result

1: Google doesn't allow any attachments.

2: This is not a binaries newsgroup so any message with an attachment
won't propagate to most news servers.

== 2 of 8 ==
Date: Mon, Aug 2 2010 6:03 am
From: "Michael A. Terrell"

Jamie wrote:
>
> Amanda Ripanykhazov wrote:
>
> > On Jul 30, 5:41 pm, Meat Plow <mhyw...@yahoo.com> wrote:
> >
> >>On Fri, 30 Jul 2010 14:03:39 -0700, Amanda Ripanykhazov wrote:
> >>
> >>>Thank you for your confidence everyone: If I wanted to wind everyone up,
> >>>dont you think I would have found a funnier way of doing it than this?
> >>
> >>Not if you're just not too funny in the first place.
> >>
> >>
> >>>If someone can get me a way of posting a wav file to a NG, let me know
> >>>and I will stick a microphone in front of the speaker and post whatever
> >>>it records
> >>
> >>>Meanwhile I will take the speaker out and report back if/when I have a
> >>>result
> >>
> >>But you've already subbed the speaker and the hiss went away or so I
> >>thought I had previously read.
> >
> >
> > Call me an old cynic and obviously I am not a technical expert but
> > doesnt simple logic mandate that when you sub a speaker and the sound
> > goes away, all it means is that (what I thought blindingly obvious
> > from the symptoms and there being no apparent logical connection
> > between the source and the hissing, which was why I posted here:
> > Because "The problem is that you are describing something that doesn't
> > seem to make any sense, or have any obvious explanation" so I wondered
> > whether anyone had come across it before) the sound wasnt coming from
> > the source? Or did I have to add that when i put the speaker back
> > again, the sound came back?
> check for electrical devices adjacent to the speaker, inside and outside
> of the wall. Your speaker coil maybe in the path of an induced magnetic
> field from a device near by..
>
> etc..

You think she has a MRI machine in her wall? The voice coil isn't
going to be affected by nearby magnetic fields, due to the narrow gap
and shielding.

== 3 of 8 ==
Date: Mon, Aug 2 2010 7:05 am
From: zekfrivo@zekfrivolous.com (GregS)

In article <cc42fb59-8483-4e9e-ba6b-a1c0a4e999e4@q35g2000yqn.googlegroups.com>, Amanda Ripanykhazov <dmanzaluni@googlemail.com> wrote:
>Thank you for your confidence everyone: If I wanted to wind everyone
>up, dont you think I would have found a funnier way of doing it than
>this?
>
>If someone can get me a way of posting a wav file to a NG, let me know
>and I will stick a microphone in front of the speaker and post
>whatever it records

I thought it was from BEHIND the speaker.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

>Meanwhile I will take the speaker out and report back if/when I have a
>result

== 4 of 8 ==
Date: Mon, Aug 2 2010 7:21 am
From: Chuck

On Tue, 20 Jul 2010 12:30:48 -0700 (PDT), Amanda Ripanykhazov
<dmanzaluni@googlemail.com> wrote:

>Anyone know what this means? This hissing sound isnt constant, it is
>irregular: It isnt related to the music or any movement of the cone
>or any signal put through it, though it doesnt happen when no sound is
>put through the speaker.
>
>Frankly it sounds more mechancial than electronic (as if there is
>something behind there!) but as I say, it isnt related to whatever is
>coming through the speaker though it does increase and decrease with
>adjustment of the volume control. Andit is louder than most signals
>put through the woofer itself??
>
>Is it indicative of some pot in the crossover needing cleaning or is
>there something else going on please? (I have seen reference to people
>improving the sound of AR11s by bypassing the tone controls in the
>speaker completely). This speaker is quite elderly and I would
>imagine that if it does use mechanical pots, they must be fairly dirty
>by now

I once lived in an old mansion that had been converted into an
apartment building where one of my KLH 32 speakers was mounted by the
main electrical entrance for the building. There sometimes was a soft
noise from the tweeter without the amplifier being on. Later on we
discovered that the owner of the building had replaced one of the
cartridge fuses in series with the hot 120 AC in with a piece of
copper pipe that was arcing at the fuse clips. I know this sounds
apocryphal but I spent 32 years in the consumer audio field as a
technician, and service and store manager so you can be reasonably
sure, in this case, that I'm not a troll . Chuck

== 5 of 8 ==
Date: Mon, Aug 2 2010 7:28 am
From: "William Sommerwerck"

> I once lived in an old mansion that had been converted into an
> apartment building where one of my KLH 32 speakers was mounted
> by the main electrical entrance for the building. There was sometimes
> a soft noise from the tweeter without the amplifier being on. Later on
> we discovered that the owner of the building had replaced one of
> the cartridge fuses in series with the hot 120 AC in with a piece of
> copper pipe that was arcing at the fuse clips.

What do you think formed the "return path" that allowed current to flow
through the speaker?

For example... In the simplest possible 2-way system, with only a capacitor
in series with the tweeter, * there would be no complete circuit for the
current to flow through the tweeter, unless the unpowered amplifier had a
sufficiently low output impedance.

* The woofer can be designed to mechanically roll off at the crossover
frequency, so no inductor is needed.

== 6 of 8 ==
Date: Mon, Aug 2 2010 8:19 am
From: nesesu

On Aug 2, 7:28 am, "William Sommerwerck" <grizzledgee...@comcast.net>
wrote:
> > I once lived in an old mansion that had been converted into an
> > apartment building where one of my KLH 32 speakers was mounted
> > by the main electrical entrance for the building. There was sometimes
> > a soft noise from the tweeter without the amplifier being on. Later on
> > we discovered that the owner of the building had replaced one of
> > the cartridge fuses in series with the hot 120 AC in with a piece of
> > copper pipe that was arcing at the fuse clips.
>
> What do you think formed the "return path" that allowed current to flow
> through the speaker?
>
> For example... In the simplest possible 2-way system, with only a capacitor
> in series with the tweeter, * there would be no complete circuit for the
> current to flow through the tweeter, unless the unpowered amplifier had a
> sufficiently low output impedance.
>
> * The woofer can be designed to mechanically roll off at the crossover
> frequency, so no inductor is needed.

The tweeter, capacitor and woofer are all effectively in series as a
loop in the speaker box, and that loop is large enough to pick up the
high M field spectrum of the arcing 60Hz so close by. Some of that
generated arc noise will fall in the band that the tweeter will
reproduce efficiently.

Neil S.

== 7 of 8 ==
Date: Mon, Aug 2 2010 9:02 am
From: Meat Plow

On Mon, 02 Aug 2010 09:21:24 -0500, Chuck wrote:

> On Tue, 20 Jul 2010 12:30:48 -0700 (PDT), Amanda Ripanykhazov
> <dmanzaluni@googlemail.com> wrote:
>
>>Anyone know what this means? This hissing sound isnt constant, it is
>>irregular: It isnt related to the music or any movement of the cone or
>>any signal put through it, though it doesnt happen when no sound is put
>>through the speaker.
>>
>>Frankly it sounds more mechancial than electronic (as if there is
>>something behind there!) but as I say, it isnt related to whatever is
>>coming through the speaker though it does increase and decrease with
>>adjustment of the volume control. Andit is louder than most signals put
>>through the woofer itself??
>>
>>Is it indicative of some pot in the crossover needing cleaning or is
>>there something else going on please? (I have seen reference to people
>>improving the sound of AR11s by bypassing the tone controls in the
>>speaker completely). This speaker is quite elderly and I would imagine
>>that if it does use mechanical pots, they must be fairly dirty by now
>
>
> I once lived in an old mansion that had been converted into an apartment
> building where one of my KLH 32 speakers was mounted by the main
> electrical entrance for the building. There sometimes was a soft noise
> from the tweeter without the amplifier being on. Later on we discovered
> that the owner of the building had replaced one of the cartridge fuses
> in series with the hot 120 AC in with a piece of copper pipe that was
> arcing at the fuse clips. I know this sounds apocryphal but I spent 32
> years in the consumer audio field as a technician, and service and store
> manager so you can be reasonably sure, in this case, that I'm not a
> troll . Chuck

An old friend used to live within a hundred feet of a radio station. He
swears that on one occasion he could hear programming coming from a
filling in one of his molars.

== 8 of 8 ==
Date: Mon, Aug 2 2010 9:27 am
From: "William Sommerwerck"

> The tweeter, capacitor and woofer are all effectively
> in series as a loop in the speaker box...

Duh. I should surrender my BSEE.

==============================================================================
TOPIC: free download endhiran song and wallpaper
http://groups.google.com/group/sci.electronics.repair/t/f2a0c7f6c7eff71d?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Aug 2 2010 7:34 am
From: "message2day.blogspot.com"

S Shankar, the director of this Rs 200 crore film, is one of the
biggest showmans India has ever seen,The film is expected to hit 800
screens across the country. It is going to be released in 120 prints
in Japan and China and 160 prints in overseas. All over 'Endhiran' is
going to be released in 1500 prints that will make it one of the
biggest films of the world
ever.......................................................http://
endhirantherobot.co.cc/

==============================================================================
TOPIC: Midiverb ii issues?
http://groups.google.com/group/sci.electronics.repair/t/aaedd7aef36420d1?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Aug 2 2010 8:03 am
From: El Grillo

Thanks everyone for your help!

nicholas

On Jul 29, 1:41 pm, "Michael A. Terrell" <mike.terr...@earthlink.net>
wrote:
> Meat Plow wrote:
>
> > On Thu, 29 Jul 2010 09:28:33 +0100, Arfa Daily wrote:
>
> > > <snip>
>
> > >>> Interesting. I wonder why the difference ? A few years back - say 10
> > >>> or so -
> > >>> I would have said that I saw as many short circuit electrolytics, as
> > >>> any other problems with them such as open circuit, low value, leaking,
> > >>> bulging
> > >>> etc. Now though, short circuit is comparatively rare. As to cathode
> > >>> caps, I
> > >>> think that I have probably seen more that were open circuit than
> > >>> short. Used
> > >>> to be a big problem in the frame output and audio output stages of TV
> > >>> sets,
> > >>> back in the day ...
>
> > >> Sprague had high standards, but you paid for it. Japanese crap hit
> > >> the US hard in the early '70s and you saw a lot more failed
> > >> electrolytics. Sprague started shutting down their plants as demand
> > >> for high quality electrolytics dropped. I still have a roll of
> > >> aluminized mylar from the Orlando plant, along with a partial roll of
> > >> 'component lead' they used on their famous 'Orange Drop' capacitors.
>
> > > Now there's another interesting thing. I wouldn't have thought that
> > > Orlando, given the extremes of humidity that it suffers, would have been
> > > a very good place for manufacturing capacitors, or was it just 'wet'
> > > electrolytics that were made there ? Or was the whole plant
> > > environment-controlled ? Guess you wouldn't be able to afford to do that
> > > these days ...
>
> > > Arfa
>
> > I don't suppose a plant manufacturing capacitors has to be very big. At
> > least the assembly building. It's easy enough to imagine a climate
> > controlled assembly room. And Mike is right about the history of
> > capacitors. I lived through the era when manufacturing stopped giving a
> > shit about quality over pumping out volumes of crap.
>
> Sprague continued to make them, but most manufacturers had been taken
> over by MBA bean counters by then. They were still making high quality
> parts, till Vishay bought them.
>
> --
> Anyone wanting to run for any political office in the US should have to
> have a DD214, and a honorable discharge.

==============================================================================
TOPIC: Parts
http://groups.google.com/group/sci.electronics.repair/t/6b4b067e1cc105e9?hl=en
==============================================================================

== 1 of 1 ==
Date: Mon, Aug 2 2010 9:05 am
From: Meat Plow

On Sat, 31 Jul 2010 21:47:46 -0600, Vince wrote:

> Hi!
> Where doI purschase Parts for Magnavox TVs?
> Thank you
> Vince

Would depend on what parts you wanted to purchase.

==============================================================================
TOPIC: Dell 1905FP Monitor, How to open the cover and repair power-off
http://groups.google.com/group/sci.electronics.repair/t/10e0727f78b6976d?hl=en
==============================================================================

== 1 of 2 ==
Date: Mon, Aug 2 2010 3:37 pm
From: "Kall, Mogens"

Heysan,

This newsletter is created just in case, if someone need the informations.

1.
How to open the cover

The monitor can be separated by sliding a thick guitar (plastic) pick along
the edge where the two halves meet.

See perhaps picture ...
https://sites.google.com/site/kallfiles1/technology/computer/monitor/repair/dell-1905-fp/how-to-open-the-cover

2.
How to repair power-off

I found 3 defect capacittors (10v 1000 µF), named C823, C824 and C825
and replaced them with 16v 1000 µF.

See perhaps picture ...
https://sites.google.com/site/kallfiles1/technology/computer/monitor/repair/dell-1905-fp/power-off

With kind regards,
Mogens Kall, The servant of Michael.
--
Coming up news: Iran hit by a Asteroid. Iran is no more (Jer.49,34-)
Last OUTPUT: 11419 news:4c541326$0$276$14726298@news.sunsite.dk
Info http://groups.google.dk/group/dk.test/msg/591d03940b49201e
Website https://sites.google.com/site/kalltree1 File no: 11423

== 2 of 2 ==
Date: Mon, Aug 2 2010 5:40 pm
From: Mat

On Tue, 03 Aug 2010 00:37:28 +0200, Kall, Mogens wrote:

> Heysan,
>
> This newsletter is created just in case, if someone need the informations.
>
> 1.
> How to open the cover
>
> The monitor can be separated by sliding a thick guitar (plastic) pick along
> the edge where the two halves meet.
>
> See perhaps picture ...
> https://sites.google.com/site/kallfiles1/technology/computer/monitor/repair/dell-1905-fp/how-to-open-the-cover
>
> 2.
> How to repair power-off
>
> I found 3 defect capacittors (10v 1000 µF), named C823, C824 and C825
> and replaced them with 16v 1000 µF.
>
> See perhaps picture ...
> https://sites.google.com/site/kallfiles1/technology/computer/monitor/repair/dell-1905-fp/power-off
>
>
> With kind regards,
> Mogens Kall, The servant of Michael.

How did you determine the capacitors were defective? Visually or test?

==============================================================================
TOPIC: What is this strange encoder motor?
http://groups.google.com/group/sci.electronics.repair/t/c033e5f3d5b31265?hl=en
==============================================================================

== 1 of 3 ==
Date: Mon, Aug 2 2010 4:50 pm
From: Ignoramus18921

Lots of new pictures here.

http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/

This is a servo motor driven rotary table Troyke U12PNC.

I thought that it was a simple servo motor with a tachometer and
encoder on the back. Nothing could be further from the truth. When I
opened it up, the tach was on the back alright, but no encoder.

I took off a box hanging on the front of this contraption and I think
this is where the encoder is. There are two cylinders.

One is called "Electro-craft moving coil tach generator". Part
0100-00-022.

The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
Hz, rotor 1 phase, stator 2 ph, spec code H.S.C.T., 11BRW-300-70/10."

Does anyone have AN idea just what are they and whether I can use it
as a quadrature encoder.

On the rear of the motor, there is not enoug free hanging shaft to
mount a modern encoder.

My uneducated guess is that it is a "resolver".

Thanks

== 2 of 3 ==
Date: Mon, Aug 2 2010 5:56 pm
From: Tim Wescott

On 08/02/2010 04:50 PM, Ignoramus18921 wrote:
> Lots of new pictures here.
>
> http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/
>
> This is a servo motor driven rotary table Troyke U12PNC.
>
> I thought that it was a simple servo motor with a tachometer and
> encoder on the back. Nothing could be further from the truth. When I
> opened it up, the tach was on the back alright, but no encoder.
>
> I took off a box hanging on the front of this contraption and I think
> this is where the encoder is. There are two cylinders.
>
> One is called "Electro-craft moving coil tach generator". Part
> 0100-00-022.
>
> The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
> Hz, rotor 1 phase, stator 2 ph, spec code H.S.C.T., 11BRW-300-70/10."
>
> Does anyone have AN idea just what are they and whether I can use it
> as a quadrature encoder.
>
> On the rear of the motor, there is not enoug free hanging shaft to
> mount a modern encoder.
>
> My uneducated guess is that it is a "resolver".

My educated guess is that it is a resolver. The frequency is right, the
labels on the rotor and stator are right.

Do you have a signal generator and an O-scope? Feed it with 2500Hz to
the rotor, and see if you get 2500Hz out the two stator windings, with a
coupling that depends on the shaft position.

There may be industrial resolver to encoder converters out there -- it
would be something that a machine designer or retrofitter might need.

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html

== 3 of 3 ==
Date: Mon, Aug 2 2010 6:48 pm
From: Ignoramus18921

On 2010-08-03, Tim Wescott <tim@seemywebsite.com> wrote:
> On 08/02/2010 04:50 PM, Ignoramus18921 wrote:
>> Lots of new pictures here.
>>
>> http://igor.chudov.com/projects/Bridgeport-Series-II-Interact-2-CNC-Mill/24-Troyke-Rotary-Table-U12PNC/
>>
>> This is a servo motor driven rotary table Troyke U12PNC.
>>
>> I thought that it was a simple servo motor with a tachometer and
>> encoder on the back. Nothing could be further from the truth. When I
>> opened it up, the tach was on the back alright, but no encoder.
>>
>> I took off a box hanging on the front of this contraption and I think
>> this is where the encoder is. There are two cylinders.
>>
>> One is called "Electro-craft moving coil tach generator". Part
>> 0100-00-022.
>>
>> The other is "Summit engineering, Boseman MT. Model 573-211-10, 2500
>> Hz, rotor 1 phase, stator 2 ph, spec code H.S.C.T., 11BRW-300-70/10."
>>
>> Does anyone have AN idea just what are they and whether I can use it
>> as a quadrature encoder.
>>
>> On the rear of the motor, there is not enoug free hanging shaft to
>> mount a modern encoder.
>>
>> My uneducated guess is that it is a "resolver".
>
> My educated guess is that it is a resolver. The frequency is right, the
> labels on the rotor and stator are right.
>
> Do you have a signal generator and an O-scope? Feed it with 2500Hz to
> the rotor, and see if you get 2500Hz out the two stator windings, with a
> coupling that depends on the shaft position.
>
> There may be industrial resolver to encoder converters out there -- it
> would be something that a machine designer or retrofitter might need.
>

There are some converters out there, Jon has one for sale too.

Tim, how much angular accuracy could I get from this resolver, in
pulses per revolution?

If this is too complicated, I may just look for the right sized modern
servo motor on ebay.

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