Looking for sewage inspection robot head spare parts

[blisca]

Hello

please,i need to repair a circular PCB board inside the rotating camera
head of a robot,a small tractor for sewage inspection.The brand is
Pearpoint,model 494/04,part of S.C.S Ex94C1001 & 1002
http://s000.tinyupload.com/?file_id=55489985001783462747
An internal short circuit,probably due to iron dust,generated heat,enough
to burn away the golden plated track and carbonize the PCB

Repairing it requires to redraw and rebuild the PCB,it would be good if
someone has the spare part,or the service manual,because i could do errors
in redraw the burned tracks and vias

Many thanks

Diego



---
Questa email è stata esaminata alla ricerca di virus da AVG.
http://www.avg.com

[Terry Schwartz]

Repairing that would be problematic, because it looks like it serves as a rotating slip ring with multiple connections. You might repair the traces but it could not be smooth, the connections thru the brushes or contacts would not be steady or reliable as it rotates. A replacement is your only real option.

Is the original company no longer supporting this device?

[blisca]

> On Thursday, April 5, 2018 at 2:56:15 AM UTC-5, blisca wrote:

>> please,i need to repair a circular PCB board inside the rotating camera
>> head of a robot,a small tractor for sewage inspection.The brand is
>> Pearpoint

Hi,

> Repairing that would be problematic, because it looks like it serves as
> a rotating slip ring with multiple connections.

Yes,exactly.A correspondig PCB mounts some spring loaded spheric
contacts(i think they are also called pogo pins),sliding on the circular
tracks.

> Is the original company no longer supporting this device?

no spare parts availabile,product out of production since long time,but i
admit that i still have to ask to their support about the drawings

> You might repair the traces but it could not be smooth, the connections
> thru the brushes or contacts would not be steady or reliable as it
> rotates. A replacement is your only real option.

I completely agree,i dont know any product that i could paint even on a
perfectly flat surface,hard enough to withstand the friction
Furthermore the burned PCB could have lost insulation.

I started drawing an identical PCB some days ago
The problem is to get the right distances and positions of tracks and
vias,and some of them almost disappeared ,despite their function looks
trivial(unless strange crossings).
The most precise method i found was doing an accurate photo,and using the
pixel meter of a free image editor as GIMP to get the distances.
Once drawn,i will print it on a transparent sheet to check it versus the
real one

Thanks for your time

[Terry Schwartz]

Ask them for the Gerber files. Then you can send them out to be reproduced. It will be expensive because you need the "hard gold" surface finish (not ENIG) on the entire board. This is usually only used on edge connectors and is almost obsolete.

Can you post a picture of the other side of the board?

[Jeff Liebermann]

On Thu, 05 Apr 2018 09:55:00 +0200, blisca <bli...@tiscali.it> wrote:

>Pearpoint,model 494/04,part of S.C.S Ex94C1001 & 1002
>http://s000.tinyupload.com/?file_id=55489985001783462747

>Repairing it requires to redraw and rebuild the PCB,it would be good if
>someone has the spare part,or the service manual,because i could do errors
>in redraw the burned tracks and vias

The best way would be to copy the PCB photographically, and make a new
PCB. However, if you want to try repair, find some thin sheet copper.
Draw the missing traces on the copper sheet. Cut out the semi
circular sections with an Xacto knife. Glue to the existing PCB. If
you overlap the new copper to the existing gold traces, you should
have a sufficiently good connection without soldering. Stained glass
copper tape should work.

You can also do this with aluminum foil duct tape, but will need to do
something to improve conductivity and prevent electrolysis. For dry
(no DC) connections, I dope the sticky glue back of the tape with
graphite powder.

Another approach would be to totally replace the PCB with a ribbon
cable. It appears to simply provide the ability to do multiple 360
degree rotations without binding. That's a useful feature, but
probably not a necessity for sewer inspections. Build an umbilical
cable between the electronics and the camera head that replaces the
function of the board. Either provide a mechanical stop that provides
over-rotation protection or just be careful when rotating. Hopefully,
you have room inside for the umbilical.

Good luck.

--
Jeff Liebermann je...@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

[et...@whidbey.com]

On Thu, 05 Apr 2018 09:55:00 +0200, blisca <bli...@tiscali.it> wrote:

I see eleven traces in that picture. Is there room for a slip ring?
See this link: https://www.adafruit.com/product/1196
This slip ring assembly has twelve conductors rated at 240 volts and 2
amps. Twenty dollars US.
Eric

[Terry Schwartz]

No Jeff, that's nonsense. Copper tape or aluminum foil tape will not hold up to the pogo pins rubbing on them. It'll last a few rotations before it wears thru, or folds up the tape, or pushes it off the substrate, likely creating another short.

I do like the slip ring idea if there is room and a way to secure it.

Otherwise, get the original gerbers, or recreate the gerbers in a PCB cad program, Eagle would do this easily. Then consult with a domestic PCB house on how to specify the copper thickness and hard gold plating. Doing it by design rather than some photocopy process would insure correct alignment with the pogo pins.

A "dry" connection does not imply no DC, by the way, it implies very low current.

[Jeff Liebermann]

On Thu, 5 Apr 2018 17:15:07 -0700 (PDT), Terry Schwartz
<tschw...@aol.com> wrote:

>No Jeff, that's nonsense. Copper tape or aluminum foil tape
>will not hold up to the pogo pins rubbing on them. It'll
>last a few rotations before it wears thru, or folds up
>the tape, or pushes it off the substrate, likely creating
>another short.

I'll admit that I haven't tried it with a similar device, but it
worked well enough on an HP8640B signal generator switch that was
somehow mangled. I don't have a photo of the repair, but this is the
switch type:
<http://www.learnbydestroying.com/jeffl/pics/HP8640B/slides/HP8640B-01.html>
I used 3 mil copper shielding tape without soldering. Something like
this:
<https://www.adafruit.com/product/1128>
The contacts are made from beryllium spring stock and do not apply
much pressure. There was a slight groove in the copper tape, but no
rips or tears. As far as I know, the generator is still functioning
about 10 years after the repair.

However, you might be right. The signal generator switch has much
less pressure, movement, and use than the robot head. However,
there's nothing lost (except time) in attempting to repair the
original with copper foil or tape. If the heads on the pogo pins are
wide and rounded enough, such a repair might hold together long enough
for the PCB to be cloned and replaced.

>I do like the slip ring idea if there is room and a way to secure it.

Agreed. Seems like a better idea than to patch together the existing
slip ring assembly. It might fit better if the it more closely
resembled the original:
<https://www.google.com/search?tbm=isch&q=slip+ring+rotary+pancake>
Maybe something like this one:
<http://www.directindustry.com/prod/bgb-innovation/product-112951-1112523.html>

>Otherwise, get the original gerbers, or recreate the gerbers in
>a PCB cad program, Eagle would do this easily. Then consult with a
>domestic PCB house on how to specify the copper thickness and hard
>gold plating. Doing it by design rather than some photocopy process
>would insure correct alignment with the pogo pins.

Or, go back to the dark ages and make a "tape up" of the board on
mylar film, probably using a drafting pen and India ink. When done,
photograph and reduce the photos to film which would be sent to the
PCB fab house. I'm not sure they know how to handle such dark ages
technology, but it's worth a try.

Nostalgia:
<http://www.learnbydestroying.com/jeffl/PCB-Layout/>

>A "dry" connection does not imply no DC, by the way, it implies
>very low current.

Sigh. I stand corrected:
<https://en.wikipedia.org/wiki/Wetting_current>
However, on a slip ring device, the contact spring pressure is
sufficient to break through any oxidation. Therefore, there's no need
to rely on DC current to break through it.

[Terry Schwartz]

> Sigh. I stand corrected:
> <https://en.wikipedia.org/wiki/Wetting_current>
> However, on a slip ring device, the contact spring pressure is
> sufficient to break through any oxidation. Therefore, there's no need
> to rely on DC current to break through it.

That in fact is correct -- hence better quality dry circuit switches are implemented with a wiping action set of contacts AND a low-reactivity contact material such as gold.

[blisca]

In data aprile 2018 alle ore 18:38:13, <et...@whidbey.com> ha scritto:

> On Thu, 05 Apr 2018 09:55:00 +0200, blisca <bli...@tiscali.it> wrote:
>
>> Hello
>>
>> please,i need to repair a circular PCB board inside the rotating camera
>> head of a robot,a small tractor for sewage inspection.The brand is
>> Pearpoint,model 494/04,part of S.C.S Ex94C1001 & 1002
>> http://s000.tinyupload.com/?file_id=55489985001783462747
>> An internal short circuit,probably due to iron dust,generated
>> heat,enough
>> to burn away the golden plated track and carbonize the PCB
>>
>> Repairing it requires to redraw and rebuild the PCB,it would be good if
>> someone has the spare part,or the service manual,because i could do
>> errors
>> in redraw the burned tracks and vias
>>
>> Many thanks
>>
>> Diego
>>

The solution >>

>>
>> ---
>> Questa email è stata esaminata alla ricerca di virus da AVG.
>> http://www.avg.com
> I see eleven traces in that picture. Is there room for a slip ring?
> See this link: https://www.adafruit.com/product/1196
> This slip ring assembly has twelve conductors rated at 240 volts and 2
> amps. Twenty dollars US.
> Eric

Thanks for the help good people,
All your very interesting hints deserve to be read again with attention,
and annotated.
ALL the proposed solutions are very interesting
I admit to ignore the existence of the slip ring that by its price and
availability is worth the attempt,in parallel of possible development the
PCB,maybe not from CAD->Gerbers but directly from 1:1 images.
In this case if impossible to have the appropriate golden plating
finishing,i could
take advantage about the small difference in having 1 or 8
boards;replacing the board periodically is not so difficult and it is not
a production machine that have to rotate thousand of times daily

Thanks again
Diego

[N_Cook]

Is it possible to mill out a bit of a groove in the broken area , to
allow thicker copper strip to be set in the then shallow groove of the pcb.

[et...@whidbey.com]

De nada.
Eric

[Jeff Liebermann]

On Fri, 06 Apr 2018 12:44:08 +0100, N_Cook <div...@tcp.co.uk> wrote:

>Is it possible to mill out a bit of a groove in the broken area , to
>allow thicker copper strip to be set in the then shallow groove of the pcb.

Good idea. However, I wouldn't do it just in the damaged area. With
a thicker piece of PCB material, one could mill concentric slots
(probably on a lathe or drill press). A copper or brass strip could
be inserted in the slot and glued in place. Bending the rectangular
strip would only work for a mounting it on edge, which might be a
problem making contact with the Pogo contacts. Flat would be better,
but that would require machining the circular contacts.

[N_Cook]

On 06/04/2018 17:59, Jeff Liebermann wrote:
> On Fri, 06 Apr 2018 12:44:08 +0100, N_Cook <div...@tcp.co.uk> wrote:
>
>> Is it possible to mill out a bit of a groove in the broken area , to
>> allow thicker copper strip to be set in the then shallow groove of the pcb.
>
> Good idea. However, I wouldn't do it just in the damaged area. With
> a thicker piece of PCB material, one could mill concentric slots
> (probably on a lathe or drill press). A copper or brass strip could
> be inserted in the slot and glued in place. Bending the rectangular
> strip would only work for a mounting it on edge, which might be a
> problem making contact with the Pogo contacts. Flat would be better,
> but that would require machining the circular contacts.
>

Worth having a go on some fresh pcb and copper. I forgot to say
previously, assuming joining old and new co[per, scarfe the joins together.

[blisca]

In data aprile 2018 alle ore 18:38:13, <et...@whidbey.com> ha scritto:

> On Thu, 05 Apr 2018 09:55:00 +0200, blisca <bli...@tiscali.it> wrote:
>
>> Hello
>>
>> please,i need to repair a circular PCB board inside the rotating camera
>> head of a robot,a small tractor for sewage inspection.

> I see eleven traces in that picture. Is there room for a slip ring?
> See this link: https://www.adafruit.com/product/1196
> This slip ring assembly has twelve conductors rated at 240 volts and 2
> amps. Twenty dollars US.
> Eric

Thanks,
i tried to simulate with a plastic spare part that i roughly filed to the
eight of one of the slip rings in the datasheet,but it looks too
thick,even removing the board with circular tracks,that could be
substituted by the slip ring.

[et...@whidbey.com]

That's too bad. It's always nice to be able to use stock parts. Since
the housing comes apart would it be possible to have a machine shop
make up a spacer so you would have a little more room to work with? I
don't know what your robot head looks like so I really don't know what
you are working with. But since I own a machine shop I tend to see
machining answers to problems. Could you post a link to a picture of
the robot head? I'm curious about it.
Eric

[blisca]

Thanks,sorry for reading and answering so late
Today i will have back the head and 'i will post a link to a pic

Thanks for your interest
Diego