DC motor in cat toy stopped working.

[David Farber]

Here is a picture of the toy:
http://www.pet2go.co.uk/wp-content/uploads/2016/03/Interactive-Mouse-Chaser-Toy-Revolving-Moving-Mouse-Motion-Game-Cat-Kitten.jpg

I removed the small motor that looks about the size of a CD spindle motor.
It measured around 1-2 ohms across its terminals. When I hooked it up to my
bench supply with the current limiter set to 0.5 amps, the overload kept
tripping. I was able to remove the motor from its case and give the brushes
a good cleaning. Now the motor works fine from my bench supply but in
circuit, it's still not working. I traced the circuit back to two pairs of
SMD transistors. They are very hard for me to see even with my magnifiers. I
think one of them has a crack in it. The only writing on the first pair is
:Y1 and the other pair is marked, :Y2 Any ideas what kind of transistors or
other three-terminal devices these are?

Thanks for your reply.
--
David Farber
Los Osos, CA

[tabb...@gmail.com]

Those toys are hopelessly unreliable. Better to junk the controller and add a manual control. If you want to fix the controller you'll need to follow the output area circuit to work out what the connections are and whether they're npn or pnp. Most likely it'll be a standard motor driver H bridge, and they'll need replacing with devices able to take peak motor current, which you can measure.


NT

[olds...@tubes.com]

My cats are just plain old fashioned farm cats who only need a common
mouse to keep them entertained. The mice dont contain any motors,
transistors, capacitors, or batteries. Low tech, and much better for the
environment.

But these modern city cats have gone high tech. Some even have
smartphones, and have their own facebook pages. Thats the problem, They
expect their owners to provide electronic gadgets to entertain them,
then they dont even earn their "pay" to cover the cost of the batteries
for these gadgets, because they dont kill any mice.

I say, the solution is to just toss all the electronics and buy your cat
a plain old mouse. If the cat refuses to play with the mouse, trade that
citified cat for a plain old fashioned farm cat. Farm cats earn their
living, and they still have the balls to tackle the biggest mouse or
even a rat. Most of these modern citified cats dont even come with balls
anymore.

Geez, I just could not resist posting this reply! :)

On a serious note, I cant see the need for any transistors to operate a
small battery operated DC motor, unless it has some sort of speed
control, or reverses or something like that. I guess you will have to
determine what this toy does, besides just rotate. Like most cheap
modern stuff, they no longer label components. That fact alone, combined
with the small size of these parts, is one reason I prefer working on
old tube gear. Maybe someone else on here can point you in the right
direction regarding that transistor. I cant....

[David Farber]

It does a few fancy things. There are three selectable speeds which can be
selected by successive presses of the power button. The last keypress of the
button selects a random mode where the speed and the direction of the motor
varies.

I've done some more checking and both of the Y1 transistors, which are NPN,
have failed. One is open B-E and the other is open B-C. I can't remember
many, or even any transistors that have ever opened B-C. I'm going to check
it a few more times to make sure I'm making solid contact with the terminals
when using my DVM. I'll still haven't been able to positively identify the
specs of those transistors.

[olds...@tubes.com]

On Sun, 16 Jul 2017 18:02:52 -0700, "David Farber"

Those transistors are the speed controls. I wonder if they might be SCRs
or Triacs, (generally used in motor speed controls and light dimmers),
rather than common transistors. It kind of sounds like your motor
failed, or shorted until you tore it apart, and that wiped out the
transistors.

But like most everything these days, they dont identify the
semiconductors, because they want you to toss the whole device and buy a
new one. All I can suggest is to try some new transistors and see if
they work. Or try some triacs. (At least you know they are NPN). Since I
mostly work on old tube gear, I cant even suggest what sort of
transistors to try. Maybe someone else on here can shed some more light
on the subject.

I suppose you could also buy another of these cat toys and measure the
parts on the new one so you know what these parts show for measurements.
I recall seeing those things advertised on tv a few years ago. From what
I recall, they were not real expensive.

(Or just buy a plain old live mouse, which have built in speed controls,
and use non-electronic sensors to run away from cats) :)

Good luck with it.

[tabb...@gmail.com]

It really would make no sense to use those in this circuit

> It kind of sounds like your motor
> failed, or shorted until you tore it apart, and that wiped out the
> transistors.

I doubt it. These toys are chinese junk construction, transistors hopelessly underrated.

> But like most everything these days, they dont identify the
> semiconductors, because they want you to toss the whole device and buy a
> new one. All I can suggest is to try some new transistors and see if
> they work. Or try some triacs. (At least you know they are NPN). Since I
> mostly work on old tube gear, I cant even suggest what sort of
> transistors to try. Maybe someone else on here can shed some more light
> on the subject.
>
> I suppose you could also buy another of these cat toys and measure the
> parts on the new one so you know what these parts show for measurements.
> I recall seeing those things advertised on tv a few years ago. From what
> I recall, they were not real expensive.

It's hardly difficult to measure the motor to see what tr specs are required

> (Or just buy a plain old live mouse, which have built in speed controls,
> and use non-electronic sensors to run away from cats) :)

I guess I'm not a fan of unnecessary torture.


NT

[David Farber]

The toy has lasted several years.and has gotten quite a workout. As far as
the live mouse thing, our cats catch plenty of mice and then try to gift
their catches to us. As a result, we've had to decommission the kitty door
to the outside world. Now they can only go out when we let them and then
will only be let back in if they are not bringing anything with them.

Regarding the mystery transistors, perhaps you could recommend some NPN SMD
transistors that can handle the peak motor current of about 300ma. The
configuration is SOT-23. The case is about 2.5mm wide.

Thanks for your reply.
--
David Farber

Los Osos, CA

[Dave Platt]

In article <okjiti$7ad$1...@dont-email.me>,

David Farber <farberbe...@aol.com> wrote:

>Regarding the mystery transistors, perhaps you could recommend some NPN SMD
>transistors that can handle the peak motor current of about 300ma. The
>configuration is SOT-23. The case is about 2.5mm wide.

A lot of people seem to like the Zetex parts, now made by Diodes Inc.
Zetex transistors seem to have low saturation voltages and good
current capacity.

ZTXN2038F is one of many examples... 1A continuous collector current,
2A peak pulse current. Digi-Key wants $0.41 in onesies.

[tabb...@gmail.com]

On Tuesday, 18 July 2017 01:01:38 UTC+1, David Farber wrote:

> The toy has lasted several years.and has gotten quite a workout. As far as
> the live mouse thing, our cats catch plenty of mice and then try to gift
> their catches to us. As a result, we've had to decommission the kitty door
> to the outside world. Now they can only go out when we let them and then
> will only be let back in if they are not bringing anything with them.
>
> Regarding the mystery transistors, perhaps you could recommend some NPN SMD
> transistors that can handle the peak motor current of about 300ma. The
> configuration is SOT-23. The case is about 2.5mm wide.
>
> Thanks for your reply.

Most jellybean transistors can do 300mA. That seems a bit low for a locked rotor current, but maybe they're small motors. You'll need trs that match the required pinout.


NT

[olds...@tubes.com]

If it lasted several years, you probably got your moneys worth out of
it. If I recall correctly, from the commercials, they sold for about $20
(plus S&H). I'd probably just buy another one, if your cat loves it.
Sounds like your cat is worth it. However I do understand you wanting to
try to fix it. But you're up against a item made to be disposible, with
no ID on the transistors. And even if you do get it to work, how long
will those motor brushes last?

But hey, we all tackle projects like this. Sometimes we win, often we
lose. If you do get it to work, maybe you will be the first to find
suitable replacment parts.... And your efforts will help someone else
with the same toy.

I wonder what these cat toys sell for on Ebay?

Yea, I know all about cats bringing dead (or sometimes live) mice into
the house. They are offering you a gift, even though I know I sure dont
want it..... But I do like cats.

[pf...@aol.com]

On Monday, July 17, 2017 at 8:01:38 PM UTC-4, David Farber wrote:

> As far as
> the live mouse thing, our cats catch plenty of mice and then try to gift
> their catches to us. As a result, we've had to decommission the kitty door
> to the outside world. Now they can only go out when we let them and then
> will only be let back in if they are not bringing anything with them.

Bad move!

Your cats think that you are a particularly incompetent hunter, eat all kinds of weird, smelly, dead food and generally are not very good cats. So, they are trying to feed you, and train you as they would their kittens. The proper response is to *immediately* praise the cat, and then pick up the gift and remove it to some location that the cat will never find in the future - make it 'gone'. Do not flush it in the presences of the cat, or dispose of it in some similar way in sight of the cat. That is, to the cat, a completely incomprehensible reaction to a sincere gesture.

Just be glad the cats are not focused on bringing you live prey for specific training. We had a big Maine Coon that decided he was going to 'train up' our Scottie when she was a puppy - he was a LOT bigger than she was at the time. Several full-sized live squirrels and one yearling raccoon later, we had to explain to him the difference between cats and dogs. Sadly we lost him to cancer (at 16) shortly there after.

Peter Wieck
Melrose Park, PA

[David Farber]

Hi Dave,

That should work great! However there was no pinout in the datasheet.
https://www.diodes.com/assets/Datasheets/ZXTN2038F.pdf

I e-mailed diodes.com tech support to see if they can supply that
information.

[tabb...@gmail.com]

On Tuesday, 18 July 2017 20:17:21 UTC+1, olds...@tubes.com wrote:
> On Mon, 17 Jul 2017 17:01:00 -0700, "David Farber"
> <farberbe...@aol.com> wrote:
>
> >> It's hardly difficult to measure the motor to see what tr specs are
> >> required
> >>
> >>> (Or just buy a plain old live mouse, which have built in speed
> >>> controls, and use non-electronic sensors to run away from cats) :)
> >>
> >> I guess I'm not a fan of unnecessary torture.
> >>
> >>
> >> NT
> >
> >The toy has lasted several years.and has gotten quite a workout. As far as
> >the live mouse thing, our cats catch plenty of mice and then try to gift
> >their catches to us. As a result, we've had to decommission the kitty door
> >to the outside world. Now they can only go out when we let them and then
> >will only be let back in if they are not bringing anything with them.
> >
> >Regarding the mystery transistors, perhaps you could recommend some NPN SMD
> >transistors that can handle the peak motor current of about 300ma. The
> >configuration is SOT-23. The case is about 2.5mm wide.
> >
> >Thanks for your reply.
>

> If it lasted several years, you probably got your moneys worth out of
> it. If I recall correctly, from the commercials, they sold for about $20
> (plus S&H). I'd probably just buy another one, if your cat loves it.
> Sounds like your cat is worth it. However I do understand you wanting to
> try to fix it. But you're up against a item made to be disposible, with
> no ID on the transistors. And even if you do get it to work, how long
> will those motor brushes last?
>
> But hey, we all tackle projects like this. Sometimes we win, often we
> lose. If you do get it to work, maybe you will be the first to find
> suitable replacment parts.... And your efforts will help someone else
> with the same toy.
>
> I wonder what these cat toys sell for on Ebay?
>
> Yea, I know all about cats bringing dead (or sometimes live) mice into
> the house. They are offering you a gift, even though I know I sure dont
> want it..... But I do like cats.

It's an easy enough repair. But need to be clear on the motor current, a motor that runs at 0.3A will kill 0.3A transistors. The question is what is the stalled motor current. Once the requirements are clear any junkbox should contain something suitable.


NT

[tabb...@gmail.com]

The odds of putting a caught mouse somewhere the cat will never know are very small. Put it in the cat's food bowl a little later & they take it as a gift and enjoy.


NT

[Dave Platt]

>Hi Dave,
>
>That should work great! However there was no pinout in the datasheet.
>https://www.diodes.com/assets/Datasheets/ZXTN2038F.pdf
>
>I e-mailed diodes.com tech support to see if they can supply that
>information.

Take a look at

http://www.electro-tech-online.com/attachments/pinouts-png.30877/

as it has a whole bunch of pinouts. From what I read, it appears that
the SOT-23-3 package for transistors has highly standardized pinouts.

[David Farber]

Yes, that matches what the old part is. I'm in no hurry so I'll wait to see
what diodes.com has to say.

[~misfit~]

I think you might be better off junking the electric mouse and instead
getting electric cats. It's cruel to expect real ones to do just what you
want and nothing more.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

[David Farber]

I finally had time to install the new transistors and they worked
perfrectly. The cats are happy again!

Thanks for all your helpful replies.

[bruce2...@gmail.com]

pf...@aol.com wrote:
> On Monday, July 17, 2017 at 8:01:38 PM UTC-4, David Farber wrote:
>
> > As far as
> > the live mouse thing, our cats catch plenty of mice and then try to gift
> > their catches to us. As a result, we've had to decommission the kitty door
> > to the outside world. Now they can only go out when we let them and then
> > will only be let back in if they are not bringing anything with them.
>
> Bad move!
>
> Your cats think that you are a particularly incompetent hunter, eat all kinds of weird, smelly, dead food and generally are not very good cats. So, they are trying to feed you, and train you as they would their kittens.

That's really the explanation?

[tabb...@gmail.com]

You could ask one, but IME they're inclined to be secretive.


NT

[Dave Platt]

In article <oqefp1$98r$1...@dont-email.me>,

David Farber <farberbe...@aol.com> wrote:

>I finally had time to install the new transistors and they worked
>perfrectly. The cats are happy again!

Excellent - very glad to hear it!

[pf...@aol.com]

On Tuesday, September 26, 2017 at 5:28:59 PM UTC-4, bruce2...@gmail.com wrote:

>
> That's really the explanation?

It is. This becomes particularly clear when a mother cat starts to train her kittens to hunt. First, freshly dead, then nearly dead, then undamaged prey.