DC motor in cat toy stopped working.

my

es

. I

or

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 th ey're npn or pnp. Most likely it'll be a standard motor driver H bridge, an d they'll need replacing with devices able to take peak motor current, whic h you can measure.

NT

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....

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.

Thanks for your reply.

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.

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

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

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

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.

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,

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

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.

Bad move!

Your cats think that you are a particularly incompetent hunter, eat all kin ds of weird, smelly, dead food and generally are not very good cats. So, th ey are trying to feed you, and train you as they would their kittens. The p roper response is to *immediately* praise the cat, and then pick up the gif t 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 compl etely incomprehensible reaction to a sincere gesture.

Just be glad the cats are not focused on bringing you live prey for specifi c 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

Hi Dave,

That should work great! However there was no pinout in the datasheet.

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

Thanks for your reply.

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

oor

inds 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 g ift and remove it to some location that the cat will never find in the futu re - make it 'gone'. Do not flush it in the presences of the cat, or dispos e of it in some similar way in sight of the cat. That is, to the cat, a com pletely incomprehensible reaction to a sincere gesture.

fic training. We had a big Maine Coon that decided he was going to 'train u p' our Scottie when she was a puppy - he was a LOT bigger than she was at t he 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 los t him to cancer (at 16) shortly there after.

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

NT

Take a look at

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.

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.

Thanks for your reply.

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.

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

Thanks for all your helpful replies.

That's really the explanation?

Excellent - very glad to hear it!