Hi everyone, new here and the names Jeremy


I am looking for help on a Baldor 1hp smartmotor that I am trying to fix. I no some about electronics, but have a lot to learn. I have tried searching for many hours with no result. Even talked with a Digikey rep online and didnt get much further.

What I need help with is finding a replacement transistor for the motor control board. Here is a pic of the one in question "Q1". The middle row of numbers are "N100E" and not "N10GE" like it kind of looks like.

I would also like to find a circuit diagram for this board but have had no luck also. If someone can point me in the direction where to find a schematic/diagram, that would be helpful too. The number on the board is "PB0002A01" here is a pic of it:

Here is the tag on the motor itself if it will assist anyone in helping me.

 

It's difficult to suggest a replacement without seeing the schematic.
Have you tried to contact Baldor?

 

Here are the motorola parts that match number

Though the number is not complete, the "MBT" may be omitted due to space constrictions.

Many of those are D-Pak/Surface mount matching what you have.

I'm guessing it's one of these 3N100Ehttp://www.datasheetcatalog.org/datasheet/motorola/MTB1N100E.pdf but cannot say with any certainty. Nothing else matches, if you look through the list in the top link.

It could be a specially marked component, which are made for high volume products. Without knowing more of the details, such as pin out, what it tests as, etc, it's hard to make a suggestion.

 

I think it could be the MTV10N100E
MTV10N100E 1000(VDSS) 1.3(Ron Ohm) 10(ID A) 250(PD Watt)

 

I originally was going to put that one, then saw the 3 on the right edge of top line.

That's a bit of an important decision, 1 amp or 3 amp, so I'm not entirely sure still.

 

Thanks for the help guys, ya I have contacted Baldor but have got no where with them. They say the numbers on the board doesnt come up in their system. But "Baldor" is silk screened right on the board. Any sugg where I can find a schematic online for Baldor circuit boards? I have searched google for all the numbers on the motor as well as on the board and nothing comes up. The gal I spoke with at Baldor said the schematics are online somewhere. I guess they just are not searchable. I de soldered the Transistor and tested it with my diode tester and get the same value on all the legs. So im sure its bad. How do I find out without a schematic the amp rating of it?

 

If this is the switching element to control a motor, then it would make sense for it to be a MOSFET.

I'd suggest trying one of the above to see if it works, after inspecting the pinout in the datasheets, so you know gate is going to some sort of circuit that generates signals, Drain is going toward +V, and Source is going toward ground.

I'm assuming there is only one of these?

What stopped working on the unit? What were the conditions immediately prior to time of failure? If we start there, it might narrow it down more.

 

Well its kinda embarrassing.....the motor worked fine. I am using this on a metal cutting lathe and was adding an rpm readout which needed a 6volt input for power. I was testing to see if there was a 6-9 volt for some stupid reason and was using my fluke voltage tester. I had one lead on ground and the other I had touched one of the legs of this transistor when I heard a pop and a green spark like light. I was so so pissed off that I did this. I knew better not to do this, but it was just one of those days where I wasnt thinking. I inspected the board and found that a resistor on the back side of the board had blew. "R11"

So now the motor wont power up at all. I am guessing this transistor controls the power to the board as one circuit leads to a transformer on the board. Just a guess though. Would any other views or angles of the board help decipher if its is indeed a switching transistor?

 

Sense mine doesnt have the "MTV10" MTV10N100E and mine is just "N100E", what dos the MTV10 reefer to? Maybe Motorola Transistor V? And couldn't a 3 amp rated be used even if it was a 1 amp?

 

They have both 1 and 3 amp transistors in that package, and as I stated earlier, it is a "best guess".

Were you able to replace the resistor with the correct value?

Do the power and signal lines into the transistor on the PC Board match the pinout of the linked datasheet? Worse case is it may blow up again, maybe take another resistor with it. If the only other option is buying a new board, and the board is expensive, you may want to think about it.

Try contacting ON Semiconductor (Motorola's discrete products division), via e-mail to see if they can be of assistance before ordering.

 

So I checked RS thinking I might find something close and found this. I know its not an exact replacement, but can I do any further damage to the board if I try to use this? If the worst that can happen is this Transistor goes out, then im only out 2 bucks or so. But if there is any chance it can ruin the board further, I need some advice on that. I am most likely going to order the right one when I find out and I will replace it, I would just like to put this one in and see if it fixes the problem my boneheaded self created.

 

Were you able to replace the resistor with the correct value?

Ya I ordered one from digikey. Color code was Red, Black, Gold, Gold which came out to be a 2ohlm 5% tolerance .5 watt resistor.

And per your previous question I missed, Yes there is only one of these transistors on the board.

By pinout, do you mean the orientation of the pins? Or which is gate, source, drain ETC? If so, how do I test my board for which is which?

Any sugg where to locate the schematics online? Or is it a crap shoot

 

I wouldn't suggest the through hole IRF510, the Surface mount is a much lower on resistance and faster switching time. That, and Radio Shack parts are generally suspect, I won't use them in anything important.

The pinout is identifying which is source, gate and drain.

With an N-Channel MOSFET, the source is connected to ground, either directly or through a resistor.

The Drain is connected to the V+, though it may have a separate source.

The gate is the part connected to the rest of the board circuitry that decides when the MOSFET should be on or off.

 

Ok, so dont even attempt to see if it works? I will replace it, just curious if this is the problem, I dont care if it blows the RS transistor, just dont wanna harm board. Just want to temporarily solder it to the contacts. I just dont know the risks in doing so. Im my mind, if it cant handle the volts, it would just blow. But it may be more in depth then that.

 

You first need to identify the Source, Gate and Drain pins on the board before you can replace anything.

The wrong pinout can cause damage to other parts of the board.

 

Which I would need a schematic for right? Or is there a way to tell by the circuitry? If I took pics of where each circuit went, could you help me identify which is which? I really appreciate all your help

 

Yes, large, clear photos of both sides of the board, in focus, and without flash bounce, would help.

 

Please bear with me. I will try to do this as best as I can. If you need further pics, please let me know. I am going to start with the large solder pad that held the body of the Transistor on. It also had continuity with the middle tab that was cut off. I am labeling this red "A"

Here is the under side of board where it goes the the second pin here which goes to that transformer(correct me if im wrong)

The right leg of the transistor I am labeling as a blue "B". It only goes to "R24, R26" resistors as blue arrows show

Then as you can see in the next pics, the other end of the SM Resistors go threw the board and all connect to "DC1" which in pics after these show these blue battery/capacitor deals that are glued in the body of the motor. I desoldered the two wires that were connected to "DC- and DC+"

 

Now for the left leg(furthest in from edge of board) I am labeling this yellow "C"

Here is all of the pics I took in case you need a different view. And if its not there, please let me know. I will do anything to assist you in helping me. I really appreciate your time. I am trying the best I can not to be a annoying newbie, I am just self teaching myself and im sure it shows. I wish someday to take a class to learn more. Just dont know where to start.

 

B seems to be source, going to V-
A seems to be Drain, driving the transformer?
C is small signal components/narrow traces, is this correct, it would be the Gate?

See if that matches the datasheet above.