motor controller from treadmill

[bubblehead1]

One last thing before I go, when I had the motor powered up on the board, I had no voltage at the motor supply terminals and the reason for me thinking the problem was in the board somewhere.

 

[MaxHeadRoom78]

No need to check resistance if it ran OK, It cannot be that much to the controller, it would be based on a similar circuit to the one I posted, maybe a little trouble shooting would point to the problem?

 

[bubblehead1]

Hooked up the two black leads to the motor to my 24v supply and it ran fine. I noticed the rectifier had been replaced at one time or another , it looks like a power transistor also.

 

[MaxHeadRoom78]

I am guessing it is the usual triac used on the input to the bridge. Which is what the TDA1085 uses for motor control.

 

[bubblehead1]

 

[bubblehead1]

The components that were replaced are the two that are mounted to the heatsink. It looks like they would be labeled T1 and B1. Do you think the triac may be bad? How would I test D6, it is different than a normal diode?

 

[MaxHeadRoom78]

D6 is a normal silicone diode.Treat it like any other common version.
The T1 & B1, pretty much indicates Triac & Bridge.

 

[bubblehead1]

So if I removed T1 from the circuit would it test like a transistor? Do you think the bridge might be bad again also?

 

[MaxHeadRoom78]

I usually use a 12vAC source, such as this method.
except use AC and forget S2, then the triac should switch on/off with S1.
The bridge could be tested with the same supply.

 

[Voltar1]

I have this motor and controller on my metal lathe. Good use for the last 15 years used four controllers in that time.
All failed the same way, unreliable starting and nonexistent speed regulation.
I would like to repair these controllers if possible