Servo 150 circuit board repair?

[matthewsx]

Discrete electronics



John

 

[T. J.]

Good to know. I may fix the mechanical issue and run it a while to see what happens.

Right now I’m struggling with 2 socket set screws that are stuck & stripped…

 

[Weldingrod1]

There's a tool called a "sock-it-out" IIRC.
Basically a tapered Allen key. Tap it into the hole with a hammer and unscrew! A lifesaver, although rarely used

Sent from my SM-S911U using Tapatalk

 

[slow-poke]

If you have thermal gun, run the board and determine hot spots on board and report back. Anything over 90deg C is too hot.

In many cases you will need to lift one end of a diode to check it.

Remote resistors in some cases can be a bad idea, raising them off the board and going up a size will help. Those solder connections need to be reflowed they are compromised from the heat. As mentioned power resistors operating at their actual full power rating will run very hot (more than 90deg C), so going up a size will help.

Sounds like there is another issue, the thermal gun might help locate it.

 

[den-den]

One thing that I have not seen mentioned is to be sure the drive is sized for the motor. Just because they came together does not mean they are supposed to be together.

 

[mikemm]

I know this is an old thread however all 3 power resistors are 10k. Two are wired in parallel so that's why you're getting a 5k reading on your meter. I have a few servo 150s that work perfect and have the same discoloration around the resistors. You can reflow the leads or replace the resistors but if your soldering skills are subpar you could end up doing more damage since in an overheated condition those copper traces are prone to separate from the board.

 

[T. J.]

Thanks!

I just realized I never posted an update to this thread. The circuit board turned out to be fine. I fixed a mechanical issue with the switch, and it works great. It’s now installed in my mill

 

[markba633csi]

Looks like they were all 10K but got so hot the colors changed. The brown ones above are 5 watt but the blue ones are probably 1 watt and should have been larger
The copper traces could have been made fatter to deal with the heat