Jaguar repair?

[kamocat]

Originally Posted by ErikRantapaa

Has anyone attempted to repair a damaged Jaguar?

I have two malfunctioning units. Both will emit smoke when driving the motors forward.

Opening them up reveals that one or more FETs (I am presuming they are FETs) show signs of heat damage - the plastic around them is melted, the grounding tab is discolored. Also, the central cap in one unit is bulging slightly.

A multimeter test indicates low resistance between V- and M+ on both units. I think this is consistent with the observed behavior (i.e. smoke) when driving the motors forward.

My plan is to simply replace the damaged FETs and the central cap in one of the units.

Has anyone done this before? Does anyone have any suggestions/comments?

Thanks,
ER

I've never done this successfully, due to U6 and U7 being fried. However, I have fixed a Victor by pulling some MOSFETs from fried Jaguars. (When the power is reversed, it tends to be the small electronics and the capacitor that are fried. When you apply power to the wrong side, it's just the MOSFETs that blow up.)

Go ahead and try. However, make sure to use a limited-current power supply (a SMALL 12v battery) and a fuse when you try it. You will probably know immediately; if it does not turn on, or if you get magic smoke, it's gone.

It takes some experience. Luminary Micro uses ROHS solder, which does not re-flow well. I had to mix it with lead-based solder to even take it off.