On Sat, 15 Jun 2019 16:09:17 -0400, Bob Engelhardt
wrote:

Part of my Habitat volunteering has involved repairing their power
tools. They get Milwaukee tools from the Milwaukee refurb/repair
facility, through a Milwaukee charitable program.

A common problem with these tools is the trigger. Which, of course,
isn't just a switch but is the trigger with 4 control wires as well as
the 2-in, 2-out power lines, a tiny PCB, and the battery connector -
also with control wires. I.e., a nightmare to diagnose and sometimes
ends with us junking the tool (a new switch assembly is much more than
what we pay for the tool).

I was able to definitively diagnose the current tool's problem as a
flakey connector on the signal cable between the battery and the PCB.
The connector appears identical to the ones used for running PC fans
from the MoBo. Like this:
https://i.imgur.com/Q7kfqQG.jpg

I found these contacts that look to be identical to the ones in the tool:
https://www.digikey.com/product-deta...7CT-ND/5287249

I'm puzzled that Molex connectors, if that's what they are, can be so
unreliable. And that Milwaukee would use such unreliable connectors.
Has anybody else seen problems with these connectors?

Bob

BTW - I fixed the tool by removing the contacts from the shell and
soldering them to the pins on the board.

If they're tin plated, they are not good for small signals. The
contact surfaces can usually be restored by simply pulling and
reinserting the connector a few times. Square pins can be brushed
clean. The problem will reoccur. It can be agravated by mixing tin
with gold flash (pins vs receptacles. Sometimes the gold flash in the
receplacles is local and hard to identify.

Depending on humidity and temperature levels, the tin/tin contacts are
good for between 6 and 10 years, between cleanings.

RL