Upgrading a Kiethley 177 DMM's Input Jacks

Tron9000Tron9000 wrote 08/03/2017 at 12:47 • 3 min read • Like

I recently scored a 177 DMM from a dumpster dive, they aren't a bad meter! 4.5 digit, 2000 count, 20mV range with 10uV resolution & 20uA range with 1nA resolution, for something built in the 70's is not bad!

However I'm not too keen on the input jacks:

They are made of some quality metal, but most modern probes now have the shrouded jacks, which don't fit these posts and I don't want to hack up my probes.

So I found an old 3.5 Blackstar DMM and stole the jacks out of that:

I then removed the posts off the Keithley:

The existing holes were too small for the new posts, so I removed the whole front plate off so I could work on it without damaging the DMM internals. This meant removing the zeroing knob on the side of the display. This was done by popping the top off the know and unscrewing the screw a little to free it of the spindle:

Whilst I had the plate off I thought i might be a good idea the stencil it out onto paper for reference just in case I broke it during drilling and maybe later CAD it out in DXF format so new ones can be laser cut if anyone needed one.

After drilling the holes out I then fitted the new posts:

And then fitted the panel and knob back onto the DMM:

Now I can use my modern probes with it!