Another Heathkit IG-102 mod

Spent another evening poking around inside the Heathkit IG-102 signal generator, this time with schematic in hand and probing around with my DMM to check voltages in various places. I wanted to make sure everything was working ok, and it seems to be. The voltages I was getting were all pretty close (within 10%) of what was printed on the schematic.

I also replaced the original 60s or 70s era power cord with a polarized power cord (harvested from I don’t remember what now). It was a simple replacement and probably not critical but I figured having a new(-ish) cord might make it a little more electrically safe. The hard part was unsoldering the old cord and getting the plastic strain relief thing out of the chassis.

I was able to set my HT to a few frequencies in the 10-30 MHz range and heard tones when I adjusted the signal generator to those frequencies. That seems like a good sign it’s working.

Heathkit IG-102 capacitor

The Heathkit IG-102 signal generator has this big 20 μF 150VDC electrolyic capacitor that has 2 leads on the positive side and one lead on the negative side. It looks like an axial capacitor, but I’ve never seen one with two leads on one side before.

20 uF capacitor
20 μF capacitor
20 uF capacitor
20 μF capacitor

Although it doesn’t seem to be showing any signs of failing, given the unknown age of the signal generator I thought it might be a good idea to replace it with something new. I’m thinking I should replace it with two caps, one for each lead on the positive side. Don’t have any axial caps in the parts bin, but there are plenty of 20 and 22 μF radial electrolytic caps. No new 20 μF caps though.

Might have to go shopping.

Heathkit IG-102 surgery

Did some surgery to replace the old connectors on the Heathkit signal generator with BNC connectors.

Heathkit IG-102 old style connectors
Heathkit IG-102 old style connectors

I thought it might be a bit of a challenge, but turned out easier than expected. The center of the connectors turns out to be just a hole/eyelet, so a bit of heat on those center contacts to melt the solder was enough to free the wires connected to them.

Behind the connectors
Behind the connectors
Behind the connectors
Behind the connectors

Once that was done, it was a simple matter to remove the connectors and replace them with a couple of BNC connectors. Solder the wires into the center connector of the BNC and done! While I was at it, I also replaced the yellow 0.01 μF capacitor with a new one.

New BNC connectors
New BNC connectors
New BNC connectors
New BNC connectors

Looks pretty spiffy and modern now with the BNC connectors. Still not entirely sure if it works or how well it works, but at least now it’ll be easier to connect the signal generator to stuff.

Heathkit IG-102 with BNC connectors
Heathkit IG-102 with BNC connectors