#hickock

Wow, it feels like forever since I posted a project thing...

Well, I’m still stuck when it comes to the Philco 39-45. Part of that is due to my test gear, which I always buy used, so it almost always needs to be repaired.

I’d already done some work on my Hickock 540 tube tester, but recently it had started misbehaving. It was giving me weird results when testing known good tubes. So today I decided I’d peek under the hood and see what might be going on. 

As you can see from the second pic, I’d already replaced one of the resistors on the resistor board, but another one (the 1.2k at the bottom) was reading 1.6k, so it got pulled and replaced. Next there was a sneaky wax-paper capacitor (5th pic) hiding under the resistor board. I hadn’t noticed it was there till now, but it was not in great shape. So I cut it out and replaced it with a new equivalent.

Lastly there was a 100k resistor that bridges the neon lamp that indicates a tube is shorted. This resistor was way off spec, which meant that no matter how good the tube was, the tester always showed that it was shorted. I pulled the bulb socket out and replaced the old one with a new 100k resistor.

I fired up the tester and now it seems to be behaving itself. So, I’ll get it back in place on my bench, then run through the tube compliment in the Philco 39-45 to just double-check that no tubes are bad. Maybe that will tell me something...

Finally finished the new box for my Hickock 540. This project has been a long time in the works and due to several setbacks, has taken even longer than I expected. 

To catch you up... I had gotten the wooden box stained and ready for the chassis to mount, but had broken the AC gauge for the unit. I had sourced another one at an antique radio show, but it turned out that even though it was a small gauge, it still didn’t fit well into the old plate. So, that left me with fabricating a new one. Used a piece of scrap metal I had lying around, drilled out a hole, then used my Greenlee punches to punch out a larger hole, then used a metal nibbler to cut away the edges until it was roughly circular (4th picture). Next I drilled out holes for the screws around the sides of the larger hole. Did a bit of filing and sanding to smooth out the metal, then primed it and painted it matte black.

Putting the chassis back on the wooden box also caused a few issues. The secondary rectifier tube (5Y3) wires had come loose where I had apparently not done a great job of soldering them to the tube socket. Fixed this and was able to re-mount the tube sockets to the metal plate inside the box.

Next challenge: the new plate and gauge doesn’t fit quite right into the existing holes I drilled in the wooden box. So... took my Dremel with a grinding wheel on it and enlarged the holes until the plate fit well. Once that was done was able to mount it to the box but then...

Taking a quick break from the Sparton radio project for a personal project that I’ve had sitting around for a while now. Sometime last year, I got a Hickock 540 tube tester from Craigslist. I did a bit of work on the faceplate last year as you can see in the first few pictures. However, the wooden case it came in was in pretty rough shape and smelled badly of cigarette smoke. I had been wanting to build a new box for it, but hadn’t gotten a chance to get started, so it sat in my man-cave for the last 8 months or so.