The Cincinnati Hamfest is happening this weekend, Saturday, August 15th at the Clermmont County Fairgrounds, just east-ish of Cincy. I went to this show for the first time last year, and it was a good regional, with enough different stuff that I’ve decided to go back this year. See you there!
Cincinnati Hamfest
Saturday, August 15th, 2026
8A-4P
Clermont County Fairgrounds
1000 Locust Street
Owensville, OH 45160
This unit was purchased at the Cuyahoga Falls Hamfest in 2022, and has sat around for a while waiting it’s turn on the bench - primarily because I knew the entire thing, range switch and all, would need rebuilt. While that seemed formidable at the time, in reality it wasn’t that bad.
The device had been purchased “rebuilt,” and I knew it probably wasn’t. And…it wasn’t. The inside had new components, but they were wrong values, wrong voltages, or in some cases, just defective components. I’m not sure how the device worked, but I had only tested the DC section and found it to be operational. The defective components are in the AC side of the device, and that’s not as important to me as the DC side is. The ohms side isn’t important at all, so I didn’t even put a battery back in after completing the build.
I did get a donor unit, which was helpful - the range switch came from it, and allowed me to pull parts, drop it in the ultrasonic bath, and get a good clean part to start with. Resistors had to be made from standard values, as the oddball stuff that EICO used were not available from normal sources. That wasn’t any real issue, it just required using some calculations to arrive at the needed values. There are plenty of calcs out there that will allow you to generate unusual values from standard ones, if you need such a thing.
Past the range switch and it’s rebuild, the rest was a teardown and replace. A couple of resistors had to be made, including a really strange 82MΩ unit that ended up being created from 4 other values, and covered in shrink.
The before picture:
The after picture:
Almost all of the wire and cable were replaced save a few jumpers, and of course the transformer wire. The capacitors were purchased as a kit from an eBay vendor: https://www.ebay.com/itm/116116838477 named “Affinity For Artifacts,” and resistors were all made from standard values in series or in parallel using a calculator that I found online: https://mustcalculat … s/resistorfinder.php.
Problems during the rebuild
The first problem was that of the 12AU7 socket. Pins 4 and 5 of the tube are connected together, tying both ends of the heater together. This effectively gives you a 6.3VAC tube. When I purchased the unit, these two pins had a massive solder blob on them. It wasn’t just careless assembly, the socket pins were broken and the previous owner had coated everything with solder to keep the pins in place. That was a simple socket replacement. While it did require drilling out, it wasn’t a terrible job and didn’t take long to do.
The second issue was that of how the AC was run. Originally, it flew up to the switch and met the transformer lead, also on the switch. The other side was on a terminal strip that connected the 9.7Ω battery resistor, and then to the battery terminal. I didn’t like this, so a larger strip was installed. The AC comes in to a terminal. One side hits a safety capacitor and the transformer, the other side connects to a twisted cable that flies up to the switch and back to the safety capacitor, which is also the other side of the transformer. The hot side is switched to avoid having hot anywhere other than the one terminal when the system is powered down. These two lines are twisted together with a ground line as a drain to try an minimize noise.
The last issue was the resistors. While it wasn’t hard to replace them, there wasn’t any way to leave some resistors in place. The old carbon film resistors will change when you hit them with heat, and that’s something I discussed during part 10. The 82MΩ resistor had to be made from 4 resistors as values this high are hard to find, and the 9.7Ω should have just been a 10Ω instead.
Past that…the rest of the device was a simple rebuild. I did regrease the switches with some dielectric grease and contact cleaner before final assembly, just because they were cleaned in the bath beforehand. Any grease there was old, and was removed beforehand.
Testing
The thing to remember about this device is it’s an analog meter. That means it is only as good as the accuracy of the meter, and if your meter is not accurate or is not linear, then the measurement is not going to be as accurate as you want it to be. In this case, something in this device is not linear - that may be the tube response, or the meter itself.
During testing, I was able to get the device to have a decent degree of accuracy in the first half of the scale, and not much at all as you approached the upper range. That’s an analog meter for you - it’s good enough to get you there, and a couple of volts at 300V wasn’t going to hurt you. I may change the 12AU7 out later just to see what happens, but for now - I’ve acceopted it as it is, and it is an analog meter.
What did this cost new?
The device was $40 in kit form in 1963. Here’s the Radio Shack catalog page for it, back when rat shack sold this kind of thing:
That’s about $440 today!
Anything else?
Here’s a couple of pages of data that were created during the rebuild.
That’s the calculations I used to arrive at the replacement zener in the selenium circuit. I had 30V specified, but 20V actually worked better.
That page was created during the 82MΩ resistor build, and will show up in a video.
That’s all. This wasn’t as bad as I thought, and I now have a large face analog meter with a lot of cool to sit on the bench.
What’s next? A couple of kits and a Heathkit scope…stay tuned!
If you hit wereboar.com yesterday (13th) then you’ll have noticed that the site was offline.
Turns out there was something happening at the data center that hosted it, apparently a fire knocked out some electricity which took down the chillers and then the hosts, subsequently, the site. It’s all back up and running now, but there may be some short outages as things are brought back up or tested. They’re still asking us to be patient while they do testing and re-launch.
In the meantime I’ll just put this fire over here with the other fire. Stay tuned for more good junk!
As I’m primarily interested in this device as a DC meter, I did a quick calibration on that section. Before that, I greased the detents on the switches and ran a bit of deoxit on the metal portions of the wafers.
This device is supposed to have a 1MΩ resistor in line with the probe, all in a coaxial cable shell. I do not have that, so this may be a little off. I believe the probe for the EICO 242 may work, so we’ll see.
The manual suggests calibrating the DC range at 3.1V, or “the voltage from two fresh flashlight batteries in series.” Ok, sure. Let’s set the power supply at 3.1VDC, measure it with a known good digital voltmeter, and dial it in using the control on the side.
That’s pretty good for an analog meter. If I replaced that cal pot with a 10-turn, I could probably dial it in even better, but that’s not necessarily worth it. I’m happy with the result.
I did check the AC briefly, it does work, but I need to get some other devices set up to do that. However, the meter works, it is as accurate as you can get with an analog meter, and it’s ready to go into service.
Most of the parts in this device had been replaced at some point - except for the voltage divider on the range switch. For the most part, with the exception of a few in the chassis, that’s all I’m going to test.
Some of these parts came from the donor unit that I had as well, and we’re not worried about them.
Here’s the two things we’ll be testing.
This is the original range switch, as well as a couple of resistors that the previous owner made. In particular, these are R28, an 18MΩ, and R29, an 82MΩ. Or, they’re supposed to be, that is. The 82MΩ was made up of parts that totaled 57MΩ.
Here’s the measurements:
You can see that most of the parts are…ok. A decent amount of them are out of tolerance, but not terrible for the age. However, the 82MΩ part is open. I tried multiple meters, and both of the resistors in the pair are open. I’m not sure if this is something that happened during operation, or if the guy the picked them and put them in without checking. In any event, one of the resistors in this pair is obviously of the correct vintage, so who knows where it came from.
So…why did these get replaced? Some of them are good! Don’t touch them! etc, etc.
I would have loved to do that, but the problem is they are old carbon film resistors, and when you start messing with old carbon film resistors they start changing values. Especially when you start hitting them with heat. Had I taken the out of tolerance devices off, their neighbors would have immediately changed values. This is due to a lot of factors - outgassing of moisture absorbed in the part over the years, potential cracking of the film, and/or other defects that show up after 70+ years and some heat. If you’re taking these off, take them all off. Sure, it means building new parts out of multiple components, but you then have everything back under 1% where it belongs.
There wasn’t much left in the EICO 249, and I decided to finish it up all last night. This session saw the AC and the meter connected, the two switches wired together, and a few more components laid in. I saw that I missed a wire, so that was put in as well, and the unit generally tidied up.
I tried to keep a layout that would allow you to get inside the chassis without too much fuss.
I did do a check on wiring and a quick operational test, that was a success. Before I call this one good, I need to replace the grease on the switches and coat the metal with contact cleaner to keep it all happy. Stay tuned, a quick test is next, then the wrapup.
I didn’t feel like fussing with switch connections last night, so I sat down and worked with the AC input.
Originally, the line cord flew directly into the unit, up to the switch, and back to a terminal. I didn’t want to do it like this, so I added a new terminal and took the old one out for later reuse.
I also wanted to add an across-the-line capacitor to help catch any noise in this device, since it didn’t have one originally. I had to think about what I wanted to switch here, and I thought about doing the neutral - but after consideration I didn’t want the transformer to be hot even when the device was off, and I felt there was enough isolation on the power switch that I could safely switch the hot side. I did the neutral thing at first, but pulled it out and re-laid everything hot.
You can see that I had to clean up the transformer lead a little because it was cut short. I ended up just lifting the transformer out and lengthening this wire a bit.
Everything laid back in without issue, although I did cut things shorter when I put it back in with hot switched.
The AC will now come in, hit the terminal strip, and fly up to the switch and back from this terminal.
The only thing I don’t like about this is the AC has to be in the air. This was the original design, so I’m trying to mitigate a little. The chassis is already busy, so I wound the to and back lines together with a ground lead, hopefully to minimize the noise levels.
It’s time to start laying in parts for the EICO 249. I’m kind of following the manual, kind of not. The only place I believe it really matters is all of the switch connections - everything else is just looking at the layout and matching what’s there.
This has been going much better than expected, and I’m up to the last column of instructions (less the AC input, which I’m going to change) in the assembly manual.
Here’s shots of the rebuild…
This might be finished up before too much longer, stay tuned!
Here’s another one of Heathkit’s plastic boxes from the 1970s. This one is the older brother to the Heathkit IM-1212 NIXIE meter, the one that was provided as part of Heathkit’s electronic labs for you to build and maybe understand how it works. Maybe…
Here’s the IM-1212 if you’d like to see what that one looks like, and you’ll certainly notice some similarities in the circuitry: https://wereboar.com … aking-it-work-again/
This one is updated to use LEDs, as by the time this was made NIXIE tubes were obsolete and getting harder to find. It has the same issues as the older one, however, that of being as stable as the drug dealer down on the corner of 6th and Walnut…
So let’s check it out. Here’s the front, it’s a good looking unit and has the same ranges as the older one.
The top, bottom, and back…there’s not much to say about those.
The device has a polarized grounded cord, which someone cut off the ground prong. Don’t do that!
Here’s the inside. Same parts with a different layout, including the calibration voltage on a tag. I’ll pull a manual to see where everything is and see if it will calibrate (at some point, not today!)
So, does it work? Yes.
That’s supposed to be 14.6VDC, so it’s off. Surprise, right?
This one will probably show up later as a one-off calibration, stay tuned!
I know I said that there would be no more Heathkit Blue Boxes…but there is. In fact, there’s this one - an IT-5283 Signal tracer, and a smaller meter.
The IT-5283 is probably one of the more desirable units in this series, being…a signal tracer, aka amplifier with a probe. It runs on AC line, or can run on batteries for those difficult jobs where being connected to the line can cause issues.
It’s a simple device:
The top of the unit is…the top.
Here’s the back with the top (cable) storage open. Note the 3-pin Molex power connector.
As mentioned, it can run on batteries - two 9V - or a split rail power supply of +/- 9V. While this Molex connector isn’t uncommon, it’s not something most have lying around in their junk bins these days.
I never cared for the battery placement in these, you have to unscrew the case to replace them. Leave it on overnight? Yeah, you’re opening the case.
The probe isn’t anything unusual, it has a built-in diode for RF troubleshooting, and has a pass-though for audio. It’s in decent enough shape.
And, of course, the money shot. Here’s the inside, it’s just a simple amp with a couple of gain stages. Could probably benefit from some new capacitors, just like the EICO unit. There was also a manual reprint included with the device, which was cool, and I’ll post a copy of that ASAP.
So, does it work? Yes. I did a short video on the unit: [this will show up much later, check back!]
There’s really not much more to say about this unit. Stay tuned for the next checkout!
