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 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!
I have no idea. It was cheap, and I like these things. They were untouchable for a while. but are reasonably priced these days. Used to be you couldn’t lay a finger on one for under $100…I’ve purchased a few for as cheap as a couple dollars.
This one was sold to me at the Columbus Hamfest by a gentleman who said it was “plug n play, not plug n pray” - I still had to open it to see. According to the documentation he provided, he purchased it on eBay in 2022 for $85 (the eBay tax on these not-EICO units is a lot less,) and recapped it. Let’s see if that’s true.
Here’s the unit itself:
The eye is nice and bright.
The unit is in good condition overall. Probably didn’t see much use.
Let’s see what’s inside.
Plenty of new parts.
One of the tubes is still branded PACO.
And here’s a bunch of those lovely blue carbon-film precision resistors. They’re fine for this kind of device.
For the most part, I’d say this device only needs 2 things, but there are three I’m going to do:
The first is the power cord. This is in good shape, but I like to at least have polarized cords. That’s an easy fix, and I prefer to have the incoming power on a cable that’s new.
The second is this guy:
This is the across-the-line capacitor. While the ratings are correct, this is not the correct type of part. You need a safety capacitor here, so this one will go.
While I appreciate the guy’s desire to keep the parts close to their original value, there’s no need for this here. Almost anything nearby would work, as these old electrolytics were +/- whatever. He may have done this to pop the voltage up, which is something I haven’t looked at - so this will get examined closely and if necessary, replaced with a single part.
Other than that - does it work? Yeah, it works fine and is as accurate as something like this can be. If you’re looking for one of these and don’t want to pay the EICO/Heathkit tax, PACO and other second-tier manufacturers are good choices as the circuits were identical across almost all of these.
As I had it out, I decided to clean the function switch in the EICO 249. The range switch already had a cleaning, so there wasn’t any reason not to do it here.
It wasn’t as dirty as the other switch, but it still turned the water yellow and lots of little dirt balls came off. It turned out looking quite nice.
There’s a short video on the subject. It would have had sound, but some silly little pig didn’t realize the vibration noise of the bath would just overpower everything.
