I’ve had a couple of these devices sitting around for a while in various conditions, but all of them had meters that weren’t in the best of conditions. When I saw this one show up online for a reasonable price, I grabbed it. While I knew it had some minor case damage, the meter face itself was in great shape, and it seemed pretty clean. There was a reason for that…
This is a unit that offers everything audio. Load resistors, AC VTVM, I/M analyzer, etc. Kind of a test bench inna box thing.
Let’s check out the unit itself before digging into the chassis.
Here’s the front of the unit with the clear meter cover.
Here’s the smashed corner. It’s not terribly bad.
Of course, a friend of mine “fixed” it for me.
The back is nothing special, but it has a replacement cord. That’s nothing unusual for a device this old.
The top and side, of course, exhibit the standard Heathkit pull-apart that you get with these big boxes that have no screws near the top.
Let’s open the device. Here’s the inside. The screw that holds that coil down is loose, but we can fix that later.
Here’s all the load resistors. They’re all intact and close to their values.
Here’s where things get interesting. This is a brand-spankin’ new capacitor…
The switches have been cleaned…these are normally black with oxidation.
Let’s take a look at the underside of the chassis.
This thing has been almost completely reworked underneath, even to the safety capacitor, which is of the correct type.
There’s some minor messes, like this set of capacitors. There’s nothing wrong with this, and it’s acceptable to get parts up to a higher voltage.
The only real issues I see here are minor.
Those are old capacitors. They probably shouldn’t be in there, but depending on where they are in the circuit it may not have mattered. If they’re low voltage, then they’re probably fine…but there’s no need to leave them in when new stuff is so cheap. There’s a handful of these in the unit.
This one is an actual problem:
That resistor, one of the many precisions in the device, is broken. I can see where the previous owner tried to fix it, but it just popped off with a minor touch. I can understand why this was done, those are bespoke parts. You can make them from combining standard values, so that’s probably what I’ll do.
I did try it out briefly, the meter moves but it’s not zero’d, which means there’s still some leakers in there. That will be corrected during some rework. In the meantime, I have a second unit that has a good faceplate, so I’ll probably swap the chassis in that one out for this chassis, and go from there. Stay tuned!
Cleveland has been a good show for me for as long as I’ve been going. While the inside building they have ebbs and flows with vendors, the outdoor flea market was well stocked with things we’d expect to see at shows. Tables of radios, piles of equipment - all the good stuff.
I didn’t take much home from this one, as I had to stop myself from buying yet more boat anchors. I went home with some tools, a power strip, and an old handheld game. I got away lucky!
I did see some other things I was interested in, but a few of the vendors here (and all shows, TBH,) seem to treat their prices as a state secret. I don’t want to have to flag you down and have you hmmmmm and hawww for a minute while you try and gauge how much I might pay you, mark your prices! I passed up a couple of interesting things for this reason.
Other than that, here’s what I saw at the show:
Rat Shack will be with us forever.
Old consumer gear.
A 1970s WE butt set.
An unusual Conar (NRI) scope.
A Heathkit distortion analyzer.
Guaranteed defective.
I think this has eleven tubes.
A table full of unpriced equipment.
One of those old VFD card games. I took it home.
An excellent condition old HP signgen.
A Heathkit power inverter. 25A input!
I don't need another VOM.
This device is in it's home town.
This tube devices power supply.
Surprise, radios!
Some Heathkit meters.
There are at least 2.61 of these monitor scopes for every person on Earth.
You guessed it, radios!
This is a nice-looking radio.
We come to shows for piles of junk.
We have the power!
Got a line voltage? Measure it here!
When it needs to be soldered.
Just stuff.
More stuff. We like stuff.
A Zenith Trans-Oceanic in decent enough shape.
I always pick up a few things from here.
This isn't far from home.
Vu-Data made scopes for data centers.
This interestingly strange radio.
Wire recorders are still fairly common.
Next show is the Early Television Museum’s fall swap, and the last one I’ll hit this year is probably MARC @ MAPS. See you there!
There are four more capacitors in the EICO 242 I’d like to replace before doing a calibration on it. Those are:
The main AC filter,
The two capacitors in the AC rectifier circuit,
The main AC input blocking capacitors.
There’s not much else to say, let’s get started.
First is the AC blocking capacitor. It’s a hefty part, 0.1 @ 1600VDC. I have some new 2KV parts for this.
This one was kind of a pain in the butt to get out without messing up other wires.
Next is the main filter. This was a matter of unbolting the board, unsoldering the capacitor, and replacing it. Not really that bad. It’s not defective, but it’s 50. Let’s get it out of there.
The old part is a 300μF @ 30V. I have 470μF at 50V. Now, this device has that as well. The old part was closer to 400μF, so we’re not far off from the new one at 460μF measured.
The last part(s) are the capacitors in the AC rectifier circuit. There are two, both 0.027μF ceramics. There’s also some diodes that I had to heat up to remove the capacitor.
Those diodes look like crap. I’ll re-do those at a later date.
Next up is the calibration. There are a few resistors in there that are off, so it’s not going to be 100% across all ranges. We’ll get to that at a later date. Stay tuned!
I went to the Findlay hamfest this past weekend instead of the Clearfield hamfest - I wanted to go to the latter, but something got in the way and I went local instead.
Unfortunately, Findlay has shrank substantially over the years. Last year was probably 1/3 of the year before, and this year maybe 1/2 of last year. I’m sad to see that happen, and it makes me wonder if it’s because the club is aging out, because there are more shows, or simply the changing fortunes of time. Probably a some of each, but it was quite small this year with a lot of open space. We used to shut the show down at 1PM, but headed out at about 9:30 for this one.
There was a bit to look at, but I had to struggle to find interesting things to photograph. Here’s a few things for you, some of these I know have showed up in the past.
Keeping the ground from blowing away.
A nice old Schauer battery charger.
These are getting rarer
An interesting VTVM.
Meters. All kinds.
Piles of junk. Hamfest gold.
I see these here quite often.
All the bearcats you need.
Next show is Cleveland, which has been pretty good so far, after that the Early Television Museum’s swap meet and I’ll probably close the year out with MARC @ MAPS and the antique show at the fairgrounds. Stay tuned!
I picked this guy up from an online sales site for next to nothing - I assume because it’s not a desirable Heathkit unit and people don’t seem to care much for these late-model EICO devices. Everyone wants the stuff with eye tubes…but I was just looking at another siggen because you can’t ever have enough of those.
This guy was probably made in 1968, because of the late ‘67 date on the meter.
The underside is decently laid out, but there’s some chaos here.
Of note is the mix of old and new carbon resistors, and the old and new style electrolytics. Those old brown carbons probably need to go, but we’ll check them in a later post.
Here’s the money shot:
I don’t necessarily like lamp being lit like that…but it’s not flickering. Usually when these go bad, you’ll get that circuit trying to balance itself and it will go up and down as the lamp gains resistance from heating up and then falls back when the resistance gets too high. However, the output is rock solid…so maybe this one is supposed to operate like this? Others of this type I have do not do this. It could be a symptom of wildly out of tolerance resistors, so…back to checking those in a later post!
And finally, here is the output. Nice clean signal.
It looks like this won’t need a whole lot, other than some of the potential failures being replaced before they fail. Being 60 instead of 80 years old probably helps there.
Stay tuned for the next part of this series. We’ll dig into the components and see what’s what!
I’m starting to think the only thing this device needs is a good cleaning and calibration. However, there are some electrolytics in this device, as well as one of those 1600VDC blocking capacitors. While those don’t appear to be bad, I’m going to replace them regardless just so this thing is ready for the ages.
As I don’t have a whole lot of low-voltage equipment, I had to order some of the larger part. I also had to order some of the 1600VDC part, since I only buy those as needed. Those are on the way, and we’ll get to those later.
The first part we’re going to replace is the little 10μF 16VDC part that’s in the zero circuit. Surprisingly, it’s not actually bad - it’s just way off of course, like all old electrolytics are. >20μF at about 11Ω - that’s about normal for this small of a part.
But here’s the new one anyway:
I did a bit of tweaking on the calibration adjustments, and I can say I was pleased by what I saw. I believe that was more the cleaning than the capacitor.
As soon as I get the other parts, Ill replace those as well. Stay tuned!
Some time ago, an EICO 242 VTOM came across the bench. While I wasn’t going to do anything with it, I decided to see if I could bring it back to life.
Here’s the issue:
The DVM is measuring 20VDC, the EICO 242 is measuring the same voltage, but reporting only ~17VDC. Something is wrong here.
It’s probably one or more of the following:
Out of calibration
Resistors out of tolerance
Switches are very dirty
Some unseen damage
There’s not a whole lot in this device. Let’s check a few resistors:
The first one is supposed to be 90Ω, the second 1.227MΩ. They’re actually pretty good.
I did about half a dozen, and all were like this - quite well in tolerance. Hmm…
The switches are really blackened from age, so I’m going to give them a cleaning and then do a calibration. We’ll see what that does for us. If it gets the meter “good enough!” I may leave it at that…but I’d still like to go through the resistors just to see what’s what, and there are a few small electrolytics in there that certainly need replaced. Stay tuned!
Some time ago, I picked up a moderate condition Heathkit IO-21 Oscilloscope. I was planning on doing some work to it, but in-between then and now, I was able to find a much better unit.
Other than a few minor dings, it’s in great shape.
Of course, it’s full of old capacitors. While these seemed to be ok-ish, the ones in the HV circuit were not.
Including this one that wasn’t soldered. I wonder how many problems this caused for the original builder.
First thing to do is install the new HV capacitors. That’s easy enough, they’re right on top, and the resistor that connects them gets replaced as well in this build.
These were old ceramic encased…somethings.
I’m not sure what type these are, but this stuff is gooey wet.
Many of the capacitors in this unit were ceramic disc, and they’re fine…for now. The rest were encased paper, so get replaced with new films, and a new electrolytic where appropriate.
The main filter didn’t seem to be in that bad of condition. A little tired, but not bad. I’m going to leave it alone for now.
So…does it work?
Sure does.
It works pretty good, and is about what I would expect for a scope this age. I’m pleased with the result, and I now have a vacuum input scope for the bench.
Capacitors
So, what was removed from this thing?
None of these tested bad, but they’re probably bad in the leakage department. I would suspect that the HV caps, with their leaking liquid, are probably not long for this world if you were to use them for any length of time.
I did a quick check on what each one read, it’s about what you’d expect:
As far as I’m concerned, this device is finished.
Wrapup
This one only needed a little bit of work, so it doesn’t get an entire series. I will probably do the filter at some point, but not now.
In all, the only two surprises waiting here was the no-solder, and the gooey HV caps. Not sure what’s going on here. I did take the time to clean the controls and give the switch a coating of cleaner, for good measure. Everything seems to be working, and no other issues presented themselves.
I have two other examples of this unit - I’ll probably keep one, and sell the other one off for whatever I can get from it. If you’re interested in one of these and you live in the Columbus-Pittsburgh corridor, let me know on Mastodon!The other unit was in bad shape, and had a broken switch, a CRT with a loose plug, and mods that made it a poor example. It is now parts.
I picked this bridge up at the Columbus Hamfest in August 2026. It’s fully operational, but I wasn’t thrilled with some of the work done to the unit.
In particular, the wrong type of capacitor was used for the across the line capacitor, and I didn’t like the way the filters were laid in. It also needs a new power cord.
The ACL capacitor is there because most don’t have the correct part laying around in stock. These are essential if you’re going to be working on this kind of equipment, get a few and put them in your parts bin. The filter capacitors are they way they are because the person probably didn’t have the correct voltage part, so he made one by putting two in series. That, of course, has the same effect on capacitance that resistors in parallel has, but it adds the working voltage together. It’s not the best way to do this, but it works and will continue working as long as you’ve sized parts properly and tried to keep some sort of balance.
I was originally going to replace the other filter as well, but it’s fine, and is properly rated even if it’s a higher value capacitance. It’s not going to hurt anything, and it’s likely the original part probably wasn’t anywhere near the actual value printed on the shell. That’s just the way older electrolytics worked - they were plus whatever minus something in value.
Let’s start with the electrolytic. Here’s a nice new 10μF @ 600VDC laid in. The original was 8μF @ 600, so this one is fine and won’t cause issues.
The ACL capacitor is similarly replaced with the correct type of part, and coated with ‘lectric sketti for safety.
And, of course, a new power cord is routed through the chassis, tied with an underwriter’s knot.
