This is kind of an unusual device in the tube tester world - it’s the only “Lunchbox” style device that I’m aware of. Most devices of this nature are suitcase or other lay-flat devices.
I picked this guy up at Athens 2025, for a really cheap price. The reason for that price is someone accidentally splashed acetone on the front panel and destroyed some of the lettering. I don’t really care about that, you can still tell what it was.
The back is nothing special, and just has two screws to hold the chassis in.
Someone attached some mangled GC pin straighteners to the top of the unit. I’ll probably take these off.
Inside, it was obviously a factory build.
Almost everything in here is laced, save for a few things…
There’s a special place reserved for people who do this.
The only part of concern in this unit is a blocking capacitor of the Elmenco style. It’s dated 1974, which is surprisingly late for a tube tester. This can be easily changed but is it really worth it?
So let’s test something. I have a 6X5 laying around from the recent EICO 950A rebuild. It’s a NOS tube, let’s see how it works…
Yeah, that’s a good tube. But, remember - this is an emissions tester only. It’s a glorified go-no-go test, but it at least will tell you if the tube is working. Sort of.
This one isn’t going to need anything except maybe that capacitor. Probably not even that.
The EICO 950A has been completed. While this wasn’t really a complex build, it was challenging in that the previous owner made a mess of it before I got it.
This unit benefitted from remove the component/replace the component methodology that I used, where possible. It wasn’t possible in the power supply, which was a horror show, but everything else was easily replaced as it was taken out, as not to have too many components on the bench and too much “Where did this go again?”
The capacitor kit was purchased on eBay, and that’s what I’d like to talk about the most during wrapup.
Capacitors…too little, too late?
While the kit I purchased contained good quality parts, there were a few issues:
1: The mica capacitor in the measurement circuit.
Mica capacitors are generally thought to be bulletproof - but they are not. They are subject to the same issues as the Automatic Electric IF cans - that is, silver mica disease. You’ll be told this isn’t the case and that a mica is good forever, but searching online will reveal more than one person mentioning how they saw these starting to fail in the 90s, just 40 years after their common use.
We’re now 35 years past that, and these things are suspect. They haven’t failed - but they are suspect. First problem, is it mica? Paper parts were made on a similar body type. Second problem, these have miniscule surface cracks in the coating that have developed over the years. It’s not a matter if, it’s when they will fail. Will that be in my lifetime? I have no idea, but a new part is cheap, and there’s no excuse not to replace it.
In particular, I had a hard time getting a stable reading on the one in my unit - possibly because of moisture ingress over the years. The surface of the part didn’t look that great either, to be honest.
2: The main 8μF filter.
There’s nothing at all wrong with the part in the kit, but B+ in this unit is 600VDC - and that’s at a reduced line voltage. If your line is running 125 like most do today, your’re going to exceed the value of this capacitor by a wide range instead of the 7VDC I was exceeding it by. While the capacitor is probably going to hold up to this without too much issue, a weakened or older part could pop. As higher voltage parts aren’t really easily available these days, the best solution (even if it’s not a good one) is to take two 350VDC parts of roughly double the capacitance, put them in series, and use that. I’m planning on doing that at some point, but not right this minute - stay tuned for the addendum to this project.
Another thing of note was the 30kΩ resistor that feeds the main circuit. When I did the final parts placement, I joked about having to use two overly-exacting parts, i.e. two 15kΩ 0.1% 15ppm resistors to make up a 30kΩ because I didn’t seem to have any. Looking back at my notes - I probably decided to go this route originally because I couldn’t get a 30kΩ part, and decided to use those 15kΩ units for just that.
I didn’t replace the tubes like I had originally planned because the eye I purchased wasn’t a whole lot brighter, and the 6X5 tests similar to the new one. I’ll stick those aside for later use or other projects.
The challenge with this one was simply in the figuring out what the previous owner did, not in the doing. I now have a good working example of this device in my collection, even if the physical condition of the device isn’t the best.
Battle scars on test equipment are fine by me.
There’s another EICO 150, a Zenth Consoltone, and an EICO 249 waiting in the wings. Stay tuned!
I did some basic power supply checks to see how things were performing:
That’s the voltage across a 600VDC capacitor. Line voltage here has been reduced to 115VAC to be more in line with what this thing was expecting when new. That’s not good, and this is even with a well-used tube. It rode as high as 607VDC, and if your line is 125, you’re going to see perhaps 612VDC or more.
There’s a chance that, if left on for a long period of time - especially with higher incoming line - that this capacitor could pop. I’m going to have to fix that. For reference, this is the main filter in the unit.
This is the other filter capacitor in the unit, and it’s a far more reasonable 145VDC. Well within the capacitor’s ratings.
Let’s see it work!
For a test, I took a 20+20μF part removed from another device. Checking with a modern meter reveals one section of this unit to be ~24.6μF. I hooked the part to the unit, and dialed in until I reached a good eye opening.
The eye opened wide, indicating that the part was useful and not leaking everywhere.
After a bit of finagling with the dial, I was able to set it to the proper place. This is about the only calibration you can do to one of these - take a known quality part, measure it, and adjust the dial until it reads what it should. Don’t have a capacitance meter? Use a high-quality film resistor instead.
The unit is functioning as expected, so beyond fixing the filter issue, we’re done! One more post, and then on to some new things.
One of the things I like to do with units I rework is save all of the components and check them when work is finished. Since the EICO 950A has been completed, it’s time to check those parts.
I know I’ve said this before, but I can’t say it enough: This thing was a mess. Someone cut every wire, every part, and J-hooked it back in. The wire…sure, that was some old thread-wrapped stuff and the few pieces left could have generously been said to have insulation. The parts, however? Wow.
Here’s everything that was removed from the unit. Most of what the previous owner put back in was of decent enough quality, even if they weren’t the proper tolerances.
Here’s some of the lovely connections made in this device:
That’s not even the worst of the lot. There were a couple of 4-splicers in there.
For the most part, the components that were newer are still in good condition, with only the resistors being problematic - as carbon comp resistors are. Surprisingly, most were reasonable for their age, so while this thing definitely shows signs of being stored damp, that didn’t seem to affect the components much. I didn’t do a “good/bad” on this one, as most of the parts weren’t original.
In all, this was more of a problem than it looked - slow and steady won here, and everything is back where it should be. Next up is the final check, and then the wrapup post with some thoughts on this unit if you have one of your own. Stay tuned:
This has been a long journey of removing and replacing things in this unit. When I started, it was “can I actually do this?” But, it’s been done. All of the components, save the transformer and the pots, have been replaced with new. All resistors are now 1% film, all capacitors are now new electrolytics or modern film parts. I even have some new tubes for the unit.
This part was finishing up the power supply, and running lines and parts for the eye tube circuit, as well as adding a terminal strip for the line cord. I had planned on adding a terminal strip on the power supply side, mostly because the OEM build had everything jammed onto that one little strip and the tube socket, and I wanted to lay out the parts in an easier to see manner. I used a long strip, and it turned out decently.
I was going to put the AC line on this strip as well, but decided to move it nearer the switch, so there’s not AC running all over the place. I used a single position w/ground strip for that, and all of the incoming AC is now close to itself.
The only issue I ran into here was R7, which runs from a potentiometer on the face to the negative side of the power supply. I can swear up and down that I ordered the part - a 30k resistor - but these were not in my stock. I either ordered them and “put them away,” or I didn’t order them. No idea which. To fix that, I took some comically over-spec’d resistors and made a 30k unit. So…there’s two 15kΩ, 15ppm, 0.1% resistors making this part up. That outstrips pretty much anything I’ve worked on to date!
Here’s the photos:
The next step is to check the wiring, re-install the eye tube mount, and then turn it on! Stay tuned!
The trim ring on this EICO 150 was a complete mess. It started shattering in transit, and didn’t survive much longer on the bench. Here’s what it looked like:
A friend modeled a new ring for me, and we printed some examples. I chose a couple of material colors - gunmetal gray and silver. This unit is going to get the gray ring, and it looks pretty good.
The new ring is a solid piece. For screws, I discarded the original screws and went with a short, course-thread piercing screw. That seemed to work better, and the material definitely requires the course threads.
That’s one issue taken care of, next part will be jumping into the electronics themselves.
This device is turning into quite the long project - but I knew that going in.
The range switch is in a good a state as it can be at the moment, but there are a few wires still hanging off that will need to be dealt with. We’ll take care of those later - it’s time to get the power supply put back together.
To start, I drilled a couple of small holes in the chassis to mount a new terminal strip. I didn’t want to mount all of the components on the tube socket itself, since some of those were quite a bit larger than I could comfortably place. That’s one of the nice things about this kind of build - you can take your time and re-plan the layout. The OEM wanted to make things as cheaply as possible (not cheap as in poor quality, but cheap as in don’t provide unnecessary parts) so they used every available point to tie things. We have the luxury of being able to rebuild for layout instead of time and costs.
Back to the terminal strip. I wanted to move the AC off the tube, so a big terminal strip was in the works. The AC line is at the bottom, and one of the filters and it’s resistor is mounted on the terminal strip as well, leaving us several tie points if needed. I also used the original terminal strip for a few things, and this will probably come back into play later. The other, smaller filter capacitor mounted on the tube socket with some creative bending after I decided there wasn’t enough room to run it over to the new strip. A quick test of the power transformer, and those leads were dressed in.
There’s a small handful of parts to finish the install, and then comes the final checks. Stay tuned!
This piece of equipment was purchased in the same lot at the EICO 150 Signal Tracer that was posted earlier. This is the other piece that caught my attention and one of the reasons I bid on the lot. This one, as with the tracer, had some issues but they are more related to age instead of customer modification.
This is a relatively unusual piece of equipment for the USA, and is built to a different design language. Here’s the front panel of the unit:
The unit has the standard eye tube as it’s indicator, much like other bridges. This one uses a European variant (of course,) the EM34. This is a relatively unusual tube that’s roughly equivalent to the 6E5. It can be replaced with, but requires some changes. It also has a strange rim-connected socket type. It also uses an EZ40 and an EF40 as the business end of the device. That’s the rectifier and a pentode amplifier. There are rough equivalents to those, but they seem to be easily available which is good because they were not in the device.
It also had this monstrosity attached as the power cord:
While that apparently is a real piece made by Leviton, it looks so janky and is so improperly used that I originally questioned if it was real.
Under a back plate is a voltage selector dial that has a number of different voltages on it:
The original serial numbers are still attached:
The unit features a set of jacks on the side that allow you access to all of the internal voltages.
Inside, the device is built like a brick s**thouse.
It does have an immediate issue, however, the dial cord that drives the dial is broken. I hate dial cords.
I’m planning on at least giving this thing a go at living again, we’ll see what happens.
I recently picked up a big lot of test equipment. There was a unique R-C bridge and this EICO 150, both of which I wanted, as well as a couple of old Leader RF generators and a couple of meters. Other than the first two items, most of the stuff was in really poor condition (foreshadowing!) and was of little interest - or was broken beyond repair.
The EICO 150 was the biggest piece I was interested in, as I have one already and wanted to obtain another for comparison and other purposes.
However…as I found out all of this equipment had been modified to extremes over the years. Here’s the front panel:
The trim ring on this, while intact in the original pictures, was completely shattered when it arrived. I tried to claim insurance on it, but the seller just said they couldn’t do it as it was all packed in the box. Well…yes, but there was very little packing material for the equipment itself. This stuff was shipped by airline, and got tossed around. All of this stuff was knocked about and this piece in particular was quite smashed.
Fortunately, a friend was able to model a trim ring, and we’re waiting on some gray filament to make a test print. Stay tuned on that one, I’ll post the files as soon as I have them and we’re happy with the quality.
The back was in ok shape, one of the cord mounts was bent. This looks to be a chassis problem and can be knocked back into shape. The cordset, however, is a mess and will need to be replaced.
Inside, it’s even worse. I could see there were some changes made just by peeking in the hole left by the ring. But to what extent, I have no idea.
That’s certainly not the OEM amp board. It’s also not the OEM power supply. Everything has been modified. The underside has a bridge rectifier power supply with a few parts just floating in the air. Did they come off their terrible joints, or were they placed like that? I have no idea.
That’s the amplifier board. It’s using an AN214, an old-school power amp from Panasonic. This one has the Matsushita triangle on it, and of course Panasonic was one of their imprints. It commonly showed up in low-power consumer electronics, and is usually rated around 4W. This board probably came out of such a device, but who knows. It’s obviously pretty old.
That’s not supposed to be there. It’s an across-the-line capacitor and looks to have come from an old radio or television of the 1960s. Soldering is poor to terrible on all of these connections.
Pretty much all of the switches have been cleaned of their connections.
The meter drive is similarly messy.
Even the power transformer has been changed out. If the label on the top is correct, it says 15V 1A, which is much less than the higher voltage unit originally present.
So…the million dollar question. Does this thing actually work?
Yes. It does, and is actually very quiet - i.e. no noise. This amp board is quite well made.
I want to make this thing work properly, so it’s going on the bench at some point. There’s a lot of cleanup, and I may lay out a board for it, just to see what I can do.
I’ve added some new documents to the library, and I’m going to try and create a new zip every quarter (or so.)
This archive contains all of the documents I’ve collected for projects - at least ones that I can share. This is currently about 400MB, and is a zipped archive of zipped files of many different kinds.
Note the Drive link provides you a .7z file with a simple password: 123456 - this is to keep a certain website from complaining that oh no there’s words in that document I recognize and you can’t do that!
