The EICO 150 was back on the bench tonight for some transistors. I started by adding a new terminal for Q4’s output, meter tie point, and transformer input.
I replaced Q4 with a NOS NTE152, new grease, and a new mica insulator of the proper size. Yeah, I got some shiners on the wire there, I tried to be careful but even my orange stick went through the insulation. I’ll get some nail polish and touch those later to coat the wire.
The part I used was an EGC152, which is the same thing as an NTE number, as NTE purchased the ECG line from Philips way back when, who in turn had purchased the line from Sylvania.
Q3 also was replaced at this time, with a generic 2N3906.
I did some noise testing to see what was going on now:
Noise levels had calmed down substantially:
There was still too much noise, so I went ahead and replaced the other two transistors.
Noise levels calmed down to what I would consider just background nosie. So are modern transistors that much better, or were these simply dying? Well, I replaced Q4 with a device that’s barely 10 years older than the one in there, so it’s certainly not “modern” - I’d have to guess that the transistors were simply breaking down from years of abuse. The Internet seems to think that these are a “replace with capacitors” item for this unit, so maybe there’s some truth in there.
There’s a little more to do, I want to make some measurements for posterity, and adjust the meter drive a little - you really have to crank the gain to get meter deflection, much like an eye tube unit. I want to dial that back some so a comfortable listening level gives noticeable deflection.
Back to the transistors, here’s what I pulled out of the unit:
Q1:
Q1 was originally an EICO number, but the previous owner replaced it with an SK3124, twice. I assume that’s because they blew it out by connecting input to B+ on a tube device. I used a 2N3391A as it’s replacement.
This part would have been an EICO part as well, but it had a Motorola HEP 726 instead. This is a generic AF transistor, ala 2N3904, etc. I used a 2N3391A as it’s replacement.
Here we have our first EICO part. This is the complement to the output transistor, and as such is PNP. Almost any PNP AF transistor will work, but may have to be selected to reduce or prevent oscillations. I used a 2N3906 which seemed to work well.
Here’s the big boy. It’s some EICO number, un-cross-referenceable. It’s an NPN power transistor, almost anything with a few watts of dissipation and an hFe of 100 or so will work here. I used an NTE/ECG152 on the suggestion of the Internets. It recieved a new mica insulator and new grease as well. The old insulator was just a little round piece of mica and the previous owner delicately balanced it under the transistor.
I’m happy with the noise levels here, all I can really hear now is the hum from the power supply. There’s a few things left to do, I want to measure voltages for posterity, and adjust that meter level some. One more part, and then final thoughts. Stay tuned!
There are only a few more parts to do on the range switch, so let’s get them done. There are two capacitors, a ?? type and a mica type. This is what they looked like:
And here’s what they ended up looking like:
I also took the time to replace some of the … more interesting jumper routing on switch terminals, and clean up the terrible solder job. Last thing to take care of on this unit is the power supply area, and I need to decide how I want to lay this one out. Stay tuned!
Today’s board is the power supply of a Sabtronics 2000 DVM. Sabtronics is known for being one of the first, if not the first company to offer a hobby priced digital meter. They eventually expanded out into other instruments, into more specialized measurements like True RMS - also at an affordable price. Unfortunately, technology marches on and a company in the USA providing USA-made devices got their lunch eaten by the cheaper array of imports. The devices they offered still have a place today, and those bright “science blue” cases are just as attractive now as they were then.
Here’s the board:
What’s of particular note is, of course, the faint orange script “T” in the upper right hand corner. This board is more akin to the Textolite made at the GE Coshocton plant, but was made there all the same.
I always like finding a piece of home in a device. Especially one that I can use, like this meter. Stay tuned, the “T” will most certainly make an appearance again!
I did some troubleshooting on this device, checked tubes, voltages, transformers, there’s even a video about it that will show up soon and will be linked as soon as it posts. But I overlooked the obvious thing.
You see that switch in the middle of the device marked “Speaker On/Off” Good. You were probably screaming at the screen going “CHECK THE SWITCH!” I finally checked the switch. It was dirty and open. Some Deoxit later, and the tracer now works just fine.
That time was not wasted, however. I did confirm that the filters are good and that the coupling capacitors aren’t leaking, so I feel confident that I can use this device without worrying that it’s going to red-plate a tube - even though that 12CA5 output gets smoking hot.
What’s the takeaway here? Always check the little things because they tend to bite just as hard. That’s all for this device, it goes on the bench as an amp. Plenty more on the EICO 950A to come!
I picked this guy up at Dayton 2026, literally the only signal tracer I saw. This was one of two magic eye laden devices I saw, the other being one of Heathkit’s larger, upright-style R-C bridges. Test equipment of this nature was absent, probably due to the fact that what’s still working is either in collections or is being sold on eBay at the eBay tax rate.
I’ve wanted one of this style for some time, and this one was a couple of sawbucks. Vendor didn’t offer me any advice on it’s status, and I assumed that it did not work. I was correct, the device is silent and the output tube seems to be getting quite warm - much warmer quicker than a simple few minute test would indicate.
I did a bit of troubleshooting to determine if the supply was working, and it is - that will show up later in both a video and a post, as I want to get this device working.
Beyond that, there’s not much to say. Here’s the device photos:
The device is clean but dusty, and hopefully shouldn’t take much to make it talk again. Stay tuned!
More parts for the EICO 950A, this time concentrating on that center switch. This takes care of the resistors on that switch, but the two capacitors in there will still need replaced.
We’re about 3/5ths of the way done here. The power supply, and some other cleanup remains.
The EICO 150 that was on the bench had a bad speaker. Now it has noise. Lots and lots of noise.
I’m going to put a scope on the transistors to see what they look like, in particular Q3 and Q4, the output pair. This is with minimal gain, no input signal. The test is trying to determine where the noise is coming from. I made a partial determination earlier with a suggested test - unhook the base of Q4 from the circuit. If the noise stays, it’s Q4. If it goes away, it’s back further in the circuit. It went away, so something further back is bad. I’m also going to measure the voltages on each transistor for reference.
Some noise there on the collector. This will also appear on the base of Q4 since they are direct-connect.
Q4
Base
Emitter
Collector (Output)
The signal is being amplified by the output transistor. Perhaps this explains the current draw? The output transistor is doing something instead of being in it’s no output state. What’s causing this? Maybe Q3 is just noisy. Maybe one of those carbon composition resistors is noisy. It’s going to take some more work to make that determination.
Voltages
Measured:
Manual says:
You can see there are some variations here. Further work is needed.
We mostly toured the buildings, but I went away disappointed as there were no test equipment vendors present - in fact, the only real TE vendor there was Bird, but they aren’t selling to me. The guy I was with was interested, however, as he needs a commercially available handheld SpecAn that isn’t a Chinese company.
I did pick up a few things here and there, but not much. Mostly rain discount stuff.
Here’s what I saw at the show:
A meter with the Niagra Power sticker on it.
Did I photograph this already?
I took it home. Gotta have a voltmeter at a show.
One Dollar Rain Discount. It has a burning smell.
UNIX, anyone?
110VAC single phase. Unusual.
Lots of reel-to-reel players.
A very precise balance beam scale.
Stacks of stuff, why we are here.
We left probably close to 1PM, as many of the flea market vendors had started to pack up. I skipped Sunday as there wasn’t anything I wanted to see, I was aching, and I wanted to play with some of the things I bought.
Next show is Breezeshooters in Butler, PA. See you there!
Friday turned out to be a just slightly damp day at the show, we had a little rain but it cleared off quick. We toured the flea market, and saved the buildings for Saturday due to the forecast of heavy rains. The steak tips and mashed potatoes vendor wasn’t here this year, so bourbon chicken and a banana milkshake subbed in it’s place.
This year, the mobile AM CB stuff was almost all gone save a few units here and there. Hobby-level test equipment, i.e. the EICO/Knight/Heath/etc. was almost not present, save for a bunch of those crappy RF generators that no one really wants - the bridges and tracers and things are pretty much no longer for sale. At least, not at Dayton. Of course, the piles of plastic radios and old televisions are long gone, and even the big boat anchor radios are vanishing. I think I saw maybe 1 Hallicrafters S-38 unit for sale…
Things are changing, but there was still a lot to see:
A nice A-K speaker.
A basket of Apples.
Just some audio stuffs.
A nicely restored cathedral radio.
Choke the Chicken…not here please.
An old Data Precision meter.
Many DEC Rainbow computers.
New, old-stock desoldering irons.
My favorite brand of tools?
Designed for butane flow measurements.
Some tunes for the ants.
No idea what this model was.
Someone's pride and joy, dumped in a bin.
I eventually took the scope for $1.
The old way of measuring standing waves.
Just some random HP things.
Ok, if you insist.
Loudenboomer!
Some info on the Loudenboomer.
Would you like to play a game?
It's not tourist season without a thumb.
Some military equipment.
Telephone B.C. (Before Cellular)
How many of these were made?
Moto comm analyzers.
A really nice condition scope.
Some old computing horsepower.
A really old opto counter.
This scope was in bad shape elsewhere.
Parts. I took a few transistors.
High voltage?
Used to be piles of this stuff.
These are vanishing as well.
Some more radios.
And some more radios.
A scope that was part of a school course.
Even if it was good, this showed bad.
Some sort of receiver.
A tape deck. Friend wanted it, you carry it!
Lots of these, no one wants.
Some of those funky round speakers.
I took the Sabtronics unit for a sawbuck.
Semiconductor testing devices…in peach.
A Shango Special.
I have no idea.
A table full of stuff.
Hallicrafters SX-62.
It's a radio that's a table that's a radio.
Teletypes for your 110 baud needs.
A cool old terminal.
daytonf26-terminalsettings-wereboar.jpg
The only signal tracer I saw.
A giant TRF radio.
A nice looking TRF unit.
Warm soda and melted candy anyone?
Surprising, more W-J stuff this year.
Some W-J stuff.
We spent pretty much the entire day, heading out at 4:45 a few minutes before closing. We went Saturday as well, but I skipped out on Sunday.
Continuing on with the EICO 950A, the components near the power input need to be changed out, especially the capacitor used as the across-the-line component.
The orange drop is being used as the across the line cap. While this would have been acceptable way back when, it’s not acceptable now. We have specialized capacitors for this purpose, and one goes there. I’m also going to clean up the power input lead to the transformer, and it’s going to get a new line cord. The 470K resistor will go, and there’s a hidden 270K on the switch that will come off but not get replaced just yet as the parts I bought decided to hide from me.
There will be a 270K placed here, eventually.
I took the time to remove the rest of the junk from the power supply:
And the entire thing is starting to look better.
Next step is to tackle the resistors on the switch itself, as well as those two capacitors buried inside. I also need to consider where things will mount on the supply…the OEM used the tube socket as tie points for all parts, but I’m not sure I want to do that. I usually like to get the AC off on it’s own. We’ll see.
