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Introducing "Old Machine Time Machine"
Love old gear? So do we! Here's a new video series to revel in all that's come before.
Like probably a lot of you, I'm a bit of a hoarder. I've got a bunch of old test gear, a bunch of old tube radios (some of them floor models from way back), and various other things I've forgotten I possess, probably sitting on top of the sump pump.
“Jeez, Pete. You should go clean out that garbage from your basement, don't you think?”
Garbage?!? No way! This stuff is awesome! And it might all still work! And I just might need it one day!
I can't remember the number, I think it's an old Tektronix scope, 25MHz bandwidth maybe? It's got the coolest knobs on it. Precision metal stuff, quality like you never see anymore – unless you're paying really big numbers. But you know what I like the most about it? The screen. It's this small, round, green thing. It's not great for taking actual measurements, but it makes me feel like I'm working on a submarine during the height of the Cold War.
Point being, we've got some nostalgia for our old electronic junk, and now we have a new video series to glorify these old examples of technical wonder. Once a month, we're going to bust out a new (old) piece of gear, maybe open it up to look at the business bits, and talk about its history. It's called Old Machine Time Machine, and here's the first one. Hope you dig it!
For the longest time when I was growing up our main TV was a HeathKit that my father assembled, and never got around to putting an enclosure around... I'm sure now-a-days that would be criminal endangerment of a minor (two counts, one for me, one for my brother)... Neither my brother nor I hurt ourselves by putting our hands inside. Not for fear of HV electricity... No, that was fear of the Wrath of Dad. ;-)
This comment made me smile. My dad built the Heathkit color TV when I was a kid. We had the best color TV of everyone I knew. Dad adjusted the guns on the CRT tube daily, so we had the only TV without color fringing. If you are old enough you will remember just how bad the color was on most TVs.
Your comment made me think of the days about 40 years ago when I was working at a TV station as an engineer. When I was on duty, I had a calibrated monitor in front of me (it cost about $10,000 at the time, and had to go in for calibration once a year, so we had to have two of them). I recall walking through the TV section at Sears and thinking how far out of adjustment their demonstrators were. I also learned how few "TV service techs" had a clue as to how to properly adjust a TV, even if they had the right equipment. (Some of the Heathkits had it built in!) For at least 10 years after I left that job, I could only tollerate watching black and white TVs, which were much more forgiving!
Pete, thanks for the fun video!
Youngster, I hate to correct you, but those are NOT PL-259's on the front. Off hand, I don't recall the number for them, but they are audio, not radio, frequency connectors. They are (were) often used for microphone connectors, until someone got the bright idea to put a "push-to-talk" button on the mike itself and needed a second pin.
Another hint as to the age of the thing is that it's marked "KC" and "MC" (for kilocycles per second and megacycles per second, respectively) rather than the more modern "KHz" and "MHz" (for kilohertz and megahertz).
Once in a great while there were professionals who needed some feature of a Heath Kit and would buy one and assemble it "on the company dime". Fourty years ago I worked as a broadcast engineer at a TV station for a few months, and (I suspect) the chief engineer had gotten a kit and built it for a clock that would auto-correct to the WWV radio signal. (Today you can just go down to the consumer electronics shop, or Amazon, etc., and buy an "atomic" clock that does this.)
On the topic of o'scopes, also back in the 70s, the Atomic Energy Commission had several different projects that each needed a bunch of high speed o'scopes, but since the actual use for them was only on the order of milliseconds, and they could be set up in a couple of weeks, what they did was to mount hundreds of them, each with a Polaroid camera, in a semi trailer that they could cart around to the various sites. (Each o'scope cost the equivalent of a new car at the time.) You can imagine how this made me drool when I saw it as an impoverished student!
Oh, BTW, two advantages of the copper plated steel: it's a LOT easier to solder to than either galvanized or aluminum (useful when you're doing point-to-point!), and it also has better electrical shielding properties than galvanized, though it's significantly more expensive (and harder to find).
'773! As always, thanks for the stories! Not a PL-259?? Ah, crud. I think the reason I said it is is because when I first saw one, I went, "ah, PL-259", and then proceeded to screw one onto it. At least, I think it fit. Or I cross-threaded that sucker into oblivion.
PL-259 connectors do fit on them. I also don't know what they're called either, but it's pretty easy to replace with a BNC connector. The center of the connector is just a hole that the wire gets soldered into. A bit of heat from a soldering iron and the wire comes right out. Replace with a BNC, solder the wire to the middle pin and Bob's your Uncle.
Take a look at what DigiKey has for PL-259 -- BTW, a PL-259 is a PLUG (usually on the end of a coax cable). The mating socket is an SO-239. Why the number difference? Who knows? I sure don't.
Back to the connectors on your signal generator, I'm drawing a blank on trying to find a reference. As you likely know, the Heathkit manual only refers to them as "Shielded connectors", not a big help. I have some muck older things at home (like a Radio Amateur's Handbook from the 60s), but I'm not at home right now and so can't reference those things!
Switchcraft calls them "Vintage Microphone Connectors". Take a look at the dates on the chassis mount male connector drawing. http://www.switchcraft.com/Drawings/2501MP_CD.pdf
The frequency pointer is NOT connected to the frequency knob, but instead to a planetary gear. This allows more resolution in setting the frequency.
The chassis is copper plated because steel has lower conductivity. The plating thickness is enough for a few skin depths for frequencies where they wanted better shielding.
I built many Heathkits including and AM-FM radio that received the first stereo transmissions from San Francisco, one channel on AM and one channel on FM.
Also built the big screen color TV with the built-in color alignment generator.
https://prc68.com/I/HeathkitGC1000.shtml#LoH
By my reckoning, I have assembled, or trouble-shot for others, over 150 heathkits, from the electronic ignition kit to the electronic organ kit and most everything in between. I currently own a VTVM, Tube Tester, two Frequency Counters (one w/LED display and the other with NIXIE tubes for the display) and an amateur band receiver .
I saw this while ordering some switches and wondered if anyone would be interested in some various Heathkit test TV equipment. I got them in a trade in the late '70s and while they have gotten beat up some I have hung on to them on the chance they might be wanted. If there is interest I would get them together and send pictures.
There's a fair amount of interest in old Heathkit gear. They made a bunch of cool TV test stuff, and while analog TV isn't broadcast much any more, people still find use for it. What do you have? Pattern generator? Vectorscope? VTVM? GDO? Demodulator probe?
I was guessing the other tube was a 6C4, and sure enough, it is. It's basically half a 12AU7. You can find the manual here: http://tubularelectronics.com/Heath_Manual_Collection/Heath_Manuals_S/SG-8/SG-8.pdf Sure enough, that connector isn't a PL-259, just a generic microphone connector which was pressed into service for a lot of test gear (VTVMs, oscilloscopes, etc.) back in the day. Everybody made 'em, but I don't know of a standard name. It's probably a 5/8-27 thread, like Amphenol 85-75MC1F, Switchcraft 2501F, or J-30.
I was given a Heathkit IG-102 signal generator a few years ago that still works pretty well. Old Heathkit test gear is fun to play with