Vintage electronics thread

[Rustward]

Although I grew up playing with vacuum tubes, I do not see myself going back to that any time soon. Well, maybe when I fully retire and have more time. Right now, antique electronics to me means individual transistors, dual-gate MOSFETs, ICs that are in DIP packages, TTL chips, Z80 and 68000 microprocessors, etc... These 30-yr old ICs take tremendous board areas and are awfully power hungry compared to SMD devices now, hence are antique to me.


I still have in my garage a venerable HP-141t spectrum analyzer which weights perhaps 50lbs. No tubes in that granddaddy, except for the CRT. All the circuits are solid-state, but the weight is because of the tremendous shielding that the thing has. For accessories, I have all the 3 plugins: HP8553 (1KHz-110MHz), HP8554 (100KHz-1250MHz), HP8555A (10MHz-18GHz). The IF is of course the HP8552B. I also have the HP8445B Preselector.

The above setup can still fetch some money, but no way I would want to sell it. Yes, even if I have a modern, lighter analyzer with a built-in tracking generator. That beauty and another piece of equipment, a lab grade signal generator, together cost me $50K when I bought them a few years ago. These are of course nowhere near top-of-the-line. For that, a top-notch best-money-can-buy spectrum analyzer with phase noise so low it brings tears to your eyes cost $99,500 back then.

PS. No, my memory was failing me. The analyzer was $25K and the signal generator was $15K for a total of $40K, not $50K.

This post reminds me of when I w*rkd at Mostek Corporation. Those were the days -- late 70's / early 80's. Mostek - Wikipedia, the free encyclopedia

The wikipedia article makes reference to fear, uncertainty, an doubt, aka FUD, which is attributed to Gene Amdahl Fear, uncertainty and doubt - Wikipedia, the free encyclopedia. I had the privilege of spending over a decade w*rking for Amdahl, and did have the opportunity to have dinner with Dr. Amdahl (me and five others that evening). Ok, well enough about me -- I doubt if anybody cares.

 

[Gumby]

Today, I received the 1930 Western Electric Model 202 (D1/E1) telephone and subset that I bought on ebay. The phone looks and works great, except that it doesn't ring. I will need to check the internal wiring in the subset (ringer box) this weekend.

 

[Telly]

Cool! What will you be using to ring it? Those old low-impedance ringers took a lot of power to ring. The ringers used for the last 50-60 years or so are known as high-impedance ringers. The whole REN (Ringer Equivalency Number) idea of the deregulated years was based on the high-impedance ringer as REN=1. Most telco's allowed you to have at least REN=5 on your line, to allow some phones around the house in parallel.

One of the hack jobs for a person who dug up an old phone that they wanted to use, was to replace the old ringer with a "modern" ringer. That was a "modern" electromechanical ringer, so even that was quite a few years ago! A common source was the electromechanical ringer pulled from an old 500 rotary or 2500 pushbutton set. Back in the day that if an intruder broke in while you were on the phone, you could club them with the receiver.

A 500/2500 ringer will not sound like the real old ringers, but at least it's a real set of bells. The DC-blocking capacitor of some of the 500/2500 sets was in the "network" block. So to avoid having to acquire a suitable external cap to go with the 500/2500 ringer, the 500/2500 network block could be used too, only using the terminals on it for its internal blocking cap.

Another thing people did, was to disconnect the old low-impedance ringer, and they would know when to pick up the old phone when they heard one of the regular phones in their house ringing.

 

[Telly]

Gumby, what did you figure out with your W.E. phone?
I hope I didn't scare you away...

 

[Gumby]

The last several weekends were filled with unexpected auto repairs and other events, so I have not spent much time trying to figure out the phone. I can see that it appears to have been retrofitted with the ringer assembly from a WE 302 (I already have two of those), but I haven't gone further than that.

 

[ls99]

Last week was poking around in Goodwill. Found a nice wooden box, with a cutout in front and labeled Sonic 2000. plugged in at the store, nothing, the light on front did not come on. Hmmm. At $ 1.00 could not resist.


Guessed it was some sort of ultrasonic gizmo.

At home did a quick internet search. Turns out it was sold by HammacherSchlemmer around 1989 for the princely sum of $139.95 as an ultrasonic pest repellent.

The next item came up was a NY times article about ultrasonic pest repellents being useless.

Never played with one these, so opened up the box, see what is in it. A small circuit board, wired to a piezo transducer. 4 small and a darlington driver transistors. An RC oscillator, gated.

A closer look revealed a broken 47k resistor lead. Poor mounting technique stressed the lead, then eventually broke from the body. Digging through my collection found a 1/4 watt 20%. Replaced the the broken one. Plugged it in an voila... some clicking sounds about 1 sec apart.

Curiousity aroused, hooked up scope to the output wires. Around 50 Khz, it drifts about a fair amount. Cycling on and off. The noise is from a transformer at turn on. I can not hear 50 Khz. Front panel light blinking at 1 sec intervals. So it is working.

The lower trace on the scope is the current to the piezo transducer, the upper is voltage.

Now, I wonder what kind of critters, animals etc. can hear 50 Khz. My guess is none.
So the upscale catalog place sold a gizmo that actually did something, though doubtful if it is of any use.

Does anyone know if deer or cats, dogs can hear that high?

 

[LauAnn]

Not a clue. But I did buy something similar at Lowes for approximately $14.00 fifteen years ago to deal with a mouse and mole issue I had. Results were inconclusive. I have a friend, however, who swears the device works for her rodent problem.

 

[ls99]

well, looks like it well in the range of hearing for Beluga whales. Some cats, dogs, bats and ........ cows!

http://www.diracdelta.co.uk/science/source/h/e/hearing range in animals/image001.jpg

 

[Telly]

Turn it off, man! You're gonna crash every bat in the neighborhood with that thing!

I have doubts about that whale spectrum, as I thought whales use very low frequency sound to comm for great distances. That chart shows the low end at 1 KHz.

The mosquito repeller idea was the rage in the 70's too. I knew a guy who built a common (at that time) circuit based on the original 4001 CMOS quad-Nor and powered from a 9 volt battery. The circuit worked. The repelling concept didn't.

 

[ls99]

The mosquito repeller idea was the rage in the 70's too. I knew a guy who built a common (at that time) circuit based on the original 4001 CMOS quad-Nor and powered from a 9 volt battery. The circuit worked. The repelling concept didn't.

Last I read mosquitos are attracted to CO2, BO, and funky sneakers.

 

[Nords]

Last I read mosquitos are attracted to CO2, BO, and funky sneakers.

Well, that explains a lot around our property...

 

[Gumby]

Gumby, what did you figure out with your W.E. phone?
I hope I didn't scare you away...

Just wanted to report back that, after getting distracted by many other chores, I finally sat down with the phone and fixed it. Turned out to be amazingly simple -- a broken lead on the ringer coils. A new wire, a little solder, and it's back in commission. Rings just fine now.

 

[ERD50]

Today, I received the 1930 Western Electric Model 202 (D1/E1) telephone and subset that I bought on ebay. The phone looks and works great, except that it doesn't ring. I will need to check the internal wiring in the subset (ringer box) this weekend.

Just wanted to report back that, after getting distracted by many other chores, I finally sat down with the phone and fixed it. Turned out to be amazingly simple -- a broken lead on the ringer coils. A new wire, a little solder, and it's back in commission. Rings just fine now.

Odd bit of timing, but I just picked a book on old telephones off the library shelf that happened to catch my eye. Actual schematics and technical details. Pretty interesting to a geek. Couldn't keep the kids and DW away from it

I was surprised to learn that the very early phones had a local battery for the transmitter side, rather than the Central Office battery configuration that I was familiar with, and thought went back to the original system. Turns out that if you study the way that works with the impedances, the local battery gave a much better signal - less power was wasted as sidetone. Some of those phones had a separate switch for the battery - this allowed one to listen, w/o wasting battery, and kept your side silent. Perfect for listening into party lines.

-ERD50

 

[Htown Harry]

I stumbled across listings for Les Paul's estate auction today. There are a ton of guitars, as expected, but also a fair number of electronic devices like amplifiers, oscilloscopes, etc. I spent an enjoyable hour window-shopping.

https://www.julienslive.com/view-auctions/info/id/71/

Julien's Auctions is proud to present Property From The Estate of Les Paul. Les Paul not only revolutionized the sound of the electric guitar, but also the technology behind modern day sound recording. Les Paul pioneered innovative techniques with sound-on-sound recording and commissioned the first 8-track tape recorder, which would become the core technology behind multitrack recording still used today. The sale will include property equipment, memorabilia and instruments that span the entirety of Paul’s career from his days as Rhubarb Red to his weekly Monday night concerts at the Iridium Jazz Club in New York City.​

An example that fits on this thread:

LES PAUL "PAULVERIZER"
A custom switching device created by Paul in 1956 to remotely control tape machines hidden off-stage enabling Paul to play along with a selection of pre-recorded backing tracks. Paul initially created the name "Paulverizer" as a joke but later created this device to allow he and Mary Ford to perform with backing tracks during live performances. Together with extension cable.

 

[Nodak]

I am in the process of restoring my E.H. Scott radio and needed a new dial strip for it. Didn't think I'd ever find one but found a company that supplies them. If anyone has a project like this going on these guys seem like a good source.
Radio Daze, LLC. - Antique Radio Parts & Service

 

[Tom52]

I wish I had the electronic skills some of you possess. At my Dad's house is a circa 1967 Magnavox console turntable and AM/FM/FM stereo. I remember back when I was a young teenager my Dad brought it home primarily for my sister and me. I remember many a night listening to 60's rock and roll albums and tuning in distant radio stations in the evening hours. Man that thing had a fantastic sound. I remember when my parents were away, treating the whole neighborhood to my music whether they liked it or not.

That Magnavox console still looks pristine but it needs some electronic "work". My parents wanted my to take it home but I said I would not know where to get it fixed. Before my Mom passed away a few years ago she had someone work on the turntable but it turns too slow. There also seems to be some sort of "shorting out" of the speakers if I remember correctly.

I wish I knew how to fix that thing or find someone that could for a reasonable cost. It sure brings back fond memories of my youth.

 

[Nodak]

I wish I had the electronic skills some of you possess. At my Dad's house is a circa 1967 Magnavox console turntable and AM/FM/FM stereo. I remember back when I was a young teenager my Dad brought it home primarily for my sister and me. I remember many a night listening to 60's rock and roll albums and tuning in distant radio stations in the evening hours. Man that thing had a fantastic sound. I remember when my parents were away, treating the whole neighborhood to my music whether they liked it or not.

That Magnavox console still looks pristine but it needs some electronic "work". My parents wanted my to take it home but I said I would not know where to get it fixed. Before my Mom passed away a few years ago she had someone work on the turntable but it turns too slow. There also seems to be some sort of "shorting out" of the speakers if I remember correctly.

I wish I knew how to fix that thing or find someone that could for a reasonable cost. It sure brings back fond memories of my youth.

Depending on the size of the city you're in you might be able to find a shop to fix it for a reasonable price. You will have to find a small independent place, the large electronics outfits probably won't touch it.

 

[ls99]

Record player run on 12 volt battery power

My latest project involves making a record player work on 12 volt DC.

In my camp Most of the electric system is 12 Volt dc. Do have three genrators for various power needs, but are rarely run unless no other way of getting something done. DC is supplied by Two 135 Watt solar panels, which were bargain basement price from Craigslist from sumeone who could not make the work. Also a 45 watt harborfreight panel set. They feed 2 deep cycle batteries in parallel.

I have a fair sized record collection, some of which I want to listen to in the camp. Before someone says why don't I digitize them, the answer is I just dont feel like it. I find pleasure in putting on a record, a pleasant exercise. More rewarding than swiping the face of an Ipod touch.

I have a good record player, but it is driven by a synchronus motor, AC only. Running an inverter just for that would be a waste of battery power.

Perusing Craigslist found a Realistic LAB 1500 linear drive turntable, vintage 1980 or so. After some haggling got it fairly cheaply. Bought a new belt, and cartridge still very reasonable.

THis particular unit has a DC platter drive motor, processor controlled, and linear tracking tonearm, similarly controlled. Consumes about 400 milliamps max while playing a record. WHile originally AC powered. All the electronics runs on DC. After examening the circuits, I found it will oprete reliably down to about 10 VDC.

Soooo. Past the bridge rectifier connected wires to the outside world, and it runs fine from the range of 16 down to 10. volts. My DC system max voltage at full sunshine is 14.7 BDC

In my junk collection found a preamp unit to convert the 5 millivolt pickup head output to line level. This too was AC powered, which I again converted to run on 12 volt nominal. Now I can feed the line level signal to a mini FM transmitter which will feed a Jensen aftermarket auto radio. The radio has a built in CD player. But no AUX input. That Radio Drives a set of KLH speakers I've had for many years.

Like the result, a fun project.

 

[Gumby]

What a clever solution. I still put vinyl on the turntable when I'm in my home office (like right now).

 

[ERD50]

... Running an inverter just for that would be a waste of battery power. ...

Interesting project, since you were successful, this is moot, but I'll still throw it out there for discussion...

If you used a small (for low idle losses) true-sine inverter (I assume a turntable motor would not be happy with a 'modified sine'?), how much battery power would be wasted? I imagine a turntable draws only about 25 watts - something in that range? So if your DC turntable dies, a cheap synchronous one might get the job done on a small inverter.

I know we've had other threads on this, but I just got back to digitizing more of my vinyl. I recorded a bunch of LPs a few years back, and the past two years I've finished up the Christmas music, now finally getting back to my eclectic stuff. It takes me a while, as the de-clicker SW I've tried alters the sound too much when you push it to actually remove the clicks. My LPs are in very good shape, so I go in and listen for the occasional pop, zoom in, and use the 'repair' function in Audacity on the pop itself. The repair just rebuilds a very small segment of the waveform by analyzing the surrounding waveform. The results are almost always perfect sounding to me. But it is a tedious, manual process. I have to be in 'the zone' to do it, and then you burn out, and that is why these have sat for a few years.

But the great thing is, I sit and listen to each and every note with full attention. I'm amazed at just how great some of this old stuff is, and mostly the vinyl is in good shape. I can go for minutes w/o feeling the need to touch up anything, but then I might spend 10 minutes on the little crackles on a fade in or fade out, or pianissimo segment before I either nail it, or say 'good enough!'.

So the process is actually kinda 'fun' in a way. And it's great when I have them digitized and can call up any song or artist I want in seconds.

There is always the no-watts option:

-ERD50

 

[ls99]

Last few days resurrected my AKAI X-200D 7" reel to reel tape machine. THis machine has a factory claimed 20 Hz to 28 Khz frequency response at 7 1/2 ips. In the garage had a big box of 7" tapes most of which have not been played in over 40 years.

One example is a soundtrack of My Fair Lady. Put the tape on, played it, still sounds beautiful. No tape oxide residue on the playback head or the capstan was visible after playing and a fast rewind. So much for dire predicitons of magnetic tape biting the dust after many years.

Another great find in the box was a "voice mail" on 7" tape made by my late brother to his then girlfriend, who became his wife in time. That tape has to be from 1957/58 or so. She too has passed on. I thionk I will copy that tape onto CD and send it to my nieces. Any day now

So whaddaya do all day??

By the way I'll pass on ERD50's suggestion of the no-watts record player. I do not have any 78s and even if I did, would not wish to re-engrave the soundtrack.

 

[NW-Bound]

My latest project involves making a record player work on 12 volt DC...

Like the result, a fun project.

I have been working on running more electronics in my RV (a 25' class C) on 12V. When I bought a 27" TV for the RV, found out that it ran on 21V DC supplied by a 115V power pack like that for a laptop. So, I went on eBay and bought a DC/DC converter that has 12V in, 21V out. Problem solved.

Just something to do. It is not truly necessary as my 2KW pure sine wave inverter takes a mere 0.5A when idling, and can be left on 24 hrs whenever I have any sunshine for the 215W solar panel.

 

[braumeister]

No tape oxide residue on the playback head or the capstan was visible after playing and a fast rewind. So much for dire predicitons of magnetic tape biting the dust after many years.

Funny story about magnetic tape.

Long ago (more than 30 years ago), I had a friend who worked for a company that produced the iron oxide (yes, essentially "rust") used to coat magnetic tape used for recording (voice/music/data).

Their plant was capable of producing 99.995% pure iron oxide.
They never got to actually ship any.

It seems that all their customers had their own standards, and consistency from batch to batch was their most important consideration.

So if a shipment required 98.46% purity, they would add enough adulterants to bring it to that level. Happy customers, but my friend just had to shake his head sadly when he saw the production specs.

 

[NW-Bound]

Speaking of magnetic tape deterioration, I have observed the following more than once with audio cassette tapes. Brand-new blank cassette tapes still wrapped in cellophane would fail to record after sitting for 3 to 5 years. On the other hand, the same tapes if used to record right away after purchase seemed to retain their magnetization after several years, though there were some sound deterioration when played back.

The last batch that I had problems with was BASF chrome type, which was of course supposedly of higher quality. Of course this was 20 years ago that I used cassette tapes.

 

[travelover]

I found something interesting recently, re Radio Shack components. I needed a 25 watt resistor and found that Radio Shack on-line had it for $1.21, but with $6.99 shipping.

Thinking that I might order one from China cheaper, I copied and pasted the description into eBay. Up comes one from Radio Shack - $1.21 with FREE shipping.

Probably packaged by the same guy, at the same facility in either case.