Switchiing Power Supplies

Dean

Well-known Member
While we're on the subject of switching power supplies, anyone remember how HV DC plate voltage was generated in automotive (6V DC) tube type radios?

Yes, it was done without RF/IF interference issues.

Showing my age here.

Dean
 
A vibrator. An aluminum can with an autotransformer and a set of points that made and broke a primary circuit, thus generating plate voltage. They were noisy in actual noise, but fairly well damped in the DC with Condenser and choke combinations. Jim
 
The car radio and TV repare shop i used to work part time at. They had several Boxes full of vibrators. Funny thing, some were three pin then there were four and I would swear a five pin. Even the pins were different sizes and positions. If you turned the volume all of the way down you could hear them buzzing under the dashboard. Near the very end they started making solid state versions of them. Funny thing is the buzz boxes for model T cars. You see that little wooden box with the buzzing point set on top. Man you want to grab hold of that sucker with the voltage hooked up !
 
I had a Narco 'Omnigator Mk II' aircraft transceiver in a 1959 Cessna 150. I remember the vibrator in the power supply failed in the 1980s. The man who ran the local avionics shop gave me a replacement from another old Mk II. What I call the power supply mounted on the floorboard behind the seat and was about the size of a toaster. The radio had 'whistlestop tuning' to match the receive frequency to one of the 18 transmit channels for communication. It had a little hand crank to tune the receiver and crystals for the transmitter.

Well that was a trip down memory lane.

Didn't the car radios like in a 1934 Ford have some kind of dynamotor in them to generate a certain type of current?

Garry
 
I agree it was a VIBRATOR. Of course, if there's pure steady unswitched non oscillating DC put into a transformer there's no transformer action (not withstanding the initial turn on or off DUH) so the old radios had that noisy humming vibrator which switched output could then be made subject to transformer action to increase the voltage

John T
 
(quoted from post at 22:48:30 09/28/17) While we're on the subject of switching power supplies, anyone remember how HV DC plate voltage was generated in automotive (6V DC) tube type radios?

Yes, it was done without RF/IF interference issues.

Showing my age here.

Dean
suppose your point is that the old & the modern were both 'switchers', so why the problem with one & not the other? Answer, filters. The engineer of the radio HV supply had to make it work in a radio. The LED bulb engineer has to make his supply light a bulb. The LED driver 'switcher' could be made quiet with enough and properly designed filter for the job. Some Tectronix oscilloscopes, the have sensitivities to measure & display microvolts, have internal switching power supplies....all designed with proper filters for the job at hand. It isn't a matter of what can be done, but a matter of what is done. How much do you want to spend?
 
(quoted from post at 12:52:18 09/29/17) Vibrator power supply was very similar in operating theory to a points ignition system
he 'similarity' would be in moving contacts making and breaking a circuit. The Kettering ign stores energy in a magnetic field then abruptly releases it, whereas the vibrator alternately supplies power to the ends of a center-tapped transformer, where it is stepped up in voltage at the secondary (now an ac waveform), then rectified to produce HV dc .
 
Well, not really, JMOR.

It was more of a nostalgia question rather than a question of design parameters.

I well remember turning the radio on my Father's 1951 Buick and listening to the vibrator hum for a minute or so until the filaments heated the cathodes enough that the tubes would function and the radio would work.

FWIW, the 1951 Buick was retired in the early 1960s to a spot behind the barn but I would occasionally start it and drive it around on the farm a bit when young. It was not scrapped until the mid 1970s and the Sonomatic radio still worked. The radio had never been out and the vibrator had never been replaced.

Dean
 
(quoted from post at 15:13:52 09/29/17) Well, not really, JMOR.

It was more of a nostalgia question rather than a question of design parameters.

I well remember turning the radio on my Father's 1951 Buick and listening to the vibrator hum for a minute or so until the filaments heated the cathodes enough that the tubes would function and the radio would work.

FWIW, the 1951 Buick was retired in the early 1960s to a spot behind the barn but I would occasionally start it and drive it around on the farm a bit when young. It was not scrapped until the mid 1970s and the Sonomatic radio still worked. The radio had never been out and the vibrator had never been replaced.

Dean
lot of old things were just built better than a lot of modern things. A Fellow who made a pot of money pedaling "quality is free" to industry in the 1970-80s, convinced almost everyone that they need not define quality the way it had always been. Edwards Deming re-defined quality as "whatever meets the customer's requirements". That meant that if the wholesaler/retailer required a LED bulb design that made light for a day, a week, a year, makes any and all RF noise that the FCC allows, costs 80 cents to manufacture, has a socket base that won't corrode to dust within a month, and whatever else you might imagine, then that my friend is a quality product. Note: for the manufacturer, the customer is NOT the consumer! That would be Walmart or the distributor between Walmart & the manufacturer. I have trashed hundreds of Deming's "quality" products in my lifetime, but like your old pre-Deming radio, I have a receiver used by the U.S. Army during WWII, that I use today to listen to broadcast from around the world. It's capacitors (unlike so many condensers on forum members tractors) & all its vacuum tubes still work. That suits my 'old fashion' definition of quality!
 
Can you imagine the look on some lady's face when you told her that she needed a new vibrator?She might say "no,it just needs a new battery".
 
And if the vibrator was getting a little worn, it sometimes took a thump on the bottom edge of the dash to joggle it and get it running.
 
"Note: for the manufacturer, the customer is NOT the consumer!"

Bingo!

I would restate this as: For the industrial manufacturer, the consumer is not the customer.

In a past life, I well remember sitting in meetings with other (more senior) GM engineers who had never worked anywhere other than GM and had no education or experience (never worked anywhere other than GM) other than their GMI engineering degree (Not meaning to demean the quality engineering education once available from GMI but such folks nearly always had tunnel vision.), though they did not so realize. Before being recruited by GM (second sojourn) I had worked for three other companies producing both consumer and industrial products. I had also earned (really earned, not just went through the motions) an MBA degree in marketing. When I would try to interject comments regarding the wishes of the customer, e.g., GM components division attempting (unsuccessfully) to secure contracts to produce components for other automotive manufacturers (no, I did not say Toyota, but you can infer as desired), the know-all "senior" engineers around the table would look at each other, nod, and proceed with their pre-determined course of action, ignoring the stated desires/requirements of the customer (not the consumer). Such is not the way to earn the business of industrial (or any) customers.

The NIH syndrome was well entrenched at GM components divisions (not just GM components divisions) as was the "he probably means well but he just does not know how things are done here" syndrome. Tunnel vision. Great engineers but unknowledgeable beyond engineering.

How many GM components divisions still exist?

Dean
 
Yeh,I remember the old 6 volt radios,have a tube go down and you could say it forgot the words to the song,but it sure can hummmmmmm.My first mobile C B I had Johnson Viking white face 6 channel 1958 or so ,110 volt or 12 volt and still have it and works great plus 2 more collected them .It had a 12 volt noisy vibrator in it when new that I replaced a few years later with a solid state silicone rectifier type vibrator and couldn't even here it.Plus it powered up the radio with more voltage and 4-5 watts more output power.The good old days late 50s & 60s before all the trash on CB and cell phones lol.
 
It was just a few years ago I had occasion to talk with a modern auto radio repair guy, and he asked me what the vibrator was for. I told him that it was basically a turn signal flasher only real fast, because until you got enough voltage to run a vacuum tube (hundreds of volts), you can't make an oscillator. So you have to settle for a square-wave input with a DC bias and pipe that to a transformer.
 
I think I still have some old vibrators in my junk box. They made a transistor replacement later that was a multivibrator but most did not last long because of the voltage spikes and lack of a heat sink. My 62 Ford Fairlane radio used low voltage tubes that had 12 volts on the plate and transistors in the audio output.
 
(quoted from post at 23:23:46 09/29/17) I think I still have some old vibrators in my junk box. They made a transistor replacement later that was a multivibrator but most did not last long because of the voltage spikes and lack of a heat sink. My 62 Ford Fairlane radio used low voltage tubes that had 12 volts on the plate and transistors in the audio output.
2 volts on the plate?.........just call me a doubter & post proof.
 
I don't remember anything about a vibrator, but remember Anode (positive) and Cathode (ground) of the tubes, and then all kinds of other biasing and signal input and output on the other pins. Been decades. Used to be radio repair when microwave was new in the Army. Our point to point and troposcatter was 4.4 to 5.0 gig, satellite was 11.0 to 12.0 gig. Our uhf was 50 to 100 meg. All started out at 220 VAC but of course was broken down to 1,000 vdc and several lower by the time went through bridge rectifiers. I remember one time a fella touched his thumb to a 1,000 vdc cap while it was not still not discharged, but the power supply still powered up...POW!!!...split his thumb open.

Tubes...once they got cooked in for a good day or so, goodness they were stable. And it would be 0 degrees outside in deep snow, stop in to see some radio rig, go inside with three huge AGR-50 radios and accompanying mux stacks fired up....toasty warm in those vans. Down in the GP medium tents with a couple of diesel pot bellied heaters going and wind still blowing through cracks "Sarge, I'm going to go up and check your radio rigs to make sure all is good", go up the hill and see those guys...toasty warm in those shelters. Tubes put off some heat. Even 8,000 vdc klystrons using solid state transmitter and receiver cabinets put off some heat, but not as good as those old ANG-50's. Once they cooked in for a day, stable and warm.

I remember day one of training on the 11 - 12 gig tactical satellite set. We were told was top, top secret, only a handful in existence in the whole world. Problem was that one of them was captured when the embassy was overrun in Tehran, Iran and that the fellas were instructed to shred and burn all documentation on everything. They shredded everything, didn't burn it and scrammed. The iranians captured everything, put the shreds back together. They had our most top secret radio setups and knew how to use it and the current comsec codes for the crypto gear out of the multiplexers that they changed daily to match ours until they either expired, or someone issued new ones.

Thanks for the memories Dean. Looking back, I should have stayed in for 30 and had a better pension.

Mark
 

Lot of the two-way radios had a vibrator and a dyno-motor in them.. and if you ran them with the engine off, you killed the battery in about 4 minutes. The dyno-motor was a 60 lb monster that would pinch off fingers if your dropped it on your hands.
 
Thanks! Just another example of 'just when you think you have seen it all. along comes something else".
:oops:
 
Yeah a mechanical "Vibrator". I didn't know anything about sparky things back then but when mom started letting me use her car for school the first thing I did was to go to a radio shop to get the radio fixed. Remember 2 things well: 5 bucks it cost me which probably broke me at the time and the word Vibrator.
 
Oh man you just kicked a memory. I remember hearing one of those
things winding up everytime the guy keyed the microphone. Todays
radios most everything is 5 volts for the circuts. Remember when the
67 Dodge Charger had the radio with the electro-luminescent dial that
glowed in the dark? Think this is right. The radio was a Motorola and
the whole dial pannel glowed at night. There was a little power supply
under the glove box, about the size of a small size of mozzarella
cheese. Ran at a 350 volt potential. Had an orange wire. Yup it bit
me.
 
HAAHHH !!! Have one of those good old Zenith transoceanic radios and one of the tubes is an 0z4. That means no voltage. We are getting old folks!
 
".............but remember Anode (positive) and Cathode (ground) of the tubes................" I remember when the word "Plate" ceased to be used in favor of the new word to be used: "Anode"...........anode, what the heck is an anode....duhhhhhhhh????? Plate made more sense....a physical thing you could see............an anode...whazzat??????? Anyway, like everything else we experience, over time I got used to it.
 

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