19 set AC power supply

Bob Phillips · #1 09-04-12, 06:13

Hey great idea to have a wireless forum!Now are there any radio experts that can tell me specifically ( not generally) how to build a 110volt AC power supply to run the receiver only on a MK3 set? I know it can be done and is straitghforward to those in the know. Any schematics available???

Mike Kelly · #2 09-04-12, 10:38

Quote:

Originally Posted by Bob Phillips

Hey great idea to have a wireless forum!Now are there any radio experts that can tell me specifically ( not generally) how to build a 110volt AC power supply to run the receiver only on a MK3 set? I know it can be done and is straitghforward to those in the know. Any schematics available???

If its a Canadian MK3 , it should have a 12v vibrator power supply running the receiver . Sounds like you don't have the original power supply with it . The British version mk3 has two seperate genemotors - one for tx and one for rx

They did this in order to lower the current drain , eg, as with the mk2 , which had one large genemotor drawing over 10 amps all of the time.

Mike

Doug Lavoie · #3 09-04-12, 18:22

Bob,
If you find a a/c power supply method, could you pass on the info.?
Thanks.
Hanno, great ad on to the forum. Much appreciated,
Doug

Bruce MacMillan · #4 09-04-12, 20:14

For the receiver to work you need only a 12vdc supply for the filaments and 265vdc for the receiver B+.

There have been circuits published in 73 & other ham radio mags.
These values are similar to most tube type receivers so something on the net might work.

All my docs are currently in a container somewhere on the Atlantic. If no one else comes up with anything it will be a few more weeks until I can access them.

Bob Phillips · #5 10-04-12, 04:47

I talked to well known radio ham /WW2 re enactor Dave Lawrence a couple of years ago at the Oshawa show. He has written extensively on the #19 set as well as set up displays at MV shows. He assured me that in the " old days" of ham radio many AC power supplies were easily built to eliminate the need for the heavy / ugly /power hungry power supply.As for the vibrator most of them are long dead. I just want a nice simple AC powr supply to run the receiver only. If I come up with a schematic I will pass it along!

Little Jo · #6 10-04-12, 12:39

Quote:

Originally Posted by Bob Phillips

Hey great idea to have a wireless forum!Now are there any radio experts that can tell me specifically ( not generally) how to build a 110volt AC power supply to run the receiver only on a MK3 set? I know it can be done and is straitghforward to those in the know. Any schematics available???

Hi Bob

I went through my old ham radio books and I have a book titled "PRINCIPLES OF RADIO" reprinted 6 times between 1929 and 1945, there is a chapter called, Properties of Alternating Current Circuits, goes for about 52 pages and I am sure what you are looking for is there for you. You may be able to view the book in a library and if that does not work I could copy the pages as long as it would not infringe on copyright.

Cheers

Tony

peter simundson · #7 10-04-12, 14:09

When we trained with the Ontario Regiment they used
19 sets in all their tanks and had about half a dozen sets
in their main building. All these sets had a power supply with
a direct feed from a 120 volt plug. You plugged them into the wall socket.
It looked like a normal power supply. I have seen one since then at a show many years ago. But not lately.
Keep looking. You'll get one.

Peter S

universalgrl · #8 14-04-12, 03:41

Brian Milroy of Campbell river BC did up a schmetatic for a power supply for the 19 set. He can be contacted through the 19 set website forum.
All the parts are avaiable in canada from Electrosonic and newark and will run about $400.00 bucks, the transformers 2 and 3 chokes (from Hammond) come to about $250.00
The whole thing should fit in the # 2 power supply case, and give enough power for both transmit and recieve, 12 v, 250 V and 550V.
I am in the process of building a pwr supply for my base station.

One change to the schmatic, use three rectifiers ( 15 A/1000V fairchild 58K1554) instead of the individual diodes.

universalgrl · #9 24-04-12, 04:13

First 5 pages of the installation instructions for installing 19 sets in CMP's.

universalgrl · #10 24-04-12, 04:17

Next 5 pages of the 19 set installation

Bob Carriere · #11 24-04-12, 05:36

.... now I can waste more time when at work....... with more to read !!!!

Maybe a dumb question but instead of converting the power supply is it not simpler to just use a large size 110 volts AC to 12 volt DC power supply..? and keep the radio original..!!!

In fact a few military surplus power supply models were floating around not to long ago..?
....and one floated to the barn.

I understand that most battery chargers do not provide a pure enough 12 volt DC output but surely that could be improved with a add-on circuit of large condenser to fill the square wave gap output of the chargers.... !!!!

Love those diagram from Roberta.....thanks.

Bob

Mike Kelly · #12 24-04-12, 10:04

Quote:

Originally Posted by Bob Carriere

.... now I can waste more time when at work....... with more to read !!!!

Maybe a dumb question but instead of converting the power supply is it not simpler to just use a large size 110 volts AC to 12 volt DC power supply..? and keep the radio original..!!!

Bob

Yes you can do that but the genemotors are rather power hungry . You would need a hefty 12V power supply capable of dissipating the heat involved . For a Mk 2 set , over 10 Amps continous . The genemotors are actually pretty good for HT voltage stability , the mechanial forces of the armature spinning around provide a good voltage regulation , eg they don't want to change speed quickly.

Some people just use a heavy truck battery in the radio shack..

And keep it well charged . The only thing is , the loud whining of the genemotor is a pain .

The other way, building a AC supply will give you a nice regulated high voltage for the transmit side if you use a reguator tube in it , if you don't , the HT voltage will change with load eg keying of the transmitter. If you are only receiving, then its not so critical. You an build them cheap from salvaged parts ..hamfests are a good soure of bits for projects . Old TV's provide chokes and bits too .

Sometimes, the output pass transistors of mains 12V supplies can be blown up by high voltage spikes eg from a vibrator HT supply running from it.

It depends on what you are planning on doing with the sets. MIKE

Bob Phillips · #13 25-04-12, 01:01

Many thanks for the schematics Roberta. My purpose is to build an AC supply to run the receiver - which has relatively low power consumption requirements. Lots of ham radio operators did this in the "old days " and I would like to set a radio up as a receiver only in the basement.

universalgrl · #14 25-04-12, 04:41

The 19 set needs 12 volts to heat the filiments in the valves.
250 volts to operate the receiver and 550 volts to transmit. If you bulit a mains pwr supply in the case have a frame built up that can slide in the box. I would modify the schematic to inculde an indicator light (12v) and maybe a fan for cooling.
The MK II needs 10 amps constantely regardless of receiving or transmitting, the MK III runs at a much lower amperage till you key the mike.

universalgrl · #15 25-04-12, 04:47

Don't forget the output pass transistors in your pwr supply will blow protecting the .25 cent fuse.

thats a joke for all you non avionics types.

sapper740 · #16 28-04-12, 11:55

Quote:

Originally Posted by Bob Phillips

Hey great idea to have a wireless forum!Now are there any radio experts that can tell me specifically ( not generally) how to build a 110volt AC power supply to run the receiver only on a MK3 set? I know it can be done and is straitghforward to those in the know. Any schematics available???

Back in the day they made original 110V AC powered Power Supply Units for the 19 Set. I sold the one and only one I have ever seen last year. It was very close in size to the standard Dynamotor equipped PS Unit except it was approximately twice as heavy due to the transformer and rectifier circuity inside. I'll see if I kept any pics of the unit and I'll post them if I find them.

CHEEMO!

Derek.

Bruce MacMillan · #17 28-04-12, 12:15

Many of the official AC supplies were built post war. Mine is dated 1952.

Yes, they are heavy due to the transformer. That is their weakness though. All the windings are on one core so when a winding shorts you have a very heavy boat anchor or tie down for aircraft. The rectifier tubes are also a problem as they short quite easily taking out a winding. I use mine with care bringing it up on a variac to 110V max.

The transformer is virtually impossible to rewind.

sapper740 · #18 28-04-12, 19:58

Here's a pic of the rectifier I had, made in 1950.

CHIMO!

Derek

Bob Phillips · #19 29-04-12, 05:58

So my question for those of you with technical/radio knowledge is.. can I run the receiver on 12 v ad 220-230 volts instead of 250 volts??? I stopped by at Sayal Electronics and there are several choices in transformers using 110 and producing 220-230 volts . Not so many choices at 250 volts (none locally) Anybody have any thoughts on this

Bob Carriere · #20 29-04-12, 06:13

..in thinking that the receiver works on 250 volts DC.......??

Hi Bob

In the old days we use to have huge heavy AC voltage regulators..... adjustable from 110 to 130 ...... so if one dialed 125 V steady and flowed it into a 2 to 1 step up tranformer you would have almost steady 250 AC volts output...(your amps reduced in half )... then you would need to convert to 250 DC.......

Another questions for the "Esspurts" ....... what voltage do the tube (valve)filaments run on the 19 sets....... 12 volts DC or the same source of 250 volts DC.?

It's been a long time since technical school....?

I still have a rotary transformer from a 19 set that my DAD used for burning is VAC initials on all his tools.

Bob

Bruce MacMillan · #21 29-04-12, 11:51

The receiver will work from about 200-265 vdc. The actual dc output voltage of the power supply depends on the transformer secondary and the type of rectifier/filter used. Besides output voltage the transformer should be rated at about 150 ma output current.

The MKIII vibrator portion generated it's receiver voltage from the battery. The output voltage would change depending on battery charge.

The filaments are run from 12vdc even with the power supply switched to 24vdc.

Bob Estabrooks · #22 29-04-12, 22:27

Just vewing the forum, I took my trg on the WS19 back in 1952 at Camp Utopia, N.B. I have forgot everything I learned. But I do have a transformer the same asthe one pictured by Derek, also dated 1950. Don"t know whether it works or not.

Bob

Bob Carriere · #23 02-05-12, 04:49

Look at this...... may already been converted to 110 V

http://www.ebay.com/itm/WWII-Signal-...item41653de675

Good luck

Bob C

universalgrl · #24 03-05-12, 05:01

That radio is heavily modified, the 'B' set and the intercom have been removed to make room for the power supply, and who knows how many other things have been done to the internals, it would be quite expensive to restore to factory specs.
If you are are looking for orignal don't waste your money, for a ham operator it's OK.

Peter Hommes · #25 10-01-13, 23:24

see circuit diagram how you can build one will easily fit into older WS19 PU housing

Peter
http://www.milmarket.org