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Author Topic: Navy MAK and the HY1269  (Read 26040 times)
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KA3EKH
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« on: May 24, 2019, 10:05:48 AM »

So a WW2 Navy model MAK 25 watt HF AM transceiver followed me home from Dayton. Been looking into using it for a portable 3.885 transceiver at various field nets and the like with others who are using things like BC-611, pogo Stick and other WW2 AM transceivers. Think it’s a good choice being it relatively small and low power and built to work with a short vertical antenna. In the process of building external Dc to DC converter power supply that will probably attach to the back of the radio out of sight and run everything from twelve volt DC source.
Lot of this is easy, being the filament strings are already configured for twelve volt operation, all the tubes in the receiver are twelve volt like 12SK7, 12A6 and the like and figure the receiver will work just fine at around 180 to 190 volts DC for the plates but the real question is what’s going on in the transmitter.
The transmitter is a four channel crystal control using a 12A6 as the oscillator that drives a HY1269 PA tube, that tube is plate modulated by two more HY1269 tubes in parallel.
This is my first exposure to the HY1269 tube and it appears to me to be a quick heating power pentode rated at 30 watts, 750 volts max DC plate at a max current of 120 MA.
Just playing around with lighting up the filament string at eight or ten volts the filament appears to be real bright. Looking at the specs I can find it shows the tube can be used at six or twelve volts with a center taped filament. The filament, cathode and suppressor grid are all tied together internally in the tube. All three tubes have their suppressor filament center taps tied together decoupled to ground thru a capacitor but also a variable resistor is involved with that circuit. From what I can determine the whole mess was feed from the common DC input with a separate switch that powered the transmitter section by itself that brought in a relay to power up the filament string and the dynamotor for the high DC voltage was activated by the PTT line.
First question: How bright are the HY1269 tubes supposed to burn? They light up real bright, almost like light bulb filaments at ten volts and being that it’s hardly the most common tube don’t want to risk burning open any of them.
Second question: what should I plan for a plate voltage for the transmitter? I figure it’s going to be around 400 DC or should I be higher? Maybe something like 500 or 650 DC being the tube is rated good to 750?
Attached is the only schematic I have been able to come up with and it’s not very good. The key thing here is to build up an external power supply but not one that puts the tubes in danger, will also be looking at things like the voltage ratings of all the bypass capacitors and the plate coupling capacitor and thinking maybe the key maybe too go with half the rated voltages?



* mo1-mak-03.jpg (102.78 KB, 480x640 - viewed 900 times.)
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PA0NVD
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« Reply #1 on: May 24, 2019, 11:40:27 AM »

The HY1269 seems to have an 8 V filament!!!
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KA3EKH
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« Reply #2 on: May 24, 2019, 01:53:02 PM »

I saw that but have also seen it listed as a 12.0, not 12.6 volt tube. It’s a very strange bottle. Assuming that has something to do with being able to turn the transmitter on separate from the receiver and not having to wait to transmit?
The base is the same as an 807! Wonder if I can stuff three of them in there and run them at 6.3 volts?
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PA0NVD
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« Reply #3 on: May 25, 2019, 10:20:28 AM »

you may use a 2E22, same connections and appearance and 6.3V fast heating. They are used in the final of the AN/GRC9
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W2PFY
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« Reply #4 on: May 25, 2019, 01:43:11 PM »

Is it possible for you to post a clearer picture of the schematic or suggest a place where I could download it? As far as the filament brightness is concerned I would bring one of the tubes up on a filament transformer connected to a variac to the rated voltage of 6 volts to see how bright it should look. (I know it runs on 12 volts as well) Then compare how it looks in the rig. If its way brighter, something is wrong. My experience with quick heating filament tubes, is that they run at an orange to yellow color but never white hot.
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KK4YY
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« Reply #5 on: May 25, 2019, 02:04:21 PM »

Unless you're a purist, give some thought to replacing the HY1269's with 1625's. Change the tube sockets, do a bit of re-wiring, and save a total of 40 watts heater power. Those HY1269's will eat your battery for lunch!

Don
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« Reply #6 on: May 25, 2019, 02:39:15 PM »

Quote
Those HY1269's will eat your battery for lunch!

If he is going to run it off a battery, 1625 tubes would be a bad choice if your doing push to talk, therefore the reason for instant heating filaments. But after re-reading his post and unless I missed it, I didn't see any mention of operation from a battery? Then again, I am somewhat a Mr. Magoo........
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« Reply #7 on: May 25, 2019, 06:24:33 PM »

The 2e22 uses less filament power than the 1625, is 6.3 Volts and has the same connections and dissipation as the HY1269, so no chages. It is a very similar tube as the HY1269 except the filament.
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KK4YY
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« Reply #8 on: May 25, 2019, 07:54:58 PM »

I get it now. The HY1269's are part of the PTT circuit and heat "instantly" at key-down. D'oh!

The thing that looks weird to me is that the radio may use the HY69 (6v) or the HY1269 (12V) depending on source voltage, yet G3 is connected to the fil CT on the HY1269 and not on the HY69. Best to make sure the correct schematic is used, if there's more than one.


Don
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KA0HCP
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« Reply #9 on: May 25, 2019, 08:50:40 PM »

http://www.navy-radio.com/xmtr-ww2-port.htm

Link to navy radio site.  Scroll down to "MAK".
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« Reply #10 on: May 25, 2019, 11:23:04 PM »

Quote
The 2e22 uses less filament power than the 1625

RISKING A HIJACK HERE. That 2E22 tube has always intrigued me with its massive plate?? The hi fi guys have done some projects with it and while it preformed ok, they didn't go nuts over it which is a good thing! I know of no other tube that has a such physically large plate area in its category? I wonder if it could take a piss beating atomic yelllooooww and not melt with about 1000 volts on the plate in a triode connected modulator circuit?

Now back to your regular reading pleasure..............
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« Reply #11 on: May 26, 2019, 12:35:52 AM »

looks like same poor resolution. Why do people bother to scan/photograph anything just to create something like that? Oh well. I like to read schematics. It's fun when they are of good quality.
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« Reply #12 on: May 26, 2019, 01:27:24 PM »

looks like same poor resolution. Why do people bother to scan/photograph anything just to create something like that? Oh well. I like to read schematics. It's fun when they are of good quality.

I just grabbed the schematic photo off eBay back when someone was selling the manual. eBayers often have unfocused close-ups. Then again, he was just trying to sell the manual, not provide us with a copy for free. If I had a manual I'd scan and post it here -
http://www.navy-radio.com/manuals-equip.htm
cheers,
Nick

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KA0HCP
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« Reply #13 on: May 26, 2019, 03:11:27 PM »

Thanks for your work Nick.  Its good to see that a schematic exists.  bill

I just grabbed the schematic photo off eBay back when someone was selling the manual. eBayers often have unfocused close-ups. Then again, he was just trying to sell the manual, not provide us with a copy for free. If I had a manual I'd scan and post it here -
http://www.navy-radio.com/manuals-equip.htm
cheers,
Nick


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« Reply #14 on: May 26, 2019, 06:45:20 PM »

I'm a little confused? Is there an actual schematic posted on these pages?
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« Reply #15 on: May 26, 2019, 10:56:53 PM »

I'm a little confused? Is there an actual schematic posted on these pages?
Yes, there is. I posted a link to navy radio page, above.  Scroll down to the "MAK" radio. Photo is there of double page schematic.  It is essentially unreadable, but here it is:

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KK4YY
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« Reply #16 on: May 27, 2019, 09:08:08 AM »

Maybe this is a little easier to read...


* mo1-mak-03_a.png (902 KB, 640x480 - viewed 876 times.)
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« Reply #17 on: May 27, 2019, 10:16:18 AM »

Thanks for the image processing!
Is it OK if I put your version on my web page?
Nick
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« Reply #18 on: May 27, 2019, 01:31:23 PM »

looks like same poor resolution. Why do people bother to scan/photograph anything just to create something like that? Oh well. I like to read schematics. It's fun when they are of good quality.

I just grabbed the schematic photo off eBay back when someone was selling the manual. eBayers often have unfocused close-ups. Then again, he was just trying to sell the manual, not provide us with a copy for free. If I had a manual I'd scan and post it here -
http://www.navy-radio.com/manuals-equip.htm
cheers,
Nick

Oh sorry I mistook the purpose of it. It has a lot of good pictures.


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KA3EKH
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« Reply #19 on: May 27, 2019, 02:17:26 PM »

Schematics are a luxury! Have to use what’s available. If I wanted easy would do something like an ARC-5 or for that matter a Bofoung. But the MAK is a strange little radio that I feel will be ideal for field operation on 3.885 and building up a power supply for field operation won’t be a big deal. The three tubes suck down around 4 amps when lit and that will be an unusual load for the battery to deal with but not an insurmountable problem. Most of the time is spent receiving anyway and with the separate switches for receiver and transmitter power can keep the transmitter filament off until needed.
Going to start with using a little solid state power supply left over from another project that will provide about 220 volts for the receiver and oscillator and around 400 for the plate of the transmitter. This power supply was from a Narco aircraft radio and also has a high level modulator included and may use that as a external modulation system and remove the two tubes in the transmitter that were used in parallel as modulators.
The transmitter is using Hessing or something like that modulation where the modulators load down the plate voltage of the PA to produce modulation but the original design requires an external modulation reactor and it may be best to dispose of the original modulation system and just modulate external. Will have to run at reduced power of maybe five watts or so but remember that this radio will be used primarily at events for short range to net with other field radios from WW2 so don’t need high power.
The other idea would be to use a hissing or what ever its called modulation reactor external of the radio but finding just such a transformer may be an issue as opposed to a regular external modulation transformer.
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KK4YY
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« Reply #20 on: May 27, 2019, 06:43:54 PM »

Thanks for the image processing!
Is it OK if I put your version on my web page?
Nick

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« Reply #21 on: May 28, 2019, 08:12:36 AM »

I wonder how bigga battery needed for a Timtron transmission ?
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« Reply #22 on: May 28, 2019, 03:02:30 PM »

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I wonder how bigga battery needed for a Timtron transmission ?

NO battery needed! His QSO's are powered by the farts & belching that are customary in his QSO's Cheesy Cheesy Cheesy i.e gas =
methane=internal combustion engine=generator in parallel with Maine Power makes his QSO's self sustaining.
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« Reply #23 on: May 28, 2019, 06:31:56 PM »

Quote
I wonder how bigga battery needed for a Timtron transmission ?

NO battery needed! His QSO's are powered by the farts & belching that are customary in his QSO's Cheesy Cheesy Cheesy i.e gas =
methane=internal combustion engine=generator in parallel with Maine Power makes his QSO's self sustaining.

I'd always imagined copper and zinc plates hung in a spittoon.
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« Reply #24 on: May 28, 2019, 07:24:19 PM »

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I'd always imagined copper and zinc plates hung in a spittoon.

As a matter of factor, I found a brass spittoon probably made in India and gave it to him on one of my visits. I envisioned it to be filled with some ungodly mixture of bacterial goodness but alas, his wife made a planter out of it per Tim Huh Huh Huh
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