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 Healing short wave converter
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 Return to top of page · Post #: 1 · Written at 8:56:15 PM on 1 March 2010.
Phil Storr's Gravatar
 Location: SA
 Member since 30 April 2006
 Member #: 39
 Postcount: 33

G'day folks
At our local HRSA auction last Sunday I picked up a Healing model 15E chassis in very poor shape but it looks like it is all there except the dial and the valves.
My guess is the valves are a 6F8 converter and an 80 rectifier.
When I bought it I was intending to use the power transformer in another project but perhaps it is worth seeing if I can at least get it to work.
The chassis is crude, a metal U with two wood ends !

Anyone out there have any information on this item ?


 
 Return to top of page · Post #: 2 · Written at 12:09:07 AM on 2 March 2010.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3796

Need a little more info on that, it sounds early. How many valves with what pins eg 80 is a UX4

If it's around mid thirties it could be an Autodyne converter. which means that it will probably use pentodes as a converter. Pentagrids did not come into being until just before WWII.

These were often (EMMCO) advertised as Screen grid radio's.

Possibly 57,58 57, 2A5 80. Perhaps a 56 as the oscillator.

After that we get the 8 pin sockets.

For a SW I would expect 6J8, 6K8, or 6SA7 with seperate oscillator.

6F8 is a Twin Triode Audio valve. They may have used 6F7 But it's not a good SW valve albeit that it is a triode pentode.

Marc


 
 Return to top of page · Post #: 3 · Written at 1:43:42 PM on 2 March 2010.
Phil Storr's Gravatar
 Location: SA
 Member since 30 April 2006
 Member #: 39
 Postcount: 33

G'day folks
Curiosity got the better of me last night and I dived into the insides of the 15E and have a bit more information from the previous owner.

The original converter valve was an AK2 with the side contact english socket. Looks like the conversion to a 6J8 happend in the 50's.
I suppose the AK2 was rare even then.

The original chassis mounted electro had been replaced with one of that era and it is obvious the converter socket was changed then.
The rewiring was done in a mixture of single core mains wire and telephone wire.

I have a couple of AK2's and if one is OK will put a side contact socket back in and see how well it works.

It only has two valve sockets and as the rectifier is a four pin socket it must have been an 80 or 280 etc.

I will put some photos and the circuit on my web site soon.


 
 Return to top of page · Post #: 4 · Written at 4:36:53 PM on 2 March 2010.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3796

AK2 is a philips "P" Based Octode. I wonder why a 6J8, need to see circuit. 6J8 would behave diferently risking destablising, albeit that it is a SW tube. Someone was possibly going for better performance.

6J8 is a Triode Heptode

80 & 280 same animal they changed the numbering system in 1930 & dropped the 2.

Should not be too difficult to get noise out of, if you have the original circuit.

Marc


 
 Return to top of page · Post #: 5 · Written at 4:53:42 PM on 2 March 2010.
Phil Storr's Gravatar
 Location: SA
 Member since 30 April 2006
 Member #: 39
 Postcount: 33

G'day folks

I looked up AK2 and it could have been an AK2 except the hole in the chassis was not big enought for the English side contact socket.

Asked the last owner again and he was sure it was an AK2
His reply was, perhaps it was a version that had a conventional socket !

I looked up the AK1 and sure enough, we have a match. This tube was first made in 1933 and this is about right.

This tube has a four volt heater and I have discovered evidence to support this.

The evidence is a flat wire wound resistor lying unused in the chassis.
There is a similar one in series with the dial lamp !
The unused one is two of the above connected in parallel.
The wire to one side of the converter heater was a new bit of telephone wire.
The other side was a bit of the original cotton covered stuff.
When the tube was changed and the resistor bypassed the original wire would have been too short.

All I need now is an advert for it so I know what frequency (wave lenght) it covered.

I did follow the suggestion from Marc that it may have been an Autodyn circuit and I looked into the possibility it had used a 36, a 77 or even the 2.5 Volt 57 tube.


 
 Return to top of page · Post #: 6 · Written at 7:10:19 PM on 2 March 2010.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3796

With one active valve there is every chance in that era that is was regenerative. However without seeing the circuit?

With AK1 being a frequency converter and having an oscillator grid (G1) there is still a possibility of Superhet., to be really successsful that would perhaps, need an IF transformer ?

AK1 has two bases listed viz. American Medium shell 7pin, or European 7 pin base. These are not the same layout. The American one is distinct by having two big pins (1&7) which are the heaters and the pin layout is virtually a ring array, in 7 fairly even divisions.

It is good to see research into what you have, rather than the common turn it on to see if it goes mentality, that kills sets & risks damage.

We, unfamilaiar with 15E, do need the circuit to make comment of any accuracy, rather than speculate

On that: It was quite common in amateur radio to have converters from higher frequencies, to those that the radio they had could handle. This could well be, one of these. Perhaps taking the 31 Metre band (most used) and have it exit at BC band?

I would therefore, not overlook Ametuer Radio, or DX publications in my reasearch.


Marc


 
 Return to top of page · Post #: 7 · Written at 10:41:17 PM on 6 March 2010.
Dial Cover Guy's Gravatar
 Location: Armidale, NSW
 Member since 20 December 2009
 Member #: 589
 Postcount: 71

Hi all,

I recently picked up a Lekmek 533i console 7 valve.

Nice unit this one. Needs alot of TLC but should be able to get it back to its glory days. Has a big 4 gang tuner and then on the inside of the chassis it has another small fine tuning gang.

I am having trouble finding info about this maker. I am also having trouble finding a circuit diagram for this model 533i. If anyone has any info on Lekmek and on this particular model I'd like to hear from you. Also if anyone has a circuit diagram my email is peter_i.hotmail.com.

Cheers
Peter


 
 Return to top of page · Post #: 8 · Written at 10:30:14 AM on 7 March 2010.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3796

Lekmek Radio Laboratories, 75 William St, Sydney.
Proprietor NS Gilmour, Cheif Engineer J Paton.
Registered 1931 in Sydney.

Did not go for all that long.

Marc


 
 Return to top of page · Post #: 9 · Written at 10:20:52 PM on 23 May 2010.
radiola49's Gravatar
 Location: Maryborough, VIC
 Member since 8 December 2007
 Member #: 204
 Postcount: 36


Speaking of Lekmek, brings to mind that they made short-wave converters in 1934:-
model 101 1 valve AC Shortwave converter 585kHz.
model 102 1 valve battery Shortwave converter 585kHz.
These obviously got their B+ and Heater/Filament supply from the receiver they were feeding the 585Kc/s into.


 
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