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Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment. |
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3rd Jun 2010, 8:06 am | #1 |
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Lafayette HE-40 receiver
Hello all, I came to this forum via a web search for information on the Lafayette HE-40. A friend of my sister left the non working radio for me as she mentioned that I hold a licence. I would appreciate any data that is available regarding test points, circuit diagrams etc.
Thanks in advance, Bill. |
8th Jun 2010, 8:30 am | #2 |
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Re: Lafayette HE-40 receiver
Well it looks as though I've drawn a blank on this one, I searched Paul Stenning's lists for a service sheet but it returned no results, I saw one for $20 dollars in America, but since my valve days are long gone with the acorn valves and RSC kits the hard wired Japanese box will be relegated to the recycling centre. Shame because it fires up and the audio amp is functional.
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8th Jun 2010, 10:28 am | #3 |
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Re: Lafayette HE-40 receiver
Hi Bill,
I'd hold fire a while longer as you've only given it a few days, including a weekend, for members to respond. You've now posted an image and this may jog memories; someone may even offer to fix it up for you. |
8th Jun 2010, 11:13 am | #4 |
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Re: Lafayette HE-40 receiver
A quick look around the web suggests that this radio is near enough the same as:
Star SR-40, Monarch HAM-1, Hallicrafters SW-500, S-120 and WR-600. Try searching for info on those. It seems to be a fairly standard 'AA5' with 150mA valves and a selenium rectifier, but with shortwave bandspread. Many of the cheaper 'American' receivers from this period were just badge-engineered Japanese designs, often from Trio-Kenwood. |
8th Jun 2010, 12:09 pm | #5 |
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Re: Lafayette HE-40 receiver
There are a few pictures of an HE-40 here:-
http://www.videokarma.org/showthread.php?p=2969309 I had one a few years ago but sold it, quite a basic thing and not a great performer... . Regards, Mick. |
8th Jun 2010, 1:47 pm | #6 |
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Re: Lafayette HE-40 receiver
There are a number of clones as suggested. I have a Vestitone CR150 [identical to the Lafayette] and a Monarch. About £10 each. I think the "Star" looks the same as well. Mick is right that these are basic sets but really, it's all there as a stripped down comms set [no RF stage though].
Doesn't deserve to be scrapped Bill. In the 60/70's I would have regarded them as an expensive chain store item when you could get a bit of superior ex-govt kit much cheaper. I'm not very technical but a friend of mine had one and" tweaked" the BFO getting good SSB results. I think the "injection" was via a piece of wire sticking out into the next stage which he moved for best results and also stabilsed the power supply. I've an idea that I have seen a circuit diagram and article somewhere, either in PW or one of the vintage radio mags. Hang fire or sell it on here. Cheers, Dave W. |
8th Jun 2010, 3:23 pm | #7 |
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Re: Lafayette HE-40 receiver
Thanks everyone for all the responses including the messages, I'm rusty and can't see a metal rectifier, there's a valve 12AV6 next to a large electrolytic and this one has a winding not shown in the photos that Mickjjo linked(thanks ) It is Japanese -they even stamp the chassis with the valve identities next to the valve bases! Also on a label on the hardboard back panel. (wouldn't get a CE mark these days.)
Following all the advice I will hang on to it for a while. Last edited by Brian R Pateman; 8th Jun 2010 at 5:31 pm. Reason: Large images converted to thumbnails. |
8th Jun 2010, 6:31 pm | #8 |
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Re: Lafayette HE-40 receiver
If I've managed the attachment process there should be a schematic for the Hallicrafters SR-120. Not great quality but should be readable.
I spent ages trying to find a schematic. This is the only one I've been able to find. Hope it helps. |
8th Jun 2010, 7:28 pm | #9 |
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Re: Lafayette HE-40 receiver
I can't see a rectifier in your photos, but it ought to be somewhere near the mains transformer and smoothing electrolytic. There are only four valves visible: these will be freq changer, IF amp, detector/audio and audio output. Maybe the rectifier is underneath - if it is silicon it might be quite small.
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8th Jun 2010, 7:58 pm | #10 |
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Re: Lafayette HE-40 receiver
A little rough but may help, I have attached schematic and some alignment info.
Les
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9th Jun 2010, 7:51 am | #11 |
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Re: Lafayette HE-40 receiver
Well - thanks to you all for the help -
Kibble-the schematic is fine thanks. G8HQP Dave - thanks for the info regarding the valves. I'll have to put a better pair of glasses on in my search for a rectifier. Top Cap -Les, all that info should be very useful. Last evening I just checked mains voltage at the winding, it feeds 110V to the solder tags. Obviously just adapted from the American market. So now I've got some exploring to amuse me thanks to you all. |
9th Jun 2010, 11:32 pm | #12 |
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Re: Lafayette HE-40 receiver
I think this uses an auto-transformer with series heaters. Not sure if the chassis is live or whether it uses the American convention of a bus-bar earth return isolated from chassis via a capacitor. I think I had one of these or something very similar about 40 years ago as an introduction to shortwaves. I don't see a BFO in any of the circuits but the one I had definately had one...a 12AT6 valve I think.
I got much better results from a home-brew set I built a few years later that had an RF amp, Q multiplier and a product detector. SB.
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10th Jun 2010, 10:21 am | #13 | |
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Re: Lafayette HE-40 receiver
Quote:
I have identified a blown resistor just below the signal meter pot in my photo, outlined in yellow, which (from the schematic kindly provided on this forum) appears to feed from the second IF transformer into the grid of the 50C5. On the circuit diagram it is shown as 300ohms. I looked in my old box of valve related components, but no luck with one of that value. I will try local TV shops and if no joy -then a 20 mile trip to Maplin. I don't know if the burnt out resistor is cause or effect? Bill |
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10th Jun 2010, 11:53 am | #14 |
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Re: Lafayette HE-40 receiver
You'll be lucky to find a 300R resistor. 270R and 330R are widely available substitutes.
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10th Jun 2010, 12:22 pm | #15 |
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Re: Lafayette HE-40 receiver
Hello,
Not sure what wattage is needed (probably not very high), but there are quite a few 300 ohm resistors on eBay. Usually need to buy more than one though. Or you could make up the value from two other values in parallel or series. Michael |
10th Jun 2010, 12:48 pm | #16 |
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Re: Lafayette HE-40 receiver
Couple of 150 in series or 470/820 or 330/3300 in parallel should do nicely.
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10th Jun 2010, 9:02 pm | #17 |
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Re: Lafayette HE-40 receiver
Is that resistor the HT feed to the IF amp V2, which just happens to come from the screen grid of V4? It shouldn't be getting hot, so is there a short somewhere around V2?
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10th Jun 2010, 11:14 pm | #18 | |
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Re: Lafayette HE-40 receiver
Quote:
That 50C5 is just the output valve surely? Maybe the BFO is shown separately on another circuit. SB
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11th Jun 2010, 11:51 am | #19 |
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Re: Lafayette HE-40 receiver
Well there definetely is a BFO Side B [an appropriate enquiry for you I think]. The circuit Kibble found for us is not very clear but the valve prior to the output stage seems to be single function or am I wrong? The one from Les has a 12AV6 Double Diode Triode at that point-quite a lot in one package and associated with Det/Agc and Pre-amp functions so this must be a candidate for the BFO. My understanding grinds to a halt here but I seem to remember my friend [post6*] saying how basic it all was. Back to the piece of wire perhaps!
Dave W |
11th Jun 2010, 12:48 pm | #20 |
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Re: Lafayette HE-40 receiver
Squinting at the circuit suggests that the BFO function is done by letting the IF valve oscillate. The pot connected to the suppressor grid presumably has some control over the oscillation level Something like a self oscillating mixer I guess. Given the obvious cost consciousness of the whole thing (AC/DC no transformer) adding another active component for the BFO would not have appealed.
Reminds me of the first SSB I ever copied using a domestic set with the IF made to oscillate using a coax cable tickler and a pot in the cathode circuit to control things. (ISTR the idea was in PW or Wireless Constructor cometime during the 60's).
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