Zener Diode Heat Sink

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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Zener Diode Heat Sink

Postby Mick D » Thu Nov 05, 2020 1:32 pm

Hi

Being a bit of a traditionalist I'll be using a zener diode in the charging circuit of my 65 G15CSR. I know most folk defer towards more modern regulator/ rectifier systems but I wonder if anyone has an original heat sink lying around that they could photograph and dimension to enable me to make one.

From Bacon it looks like two square / rectangular plates and some spacers so easy enough to make, just like to get the dimensions correct.

Regards Mick

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Re: Zener Diode Heat Sink

Postby ajscomboman » Thu Nov 05, 2020 2:00 pm

I chopped mine up! You could have had it otherwise. I'm all for adopting modern tech as I don't have faith in 60's technology plus AGM batteries are quite sensitive to charge rates.

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Re: Zener Diode Heat Sink

Postby g80csp11 » Thu Nov 05, 2020 3:02 pm

1969 G15CSR.jpg


If its the same as my G15CSR and P11 , they are round aluminium discs separated by a thin spacer
I have then fitted by not connected and run a Podtronics rectifier unit
Its mounted under the front of the petrol tank on the fixing that is also used for steering damper
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Re: Zener Diode Heat Sink

Postby Rob Harknett » Thu Nov 05, 2020 3:06 pm

http://archives.jampot.dk/technical/Ele ... ulator.pdf
I have a finned heat sink on my 63 G12CSR the above shows just a flat plate.

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Re: Zener Diode Heat Sink

Postby g80csp11 » Thu Nov 05, 2020 3:26 pm

the 64 parts list has 030042 listed for the plates , and carry forward to 1965
Norvil have then listed but i cant see a picture
1966 onwards is different part no 032018 (round)

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Re: Zener Diode Heat Sink

Postby Mick D » Thu Nov 05, 2020 3:32 pm

Hi Rob

Was yours square / rectangular like Bacon pages 98 and 161 or circular as per Peter's?

Peter, any chance of a couple of close ups when you get a chance so as I can see how it's mounted, is it attached to the same point as the head steady?

Regards Mick

Edited to add: Crossed post Peter, making more sense now, guess I should have rectangular plates - close up of the mounting would still be helpful though.

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Re: Zener Diode Heat Sink

Postby Rob Harknett » Thu Nov 05, 2020 6:12 pm

Mick D wrote:Hi Rob

Was yours square / rectangular like Bacon pages 98 and 161 or circular as per Peter's?

Peter, any chance of a couple of close ups when you get a chance so as I can see how it's mounted, is it attached to the same point as the head steady?

Regards Mick

Edited to add: Crossed post Peter, making more sense now, guess I should have rectangular plates - close up of the mounting would still be helpful though.


Mine is like half an egg, diode fits in the middle, I fitted it facing forward via the twin head steady screw into the threaded hole in the bottom.
I scanned a spare I have below, too lazy to get the camera out. I do not have the bacon book to see the picture you refer to.
front.jpg

bottom.jpg

back.jpg

here you can see a pic on e bay https://www.ebay.co.uk/itm/Zener-Diode- ... SwuAVcfT2t
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Last edited by Rob Harknett on Thu Nov 05, 2020 6:20 pm, edited 1 time in total.

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Re: Zener Diode Heat Sink

Postby Mick D » Thu Nov 05, 2020 6:19 pm

Thanks Rob

That's the one I have fitted to my T160V, the Bacon photos are more akin to the Lucas illustration you linked.

Regards Mick

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Re: Zener Diode Heat Sink

Postby Rob Harknett » Thu Nov 05, 2020 6:25 pm

Yes I have seen it listed as Triumph Mick, I guess the flat one I linked would be correct. Perhaps depending on year of bike.
It looks quite neat on my bike.

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Re: Zener Diode Heat Sink

Postby clive » Thu Nov 05, 2020 7:34 pm

My 67 G15mk2 has 2 circular flat plates which bolt to the same place as the head steady. Given what i know about the bike its likely to be original spec. The garage is off site so you will have to wait until i take my daily exercise in that direction with the mag in my pocket as it needs refitting. I will try to take some photos.
clive
if it ain't broke don't fix

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