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Author Topic: 12V coil (L1 on schematic) (Read 528 times)

Offline Witchy

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12V coil (L1 on schematic)
« on: 2017.August.23. 01:00:59 »
Hi folks,

One of my EPs has a dead coil so I've done what I normally do with ZX Spectrum coils and unwound it to remake it with new magnet wire, only to discover these coils use a thinner wire than 0.3mm. Since I don't have any calipers to measure this wire I have to send it off to a wire company so before I do...Questions:

: has anyone successfully remade one and if so what size wire did you use?
: is there a modern equivalent
: can I rewire this one in the same way I do Spectrum ones with the same turn ratio and 0.3mm wire? I'm ashamedly crap at maths to work this out for myself :)

There's one post here from 2014 where Zozo suggests replacing the entire 12V circuit which is easily done I guess but I'd like to rewind this coil if I can.

Cheers!
« Last Edit: 2017.August.23. 01:56:25 by Witchy »

Offline Zozosoft

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    • http://enterprise.iko.hu/
Re: 12V coil (L1 on schematic)
« Reply #1 on: 2017.August.23. 09:47:58 »
Unfortunately all parameters of this coil are unknow :-( Then hard to find replacement...

Are you really sure the coil are the dead? The most common failure in the 12V circuit the dried out C9 capacitor which are kill the TR2 transistor.
I only once found a dead L1, then it is replaced from a chip dead machine.
In a case when no donor machine available, then I will look for a 5V to 9V DC/DC converter. If i remember right few users done this.

But if you find a way for a repair or replacement then will be great!


Offline Witchy

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Re: 12V coil (L1 on schematic)
« Reply #2 on: 2017.August.25. 19:58:09 »
I thought it was dead because it wasn't buzzing :)

There's a specialist wire company not far from me that will gauge the thickness of the existing wire and sell me a spool of new stuff, rewinding them is fairly straightforward so I'll do that next week.

W