Spectrum + 128K with no toroid

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Lardo Boffin
Posts: 2160
Joined: Sat Nov 26, 2016 2:42 am

Spectrum + 128K with no toroid

Post by Lardo Boffin »

Hi all

I recently bought a toastrack spectrum and after opening it was surprised to see no toroid. I have only seen the insides of 4 or 5 of these so not sure if this is a common thing?

33895214-8136-4F6A-AAA5-DDB517D19AE1.jpeg

It does not obviously look like it has been removed. Although there was a repair / warranty sticker on it (not details though).

It works fine apart from a slightly jumpy video on RGB SCART on one of my TVs (most are fine). Research suggests it may be a similar issue to the ghosting on the +3 (https://spectrumforeveryone.com/technic ... compliant/)

I have seen a few photos of them minus toroid on Spanish websites.
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1024MAK
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Re: Spectrum + 128K with no toroid

Post by 1024MAK »

The toroid is actually part of a filter circuit to suppress noise escaping on the power supply input. The toroid would have had two windings on it. Only fitted where deemed to be needed...

The 128k, +2, +2A, +2B, +3 etc were never designed to control the SCART signalling pins...

They work fine if your telly can be manually controlled by a remote control or menu option (like one of mine 8-) ).

Otherwise you need to provide a proper +12V and a higher current 1.5V to 3V (to feed 75Ω input impedance). Either from an external supply or by making changes to the computer and the DIN to SCART lead or both.

Mark
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