Power Supply switching between ZX81 & Speccy

Discussions about Sinclair ZX80 and ZX81 Hardware
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RetroMike
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Re: Power Supply switching between ZX81 & Speccy

Post by RetroMike »

:lol: I do however quite like the racy red stripe on the wire. ;)
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RetroMike
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Re: Power Supply switching between ZX81 & Speccy

Post by RetroMike »

I tested the lead with a multi-meter before trying it live, and you'll be apathetic to know that it works just fine Image The new plug on the Speccy lead also fixed its random resetting/going off problems Image
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1024MAK
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Re: Power Supply switching between ZX81 & Speccy

Post by 1024MAK »

My god man! :shock: You can't come here and use words like "new" here you know :lol:

And while we are on about such things, this is a hardware section on a retro computer forum, so drop the "apathetic" and post more old tech p0rn please... :?

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
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RetroMike
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Re: Power Supply switching between ZX81 & Speccy

Post by RetroMike »

:lol: ok... I will try. There's not much more I can do to the Zed now, but I'm currently girding up my loins to tackle the re-cap of my Speccy. I did my A1200 last night, which was quite fraught, mainly because most of the caps were SMDs and they were leaking, so I lost a couple of pads and had to botch a few with some wire. To my surprise it still works! :shock: All outside the purview of this 'ere forum, so I'll not bore you with the gory details ;)
gozzo
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Re: Power Supply switching between ZX81 & Speccy

Post by gozzo »

No need to 'recap' a speccy, at least, not all of it, just the around the DC-DC converter circuit, as that can be troublesome...
gozzo
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Re: Power Supply switching between ZX81 & Speccy

Post by gozzo »

ps. gold plated sockets/plugs can still give trouble with bad contacts.. ;)
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RetroMike
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Re: Power Supply switching between ZX81 & Speccy

Post by RetroMike »

:? Deep joy :roll: The Speccy is completely re-capped now, and working well, apart from a little shifting interference on the screen when I'm processing summit.

I'll bear in mind the gold-plated thing, but I thought that gold-plated was the bee's testiclons? Why is everyone going on about how good it is in hifi and computing :?:
gozzo
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Re: Power Supply switching between ZX81 & Speccy

Post by gozzo »

I had trouble with a gold plated SCART lead, had to brush the contacts with WD40 (not ideal, I know), and insert/remove several times to get it to work reliably (admittedly the socket in the TV was not gold plated, just a 'normal' one...did they ever make gold plated SCART sockets, never heard of any??), they probably ARE better than standard connectors, but not 'perfect' ..(is anything?! ;) )
gozzo
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Re: Power Supply switching between ZX81 & Speccy

Post by gozzo »

.. 'shifting' interference????.....
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1024MAK
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Re: Power Supply switching between ZX81 & Speccy

Post by 1024MAK »

Gold plated connectors are only an improvement if both the male and female connectors are gold plated.
Gold is an excellent conductor and is normally non-reactive.

However, when any dissimilar metals are in contact, sometimes a reaction can occur which increases the contact resistance at the junction between the contacts. A damp environment, or a situation where large or rapid temperature changes (which allows water vaper in the air to condence on the cooler metal parts) take place can also help to cause or speed up the problem.

There are gold plated female / sockets available. However, you will not find them on most consumer electronics products for cost reasons.

And by the way, some industrial users fall for the same spin that some audio hi-fi buffs fall for. In my line of work, we regularly have to clean connection contacts on equipment that has gold plated contacts, but the base it plugs into has tin plated contacts. We find a white deposit forms on both contacts.

Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp

:!: Standby alert :!:
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb :!:
Looking forward to summer later in the year.
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