Power Supply switching between ZX81 & Speccy

[RetroMike]

I do however quite like the racy red stripe on the wire.

[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 The new plug on the Speccy lead also fixed its random resetting/going off problems

[1024MAK]

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

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

[RetroMike]

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! All outside the purview of this 'ere forum, so I'll not bore you with the gory details

[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]

ps. gold plated sockets/plugs can still give trouble with bad contacts..

[RetroMike]

Deep joy 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]

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]

.. 'shifting' interference????.....

[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