General Stuff(tm)

[exxos]

Progress :)

[rubber_jonnie]

So do you need to use fishplates at the join? Or will that not work with the join.

[stephen_usher]

So do you need to use fishplates at the join? Or will that not work with the join.

No fishplates. The idea is that the special sleepers are soldered to the rails and strongly fixed to the baseboard so that when the rails are cut they keep their relative positions. The aligning pins and cups on the the baseboard ends then make sure the two boards are accurately aligned. The two rail ends are powered by dropper wires on their respective baseboards.

[HigashiJun]

Can't wait for the final result !

[rubber_jonnie]

So do you need to use fishplates at the join? Or will that not work with the join.

No fishplates. The idea is that the special sleepers are soldered to the rails and strongly fixed to the baseboard so that when the rails are cut they keep their relative positions. The aligning pins and cups on the the baseboard ends then make sure the two boards are accurately aligned. The two rail ends are powered by dropper wires on their respective baseboards.

Neat, sounds like a neat way of doing it :)

[stephen_usher]

Today I wired up all the tracks and did a little bit of planning for the landscaping. Eventually the interconnection plugs/sockets arrived from Amazon so I was able to run the first test...





Success!

I still have to work out how to wire up the accessory decoder so that I can control two of the points and two signals.

[stephen_usher]

A little diversion from the model railway...

On Thursday I took a trip up to West Cambridgeshire to meet with an old school friend who gave me his and a mutual friend's ZX81s plus a few manuals.

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Amazingly two of the three ZX81s actually worked and the keyboard membrane on the hacked up top cover could be made to work!

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There was also in the boxes a ZX81 sound card.

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I've also been restoring a Waltham cassette recorder, the same model as my original (which has a bad amplifier amongst other things) and my Uncle's which I used after mine stopped loading programs. This morning I finally completed the refurbishment and tested it on a Spectrum... All good!

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Unfortunately one of the ZX81s, the least messed about board, stopped working so I spent most of today trying to diagnose the issue. After hours and hours I traced it down to the ROM socket. It was a strange dual wipe socket but with uncoated brass contacts. Obviously they'd become tarnished and weren't making contact. Also, as I had quite a few 32Kx8 SRAM chips I installed an internal 16K RAM upgrade on the machine. All working now.

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I'm now printing a new lower case for the machine as it didn't have one in the box.

[rubber_jonnie]

Nice haul 😁

[PhilC]

Interesting haul.

Those ZX81s make you go back to basics when it comes to fault finding.

[mrbombermillzy]

Good bit of kit you picked up. Soundcard looks interesting. I love the home made kb. :)