My solution to RAM module wobble

Discussions about Sinclair ZX80 and ZX81 Hardware
Tackemon
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Joined: Fri Aug 20, 2021 6:53 pm

My solution to RAM module wobble

Post by Tackemon »

Dug out a TS1000 I had in a box that I bought at an antique store at least 25 years ago. It didn't come with a power supply, so I guess I never bothered with it. Well, for $8 on eBay I got a power supply and to my surprise, it fired up. Keyboard works fine. I then tried it with the RAM expansion and ran into some *serious* wobble. Like, it would boot if I held it tightly against the TS1000, but letting off my grip even a little would lead to Crash City.

So I 3D printed little shim/wedge/spacer, whatever you want to call it that puts some pressure on the bottom of the connector. Surprisingly solid so far, though the RF signal to a CRT is quite a bit nastier looking than without the module installed. Not sure what that's about.

I'm planning on messing around mostly with emulators, but of course seeing stuff working on real hardware occasionally is fun, so I don't need a more robust solution.

https://imgur.com/a/K7Hwgg2

I can post the STL, etc somewhere if there's interest. It's a simple shape that's just extruded the width of the module.
sboisvert
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Re: My solution to RAM module wobble

Post by sboisvert »

I've always wondered if that recessed slot at the bottom of the case next to the edge connector was meant to attach peripherals more securely (with screws) to avoid any wobble.
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1024MAK
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Re: My solution to RAM module wobble

Post by 1024MAK »

Myself and lots of other people have had similar thoughts. But no evidence has ever emerged. And this ‘feature’ does not exist on the later ZX Spectrum.

So who knows?

Mark
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Tackemon
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Re: My solution to RAM module wobble

Post by Tackemon »

sboisvert wrote: Sun Aug 22, 2021 2:42 am I've always wondered if that recessed slot at the bottom of the case next to the edge connector was meant to attach peripherals more securely (with screws) to avoid any wobble.
That seems like a fair bet. Would have been nice...
Neurogate
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Joined: Tue Aug 31, 2021 6:46 pm

Re: My solution to RAM module wobble

Post by Neurogate »

My solution is more simple - a piece of double sided scotch between RAM pack and ZX81, above of connector. You know - scotch can solve many problem in our life and it's one of such case.
Sinclair ZX81, Sinclair QL, Sinclair ZX Spectrum +2, Atari 130XE, Commodore 64C, Commodore C128, Yamaha YIS503IIIR MSX2 & etc
Spinnetti
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Re: My solution to RAM module wobble

Post by Spinnetti »

Upgrade ram internally, attach ram pack as an empty box on the back for looks? :)
Zeddy: ZX80, ZX81/ZXpand, TS1000/ZXpand, TS1500/Zxpand+
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Paul
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Re: My solution to RAM module wobble

Post by Paul »

Never thought about a dummy RAMPack. Nice idea.
In theory, there is no difference between theory and practice. But, in practice, there is.
Neurogate
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Re: My solution to RAM module wobble

Post by Neurogate »

Internal RAM mod and empty case is not authentic hardware solution, it's not like in 80s. As for me is better to tried save original hardware, because in other case is emulator enough.
Sinclair ZX81, Sinclair QL, Sinclair ZX Spectrum +2, Atari 130XE, Commodore 64C, Commodore C128, Yamaha YIS503IIIR MSX2 & etc
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1024MAK
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Re: My solution to RAM module wobble

Post by 1024MAK »

Spinnetti wrote: Wed Sep 01, 2021 2:48 am Upgrade ram internally, attach ram pack as an empty box on the back for looks? :)
Hmm, ZX computing for Dummies :lol:

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.
Neurogate
Posts: 24
Joined: Tue Aug 31, 2021 6:46 pm

Re: My solution to RAM module wobble

Post by Neurogate »

Next level - Raspberry Pi inside real ZX81 case, but I do not sure, that it will be Sinclair ZX81
Sinclair ZX81, Sinclair QL, Sinclair ZX Spectrum +2, Atari 130XE, Commodore 64C, Commodore C128, Yamaha YIS503IIIR MSX2 & etc
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