520ST PSU Remake

Repairs & upgrades.
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rubber_jonnie
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Re: 520ST PSU Remake

Post by rubber_jonnie »

This will be important going forward :)
Power_In.jpg
Power_In.jpg (11.79 KiB) Viewed 5025 times
I have the machine running on 5v at present, but having traced the 12v lines, they're definitely connected, so I think the machine needs 12v to run properly.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
tzok
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Re: 520ST PSU Remake

Post by tzok »

As far As I remember it needs +/-12V solely for UART (RS232/MIDI), and of course +12V also for floppy. Good thing is, a custom PSU may have two plugs - one for ST and one for SF floppy.
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rubber_jonnie
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Re: 520ST PSU Remake

Post by rubber_jonnie »

tzok wrote: Wed Mar 27, 2019 6:21 pm As far As I remember it needs +/-12V solely for UART (RS232/MIDI), and of course +12V also for floppy. Good thing is, a custom PSU may have two plugs - one for ST and one for SF floppy.
Indeed, I did trace the 12v lines to the UART. I don't have an external SF, but I do have an external DATEL drive, which I could power from the PSU no problem, so something I'll certainly consider.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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rubber_jonnie
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Re: 520ST PSU Remake

Post by rubber_jonnie »

Adding to the list of parts, I now have 2 of these: https://www.ebay.co.uk/itm/Black-Power- ... 2749.l2649 at a cost of £2.39.

Internal diameter is 6.5 mm. The original case design on Thingiverse called for white, but I'll be printing in black, since that's the filament I have, and I think its closer to the original Atari PSU.

I've also bought 2M of this: https://www.ebay.co.uk/itm/12V-24V-2-3- ... 2749.l2649 at a cost of £4.39.

I've gone for 4 core cable, since there are 2 shared 5v pins and 2 shared GND pins, so only 4 wires are needed, plus at 14A it is way over the spec of what the PSU can deliver.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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rubber_jonnie
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Re: 520ST PSU Remake

Post by rubber_jonnie »

So, here it is in all it's glory!

Todays work involved making the Molex plugs up for the mains in, and the power out lead, which was a Molex plug on the PSU end of the lead, and the 7 pin DIN plug.
IMG_20190406_160158.jpg
IMG_20190406_160158.jpg (299 KiB) Viewed 4952 times
All required voltages were tested at the plug prior to connecting and powering up, but all is 100% fine, so I just need to print the case, do the final assembly and the job is done.

Here it is powered uo:
IMG_20190406_160041.jpg
IMG_20190406_160041.jpg (232.25 KiB) Viewed 4944 times
Total cost of parts so far has been £49.63. I reused an old mains lead that I had that was surplus to requirements, so if you add the cost of that and the 3d Printed case, plus the DIN plugs I already had, the total price is about £55.

So far the only snags I've hit are that I ordered 2 pin Molex plugs for the mains lead connection. Wrong, it has 2 pins, but is spaced for 3 pin, so I cut down one of the 6 pin plugs I had to get around that. The other was the 7 pin DIN plug. The black plastic sheath that goes around it is too long, but the solution is simply to cut it down with scissors or a knife by about 10-12mm, which is enough to allow the plug part to protrude enough to plug nicely into the Atari power jack.
Attachments
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Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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rubber_jonnie
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Re: 520ST PSU Remake

Post by rubber_jonnie »

With a bit of tweaking, I have shaved and hour of the print time for each the case halves.

Files are attached and will also go into the 3d models section.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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PhilC
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Re: 520ST PSU Remake

Post by PhilC »

Any pics of the printed case?
If it ain't broke, test it to Destruction.
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rubber_jonnie
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Re: 520ST PSU Remake

Post by rubber_jonnie »

PhilC wrote: Sun Apr 14, 2019 12:24 pm Any pics of the printed case?
There will be as soon as I've finished printing both halves.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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rubber_jonnie
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Re: 520ST PSU Remake

Post by rubber_jonnie »

PhilC wrote: Sun Apr 14, 2019 12:24 pm Any pics of the printed case?
Just to tease you, lower half currently printing :)
IMG_20190414_194130.jpg
IMG_20190414_194130.jpg (283.1 KiB) Viewed 4854 times
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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PhilC
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Re: 520ST PSU Remake

Post by PhilC »

How long to print in total?
If it ain't broke, test it to Destruction.
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