To ditch the 12V PSU rail...

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To ditch the 12V PSU rail...

Post by exxos » Fri Oct 23, 2020 1:51 pm

I have talked about this on and off for a long time in other threads.. Basically just making the power supply five alternately and have a small step up inverter to power the 12 V rail... nothing really uses 12 V other than the monitor port pull-up.. But even if something did require 12 V future down the line, the existing power supply could still be used, or as these modules look to be able to supply up to half an amp, it still should be pretty future proof I think anyway..

Such as this one...

https://www.aliexpress.com/item/4000626913742.html


Capture.JPG
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It would open up the door to a lot wider range of alternative power supplies being only 5V required. There are some really low cost mains switch modes for under £10 in general from China.
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Re: To ditch the 12V PSU rail...

Post by PhilC » Fri Oct 23, 2020 1:56 pm

Sounds like a good idea if we only need 500mA max but that presumes someone doesn't try putting an ancient floppy onto the H5 i guess.

Also going the MeanWell gets my vote too. Good product for price range.
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Re: To ditch the 12V PSU rail...

Post by exxos » Fri Oct 23, 2020 2:02 pm

PhilC wrote:
Fri Oct 23, 2020 1:56 pm
Sounds like a good idea if we only need 500mA max but that presumes someone doesn't try putting an ancient floppy onto the H5 i guess.

Also going the MeanWell gets my vote too. Good product for price range.
Legacy board Phil ;)

But yeah, I am not really supporting those really old brick drives which need 12V anymore.. The original 720K drives are dropping like flies, nevermind older stuff. So I am really gearing up for 1.44 drives or gotec.
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Re: To ditch the 12V PSU rail...

Post by juz400 » Fri Oct 23, 2020 5:28 pm

Looks like a bloody good Idea!
Big supplier Vanilla PC boxes seem to be ditching the ATX or multi-voltage style PSU`s for a Single rail and something similar on the Mainboards for whatever extra may be required

I think I would pass on the cheap-o 5V bricks from china for £10, People seem to like Mean Well products, Ive not had the chance to use myself but
may need a Quality unit for an Upscaler I recently sprung for.

Not saying Purchase from RS(other suppliers out there) but if I have the right thought for the 5V supply Amperage range would looking at something in this sort of area be a good starting point for the 5V base supply?

https://uk.rs-online.com/web/c/power-su ... 4294883236

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Re: To ditch the 12V PSU rail...

Post by exxos » Fri Oct 23, 2020 5:41 pm

Yeah I mean 3 amps is probably plenty for it all with a bit of head room.. I dare say it could even just use a wall PSU.
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Re: To ditch the 12V PSU rail...

Post by stephen_usher » Fri Oct 23, 2020 6:14 pm

Surely the RS232 port uses 12V, unless you want to change it to TTL Serial, which isn't fully RS232 compliant?
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Re: To ditch the 12V PSU rail...

Post by PaulJ » Fri Oct 23, 2020 6:28 pm

stephen_usher wrote:
Fri Oct 23, 2020 6:14 pm
Surely the RS232 port uses 12V, unless you want to change it to TTL Serial, which isn't fully RS232 compliant?
Not needed for the H4/H5 which use the max chip for RS232. They generate their own rs232 levels.

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Re: To ditch the 12V PSU rail...

Post by exxos » Fri Oct 23, 2020 6:29 pm

stephen_usher wrote:
Fri Oct 23, 2020 6:14 pm
Surely the RS232 port uses 12V, unless you want to change it to TTL Serial, which isn't fully RS232 compliant?
No +12 or -12V on the H4 / H5.
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Re: To ditch the 12V PSU rail...

Post by sporniket » Fri Oct 23, 2020 7:21 pm

stephen_usher wrote:
Fri Oct 23, 2020 6:14 pm
Surely the RS232 port uses 12V, unless you want to change it to TTL Serial, which isn't fully RS232 compliant?
PaulJ wrote:
Fri Oct 23, 2020 6:28 pm
Not needed for the H4/H5 which use the max chip for RS232. They generate their own rs232 levels.
exxos wrote:
Fri Oct 23, 2020 6:29 pm
No +12 or -12V on the H4 / H5.
It's good to know

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Re: To ditch the 12V PSU rail...

Post by terriblefire » Fri Oct 23, 2020 9:54 pm

How a i supposed to use my ST as an arcwelder if you remove the 12v line :P
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