How to: recapping the Mega STe power supply

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Pacman
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Re: How to: recapping the Mega STe power supply

Post by Pacman » Thu Nov 08, 2018 10:44 am

frank.lukas wrote:
Wed Nov 07, 2018 5:00 pm
Pacman wrote:
Mon Oct 16, 2017 11:41 pm

Replacing the (noisy) cooling fan
The Noctua fan has a 3-pin female connector attached but there is no need to cut it off and replace it with the original 2-pin connector. Just make sure only the two leftmost pins (black and red wires) attaches to the Mega STe power supply. The yellow wire isn't used.
The Fan is connected between -12V and GND ...

+12V is wrong !
Are you sure?
Unfortunately I don't have access to my MegaSTe at the moment or I'd check with a multimeter. I did take a look at the power supply schematic though, and it might be +12V and -12V (instead of +12V and GND as I said), but you're saying it should be -12V and GND?
mste_psu_fan.png
mste_psu_fan.png (330.91 KiB) Viewed 75 times
I'll check when I get things up and going again, but it may take a while, so please chime in anyone who can confirm/deny the above info.
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Re: How to: recapping the Mega STe power supply

Post by exxos » Thu Nov 08, 2018 10:48 am

Fan across -12 there. +12 is top of diagram.

Can also confirm -12 is -12 because of lower capacitor values on that compared to +12 which makes sense, also stated current 0.3A.
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Pacman
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Re: How to: recapping the Mega STe power supply

Post by Pacman » Thu Nov 08, 2018 11:25 am

Thanks for confirming, Exxos.
Here's the corrected pinout. I'll also replace the pinout diagram in my original posting along with all the instructions to avoid any confusion (Oops: that didn't work -there's no "edit post" button there any longer. Any chance you could replace the diagram in the first posting with the one attached here?).
Noctua fan connector corrected.png
Noctua fan connector corrected.png (14.38 KiB) Viewed 67 times
Mega STe | MonSTer with dual IDE-CF memory card adapter | STe | SM-144 |NEC Multisync 1990SXi | IDE doubler | ST_ESSC | RSVE | ICD Link II | Link '97 | HD floppy drive/AJAX | HD floppy module | Minolta PCMCIA card-drive | Realtime Clock module | Discovery cartridge | Unitor-2 | Export | Combiner | Steady Eye | Human Touch | Unicorn USB

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Re: How to: recapping the Mega STe power supply

Post by rubber_jonnie » Thu Nov 08, 2018 11:30 am

Just wondering if after all these posts on capacitors, Pacman should change name to Capman :D
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Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
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Re: How to: recapping the Mega STe power supply

Post by exxos » Thu Nov 08, 2018 11:30 am

Send me a PM with new images.. also link to the exact post where image is to be replaced and I will update it for you :)
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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frank.lukas
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Re: How to: recapping the Mega STe power supply

Post by frank.lukas » Thu Nov 08, 2018 11:31 am

RTN = GND

So the Fan is connected between RTN over a 10 Ohm (R35) Resistor and -12V. I replace R35 with a 1W/47 Ohm one ...

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Re: How to: recapping the Mega STe power supply

Post by troed » Thu Nov 08, 2018 11:40 am

Exactly - it's not -12 and +12 as the new diagrams show.

It does mean that everyone might be running these fans "backwards". I need to look at how I connected mine.

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Re: How to: recapping the Mega STe power supply

Post by Steve » Thu Nov 08, 2018 11:45 am

Just a warning to anyone using the Noctua fan! I used the 'silent' slowest fan speed option at first, my PSU blew up and almost destroyed my TT. Since I got my PSU fixed I've stuck the Noctua on the highest setting, as the guy who fixed my PSU told me it overheated.

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Re: How to: recapping the Mega STe power supply

Post by troed » Thu Nov 08, 2018 11:54 am

Steve wrote:
Thu Nov 08, 2018 11:45 am
Just a warning to anyone using the Noctua fan! I used the 'silent' slowest fan speed option at first, my PSU blew up and almost destroyed my TT. Since I got my PSU fixed I've stuck the Noctua on the highest setting, as the guy who fixed my PSU told me it overheated.
Thanks. I'm indeed running mine on the slowest speed but I haven't used it extensively since the change.

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Re: How to: recapping the Mega STe power supply

Post by mikro » Thu Nov 08, 2018 7:54 pm

troed wrote:
Thu Nov 08, 2018 11:40 am
It does mean that everyone might be running these fans "backwards". I need to look at how I connected mine.
I've been wondering about the same. So what is the original direction? Is the fan sucking new air in or blowing hot air out?

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