How to: recapping the Mega STe power supply

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

Post by exxos »

Bikerbob wrote: Sat Nov 11, 2017 12:04 am MSTE PSU REPAIR KIT PHIHONG PSM-5341 240V type £25 22 In Stock [0064]
So this is what I want I assume.. but I have a questions.. your line there says 240v type - but I am to understand this is a switching PSU.
SO.. am I buying this.. because its for the PSM-5341? OR have you changed something that only makes it a 240v kit?
I don't know if there is a 110V version.. possible the PSU does 100-250V, but I forgot to check when I had my PSU.. So see what it says on the label.. see if it matches the PSU I had..
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Bikerbob
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Re: How to: recapping the Mega STe power supply

Post by Bikerbob »

OK, well not sure how to check, but this is the doc on the psu

http://dev-docs.atariforge.org/files/PS ... 30_PSU.pdf

SO, long and short I would like to buy your kit, assuming its the one I need. What is the list of components in your kit? and I can compare to that doc?

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

Post by exxos »

It says universal 100 - 240. So its just one PSU then :)
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Re: How to: recapping the Mega STe power supply

Post by Icky »

Icky wrote: Wed Nov 08, 2017 11:39 pm Great guide. I have added one more thing to finish off the PSU recapping and refurb. I found that the floppy and HDD cables were all loose and sometimes got in the way when closing the case. My MegaSTE had black insulating tape around the cables at various places. I had seen that modern PSUs for PCs employ an expandable braiding around the cables. After sourcing 1m of 4mm braiding that goes from 2mm - 8mm It made a better job of the cable management.

Image

Using some heat shrink wrap finishes off the ends to stop the braiding coming unraveled

I picked up my braiding from http://www.hobbytronics.co.uk/braided-s ... d=sleeving for just over a £1
Below is the finished PSU with the braiding.
IMG_2629.JPG
IMG_2629.JPG (1.82 MiB) Viewed 6856 times
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Re: How to: recapping the Mega STe power supply

Post by exxos »

Icky wrote: Sun Nov 12, 2017 2:23 pm Below is the finished PSU with the braiding.
Nice work! :bravo:
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Peter_John48115
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Re: How to: recapping the Mega STe power supply

Post by Peter_John48115 »

Hi...i am a new user here. I would have thought screen flickering would be more related to ageing capacitors than anything else.
Some optos do have better ratings and speed great than others, ultimately if it makes any difference or not.. it is not something I have tried with the mega power supply.
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Re: How to: recapping the Mega STe power supply

Post by mikro »

What a great guide!

There is an error with C14 - it doesn't have + on the left on and - on the right but - on the top and + on the bottom.
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frank.lukas
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Re: How to: recapping the Mega STe power supply

Post by frank.lukas »

Pacman wrote: Mon Oct 16, 2017 11:41 pm
Replacing the (noisy) cooling fan
No doubt about it -the factory installed fan is quite noisy! Besides, cooling fans don't last forever -they accumulate dust and dirt, they wear out etc. so I recommend you replace it with something better.
This page describes in detail how to replace it with a low-noise Noctua A6x25. There's no need to modify the power supply or Mega STe case (although some people cut away the ventilation slits for a better airflow. Some people like to do this while others would never cut or modify the appearance of the computer in any way).
20171102-131127__MG_2263.jpg


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.
Noctua fan connector.png
The fan also comes with two "noise reduction cables" which effectively slows down the fan and thereby lowers the sound even more. Whether this is a smart move or not (will it overheat the PSU and/or computer?) is guesswork, but on the other hand, if your Mega STe internal SCSI hard drive is disconnected (or not installed in the first place) and a MonSTer board for instance is used as a super-fast solid state (and completely silent) storage solution (using an IDE to Compact Flash memory card adapter) it might be a consideration as the SCSI hard drive would surely draw more power and generate more heat.
The Fan is connected between -12V and GND ...

+12V is wrong !
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Re: How to: recapping the Mega STe power supply

Post by czietz »

Regarding the opto-coupler discussion that took place in this thread a while ago: it's not the switching speed that makes the PC111 more suited than the CNY17, it's the common mode transient immunity (CMTI) that is significantly better for a opto-coupler without a base connection such as the PC111. In case the PC111 is hard to get, I've tested that a CNY17F-3 is an adequate replacement as well. The "F" (=floating base) makes all the difference here.
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Re: How to: recapping the Mega STe power supply

Post by exxos »

Interesting to know thanks!
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
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People should find solutions to problems, not find problems with solutions.
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