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General Category => Amstrad CPC hardware => Topic started by: llopis on 21:17, 02 October 18

Title: What to look for in a power supply for the CPC?
Post by: llopis on 21:17, 02 October 18
I know the power supply for the CPC 6128 needs to output 5V and 12V at around 2A each. But what else do you look for in a power supply to make sure that:
a) It doesn't cause video interference.
b) Is good quality (or at least, if it blows up it doesn't take the CPC with it)


I'm asking this because a few years ago I built a power supply from a Cisco router and it was great. Then, recently, I used a power supply intended for external hard drives, and while it works, it also has some amount of interference on the screen. Also, this power supply is much lighter than the Cisco one. I don't know if that's a tell of the quality since I actually don't know much about power supply construction.
Title: Re: What to look for in a power supply for the CPC?
Post by: rpalmer on 21:39, 02 October 18
It sounds like the interference is because the voltage supply is using "buck" converters which just switch the supply on and off at a high frequency resulting in a "average". These types are very common nowadays since their manufacture is real cheap and very small.

The switching on and off is what you are seeing.

rpalmer
Title: Re: What to look for in a power supply for the CPC?
Post by: Poliander on 21:44, 02 October 18
I'm using an old MP-2, the RF/video stuff is ripped out...
Title: Re: What to look for in a power supply for the CPC?
Post by: llopis on 21:44, 02 October 18
Quote from: rpalmer on 21:39, 02 October 18
It sounds like the interference is because the voltage supply is using "buck" converters which just switch the supply on and off at a high frequency resulting in a "average". These types are very common nowadays since their manufacture is real cheap and very small.
The switching on and off is what you are seeing.
Oh interesting! I was just wondering if the cause of the interference was bad shielding or something else. It's actually a band of about an inch or so wide that moves down the screen in about 10-15 seconds.


Is there a way to know if a power supply is a buck converter from the description on an online store? What are non-buck power supplies called?


Thanks!
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