Replacing 7805 with RECOM 78B50.5-1.5

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Nidhoegger
Posts: 15
Joined: Sun Jun 14, 2009 6:35 am

Replacing 7805 with RECOM 78B50.5-1.5

Post by Nidhoegger »

Hi,

I wanted to try replacing the 7805 with a RECOM 78B50.1-1.5. It kinda works, but I get some kind of rolling lines with higher brightness, especially for blue images. It disappears when using the original 7805. I thought that the Caps might be through, so I recapped the SNES as well, so I can rule out the caps.

Any help is appreciated!

I made a Video of it, its kinda hard to see there, see especially the flickering and rolling area where link is standing on: https://www.youtube.com/watch?v=QajJ_THKios

Best,

Nidhoegger
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Ben Boldt
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Location: Minnesota, USA

Re: Replacing 7805 with RECOM 78B50.5-1.5

Post by Ben Boldt »

Why did you replace it? The new one might need different caps than the old one.
Nidhoegger
Posts: 15
Joined: Sun Jun 14, 2009 6:35 am

Re: Replacing 7805 with RECOM 78B50.5-1.5

Post by Nidhoegger »

The answer to your question is: Because I wanted to try it, it runs much cooler (does not need the heatsink) and I had some around ^^.

The 78B5 should be compatible with the 7805.
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TmEE
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Re: Replacing 7805 with RECOM 78B50.5-1.5

Post by TmEE »

This is normal for switch mode regulators that are not running in sync with video signal. These little modules have very high ripple and this is what you are seeing.
If you want to reduce heat with the original 7805, run them with a 7.5V power supply, they will only get warm then rather than hot.
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