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Evidious

replacing the the regulators in the 1050 disk drive

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Posted (edited)

Is it a good idea or bad idea to replace the 12v and 5v regulators with more efficient Switching regulators?

I was wonder if anyone had any thought on this 

Edited by Evidious

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I use them in my 1088XLD and they work great without any need for a heatsinks, and also result in less demand from the 9VAC power adapter, as well as way less heat being generated within the case.

 

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they work fine, ive done a few now and as Mytek said, no heat! 😎

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Only potential downside is a slightly noisier DC output due to the high frequency switching and limited filter caps, which has been debated as to any potential downside in reliability, but many have done it, and will reduce draw on the PSU by about 40% and no heat output....

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9 hours ago, Nezgar said:

Only potential downside is a slightly noisier DC output due to the high frequency switching and limited filter caps, which has been debated as to any potential downside in reliability, but many have done it, and will reduce draw on the PSU by about 40% and no heat output....

Yes this can indeed be an issue where audio and video are concerned, and does require additional filtering which was done on the 1088XLD. However neither audio or video noise would be a concern for a disk drive, so it should be safe to go this route.

 

5 hours ago, blacka013 said:

where can you get these please?

These are what I used for the 1088XLD.

 

5V:   TPSM84205EAB

12V: TPSM84212EAB

 

And might be a little cheaper then the Tracopower devices depending upon where you purchase them.

 

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What additional filtering would be needed ?  with the rapid switching, I wouldn't think it would need a large cap....

 

Anyone ever use these in a 400/800 ?  Any issues with noise ?

 

 

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7 hours ago, cwilbar said:

What additional filtering would be needed ?  with the rapid switching, I wouldn't think it would need a large cap....

None would be needed for the 1050 application, which is what this topic is about.

 

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y, I got that.... was just curious, that if noise was an issue in a 1050 (which it is not), what sort of filtering would be required which then led into my curiosity of these had ever been used in the Atari computers with on-board regulators....

 

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1 hour ago, cwilbar said:

y, I got that.... was just curious, that if noise was an issue in a 1050 (which it is not), what sort of filtering would be required which then led into my curiosity of these had ever been used in the Atari computers with on-board regulators....

I've never tried that, but there might be enough filtering via the ferrite beads and the capacitors to be ok. If not the first indication usually is a high pitched whine in the audio when you crank up the volume and listen to the background without anything else playing. Next indication of a problem would be herringbone patterns in the video.

 

Here's the filter circuit I used in the XLD to eliminate these issues.

 

XLD_power_ckt.thumb.png.9a11ef8a414a8bc9b734a836449b7487.png

 

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6 hours ago, mytek said:

Here's the filter circuit I used in the XLD to eliminate these issues.

Bear in mind, the filter circuit needed will depend on the frequency the regulator is running at, the

ones I've looked at are running at 400KHz , not sure if that's a standard or every manufacturer chooses

their own frequency.

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On 8/25/2020 at 11:40 PM, mytek said:

I've never tried that, but there might be enough filtering via the ferrite beads and the capacitors to be ok. If not the first indication usually is a high pitched whine in the audio when you crank up the volume and listen to the background without anything else playing. Next indication of a problem would be herringbone patterns in the video.

 

Here's the filter circuit I used in the XLD to eliminate these issues.

 

XLD_power_ckt.thumb.png.9a11ef8a414a8bc9b734a836449b7487.png

 

Is the filtering on the post regulator 5V more complex than the 12V due to more current, different switching frequencies, ???  The 12V post regulator is much simpler with no inductors too.

I'm pretty good in the digital realm, and I'm learning more of the analog realm, but this is well outside of my familiarity 🙂

 

Thanks for sharing the schematic.

 

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17 minutes ago, cwilbar said:

Is the filtering on the post regulator 5V more complex than the 12V due to more current, different switching frequencies, ???  The 12V post regulator is much simpler with no inductors too.

I'm pretty good in the digital realm, and I'm learning more of the analog realm, but this is well outside of my familiarity 🙂

 

Thanks for sharing the schematic.

The 5 volts is powering the logic, audio, and the video circuits so it needed to be clean. Whereas the 12V was mainly provided for accessories that would likely have their own on board down regulation plus additional filtering. The only on board use for the 12V was to drive the precision 10V zener regulated power supply for the GTIA color adjust circuit.

 

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