Anyone put a voltage regulator in their XL/XE?

[ApolloBoy]

A few days ago I decided to experiment with my 800XL by adding a homemade voltage regulator PCB, that way I could run it off a barrel-tip PSU as opposed to that weirdo DIN-plug deal. I was just curious if anyone else has tried this, it's actually very easy to do and the results are worth it.

Edited November 16, 2012 by ApolloBoy

[Stormbringer]

Go on......

[Fox-1 / mnx]

I was just curious if anyone else has tried this

 

I only used an external regulator when I mounted a 600XL in my car, to run it on 12-14VDC. I actually used 2 regulators to spread the load (~13V->78K09->9V->78K05->5V->600XL). Can't see the need of mounting one in an XL/XE. They already run on 5VDC which is a very common voltage.

[31336haxx0r]

I'd take a switch mode PSU for 5V output. Internally, I'd hook up a fuse and a crowbar diode that shorts the input and kills the fuse whenever the wrong polarity is applied to the computer.

[ApolloBoy]

Internally, I'd hook up a fuse and a crowbar diode that shorts the input and kills the fuse whenever the wrong polarity is applied to the computer.

I used a voltage rectifier so that I can use any type of PSU. I haven't put in a fuse yet but I'll get around to it before too long.

[31336haxx0r]

I was referring to a PSU that already puts out +5V. Adding a bridge rectifier to that drops voltage down to 3.8 Volts.

[ApolloBoy]

I was referring to a PSU that already puts out +5V. Adding a bridge rectifier to that drops voltage down to 3.8 Volts.

Ah, didn't catch that bit in your post. But anyway, in my case I added a rectifier directly to the input of the power jack so I could use any type of PSU in a pinch. I originally thought of just adding a diode or two as protection but I figured a bridge rectifier would be a lot better.

[eeun]

That seems like a good idea, given that some of the Atari power supplies I've come across are aging poorly and no longer outputting a proper +5V. One of them, which I believe fried several chips on my XE, was putting out almost 6V. I suppose it was foolish of me to not first check the voltage on a newly acquired 8-bit, but at the time I had no idea just how sensitive the XE internals were.

 

There's also quite a few Instructables on converting AT/ATX PC PSUs to multi-purpose "benchtop" power supplies, including adding LM317 regulators to add a variable source.

 

One further option is a mini-itx adapter board. They can use silent laptop AC adapters for 12V input, and offer the standard 12V, 5V, 3.3V, etc. on output. That starts to get pricey compared to a regulator, though.

[Fox-1 / mnx]

As I wrote before: Apart for the challenge, there's no point making regulators for exotic power supplies with strange voltages when 5VDC is so common. No need for rectifiers or whatever. A single XL/XE runs fine on a cheap 5V/1.5A adapter. A bunch of XL's with their disk drives (requires simple mod) can all be connected to a cheap AT/ATX power supply. As a bonus, those modern ATX PS have an AC filter, multiple output leads, are pretty well protected against shorts and over-voltage and easy to replace if it happens one breaks down. Many also have an intelligent cooling fan and since the power required for the A8's is peanuts for an ATX the fan just spins too slow to hear it or doesn't rotate at all.

 

But that's just me...

[ApolloBoy]

My idea behind this was to use the same PSU for my 800XL as many of my other systems. Most of my systems use the same PSU as the model 1 Genesis (9VDC, tip negative) and I like to use standardized hookups for most of my consoles as that means I don't have a bunch of proprietary cables and AC adapters to worry about. By adding a voltage regulator to my 800XL in addition to having dedicated RCA and S-video jacks, I can swap between my systems with minimal fuss.