Moving UK STs to the US: SR98 110v mod?

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stween
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Moving UK STs to the US: SR98 110v mod?

Post by stween » Tue Dec 25, 2018 5:09 pm

Has anybody done this? I have three STs, I think all with SR98s in them. I'm planning on shipping them with me to the US early next year.

I like to keep close to original hardware where possible, so I'd be interested if there's an easy/obvious routine to switch out some of the ressistors and/or the big cap to safely operate against the US mains supply.

Failing that, I guess of course I could source some US PSUs, or picoPSUs, or similar. But as I say, I like as much original hardware in my machines as possible!

Edit: I didn't spot it in search, but the related threads throws me this; information like that but for the SR98 is what I'm after :)

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Re: Moving UK STs to the US: SR98 110v mod?

Post by exxos » Tue Dec 25, 2018 5:48 pm

I don't think it would be easy. Mostly there is 2 mains caps to form in effect a voltage doubler for 230v. It would end up being a hack job, and on the mains its not a good idea.

I think you be better looking for a 110v version. Ask around and I'm sure you would find one somewhere.
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Re: Moving UK STs to the US: SR98 110v mod?

Post by czietz » Tue Dec 25, 2018 5:57 pm

Probably, the most significant change needed would be replacing the switching transformer. Half the voltage means twice the current on the primary side to deliver the same power. Most likely, the transformer they used will not be able to handle that.

stween
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Re: Moving UK STs to the US: SR98 110v mod?

Post by stween » Tue Dec 25, 2018 7:05 pm

exxos wrote:
Tue Dec 25, 2018 5:48 pm
I don't think it would be easy. Mostly there is 2 mains caps to form in effect a voltage doubler for 230v. It would end up being a hack job, and on the mains its not a good idea.

I think you be better looking for a 110v version. Ask around and I'm sure you would find one somewhere.
Okay, fair! I'm not interested in fooling around with this, I was hopeful there'd be a simple, reliable hack to handle the different inputs.

In that case: I might pick up one of your 110V PSUs for my favourite machine, and some other US PSUs for the other machines.

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Re: Moving UK STs to the US: SR98 110v mod?

Post by PaulJ » Tue Dec 25, 2018 7:25 pm

stween wrote:
Tue Dec 25, 2018 7:05 pm
exxos wrote:
Tue Dec 25, 2018 5:48 pm
I don't think it would be easy. Mostly there is 2 mains caps to form in effect a voltage doubler for 230v. It would end up being a hack job, and on the mains its not a good idea.

I think you be better looking for a 110v version. Ask around and I'm sure you would find one somewhere.
Okay, fair! I'm not interested in fooling around with this, I was hopeful there'd be a simple, reliable hack to handle the different inputs.

In that case: I might pick up one of your 110V PSUs for my favourite machine, and some other US PSUs for the other machines.
I purchased one of Exxos's new red supplies and wired the primaries in serial and the 12 velds was approximately 7 volts. Wired properly for 110 (is connecting the primaries in parallel) all worked fine. You should ask if that's all that is necessary to switch from 110 and 220.

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Re: Moving UK STs to the US: SR98 110v mod?

Post by rubber_jonnie » Wed Dec 26, 2018 10:08 am

Have you considered a step up transformer as a short term solution?

It would at least allow you to use your STs until you could find an alternate PSU to replace the SR 98s.
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Re: Moving UK STs to the US: SR98 110v mod?

Post by stween » Wed Dec 26, 2018 2:15 pm

PaulJ wrote:
Tue Dec 25, 2018 7:25 pm
I purchased one of Exxos's new red supplies and wired the primaries in serial and the 12 velds was approximately 7 volts. Wired properly for 110 (is connecting the primaries in parallel) all worked fine. You should ask if that's all that is necessary to switch from 110 and 220.
That's a good point! exxos, how easy is it to convert your red PSU design between 110v and 230v?
rubber_jonnie wrote:
Wed Dec 26, 2018 10:08 am
Have you considered a step up transformer as a short term solution?

It would at least allow you to use your STs until you could find an alternate PSU to replace the SR 98s.
Good idea! I remember looking at these years ago and decided they weren't worthwhile, but now I see there are some lower wattage transformers that might work and aren't super expensive. Thanks for the idea!

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Re: Moving UK STs to the US: SR98 110v mod?

Post by exxos » Wed Dec 26, 2018 2:23 pm

stween wrote:
Wed Dec 26, 2018 2:15 pm
That's a good point! exxos, how easy is it to convert your red PSU design between 110v and 230v?
You don't need to convert anything, I sell a 240V and 120V version..


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Re: Moving UK STs to the US: SR98 110v mod?

Post by stween » Wed Dec 26, 2018 2:29 pm

exxos wrote:
Wed Dec 26, 2018 2:23 pm
stween wrote:
Wed Dec 26, 2018 2:15 pm
That's a good point! exxos, how easy is it to convert your red PSU design between 110v and 230v?
You don't need to convert anything, I sell a 240V and 120V version..


https://www.exxoshost.co.uk/atari/last/storenew/#0030
Let's say I buy the 110v one, use it in the US, and then in the future I move it back to the UK. Is it easy to convert between the two?

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Re: Moving UK STs to the US: SR98 110v mod?

Post by exxos » Wed Dec 26, 2018 3:12 pm

stween wrote:
Wed Dec 26, 2018 2:29 pm
Let's say I buy the 110v one, use it in the US, and then in the future I move it back to the UK. Is it easy to convert between the two?
Yeah, its just a primary tap on the transformer, its labeled up what the windings are.
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https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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