[vcf-midatlantic] OT - 120v to 240v step up recommendations

Sentrytv sentrytv at yahoo.com
Sun May 2 19:59:23 UTC 2021


In my opinion and this is what I would do is get a 12 V five amp brick power supply and rewire it.
That will take care of your entire problem and be done with it!
My 2 pennies worth
Mike

Sent from:
My extremely complicated, hand held electronic device.

> On May 2, 2021, at 3:36 PM, John Heritage via vcf-midatlantic <vcf-midatlantic at lists.vcfed.org> wrote:
> 
> Sentry, here's the thread where I asked about the 120V option:
> https://forum.icomp.de/index.php?thread/1830-aca500-i-may-have-damaged-the-boot-cf-slot-questions/
> 
> 
> He never directly said no to 120V input, but mentioned using either a 240V
> transformer or rewiring with a 12V/5A DC PSU.    (Replies #5 and #6).
> 
> The link for the item for sale also says 200-240V input source.
> 
> I'll just order a $20 240V step up transformer and call it a day -- a
> little larger of a solution than I hoped (I'd prefer to have less equipment
> not more :) ) but enough to at least verify operation.  Maybe later I'll go
> the DC wiring route..
> 
> 
> 
>> On Sun, May 2, 2021 at 3:30 PM Sentrytv via vcf-midatlantic <
>> vcf-midatlantic at lists.vcfed.org> wrote:
>> 
>> After looking at the picture on the website
>> It looks like the power supply is actually a standard switch mode power
>> supply brick which should be able to handle from something like 80 V to 240
>> V most of them do if I am correct,  if not please correct me.
>> 
>> Mike
>> 
>> Sent from:
>> My extremely complicated, hand held electronic device.
>> 
>>> On May 2, 2021, at 3:09 PM, Ian Primus via vcf-midatlantic <
>> vcf-midatlantic at lists.vcfed.org> wrote:
>>> 
>>> I see a lot of very complicated explanations and responses, and a lot
>>> of very technical "what-if's" attempting to consider every single
>>> angle. After all, electronics is the passion of many, myself included.
>>> 
>>> But at the end of the day, it's a power supply. For a home computer.
>>> It's been designed to work with ordinary household power - it's not
>>> going to be super picky about tiny differences in voltage, and
>>> basically nothing in this entire realm is going to have a problem with
>>> a difference in frequency. That really only affects AC synchronous
>>> motors like in a record player or something.
>>> 
>>> A step-up transformer is more than sufficient, just get one that's
>>> beefy enough to handle whatever you intend to run. Being that this is
>>> an Amiga, it doesn't exactly pull a ton of power, so nearly anything
>>> should be fine.
>>> 
>>> I have a whole bunch of equipment from foreign countries. For
>>> operating 240v hardware, I have a couple of step up transformers. One
>>> is simply the isolation transformer scavenged from an old arcade
>>> machine - one that had multiple input taps. I'm using it backwards,
>>> restrapped as 240v, operating it as a step-up. No idea what the
>>> wattage is, but it was meant to power an arcade monitor, so probably
>>> around 100W or so. Ish. It works fine, I've powered lots of British,
>>> Soviet, and other European machines on this thing,
>>> 
>>> Another step-up I use is actually a travel converter meant to be used
>>> as a step-down, to power 120V stuff overseas, converting 240V to 120V.
>>> It's an autotransformer, so it does not isolate in any way, and this
>>> is likely how most transformers you see on Amazon are built, because
>>> it's cheaper. I've rewired it backwards so it converts the 120V up to
>>> 240V. This also works just fine and I've powered lots of foreign
>>> equipment off of it.
>>> 
>>> Nearly every product on Amazon has some "scary reviews" thanks to
>>> people that simply don't know how to use it. My favorite being from
>>> some lithium batteries, two different people complained they caused
>>> their devices to catch fire and nearly burn down their house, with
>>> photo evidence. One of these photos shows the batteries, burnt and
>>> swollen, in the compartment of the device. One of which is installed
>>> backwards. So, huh. You take two 10,000mah batteries, and short them
>>> out with each other by installing one battery backwards in a device
>>> that uses two batteries in parallel, and it catches fire? Who knew?
>>> Silly physics. What will it think of next? It should have *known* what
>>> this user intended the batteries to do, and not allowed them to
>>> explode like that. So, yes. You have to take reviews with a grain of
>>> salt. While people may have had horrible experiences, there is a
>>> reasonable chance these experiences were self inflicted.
>>> 
>>> And yes - precise US line voltage is technically 117V, and I'm pretty
>>> sure the UK is technically 230V, etc, etc. But the line voltage will
>>> vary from area to area, and sag during periods of high usage and on
>>> circuits that are heavily loaded. Any device designed for use in the
>>> home will be tolerant of these sorts of voltage drifts, and the
>>> voltage regulation in the power supply of any given home computer, TV
>>> set, or piece of stereo equipment will be able to handle a reasonable
>>> amount of deviation.
>>> 
>>> In the end, it really doesn't matter - close enough is close enough -
>>> 220, 221, whatever it takes. It's fine. Any given step-up transformer
>>> should have no problem powering an Amiga, and any reasonably designed
>>> power supply is going to work just fine on either 50 or 60hz, and
>>> within any reasonable deviation of it's intended input voltage. Power
>>> in houses is FAR from perfect.
>>> 
>>> -Ian
>>> 
>>>> On Sun, May 2, 2021 at 8:56 AM John Heritage via vcf-midatlantic
>>>> <vcf-midatlantic at lists.vcfed.org> wrote:
>>>> 
>>>> Ok so you recommend just getting a step up transformer and be done with
>> it ?
>>>> 
>>>> Any brands you recommend that are UL or similar? (Or anyone else
>>>> recommend?) .  The models on amazon almost all seem to have at least a
>>>> percentage of very scary reviews..
>>>> 
>>>>> On Sun, May 2, 2021, 8:03 AM <dave.g4ugm at gmail.com> wrote:
>>>>> 
>>>>> John,
>>>>> 
>>>>> I like to keep equipment original so would not be tempted to mess. In
>>>>> addition is the new supply accurate. I run my NTSC CoCo off a
>> transformer
>>>>> and its fine.
>>>>> 
>>>>> 
>>>>> 
>>>>> The AC does permeate a little past the transformer, so the diodes and
>>>>> smoothing capacitor will usually see 100Hz or 120Hz ripple. (a full
>> wave
>>>>> bridge rectifier acts as a frequency doubler.)
>>>>> 
>>>>> In theory there could be components tuned to this frequency, but even
>> so
>>>>> they would usually not have a high enough “Q” for you to notice or to
>>>>> affect the operation.
>>>>> 
>>>>> 
>>>>> 
>>>>> Dave
>>>>> 
>>>>> 
>>>>> 
>>>>> *From:* John Heritage <john.heritage at gmail.com>
>>>>> *Sent:* 02 May 2021 12:14
>>>>> *To:* dave.g4ugm at gmail.com
>>>>> *Cc:* vcf-midatlantic <vcf-midatlantic at lists.vcfed.org>; W2HX <
>>>>> w2hx at w2hx.com>
>>>>> *Subject:* Re: [vcf-midatlantic] OT - 120v to 240v step up
>> recommendations
>>>>> 
>>>>> 
>>>>> 
>>>>> Thanks Dave, Dave,  and everyone - I reality do appreciate the comments
>>>>> and thoughts.
>>>>> 
>>>>> 
>>>>> 
>>>>> The computer in question is the Commodore Amiga 500 (Rev 5A / NTSC)
>> and is
>>>>> definitely working fine with my other (120VAC at 60Hz to DC output) power
>>>>> supply.   So I'm assuming the only 'risk' item here for 60 hz input
>> would
>>>>> be the (AC to DC) power supply created by the engineer and not
>> anything on
>>>>> the computer itself.
>>>>> 
>>>>> 
>>>>> 
>>>>> In this case I'm planning to run here in the US (= 60 hz AC) so worst
>> case
>>>>> it would be a '50 hz transformer running at 60hz'.
>>>>> 
>>>>> 
>>>>> 
>>>>> Does the frequency of the mains carry over to the DC side somehow?
>> One
>>>>> other option the guy mentioned was wiring a 12V/5A DC power supply
>> directly
>>>>> to the DC to DC converter within the new Amiga power supply, bypassing
>> the
>>>>> AC to DC conversion.  This would have the benefit of being a smaller,
>> more
>>>>> power efficient (less conversions) and slightly cheaper solution.
>>>>> 
>>>>> 
>>>>> 
>>>>> Thanks!
>>>>> 
>>>>> 
>>>>> 
>>>>>> On Sun, May 2, 2021 at 4:38 AM <dave.g4ugm at gmail.com> wrote:
>>>>> 
>>>>> Even if the grid frequency is "not used for anything" it can still
>> matter.
>>>>> Some older, larger computers used resonant transformers and these
>> simply
>>>>> won't work.
>>>>> Going from the UK/EU 50Hz world to the US 60Hz world is not usually a
>>>>> problem. In general transformers are slightly more efficient at 60hz.
>>>>> Going the other way can be a problem and US transformers can run warm
>> and
>>>>> over heat.
>>>>> 
>>>>> Dave
>>>>> G4UGM
>>>>> 
>>>>>> -----Original Message-----
>>>>>> From: vcf-midatlantic <vcf-midatlantic-bounces at lists.vcfed.org> On
>>>>> Behalf
>>>>>> Of John Heritage via vcf-midatlantic
>>>>>> Sent: 02 May 2021 00:45
>>>>>> To: W2HX <w2hx at w2hx.com>
>>>>>> Cc: John Heritage <john.heritage at gmail.com>; vcf-midatlantic <vcf-
>>>>>> midatlantic at lists.vcfed.org>
>>>>>> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up
>> recommendations
>>>>>> 
>>>>>> Per the guy who designed it (iComp.De - he makes tons of
>>>>>> amiga/commodore custom electronics) - the input frequency doesn't
>> matter:
>>>>>> 
>>>>>> does 60 hz / 240V power vs 50 hz / 240V power matter for this power
>>>>> supply
>>>>>> if I go the transformer route?
>>>>>> 
>>>>>> It shouldn't - it's a simple rectifier design where grid frequency is
>>>>> not used for
>>>>>> anything.
>>>>>> 
>>>>>> On Wed, Apr 28, 2021 at 8:13 PM W2HX <w2hx at w2hx.com> wrote:
>>>>>> 
>>>>>>> Are you sure the PS in the amiga is expecting 60 Hertz power? It
>> might
>>>>>>> be expecting 50 Hz depending on where it is from. This is a bigger
>>>>>>> problem that a transformer won't solve
>>>>>>> 
>>>>>>> -----Original Message-----
>>>>>>> From: vcf-midatlantic <vcf-midatlantic-bounces at lists.vcfed.org> On
>>>>>>> Behalf Of John Heritage via vcf-midatlantic
>>>>>>> Sent: Wednesday, April 28, 2021 4:57 PM
>>>>>>> To: Ethan O'Toole <telmnstr at 757.org>
>>>>>>> Cc: John Heritage <john.heritage at gmail.com>; John Heritage via
>>>>>>> vcf-midatlantic <vcf-midatlantic at lists.vcfed.org>
>>>>>>> Subject: Re: [vcf-midatlantic] OT - 120v to 240v step up
>>>>>>> recommendations
>>>>>>> 
>>>>>>> Yep - that's exactly what i'm looking for advice on -- I think
>>>>>>> transformers are pretty standard/minimalist, but just looking for
>> some
>>>>>>> links or models of 'ready to use' step up transformers that will plug
>>>>>>> into my US 120V outlet and give me a 240V UK or EU style plug
>> output..
>>>>>>> 
>>>>>>> thanks!
>>>>>>> 
>>>>>>> On Wed, Apr 28, 2021 at 4:49 PM Ethan O'Toole <telmnstr at 757.org>
>>>>> wrote:
>>>>>>> 
>>>>>>>>> Hey folks
>>>>>>>>> I have a new Amiga PSU coming on from icomp that is 240V only.
>>>>>>>>> I'm
>>>>>>>> looking
>>>>>>>>> for recommendations for a 120 to 240V step up transformer rated
>>>>>>>>> for at least 100W (so it doesnt have to work hard).  Preferably
>>>>> silent.
>>>>>>> Etc.
>>>>>>>>> Also what should I avoid in this space ?
>>>>>>>> 
>>>>>>>> I mean you can get a transformer that will take 110 and put out 220
>>>>>>>> before the Amiga PSU.
>>>>>>>> 
>>>>>>>> The Amiga runs on voltages that you could find on any ATX power
>>>>> supply.
>>>>>>>> You could make a cable that would go from the funky square DIN to a
>>>>>>>> PC motherboard ATX connector and use any old ATX Flex PSU.
>>>>>>>> 
>>>>>>>>                       - Ethan
>>>>>>>> 
>>>>>>>> 
>>>>>>> 
>>>>> 
>>>>> 
>> 
>> 



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