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

[John Heritage]

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
> >>>>>>
> >>>>>>
> >>>>>
> >>>
> >>>
>
>