A1000 PSU - convert to 230V? Possible?

[chiark]

Folks, I've just bought an a1000 from the USA.  I live in England

The PSU will be 110v, and the video output will be NTSC.  NTSC isn't a problem, but the psu is.

Is it possible to reconfigure the PSU to convert 240v to the required internal voltages?

Any ideas?

[Oliver]

Hi,

You may be able to modify the power supply, but alternatively, you may like to use a 240V to 110V transformer, situated between your mains outlet and your A1000 power supply.  There are commercial products available to end users for just this purpose.  It would also be a pretty simple project to build such a converter.  Although the electrical design is simple enough, be aware that dealing with mains power is hazardous.  It may also be illegal for you to make your own mains powered devices, and you may void any health/property insurance etc. if you do so.

Good luck.

Oli

[chiark]

Thanks Oli, I've got an external converter (only low power - so I need to get another beefier one) but I'm wondering if it would be a fairly straightforward job to do an internal conversion

Thankfully my health insurance and home insurance covers me for doing daft things - I'm in England, not the USA

[CLS2086]

Hi,
look in your PSU if there is not a switch

[chiark]

well, after 6 weeks on a boat, it's finally here :-D

I've disassembled it - it's a thing of beauty - and there's nothing in the PSU that is switchable.

I am wondering about using a PC PSU, as it needs
+5v,-5v,12v, GND and ! 60Hz
Everything apart from 60Hz is right on a PC psu...

I've also got the problem of 50 vs 60 Hz...  

Anyone know what'll happen if I feed an NTSC amiga a 50Hz power supply, even at 110V?

[Homer]

Hi Chiark, although the USA psu is 60Hz INPUT, the outputs are DC, i.e. direct not alternating current. This means a UK 50Hz INPUT PC psu will output the same +5,-5,12V DC as a USA one would do in America. The input frequency does not matter, its all converted to DC. Do make sure you use a 240VAC psu in the UK tho ;-)

[chiark]

Homer, yes, I understand all that...

However, as well as +5, -5, 12V and ground, there's a 60Hz frequency output from the PC to the Amiga.

I don't know if the 'miggy derives part of its clock or sync from that

[Homer]

Hi Chiark,
I did a PC AT supply conversion for my A1200T so that is the only one I truly understand and that did not have any alternating waveforms input to the Miggy.
Does the A1000 have an internal psu then ? If so I suppose its feasible since some other large case models have their 'tick' signals.
If its an external psu however I would be very surprised if there is any 60Hz pulse. I will however hide my hat just in case. Oh yes, and less of the ........ please, I am trying to help you and you have not informed us of your competancy level with Amiga or electricity, so I am simply trying to assist......

[Tomas]

There is often a switch on psus, which let you switch between 110 and 220/240v. I do knot know if this is the case with the a1000 though.

[chiark]

Cheers Homer, appreciated.  I didn't mean the ... as an insult...  ;-) :-D

Well, it's working despite being fed a 110V 50Hz signal - I'm just using a cheapo 100W converter from maplins.  The 1000 states it'll draw 1A max at 110V, so I'm hoping that VA is near enough to Watts to make no difference.

I don't know what the internal tick signal is - I guess it might just be AC, or it might be some pulse derived from the AC.  I'm not going to mess, seeing as its working using the external converter.

Tomas, unfortunately there's no switch on it, and nothing inside the PSU.

Of course, the whole board is running in NTSC mode, meaning my resolutions are 200 vertical lines rather than the PAL 256.  There's no jumpers at all in the 1000, so no easy option to change.  I wonder what the difference is - is it just Denise?

It's quite nostalgic booting into WB 1.2 with KS1.2 and 512KB of memory...

[InTheSand]

Glad you got your A1000 running! This page might be of use re: power supplies.

As for good ol' 1.2, the joys and delights of running everything from floppies and the lovely old orange/blue colour scheme can't be beaten!

 - Ali

[Zac67]

To convert your video to PAL you'd need a PAL Agnus (8367 AFAIR). If you're using special video equipment (genlock, A2024 Hedley monitor), you'll have to swap the oscillator clock as well, but for standard use the difference doesn't matter.

[chiark]

Thanks for the link, and for the info on Agnus.  I never realised it was agnus that controlled the available resolutions (either that, or I forgot... I've still got the HRM somewhere :-D )

Only question is where on earth to find an 8367 agnus :-) - I'm looking :-D