1050 floppy disk drive power supply question AC / DC?

[Chandler]

i have a 1050 floppy drive without a power supply

 

i believe it is a 9vAC type

 

would i be able to use a 9v DC type?

 

just wanted to ask before i plugged anything in!

 

thanks

[Rybags]

No, has to be AC.

 

The actual innards of the drive I believe use 5 and 12 V DC, so it's possible to power from a standard PC power supply, but I don't have the info readily available as to what goes where.

Edited August 2, 2012 by Rybags

[Chandler]

ok thanks

 

so how does a 9V AC PSU power a 12v device anyway?

 

it seems finding a 9v AC replacement psu is no as common

[protek]

Here's one: http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_100061_-1

[bandit]

so how does a 9V AC PSU power a 12v device anyway?

 

rectifier to DC, doubler then regulator to 12vdc .

That one for $9 is ok, however most all have an extra power supply if you have someone near. also B&C and best.

Edited August 2, 2012 by bandit

[atari8warez]

Here's one: http://www.jameco.co...10001_100061_-1

 

@Chandler

 

That PS probably won't do as the current output is only 500ma. Original 1050 PS is rated at 31VA

 

VA (Volt Amperes) = Volts x Amperes so,

 

31 = 9 x Amperes and,

 

Amperes = 31 /9 = 3.44A

 

Perhaps the drive won't use all rated power but do not skimp on the adaptor's power output..

 

Here's one original PS for sale at eBay. It's a good deal at $10..

[jmetal88]

so how does a 9V AC PSU power a 12v device anyway?

 

rectifier to DC, doubler then regulator to 12vdc .

That one for $9 is ok, however most all have an extra power supply if you have someone near. also B&C and best.

 

Not to mention, fully rectified AC will give you about 1.4 times the input voltage, although 12.6v isn't quite enough to power a 12v regulator, so there probably is a doubler involved (but I would suspect an AC doubler before rectification rather than a DC doubler, or else they would have used a DC power brick).

 

EDIT: Well, I mean a doubling rectifier, really, as a conventional AC voltage doubler will still put out DC. Like this one:

 

http://www.coolcircuit.com/circuit/voltage/vd.GIF

 

I did something similar on a device I built recently, but I needed positive and negative voltage, so I referenced the point between the capacitors as ground.

Edited August 2, 2012 by jmetal88

[Chandler]

can anyone tell me if the positive pin on the original power supply is the centre pin or the outer part of the plug that goes into the disk drive?

 

 

thanks

[31336haxx0r]

It's AC. It doesn't have a positive or negative pin in that sense.

[Thorsten Günther]

BTW, tfhh published a modification for the 1050 from 9V AC to 12V DC in issue 108 (I think) of the ABBUC Magazin. I haven't applied it since I do have more than enough 9V AC European PSUs, but if anyone has problems finding them...

[MEtalGuy66]

You guys are all right..

 

The 1050 uses a very common PSU design (for its time).. 9vac > rectifier > 7805 regulator = 5v... 9vac> AC voltage doubler > rectifier > 7812 regulator = 12v..

 

You can use a DC brick with it, but it needs to be at least 15v, and about 2amp to be safe.. All of the caps inside are rated to at least 25v, so there is no problem there.. Might wanna keep an eye on the recifier diodes (I dont know how closely they are rated to capacity) as 2 of them will be operating at full duty cycle versus all 4 operating at half duty cycle when an AC brick is used...

[retrotechshop]

For those still looking, I found this power adapter: https://www.acdcpowershack.com/products/ac-ac-power-supply-9v-ac-3330ma-2-1-x-5-5mm?variant=44704878982

 

The connector is too small for the socket so I soldered a compatible connector on it and I can report the drive is powered up and working. This one is rated at 3.33A vs. the original brick of 3.44A. I can continue testing to see what the drive actually pulls.

[Beeblebrox]