Need a power supply that is no longer made... will this work?

Odd E O

Odd E O

New member
I was recently given a pair of Rane FPM44 program mixers without power supplies. The power supplies are no longer offered by Rane, and used ones are very expensive - if you can find them - so I am thinking of building one that can power both units. I have the skills/tools to do this, but lack the knowledge of circuit design to come up with a sound design. From what I have been able to find online, it should be a pretty straight forward, but I am seeking someone on this forum who can verify what I am looking at is sound and will work.


Copy of the user's manual...
http://www.rane.com/pdf/old/fpm44man.pdf

Here is the spec sheet for the OEM power supply...
http://www.rane.com/pdf/rs1dat.pdf


Using this transformer...
18V, 1.5A Center Tapped (9-0-9) Transformer - Power Supply Depot

Description of circuit (mounted in vented metal enclosure):
AC mains - switch - (?) amp slow blow fuse - ground (green from mains) to suitable point on enclosure, hot (black from mains) to black on primary side of transformer, neutral (white from mains) to red on primary side of transformer - yellow from secondary side of transformer to pins 1&6 of RJ12 jack, left blue from secondary side of transformer to pins 2&5 of RJ12 jack, right blue from secondary side of transformer to pins 3&4 of RJ12 jack.

Do I have this correct???

Thanks
 
Thank you Boulder Sound Guy!

Yes, the yellow on the secondary side of the transformer is the center tap - but the red and black on the primary side are not marked for "hot" and "neutral". I was assuming that black was hot as in standard 110v ac wiring.

So there are no other components required?
 
Odd E O said:
What amperage fuse should I use?
Click to expand...

Looking at the power supply spec sheet, the max current is 750 mA +10%. Round that up to 760 mA. That is the size fuse I would go with, 25 watts at 110 VAC is .23 amp draw. I would try a 760 mA fast blow fuse.:D
 
Atkron205 said:
Looking at the power supply spec sheet, the max current is 750 mA +10%. Round that up to 760 mA. That is the size fuse I would go with, 25 watts at 110 VAC is .23 amp draw. I would try a 760 mA fast blow fuse.:D
Click to expand...

But I am looking to power two of these units off of the one transformer - and the plug on each mixer says 400mA. So should I go with a 1A fuse? And just to clarify - I am using the fuse between the mains and the primary side of the transformer on the "hot" side - correct?
 
Odd E O said:
But I am looking to power two of these units off of the one transformer - and the plug on each mixer says 400mA. So should I go with a 1A fuse? And just to clarify - I am using the fuse between the mains and the primary side of the transformer on the "hot" side - correct?
Click to expand...

I was going off the max output from the power supply, if the mixer is 400 mA then a 1 amp fuse for 2 should work. the fuse would go between the output of the transformer and the input to the mixer, yes hot side.
 
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