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Power supply for Roland M240

Power supply for Roland M240

2008-12-22 by babouche369

Hi there,
I recently bought a Roland M240 Line Mixer, but the power supply 
(ACC120) was missing. I first thought it would be a piece of cake to 
find one on the net, but it seems not to be. I'm now looking to find an 
equivalent or to build one.
It must supply a DC symmetrical 21.5 volt (i.e. +21.5V / 0V / -21.5V) 
at 500 mA.
So, does someone have:
- a living or dead ACC120 to sell at reasonable price?
- the schematics for the ACC120 or an equivalent?
- an idea to solve my problem?
Because of the low needed current, I also thought twinking a standard 
PC power supply (most are able to yield at least +/- 12V @ 3A = 36 W, 
and I require less than 11 W). I know SMPS (SwitchMode Power Supplies) 
might behave nastily when twinked; does someone have ever done it?

Thanks,

Francois

Re:Power supply for Roland M240

2008-12-22 by scott frye

Hi...

I wouldnt mess with a modified PC supply.



1st...try some surplus electronics places online.



You can get a little leeway on the volts out (if Roland wants 21.5 ,
you can supply up to 24vdc most likely as long as the supply can do the
+/- 500mA.)



A used one is possible too



The transformer inside will have 24VAC with CenterTap then a full wave
rectifier, an LM317 and LM337 adjustable +/-regulators inside. Each set
up for the 21.5 Of course they'll be a couple of resistors and filter caps too.(Thats how I'd design one.)

Scott  Frye
AudioFixation
Consumer / Pro Audio Repair
Southern VT 

"Resistance is futile but.....
Impedance is much more complex"
  
Scott  Frye
AudioFixation
Consumer / Pro Audio Repair
Southern VT 

"Resistance is futile but.....
Impedance is much more complex"

RE: [vintagesynthrepair] Re:Power supply for Roland M240

2008-12-22 by francois

Hi Scott,

thanks for your advice. You're right: modifying a PC supply could be a long and painful process, far above my available time.
Actually, some better googling revealed abundance of adjustable symmetric PSU schematics, mostly based on LM317/337. Sounds to be a better option if I don't find a genuine ACC120 at reasonable price.

François



To: vintagesynthrepair@yahoogroups.com
From: painintheamp@...
Date: Tue, 23 Dec 2008 02:06:51 +0800
Subject: [vintagesynthrepair] Re:Power supply for Roland M240



Hi...
I wouldnt mess with a modified PC supply.

1st...try some surplus electronics places online.

You can get a little leeway on the volts out (if Roland wants 21.5 , you can supply up to 24vdc most likely as long as the supply can do the +/- 500mA.)

A used one is possible too

The transformer inside will have 24VAC with CenterTap then a full wave rectifier, an LM317 and LM337 adjustable +/-regulators inside. Each set up for the 21.5 Of course they'll be a couple of resistors and filter caps too.(Thats how I'd design one.)

Scott Frye
AudioFixation
Consumer / Pro Audio Repair
Southern VT

"Resistance is futile but.....
Impedance is much more complex"

Scott Frye
AudioFixation
Consumer / Pro Audio Repair
Southern VT

"Resistance is futile but.....
Impedance is much more complex"




Messenger vous offre un voyage. Participez aujourd'hui.

Re: [vintagesynthrepair] Power supply for Roland M240

2008-12-22 by Russell Rose

Francois, i have a used original Roland power supply that you may have.
Please email me after Christmas as I am currently on the road. Russ
russrose@...
Show quoted textHide quoted text
On Dec 22, 2008, at 10:55 AM, babouche369 wrote:

> Hi there,
> I recently bought a Roland M240 Line Mixer, but the power supply
> (ACC120) was missing. I first thought it would be a piece of cake to
> find one on the net, but it seems not to be. I'm now looking to  
> find an
> equivalent or to build one.
> It must supply a DC symmetrical 21.5 volt (i.e. +21.5V / 0V / -21.5V)
> at 500 mA.
> So, does someone have:
> - a living or dead ACC120 to sell at reasonable price?
> - the schematics for the ACC120 or an equivalent?
> - an idea to solve my problem?
> Because of the low needed current, I also thought twinking a standard
> PC power supply (most are able to yield at least +/- 12V @ 3A = 36 W,
> and I require less than 11 W). I know SMPS (SwitchMode Power Supplies)
> might behave nastily when twinked; does someone have ever done it?
>
> Thanks,
>
> Francois
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

Re: [vintagesynthrepair] Power supply for Roland M240

2008-12-23 by Ron Petty

You can use two external wall power supplies wire them with a common and you have a power supply. I'm sure you could find something you could mount inside the mixer. The voltage could be set with rheostats. Just an idea.
Ron
Show quoted textHide quoted text
----- Original Message -----
Sent: Monday, December 22, 2008 4:48 PM
Subject: Re: [vintagesynthrepair] Power supply for Roland M240

Francois, i have a used original Roland power supply that you may have.
Please email me after Christmas as I am currently on the road. Russ
russrose@mindspring.com
On Dec 22, 2008, at 10:55 AM, babouche369 wrote:

> Hi there,
> I recently bought a Roland M240 Line Mixer, but the power supply
> (ACC120) was missing. I first thought it would be a piece of cake to
> find one on the net, but it seems not to be. I'm now looking to
> find an
> equivalent or to build one.
> It must supply a DC symmetrical 21.5 volt (i.e. +21.5V / 0V / -21.5V)
> at 500 mA.
> So, does someone have:
> - a living or dead ACC120 to sell at reasonable price?
> - the schematics for the ACC120 or an equivalent?
> - an idea to solve my problem?
> Because of the low needed current, I also thought twinking a standard
> PC power supply (most are able to yield at least +/- 12V @ 3A = 36 W,
> and I require less than 11 W). I know SMPS (SwitchMode Power Supplies)
> might behave nastily when twinked; does someone have ever done it?
>
> Thanks,
>
> Francois
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

Re: [vintagesynthrepair] Power supply for Roland M240

2008-12-23 by Russell Rose

My co-workers emailed me back to say that the Roland ac adaptor was  
indeed an ACC-120
and that it tests good under  a load . and then that just leaves the  
cost which depends on where it is shipped.
jes let us know, preferably after the 26th.
Show quoted textHide quoted text
On Dec 22, 2008, at 10:55 AM, babouche369 wrote:

> Hi there,
> I recently bought a Roland M240 Line Mixer, but the power supply
> (ACC120) was missing. I first thought it would be a piece of cake to
> find one on the net, but it seems not to be. I'm now looking to  
> find an
> equivalent or to build one.
> It must supply a DC symmetrical 21.5 volt (i.e. +21.5V / 0V / -21.5V)
> at 500 mA.
> So, does someone have:
> - a living or dead ACC120 to sell at reasonable price?
> - the schematics for the ACC120 or an equivalent?
> - an idea to solve my problem?
> Because of the low needed current, I also thought twinking a standard
> PC power supply (most are able to yield at least +/- 12V @ 3A = 36 W,
> and I require less than 11 W). I know SMPS (SwitchMode Power Supplies)
> might behave nastily when twinked; does someone have ever done it?
>
> Thanks,
>
> Francois
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

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