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power supply E-MU Proteus MPS

PostPosted: Sun Apr 16, 2017 12:14 pm
by Fred
Hi, I have lost the powersupply of my E-MU proteus MPS.
Can somebody help me for the electr. diagram/circuit of the powersupply? Or other info?
On the photo of the original powersupply is listed only: Out CT 18V AC 1,5 amp.
But there are going three wires in the synths. Two to the on/of switch and one directly to the bottom of the print (probably the 'ground'?).
So I am wondering, what kind of AC transformer do I need? Probably a dual- trafo, but......2 x 18 V or 2 x 9 volt?
Interesting: the Proteus FX uses a singel 9 V AC powersupply.
Thanks for helping!
Fred

Re: power supply E-MU Proteus MPS

PostPosted: Mon Apr 17, 2017 12:57 pm
by madtheory
If you don't understand why the switch is wired that way, you should hand this over to a tech. That's a basic circuit- you'll electrocute yourself.

Re: power supply E-MU Proteus MPS

PostPosted: Mon Apr 17, 2017 1:57 pm
by Fred
Thanks for the warning MT, but I am not uncommon working with wiring, My only problem is - in the absence of the electr. diagram - that I like to know the AC voltage the trafo should deliver, read my question above. I wished somebody owns the powersupply and can measure the three outs of the trafo.

Re: power supply E-MU Proteus MPS

PostPosted: Mon Apr 17, 2017 10:28 pm
by Yekuku
Hi Fred and welcome aboard.
According to this pic from syntaur :
Image
It looks like it is a center tapped (CT) transformer that outputs 2 x 9V = 18VAC (9V-0V-9V).
I think that the pinout is also printed on the top, but the pic quality doesnt help to take a readout. My guess is , according to the printed pinout, 9V (Left pin) - 0V (Top pin) - 9V (Right pin)
Dont get madtheory wrong, power mains transformers can be lethal, if you don't know _exactly_ what you're doing.

Re: power supply E-MU Proteus MPS

PostPosted: Mon Apr 17, 2017 10:55 pm
by commodorejohn
I think it's actually 18V-0V-18V, but I'll try to remember to dig mine out this evening and check.

Re: power supply E-MU Proteus MPS

PostPosted: Tue Apr 18, 2017 8:41 am
by Fred
commodorejohn wrote:I think it's actually 18V-0V-18V, but I'll try to remember to dig mine out this evening and check.

Thank you for your reply Yekuku and CommodoreJohn !!
Yes I suppose also that it is a center tapped transformer. I saw the photo before.
CommodoreJohn, I really hope you can find out what is the case 9-0-9 or 18-0-18? That will be of great help!!
The top pin will be the 'zero'?
And do you think the synth needs 2 x 1,5Amp or in total 1,5Amp?
(pfff..... I've wrote several times to E-mu, but no reaction at all...)
Fred

Re: power supply E-MU Proteus MPS

PostPosted: Tue May 02, 2017 9:54 am
by Fred
commodorejohn wrote:I think it's actually 18V-0V-18V, but I'll try to remember to dig mine out this evening and check.

This is a polite reminder for CommodoreJohn:
I really hope that you or an other user can make it clear: 9-0-9 Volt or 18-0-18 Volt?

Re: power supply E-MU Proteus MPS

PostPosted: Tue May 23, 2017 10:50 am
by Fred
For anyone who wants to build this powersupply:
I've got my Proteus MPS working!
I bought a 230 (or 115) V to 2 x 9 Volt transformer like this one
http://docs-europe.electrocomponents.co ... 59b32a.pdf
You need 2 x 9Volt AC 1,5 amp ( or a 18V CT [center tapped]), not 2 x 18V AC!
The connector to the MPS is a mini-din-connector with 3 pins.
You connect two pins on the transformer, so it delivers
on the din connector:
left - middle pin 9V
right - middle pin 9V
right - left pin 0 (zero) V. (I didn't dare to try 18V here).

NB: Only for experienced technicians to construct, working with electricity is live threatening!!

Re: power supply E-MU Proteus MPS

PostPosted: Wed May 23, 2018 5:37 pm
by iamrcb
I've just picked up an MPS without a power supply so decided to make my own.

Bought a 30VA, 2 x 9V output at 1.5A each.

Connected 9V to left and 9V to right, with 0V to centre.

Plugged it in, all LEDs except for one light up and stay on. The LCD lights up and stays on but the characters are all "filled boxes" on the top line.

All components, traces etc look good. Voltage regulators have outputs, but the MPS unit won't operate.

Have I got something wrong in the power supply? Could it be something in the MPS?

Re: power supply E-MU Proteus MPS

PostPosted: Wed May 23, 2018 5:39 pm
by iamrcb
Can this be moved to the Help section?

Re: power supply E-MU Proteus MPS

PostPosted: Wed May 23, 2018 10:01 pm
by Yekuku
iamrcb wrote:I've just picked up an MPS without a power supply so decided to make my own.

Bought a 30VA, 2 x 9V output at 1.5A each.

Connected 9V to left and 9V to right, with 0V to centre.

Plugged it in, all LEDs except for one light up and stay on. The LCD lights up and stays on but the characters are all "filled boxes" on the top line.

All components, traces etc look good. Voltage regulators have outputs, but the MPS unit won't operate.

Have I got something wrong in the power supply? Could it be something in the MPS?


By zooming on the picture it looks like the pinout is correct, but i cant be 100% sure since I dont have the PSU in my hands.
The PSU should output AC, but I guess you already know this since you are confirming that the regulators are working .
The behavior that you describe means that the system does not initialize at start up , the main digital components (Eprom/CPU/DSP/RAM) are not working right. Are they getting 5Volts?
No wonder why it was sold without a psu.

Re: power supply E-MU Proteus MPS

PostPosted: Sun Jun 03, 2018 8:31 pm
by iamrcb
Progress made. My DIY replacement power supply works well and looks like a retail item.

It now starts up, screen works and diagnostics check out ok, but there is no sound. I can get the diagnostic test tones to sound, but none of the actual Proteus sounds.
I also tried using MIDI IN.

Voltages throughout the unit seem ok. The RAM bank data was all garbled and thew up errors, which went away when I copied the ROM sounds to the RAM bank.

Any ideas on what to check to determine where the fault is?

Re: power supply E-MU Proteus MPS

PostPosted: Fri Jun 08, 2018 9:21 pm
by iamrcb
Its gone off again. I suspect this is an intermittent connection problem between the main board and the switch/display board. I should be able to fix that

As for the no sound issue, if i'm getting the test tones out of the diagnostic test then the DAC, Op amps etc should be ok (total guess), so it may be that the sounds are just missing and need to be copied from one bank to another?