First post and Pro-Mars 8048 question.

The Roland Jupiter-4 and ProMars Compuphonic Analogue Synthesizer
Ohm's Law
Posts: 1
Joined: Fri Mar 18, 2011 12:43 am

First post and Pro-Mars 8048 question.

Postby Ohm's Law » Mon Mar 28, 2011 10:05 pm

Hi,

After looking at my ProMars more i'm worried the CPU maybe dead.

Most pins are at +5VDC including the ABC output to the front-panel multiplexer's inputs.

Any ideas of anything else to check? Crystal input is still there.

Did Roland use the rom in the Intel chip or an external? Can it be swapped?

A bit sad

Thanks,

Tim.

Mr Arkadin
Posts: 27
Joined: Sun Jul 26, 2009 9:10 pm

Postby Mr Arkadin » Mon Mar 28, 2011 11:54 pm

I can't help on specifics, but I wonder if Covariance's kit would fix your problem (and give you MIDI and extra features into the bargain).

Hopefully he'll chip in.

covariance
Posts: 47
Joined: Fri Oct 16, 2009 8:53 pm

Re: First post and Pro-Mars 8048 question.

Postby covariance » Wed Mar 30, 2011 8:45 am

Ohm's Law wrote:Hi,

After looking at my ProMars more i'm worried the CPU maybe dead.

Most pins are at +5VDC including the ABC output to the front-panel multiplexer's inputs.

Any ideas of anything else to check? Crystal input is still there.

Did Roland use the rom in the Intel chip or an external? Can it be swapped?

A bit sad

Thanks,

Tim.


The CPU periodically switches most of its digital lines. There are nice diagrams in the service manual. Static lines is the symptom of a faulty CPU.
As Arkadin said the Io patch programmer is a direct replacement for a Promars CPU with tons of extras (64 patch memory, full midi on parameters, patch reedit, copy, dump).

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Senso
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Joined: Thu Aug 19, 2010 1:29 pm
Location: Amsterdam - Netherlands
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Postby Senso » Thu Jun 09, 2011 8:49 am

Yes, the internal ROM is pre-programmed during manufacture and holding the operating system, supplied to Nec by Roland. Same for the second 8048, the keyboard controller.
So they were only for sale through Roland and sold out for many years now. However, I do have re-issues available for both (and several other 8048 & 8049 synth CPUs).
You will find them on the site below. :wink:
---------- VINTAGE PLANET --------
----- Synthesizer Parts Service ----
--- http://www.vintageplanet.nl ---


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