[sdiy] Ensoniq ESQ-1 Serving Questions

[Kyle Stephens]

Rainer,

I didn't try turning it on w/out the battery, though I suppose I could undo the solder and tilt it up to try that.

It's pre-3.5, so guess I'll do an upgrade (I know you've the OS up on your site). And the keyboard cable's just a ribbon one, shouldn't be a problem swapping that or running my meter along the main board/keyboard socket area to check the pins there.

Thanks!


_Kyle

--- On Thu, 4/16/09, Rainer Buchty <rainer at buchty.net> wrote:

> From: Rainer Buchty <rainer at buchty.net>
> Subject: Re: [sdiy] Ensoniq ESQ-1 Serving Questions
> To: "Kyle Stephens" <lightburnx at yahoo.com>
> Cc: synth-diy at dropmix.xs4all.nl
> Date: Thursday, April 16, 2009, 3:44 PM
> On Thu, 16 Apr 2009, Kyle Stephens
> wrote:
> 
> > It still does not get past a screen telling me the
> name, make, model and OS, as it did before replacing the
> battery even (even with a low battery it's supposed to still
> function). No amount of button pushing or doing the system
> reset button combo press has any effect.
> 
> When you remove the battery, does it go past the reset
> routine?
> 
> Usually, the reset procedure is as follows: it is checked
> for some "magic cookie" of 4 bytes, if that is found, then
> only the small reset routine is executed (basically
> initializing the peripherals), otherwise a full factory
> reset is performed including playing back the factory preset
> sounds (not present with OS<3.5, with earlier versions
> you end up with 40x BRASS1).
> 
> > Might replacing the EPROMs solve my issues? I can't
> think of anything else.
> 
> If you are pre-3.5, it's definitely worth an upgrade, even
> though the no-boot problem should be unrelated.
> 
> > Another quirk is a small set of keys are dead for the
> synth engine, but work with the MIDI according to Tim. The
> 3rd G# to the 4th D# are the offending keys. Tim reckoned
> one of the diodes in the scanning matrix are dead, but how
> would one go about checking that?
> 
> That's a cluster of 8. From my experience with those
> machines, I somewhat doubt that it's diode-related, but
> rather a defective keyboard controller.
> 
> The keyboard is organized in 8 rows of 8 columns. So if you
> select a row (a cluster of 8 consecutive keys) with a diode
> tester, you should see a connection to the 8 individual
> columns: for these you have either the idle column or the
> pressed column.
> 
> > I've the keyboard assembly in front of me now, and
> it's rather clever imo - there's two buss wires for
> measuring the attack time, as actuated by a small length of
> fine spring attached to each key, with the other end
> soldiered to the diode and so on.
> 
> Have a look at
> 
>     http://www.buchty.net/ensoniq/files/esq1-tg/20.jpg
> 
> for the schematics of the keyboard control logic.
> 
> Rainer
> 
> 
> 
>