Synth-DIY Yahoo! Groups Archives

Emax II Key response delay issue

2014-07-11 by stevelimbrick@...

Been having intermittent problems with my Emax II 2212 where I don't always get an immediate sound when I play a number of keys. Some of the keys really take a number of goes to get a response from, others may take one or two plays while others produce a sound a second or two after playing the key. The majority of keys are working fine and the offending keys are spread randomly across the keyboard.

I've tried using Deoxit to clean the contacts under the keyboard but it doesn't seem to have helped at all.

Any ideas? I'm in no way an electronics person, but am game to check anything suggested so long as specific enough instructions are provided and it isn't too technical!

Thanks,

Steve

Re: [emax] Emax II Key response delay issue

2014-07-11 by JAMIE logan

does it work allright with midi

do any of the buttons on the front panel also play up

i would say its the rockwell scanner chip the only place that stocks them are epr electronics

they are expensive

the scanner chip deals with the front buttons and the emax keyboard

same chip is used in the emax1/2/EIII rack and keyboard

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On 11 July 2014 09:23, stevelimbrick@... [emax] <emax@yahoogroups.com> wrote:

Been having intermittent problems with my Emax II 2212 where I don't always get an immediate sound when I play a number of keys. Some of the keys really take a number of goes to get a response from, others may take one or two plays while others produce a sound a second or two after playing the key. The majority of keys are working fine and the offending keys are spread randomly across the keyboard.

I've tried using Deoxit to clean the contacts under the keyboard but it doesn't seem to have helped at all.

Any ideas? I'm in no way an electronics person, but am game to check anything suggested so long as specific enough instructions are provided and it isn't too technical!

Thanks,

Steve

Re: [emax] Emax II Key response delay issue

2014-07-11 by stevelimbrick@...

Hi Jamie,

No problems with any of the front buttons that I've noticed.

Not sure about MIDI performance as it's not connected up to anything at present.

Steve

Re: [emax] Emax II Key response delay issue

2014-07-11 by JAMIE logan

is it the same keys in every octave as you might have a faulty diode

please check midi first

where do you live as i have spare keyboards and can repair component level to the key contact boards

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On 11 July 2014 13:14, stevelimbrick@... [emax] <emax@yahoogroups.com> wrote:

Hi Jamie,

No problems with any of the front buttons that I've noticed.

Not sure about MIDI performance as it's not connected up to anything at present.

Steve

Re: Emax II Key response delay issue

2014-07-11 by stevelimbrick@...

No, not the same keys in each octave.

I live in Australia - unfortunately moved a few hours out from Sydney 18 months ago, so not as easy to get it serviced anymore (found Steve Jones in Sydney before we moved).

Re: [emax] Re: Emax II Key response delay issue

2014-07-11 by JAMIE logan

ok i recon its the scanner chip

what happens is there are many channels and they short out

and those channels are no good usually its the keyscanner part that goes and the keyboard scanning part is fine

mostly on emaxes

the buttons also multiplex with the lcd so that the lcd uses the correct names and presses with the cpu

through 74 logic chips

on the ensoniqs they also control the vfd row and column that they no longer trigger

they are a cpu with logic and they have a custom mask rom so that the logic switches to the programmed

on the ensoniqs they have 2 of the same chips one does the scsnning of the keyboard and the other does the vfd and button scanning

but on the emax they use it for both the keyboard scanning and the buttons

so if it fails in any department you have to change the chip

it sounds like the scanner chip is failing to check this you really need a logic analyzer so that you can measure the voltages and the logic functions

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On 11 July 2014 13:48, stevelimbrick@... [emax] <emax@yahoogroups.com> wrote:

No, not the same keys in each octave.

I live in Australia - unfortunately moved a few hours out from Sydney 18 months ago, so not as easy to get it serviced anymore (found Steve Jones in Sydney before we moved).

Re: [emax] Re: Emax II Key response delay issue

2014-07-11 by Lorne Hammond

agreed, if it hops about its in the scanning.  those delays are keys you
hold down right, so it misses it on the depression and gets it the next
scan.  Look for scanner chip, logic divider chips feeding it/cpu from it.
Do not trust sockets for any chips. also a gentle quick 275 degree hot aiir
pass might reflow solder if its a flakey connection, in the right area.  But
you need to understand the flow of scan data from the keyboard to the cpu
and then figure out if its moving about in a pattern, ie, missing every 3
&7th note which is on bus "n" whereas note 14 are on Y handled by a
different chip all of them eventually being joined.  Could be a feeder chip
serving the scanner.  Note, I could have it all wrong as a guess, I liked
the first bit of advice you just got.  My point is "random" is not "random",
From teh scanner's perspective the events are random (keys you push or
switches touched, nd there is a consistent non-reporting happening due to a
chip fail/solder fail in teh bus lines.  So you have to understand the
pattern of what is being missed, how it "reads"..  Then zero in from there:
Bad important chip, cheap serve chip, bad socket, cold solder joint, bad
diode on a line, cap & ground issue.  Its a different way of looking than an
analog mechanical keyboard.  Lorne

Re: [emax] Re: Emax II Key response delay issue

2014-07-11 by stevelimbrick@...

OK, thanks.

Sounds like stuff beyond my ability to work on or diagnose properly.

Looks like I'll be trying to get the keyboard down to Sydney sometime (though I hear Steve Jones isn't doing so much repair work these days due to other commitments - guess I'll contact him to see if anything can be sorted out).

Anyone know another synth repairer in Sydney they'd recommend just in case?

Re: Emax II Key response delay issue

2014-07-12 by Steve Limbrick

Is the Rockwell chip soldered in or can it be lifted off and replaced easily - assuming I could find one, as the company mentioned in an earlier post currently says 'out of stock' on their website. Though their price of $56 is not anywhere near as bad as I was expecting when it was mentioned that the chips are expensive.

Re: Emax II Key response delay issue

2014-07-12 by cadena100rb@...

Steve:
I wouldn't go for the Scanner chip at first. Moreover I would go for stuck keys (spring problems). I often get those errors on my two Emax I when I take a while since I don't play them.

Same symptoms: Notes sound bit after depressing keys, double triggers sometimes, etc etc.

When depressing the keys several times, things start to run fine for a while.

I would try to replace the key springs (Ebay provides you sellers with that stuff). Just in case this method don't work, I would go for the Rockwell scanner chip. As Jammie pointed before, an expensive one.

Best..

DX5.

Re: Emax II Key response delay issue

2014-07-13 by Steve Limbrick

Thanks DX5, keyboard hadn't been played much in the last year (a few house moves and so on in that timeframe), so that might definitely be a contributing factor. I've seen the key springs for sale a couple of times, in fact I bought some a while ago - just need to find then again now!

Steve

Re: Emax II Key response delay issue

2014-07-14 by jammie.emma@...

key springs have nothing to do with the contacts they just take the key back to the start position

now the contact spring wires these have to be soldered into position and they have 2 balls that fit into the recess of the key and the contact board

these just need to be cleaned with some deoxite

its a fatar keyboard and its the rev 1 types these do not have bubble contacts like later generations that suffer from the carbon bubble contacts with bad triggering

on these keyboards there is a note on bar and a not off bar when you hit a key the spring wire contact hits the bottom bar making a circuit the diode conducts then you let go of the key and the return spring takes the wire back to the note off bar

which sets the note on and off messages

Re: Emax II Key response delay issue

2014-07-15 by cadena100rb@...

Obviously I was meaning Key Contact Springs when referring to key springs.

I had exactly the same problem on both Emax 1 of mine.

I also had the IM386 Scanner fault. The Emax got frozen. No key at all was working then.

Re: [emax] Re: Emax II Key response delay issue

2014-08-10 by djrgary@...

There are also contact springs (2 for each key, 1 for key released, other for key pressed) that you may want to check for cleanliness. They use this setup to control timing for key response. If you have to replace any Syntaur had them the last time I checked.

Sent from Yahoo Mail on Android

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From: cadena100rb@... [emax] ;
To: ;
Subject: [emax] Re: Emax II Key response delay issue
Sent: Sat, Jul 12, 2014 1:48:05 PM

Steve:
I wouldn't go for the Scanner chip at first. Moreover I would go for stuck keys (spring problems). I often get those errors on my two Emax I when I take a while since I don't play them.

Same symptoms: Notes sound bit after depressing keys, double triggers sometimes, etc etc.

When depressing the keys several times, things start to run fine for a while.

I would try to replace the key springs (Ebay provides you sellers with that stuff). Just in case this method don't work, I would go for the Rockwell scanner chip. As Jammie pointed before, an expensive one.

Best..

DX5.

Re: Emax II Key response delay issue

2014-08-15 by Steve Limbrick

Thanks for that, I haven't noticed these other 2 springs before - where are they located? I'm assuming as I haven't seen them when cleaning the obvious springs that they are hidden underneath something?

Steve

Re: [emax] Re: Emax II Key response delay issue

2014-08-15 by JAMIE logan

the keys its one spring it connects to the key and there are 2 contact bars

you need to remove the key to get at them

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On 15 August 2014 01:58, Steve Limbrick stevelimbrick@... [emax] <emax@yahoogroups.com>; wrote:

Thanks for that, I haven't noticed these other 2 springs before - where are they located? I';m assuming as I haven't seen them when cleaning the obvious springs that they are hidden underneath something?

Steve