Emax

front panel is done by the scanner chip and cpu

so are the keys

sustaning notes is usually a bad diode on the keyboard some where
  ----- Original Message ----- 
  From: cheju_99 
  To: emax@yahoogroups.com 
  Sent: Sunday, July 22, 2012 11:42 PM
  Subject: [emax] Re: No black boxes boot


    
  Finally after reseating some ic´s the unit began to boot from the diskette, now the problem is : it load the preset tone but i have no access to the front panel buttons, even no lights form the form panel leds, and also when i press the music keyboard it becomes a totally mess, with tones in chaos no scale, sustain for ever......recently i changed the scanner chip with a nes one form eprelectronics but nothing happens.... any idea?

  --- In emax@yahoogroups.com, "cheju_99" <cheju_99@...> wrote:
  >
  > Ok great advice i'll ask Ted
  > Thanks for your time
  > 
  > --- In emax@...m, "jammie" <jammie.emma@> wrote:
  > >
  > > basically send it to ted who can test against another mainboard to see where the problem is
  > > 
  > > as you could be nocking your head against the wall not know what is actually wrong
  > > 
  > > you could be changing chips that dont need changing 
  > > 
  > > as it could be a cap thats gone down to earth and dropping a signal to zero volts
  > > 
  > > with out a scope or a anilyser you cant tell
  > > 
  > > as ted can test a good working machine and compare the functions from the none working machine to see if the signals are correct
  > > ----- Original Message ----- 
  > > From: cheju_99 
  > > To: emax@yahoogroups.com 
  > > Sent: Sunday, June 10, 2012 10:05 PM
  > > Subject: [emax] Re: black boxes No boot
  > > 
  > > 
  > > 
  > > Its a keyboard i upload some photos to the forum
  > > 
  > > --- In emax@yahoogroups.com, "jammie" <jammie.emma@> wrote:
  > > >
  > > > no the lcd control is seperste from the scanner cpu
  > > > 
  > > > the scanner cpu deals with the keyboard matrix of notes and velocity
  > > > 
  > > > and also scans the front control buttons when a momentary pulse from a button it goes to the correct software access and lights a led if there is a led function for it via some logic switches
  > > > 
  > > > the scanner interfaces with the main cpu giving it all the control information
  > > > 
  > > > cpu with other logic chips deals with the lcd but gets the control information from the scanner cpu and duart
  > > > 
  > > > what board do you have rack or keyboard
  > > > ----- Original Message ----- 
  > > > From: cheju_99 
  > > > To: emax@yahoogroups.com 
  > > > Sent: Sunday, June 10, 2012 8:44 PM
  > > > Subject: [emax] Re: black boxes No boot
  > > > 
  > > > 
  > > > 
  > > > I am thinking this must be related to a failure in the front panel panel, what do you think?
  > > > 
  > > > --- In emax@yahoogroups.com, "jammie" <jammie.emma@> wrote:
  > > > >
  > > > > broken floppy
  > > > > 
  > > > > this can also make the lcd screen crash
  > > > > 
  > > > > remove floppy drive idc cable and see if it comes up with the emu screen
  > > > > 
  > > > > it could be a number of chips but i would check the floppy disk controller
  > > > > 
  > > > > if your brother is a digital electronics technician then he can check the pulses with a logic anilyser and cross reference with the pdf for the pulse signals to see if he is getting correct signals
  > > > > 
  > > > > also have you got the cable the corect way on the floppy is it an original or a replacement as if its a replacement the floppy cable goes the oposit to the original version 
  > > > > 
  > > > > as you have to do that on all models due to the manufactureres setting the to pc standard and pin 1 is the oposit side
  > > > > ----- Original Message ----- 
  > > > > From: cheju_99 
  > > > > To: emax@yahoogroups.com 
  > > > > Sent: Sunday, June 10, 2012 6:58 PM
  > > > > Subject: [emax] Re: black boxes No boot
  > > > > 
  > > > > 
  > > > > 
  > > > > Yes i already check the cables pin 1 is ok. My brother (digital electronics technician) insist that is a power issue, 'cos no spin on the floopy but we checked completely the psu and q2 on the board but the volts are ok, i am seriously thinkig my pal chips are dead, what do you think???
  > > > > 
  > > > > --- In emax@yahoogroups.com, Ted Summers <djtbs1@> wrote:
  > > > > >
  > > > > > You may also wish to reseat the IC's on the right half of the Emax logic board including the EPROM.
  > > > > > My testbed for the SCSI kits does this as it gets flexed from many IC removal / replacement and so the seating of IC's isn't great.
  > > > > > 
  > > > > > Once I reseat everything I will get my display back and floppy whirring away- IT's ALIVE, ALIVE!!!!
  > > > > > BWAHAHAHA!!!
  > > > > > 
  > > > > > Just a thought.
  > > > > > The other option is to send it to jammie or me (depend on where you live). I doubt it is dead, you may just be looking at the wrong thing / area of the board.
  > > > > > 
  > > > > > or Jammie has some boards... I do believe.
  > > > > > 
  > > > > > Thx,
  > > > > > Ted
  > > > > > 
  > > > > > 
  > > > > > 
  > > > > > 
  > > > > > On Jun 10, 2012, at 2:12 AM, jammie wrote:
  > > > > > 
  > > > > > check the digital to audio board cable have you got it reversed
  > > > > > ----- Original Message ----- 
  > > > > > From: cheju_99 
  > > > > > To: emax@yahoogroups.com 
  > > > > > Sent: Sunday, June 10, 2012 3:50 AM
  > > > > > Subject: [emax] black boxes No boot
  > > > > > 
  > > > > > After spending many dollars buying the technical manual, and the 6500 scan processor from eprelectronics, definitely with no success triying to start an emax 1- Right now got the unit with the display showing black boxes, a floppy drive who doesn´t spin, and definitely no boot. Any idea from the people´s forum????......hurry the trash truck is coming. 
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