Emax

Hello,

I tried to swap RAM ICs = error remains the same.
changed the two 74HCT157 near the E-Chip = error remains the same.
removed the pal = error remains the same.
removed the E-Chip = error remains the same.

The Service Manual shows a procedure to calibrate the E-Chip.
Is it possible to perform a calibration when there is no sound?
Is there any other way to test the E-Chip or the PAL?

Regards,

Odyssey3001



--- In emax@yahoogroups.com, Ted Summers <djtbs1@...> wrote:
>
> You should be swapping the indicated IC # with an IC location that is higher / different.
> 
> Then, if the ic problem is indicated during the test at this new location, that IC is likely bad.
> 
> -T
> 
>  
> On Aug 16, 2013, at 3:22 AM, odyssey3001 wrote:
> 
> 
> 
> Hello,
> 
> The files section holds a pdf called "Emax Diagnsotics.pdf". This file seems to contain the missing pages of the service manual.
> 
> If you pull one of the RAM-chips does the error message stay the same?
> 
> As for the floppy issues: Can you swap the drive with a known good one or a floppy emulator like HXC?
> 
> Regards,
> 
> Odyssey3001
> 
> --- In emax@yahoogroups.com, "ajarlev" <ajarlev@> wrote:
> >
> > Hello
> > 
> > I have the same problem. Eram test says is 71sbc bk01c, AD777778 ADRESS
> > The emax se plus works somtimes, but suddenly it frezes up. Also somtimes difficult to load disks. I found the service manual, but the eram dignostics pages were missing.
> > 
> > I tried the ic cleaning on the ram board. I will try to take it out to see if there is a problem
> > on the backside.
> > 
> > I hope someone here has the answer
> > 
> > -alx
> > 
> > 
> > 
> > --- In emax@yahoogroups.com, "odyssey3001" <odyssey3001@> wrote:
> > >
> > > 
> > > Hello fellow EMAX users,
> > > 
> > > 
> > > 
> > > I recently acquired an EMAX Rack. As it seems the unit was stored in a
> > > damp environment for quite some time.
> > > 
> > > It boots up until the "Please Insert Disk" message appears and
> > > the following LEDs are lit:
> > > 
> > > Master, Transponse and Enter.
> > > 
> > > The Floppy drive did not take any disks, so a HXC-emulator was hooked
> > > up.
> > > 
> > > It is possible to load floppy images with the HXC.
> > > 
> > > There is no sound, the only thing that is heard is a click sound if
> > > notes are sent via midi.
> > > 
> > > The following measures were taken so far with measures against static
> > > discharge:
> > > 
> > > - PCB cleaning.
> > > 
> > > - Reseating of all socketed ICs on the digital board, except for
> > > the E-Chip because it was not possible to get it out of the socket.
> > > 
> > > - Results of The Internal tests: Bank RAM test passed, ERAM test
> > > failed.
> > > 
> > > Message:
> > > 
> > > is80sb01 bk0ic??
> > > 
> > > ad000000 galpat
> > > 
> > > - If I remove any of the RAM chips the message stays the same.
> > > 
> > > 
> > > 
> > > To make a long story short: What can I do to bring the unit back to
> > > life?
> > > 
> > > As for test equipment I am in possession of a scope and a logic
> > > analyzer.
> > > 
> > > I don't know exactly where to start to look for errors.
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 
> > > [Non-text portions of this message have been removed]
> > >
> >
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>