Vintage Synth Repair

Maybe there's a contrast adjustment for the display? ?

Hi.. yes there is a trim pot although I haven’t touched it yet
will have a look later at psu
I checked caps for ESR in circuit although could be they need to be out of cct.. I do not have schematic
thank you for your info re internet board and also your help
NoelBuhagiar









there should be a trimpot in the psu for adjusting to the correct voltage of 5,5 volts. however in some cases there is no trimpot, but instead only some resistors where it should be. i had one like that once, and swapped out the resistors for a trimpot. do you have a trimpot in your psu ?
there is a good internet board for Emu stuff:


http://www.eiiiforum.com


Med venlig hilsen


Kim G. Hansen
Redaktør, Radio24syv


On 24/02/2015, at 17.04, "NoëlBuhagiar laser@... [vintagesynthrepair]" <vintagesynthrepair@yahoogroups.com> wrote:





  Hi... have been given an Emulator III with a removed SCSI drive but owner said it worked loading OS from floppy.
  When I checked it it did not work and LCD had black square characters. Checked all SMPS voltages and the +5V is low at 4.6V.
  E-mu did not repair or supply schematic for the power supply. Are E-mu still in operation? Anyone has been here, before I dig in the power supply?
  All caps seem to be ok although best to remove them to check to be sure.
  Any help please, thanks,
  cosmo

hi Jamie, thank you for your very useful information you have much experience I know
there is a switch at back to set voltage yes.. it is set proper for 230/240Vac ok
e3 doesn’t look seen by someone else, psu looks quite okey...
the guy is a client friend of mine from Britain
he lived here for last few years.. a very nice guy
with lots of experience with regards to vintage synths as he used to work in studios of well known
British record companies but now things changed
thks, NoelBuhagiar









epr electronics are the emu repairer




i have replaced the psu before with a switchmode version from rs the voltages 12/-12/5v/0v




the psu is also used in the emax 1 and 2 there is a trimmer to adjust the 5v 4.6v is still with in range




emu did not make any of the psu they were sub contracted out to a korean firm called skynet and hence why there were no schematics as there were several versions of the same psu that used different methods of doing 110v and 220-240 switching




in later models some later e3 and emax2 used switchmode active sensing circuits the older versions need to have the switch on the back set




black boxes could be a bad scanner cpu chip common problem also on the emax1 and 2 the e3 and the emax1/2 all use the same button scanning chip its a masked rom rockwell 8bit cpu it interfaces with the main cpu and the usart if part of it fails you get the dreaded black boxes or no button scanning




epr did have spares




also who was the person you got the e3 from as there is a tinker from germany that bodges bits and recks traces who i had to repair a sp1200 because he tinkered with that




On 19 February 2015 at 14:22, NoëlBuhagiar laser@... [vintagesynthrepair] <vintagesynthrepair@yahoogroups.com> wrote:



  Hi... have been given an Emulator III with a removed SCSI drive but owner said it worked loading OS from floppy.
  When I checked it it did not work and LCD had black square characters. Checked all SMPS voltages and the +5V is low at 4.6V.
  E-mu did not repair or supply schematic for the power supply. Are E-mu still in operation? Anyone has been here, before I dig in the power supply?
  All caps seem to be ok although best to remove them to check to be sure.
  Any help please, thanks,
  cosmo

Hello and thank you!
doesn’t look like a contrast setting problem as characters
are seen ok on LCDisplay but they’re not right
thks, NoelBuhagiar





Maybe there's a contrast adjustment for the display? ?

thanks for your time and help
temperemental instrument??!!... will check that out.. LOL
NoelBuhagiar





i wrote that it should be trimmed to 5,5 volts. that was from memory and it was not quite correct: it shiuld be 5,05 volts. not much, but it can make  a difference in this temperemental instrument


Med venlig hilsen


Kim G. Hansen
Redaktør, Radio24syv


On 05/03/2015, at 22.41, "NoëlBuhagiar laser@... [vintagesynthrepair]" <vintagesynthrepair@yahoogroups.com> wrote:





  Hi.. yes there is a trim pot although I haven’t touched it yet
  will have a look later at psu
  I checked caps for ESR in circuit although could be they need to be out of cct.. I do not have schematic
  thank you for your info re internet board and also your help
  NoelBuhagiar







  there should be a trimpot in the psu for adjusting to the correct voltage of 5,5 volts. however in some cases there is no trimpot, but instead only some resistors where it should be. i had one like that once, and swapped out the resistors for a trimpot. do you have a trimpot in your psu ?
  there is a good internet board for Emu stuff:


  http://www.eiiiforum.com


  Med venlig hilsen


  Kim G. Hansen
  Redaktør, Radio24syv


  On 24/02/2015, at 17.04, "NoëlBuhagiar laser@... [vintagesynthrepair]" <vintagesynthrepair@yahoogroups.com> wrote:





    Hi... have been given an Emulator III with a removed SCSI drive but owner said it worked loading OS from floppy.
    When I checked it it did not work and LCD had black square characters. Checked all SMPS voltages and the +5V is low at 4.6V.
    E-mu did not repair or supply schematic for the power supply. Are E-mu still in operation? Anyone has been here, before I dig in the power supply?
    All caps seem to be ok although best to remove them to check to be sure.
    Any help please, thanks,
    cosmo