Patches and discussion for Ensoniq VFX family

you could change many parts to find out its not that that was broken

you need a logic anyliser to see whats wrong with cpu and logic chips and the data sheet so you can see

what cycles and voltages and timmings are supposed to happen

and getting the data sheet for the 6500 which has a prom on it with ensoniq specific code for the job it performs so you would also need this data

and the problem is its not available

we have had to do it the brut force method with a logic anyliser and recording all the functions

and then copying them onto a fpga logic circuit

its alot of work and we are still in the design phase of the project with this new interface chip

as it is needed to keep alive lots of ensoniq synths

as in the past i have had to put to pastures several metal case esq1 becuase of this chip

you are better of buying that vfd board for the vfx from syntuar and then you will hve spare parts

as you could be changing lots of parts for nothing and it might still not work
  ----- Original Message ----- 


  From: Daeron 
  To: Ensoniq-VFX-SD@yahoogroups.com 
  Sent: Thursday, September 06, 2012 2:48 PM
  Subject: Re: [Ensoniq-VFX-SD] Ensonix VFX-SD no work!


    

  Yes! i change the power supply thinking that was the problem the but it was not!



  Daeron...


------------------------------------------------------------------------------
  De: Christian Brunschen <cb@...>
  Para: Ensoniq-VFX-SD@yahoogroups.com 
  Enviado: Jueves, 6 de septiembre, 2012 8:37:01
  Asunto: Re: [Ensoniq-VFX-SD] Ensonix VFX-SD no work!



    
  On Sep 6, 2012, at 2:34 PM, Daeron <daeron_elf@...> wrote:


    Dear Christian!
    thanks for you support! it's a very complete information, i will try to check every chip separately!



  Hi Daeron,


  from the video you showed, there's a brief flash of something on the display before it all goes blank; that's not really the kind of problem that I think has to do with any one of the driver chips being bad, alas. I think that as has been said elsewhere in this thread, it may be the microcontroller. Possibly, though, it might be a power-related issue?


    Daeron...


  // Christian





----------------------------------------------------------------------------
    De: Christian Brunschen <cb@...>
    Para: Ensoniq-VFX-SD@yahoogroups.com 
    Enviado: Jueves, 6 de septiembre, 2012 7:10:19
    Asunto: Re: [Ensoniq-VFX-SD] Ensonix VFX-SD no work!



    On Sep 2, 2012, at 9:00 PM, Daeron <daeron_elf@...> wrote:


      Oh! thanks a lot for your support! somebody know the part number of the controller chip? i found this: Display driver integrated circuit chip, TL4810BN on syntaur!



    Actually, the display board on the VFX-series of boards uses two different driver chips to drive the VFD (Vacuum Fluorescent Display). In that respect it is similar to the ESQ1 - whose display board schematic is here: http://memi.de/~buchty/ensoniq/schematics/esq1/esq1-display.jpg


    As on the VFX / VFX--SD / SD-1, there are two different chips, both with similar function:


    4 * TL4810A to drive the choice of segments; and
    2 * TL5812 to drive the columns.


    Basically, the VFD works by lighting up those segments that are addressed by the combination of the selected column (40 columns, one pin for each column => 40 pins) and the selected set of segments (2 rows of characters with 14 segments per character => 28 pins).


    The driving chips are shift registers, into which data are written sequentially, and then presented in parallel. The TL4810A chips are 10-bit shift registers, and the TL5812 chips are 20-bit shift registers.


    The two TL5812:s are arranged sequentially to comprise effectively a single, 40-bit shift register, their 40 outputs each connected to one of the 40 'column' pins on the VFD; the 4 TL4810A:s are separate, each connected to separate input pins from the 6500 processor, and each having 7 of its outputs connected to 7 of the 'segment' driving pins on the VFD.


    In order to draw a complete screenful, I believe the display board does the following.


    The display board iterates through each column on the board. It does this by shifting a single '1' into  the 40-bit shift register comprised of the 2 TL5812:s. At the beginning of displaying a screenful, we thus have a single '1' and 39 '0's present on the column-driving pins of the VFD, thus effectively selecting column 0.


    At the same time, it shifts 4 sets of 7 bits, one into each of the TL4810A:s, thus specifying which 4*7 = 28 segments should be lit in the 0:th column of the display. 


    This means that the display will light up precisely those selected segments in column 0.


    Then a '0' is shifted into the 'column' shift register, advancing the '1' to select column 1; and a new set of 7 bits per register are shifted into the 4 TL4810A:s, to specify the set of segments lit in that column, and so on.


    Troubleshooting-wise, this basically means that if you have symptoms where the left or right half of the display is messed up but the other (right / left) half is OK, it's likely a problem with one of the TL5812 chips. If you have problems with some of the segments in all characters in one row, that indicates an issue with one (or more) of the TL4810A chips.


    Intriguingly enough, I've found both TL5812:s and TL4810:s  on eBay:


      http://www.ebay.co.uk/itm/120922031767


      http://www.ebay.co.uk/itm/110886748416


    (the TL4810BN is an improved version of the TL4810A).


    Best wishes,


    // Christian Brunschen






       please sorry for my bad english is not my native language!

      Daeron...


--------------------------------------------------------------------------
      De: jammie <jammie.emma@...>
      Para: Ensoniq-VFX-SD@yahoogroups.com 
      Enviado: Domingo, 2 de septiembre, 2012 14:52:01
      Asunto: Re: [Ensoniq-VFX-SD] Ensonix VFX-SD no work!



      the fip controller chips are fualty

      its a common problem on the asr10

      and the esq1 sq80

      so its no suprize that the vfx has the same fualt as the esq1 and sq80 vfx sd and the ts10 all use the same display

      and you cant get the chips any more i know i have tried as i fix these all the time

      we are working on an fpga design to replace but still in the designing and testing phase
        ----- Original Message -----
        From: STEPHEN PRATT
        To: Ensoniq-VFX-SD@yahoogroups.com
        Sent: Sunday, September 02, 2012 8:21 PM
        Subject: Re: [Ensoniq-VFX-SD] Ensonix VFX-SD no work!


         
        How old is the backup battery?


        On Sep 2, 2012, at 2:58 PM, Daeron wrote:


           
          Hi! some body help me! my vfx-sd don't work any more, i change the power supply but nothing! i push the power on and just a little flash on the display!
          like this: http://www.youtube.com/watch?v=dNBW3DluHj0&feature=plcp