ULA6C001E-7 and 48K Issue 2

edited June 2012 in Hardware
Dear Sirs,

Could you please let me know if ULA6C001E-7 or ULA6C001E-6 chip was suitable for 48K board issue 2 ?

I heard some mods are neccessary but I can't find which mods...

Thank you,

Kind regards

Marcin
Post edited by ikci on

Comments

  • edited June 2012
    Yes, it is. Thought if you had an older ULA, there is a "hardware patch" to fix a bug with that ula in place on the board. I am not sure if you have to disconnect this or not. I used a later revision ULA for testing purposes on my Issue 2, and had no issues with that, even though I did not remove the "patch".
  • edited June 2012
    What is this hardware patch? Are you reffering to a transistor on top of the Z80?
  • edited June 2012
    gtsamour wrote: »
    What is this hardware patch? Are you reffering to a transistor on top of the Z80?

    Exactly, that is the patch.
  • edited June 2012
    Thank you for your reply.

    I also found some interesting information here:

    http://www.worldofspectrum.org/hardware/rep6.html


    Issue 2 Modifications

    (...)
    (...)
    (4) The only currently available ULA is type 6C001. When this is used to replace an earlier type the following modifications should be made: change R47 to lkohm. R49 to 10kohm and R56 and R63 to 470ohm.


    Yesterday I spent a few hours searching for this information without success.

    Today I just googled "ula hardware patch transistor" mentioned by you and third position @ google was what I needed.

    Thank you!

    BTW: I also placed new ULA 6C001 to Issue 2 without any modifications and it worked. But I am afraid of compatibility issues. So I would prefer to ask rather than make a mistake...
  • edited June 2012
    The "dead spider" transistor is still required as this was incorporated into the motherboard of later models.
    The ULA book suggests some resistors might have to be changed when using a 6C series ULA instead of a 5 series but has no details.
  • edited June 2012
    Ok. Thank you for that info. Then I know I can run a newer ULA on my issue 2 without removing that transistor :)
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