jlopez Intermediate

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  • Member since Apr 28th 2019
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  • jlopez

    Replied to the thread P3 - Reverse engineering.
    Post
    (Quote from PAW)


    Removing them all was a must, certain components can interfere multimeter readings (low impedance resistors, dead capacitors, etc.). And yes, I was going the scanner way (scanners don't have either lightning or perspective problems). You…
  • jlopez

    Like (Post)
    Hi Jaume,
    (Quote from jlopez)

    did I understood well, that you put off all components of the PCB to get an empty board? Then you want to draw a circuit diagram of the board?

    In the 1990s a colleague and I did a similar job, but we did not destroy the…
  • jlopez

    Replied to the thread P3 - Reverse engineering.
    Post
    (Quote from helwie44)

    Fortunately the worst part is nearly finished... albeit the connector will prove to be a nightmare. ;)

    At this point six ICs, two resistors, four resistor arrays, four capacitors, a socket and the connector remain soldered. Three new…
  • jlopez

    Like (Post)
    Thanks Jaume;
    You chose a tedious job.
    It is a pity that we really do not have circuit diagrams of the TA Triumph Adler / sks of the Px machines of the plug-in cards.

    I still have a sks-KISS CPU card - which I successfully tested in a P2U. But I had to…
  • jlopez

    Posted the thread P3 - Reverse engineering.
    Thread
    Greetings,

    A few days ago I started to desolder the P3's CPU board (CAAA08 - CA1102/8HP00067). The desoldering hand pump broke soon afterwards and this Monday received a replacement (which broke after 1h of use, but that's another story :D). Approximately…
  • jlopez

    Replied to the thread New memory boards for the P2.
    Post
    (Quote from gpospi)

    I have a newer design that has to surpass the 64KB limit. The problem is that either the original trigger and its interactions with the other boards are still not documented. A few months ago I started to trace the board using…
  • jlopez

    Replied to the thread New memory boards for the P2.
    Post
    (Quote from Toshi)

    It's U1 A/B :). The same ic, different packages. But I have yet to see a narrow 128K x 8 sram.:/
  • jlopez

    Like (Post)
    Hallo miteinander,
    Ich durfte heute an einer Alphatronic P1 (!!!) die ROMs auslesen - beim Tastaturtreiber hat mich dann fast der Schlag getroffen, da nicht wie bei MOS und Zeichengenerator die eh schon grausamen TMS2716, sondern ein noch gruseligerer…
  • jlopez

    Replied to the thread About TMS9927/5027 internals.
    Post
    (Quote from Toshi)

    Yes, the memory boards. Piggybacking may help; doesn't always work but most time is a useful trick to test for defective RAM without desolder.

    Do you know if the memory is directly connected to the data bus or there is something in…
  • jlopez

    Replied to the thread About TMS9927/5027 internals.
    Post
    (Quote from Toshi)

    You had no option... sad.

    Other than continuity, what tests have you performed on them?

    Regards,
    Jaume
  • jlopez

    Replied to the thread About TMS9927/5027 internals.
    Post
    (Quote from helwie44)

    No apologies, sir. Your considerations were fair. And now is more than plausible. ;)

    (Quote from Toshi)

    Really bad news.;(
    I don't know the KISS enough to know but if it is similar enough to the P2 then it shouldn't. Do you have any other…
  • jlopez

    Replied to the thread About TMS9927/5027 internals.
    Post

    (Quote from helwie44)

    Hello helwie44


    Not sure. The reason I started the thread long ago was to find a better datasheet of this ic, which may be used by many computers of different origin. I found one better (I think it was) at bitsavers.



    Regards
  • jlopez

    Replied to the thread About TMS9927/5027 internals.
    Post
    (Quote from Toshi)

    5027 is the Intersil reference, while TMS9927 is its reference given by TI (it was second-sourced).
    The VTAC 5027 does not behave the same way as the 5037 while in interlaced mode, but in non-interlaced mode they should be completely…
  • jlopez

    Posted the thread Biete Gaelco Speed Up.
    Thread
    Greetings,

    I have a board from the arcade "Speed Up" (checked by its reference), from Spanish manufacturer Gaelco. The board seems to contain the EPROMs with the game and its graphics, as well seven custom ICs and what I think it is a Jamma connector (I…
  • jlopez

    Like (Post)
    Kumpel hat den Handel mit Konsolen aufgegeben, hat dann gesagt, komm vorbei, hol den Mist ab.
    34 Konsolen, Sprit für Fahrt ca. 10€, fertig.
    Zwei Tage dran repariert, gereinigt, gemacht, getan. Ein paar Sachen schon verschenkt.
    Habe nur ein Spiel und…
  • jlopez

    Liked Toshi’s post in the thread Mein neuestes Etwas.
    Like (Post)
    Neuzugang in meiner Altpapiersammlung.

    Da wird eine Plotterkarte beschrieben, die mittels zweier DACs einen analogen XY Schreiber ansteuert.

    Das wird ein schönes Projekt!