About TMS9927/5027 internals

  • Greetings!


    In December I got interested on the TMS9927 and tried to dive in its internals. I've got the datasheets for both it and its second source 5027. The block diagram on the TMS9927 isn't very useful, it shows nearly no logic between different blocks. However, the 5027 block diagram reveals some interesting interactions between blocks. Unfortunately, all I could get is a lo-res scan of the datasheet where a lot of lines are missing, logic symbols are unrecognizable on some cases and labels are blurry. That's better than nothing, but if someone could provide me this diagram with better quality I'd be very pleased.


    (The foresaid block diagram, partially hand-redrawn)


    Thank you very much!

    When I tried to list all retro systems I have at home, the "The message is too long, must be under 500 characters" error appears! :lol:

  • Hello Helmut!


    That's the same document I used but unfortunately the diagram seems partially erased too... :(

    I'll try to check some combinations and see if some of them have sense.


    Thank you very much!

    When I tried to list all retro systems I have at home, the "The message is too long, must be under 500 characters" error appears! :lol:

  • jlopez Does that mean the CRT-5027 / 5037 and TMS9927 are identical and interchangeable? At least for use in TA/KISS machines?

    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 compatible.


    Regards,

    Jaume

    When I tried to list all retro systems I have at home, the "The message is too long, must be under 500 characters" error appears! :lol:

  • 5027 is the Intersil reference, while TMS9927 is its reference given by TI

    Thaks a lot Jaume - I have here a running Kiss machine with a CRT 5027 controller, and a P2 with a probably defective video card (at leat its status is unknown). Do you think its safe to test the 5037 video chip from the P2 in the KISS video card?

  • MC 80 (sks, KISS) / TA P2 CRT Controller- Schaltpläne

    Diesen thread meine ich - optimal bei dem Oberbegriff „sks“ verschoben zu sein sollte.

    Weil ich damals schon den sks DISPLAYCONTROLLER -Schaltplan mit CRT-CHIP-Programmierparameter abgelegt hatte.

    Denn viele TA P2, P3, P30 USER schauen / suchen Infos in den „sks“ Bereich auch rein!!!


    Denn es ist vielen klar - dass sks KISS / zu TA Px alphaTronic Systemen verwandte sind. (Entwicklungsbereichen)

    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

    When I tried to list all retro systems I have at home, the "The message is too long, must be under 500 characters" error appears! :lol:

  • YES - testen it - must running both CHIP.

    jlopez : Bad news.:wand:

    I have placed the 5037 chip from the P2 video card onto the KISS-II video card.

    Result was a non working Kiss.

    After switching back to the original 5027 video chip, the KISS-II was still not working.


    I tried restarting the machine with the 16kb SRAM card removed and it is working again.


    Does it make sense that a bad video chip could kill the RAM card?


    Or just a bad coincidence ?

  • That looks like a bad spell!


    The two 5027 should be compatible with the 5037.

    Have a look at the data sheet! (is available here as .pdf).


    I can not imagine it?


    Everything plug-in cards in place and the CHIP right with all the pins? Something like that only if a function would not work properly?


    Test if the 16 kB card moved out with the ohmmeter (like jlopez suggestion, lines of tension!) If something striking appears?

    I actually always test something like this before POWER ON on many cards.

  • Test if the 16 kB card moved out with the ohmmeter (like jlopez suggestion, lines of tension!) If something striking appears?

    I actually always test something like this before POWER ON on many cards.

    Sure, I did this, nothing suspicious detected (resistance 2-3 kOhm bettween 0-5V, 0-12V, 0 to -12V).


    Is there any logic on the video card that interacts with the ram board?


    The video boards ist working again with the 5027 (I get a correct display from MOS when I switch on the computer), but only with the 16k board removed.

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


    Is there any logic on the video card that interacts with the ram board?


    The video boards ist working again with the 5027 (I get a correct display from MOS when I switch on the computer), but only with the 16k board removed.

    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 memory board to replace them?


    My piece of advice: next time don't test on the KISS... better use a spare unit as a sandbox.

    Do you know if the SRAM boards work on another system?


    Regards,

    Jaume

    When I tried to list all retro systems I have at home, the "The message is too long, must be under 500 characters" error appears! :lol:

  • Actually no actions of the two cards automatically.

    the crt card is the image storage area from 3000h.

    the chip registers are mapped in the upper memory of the cdt kate.

    Have a look at my .pdf for the sks-display circuit diagram.


    As found, the memory would be set to 4000 hours.

    If what happened to the DIPs by accident - yes because everything should block !!!!!


    Have the 4 small DIPs in the 16 kB memory flipped over?


    What else could be problems with the STORAGE of purely static RAM?


    Ich denke mal ruhig durch.... zum Kaffee ist es ja zu spät...

  • My piece of advice: next time don't test on the KISS... better use a spare unit as a sandbox.

    Do you know if the SRAM boards work on another system?


    Regards,

    Jaume

    I do not own a spare unit. I have a working P3 and I had a working KISS.


    The P2 I received last weekend is dead.

  • Aus meiner P2U und der KISS tausche ich bis auf den Keyboard alle anderen Karten auseiander aus.


    KISS ist die MUTTER der P2 - bis auf geringe Änderungen (Keyboard, klar anfangs FM).

    Selbst bei der CPU muss ich nur bei mir den Floppytreiber/ Keyboardtreiber EPROM richtig tauschen.


    Es war doch bei Toshi der P2 immer schon die Gleichspannungen defekt?? Oder?

    Wir haben doch die TA P2 Netzschaltpläne - habe doch im TA Showroom abgelegt!!!!!


    ok habe gerade gesehen.

    Unchanged since the first phot I have taken


    DIPs sind offenbar ok - für ANFANG MEMORY 4000h !

  • I do not own a spare unit. I have a working P3 and I had a working KISS.


    The P2 I received last weekend is dead.

    You had no option... sad.


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


    Regards,

    Jaume

    When I tried to list all retro systems I have at home, the "The message is too long, must be under 500 characters" error appears! :lol:

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


    Regards,

    Jaume

    On the P2?


    None very exhaustive because I have to repair the PSU first.

    All I know now is that the monitor ist working and the FDC card.


    On the 16kB SRAM card, what do you propose?

    Desolder all parts, put sockets in in replace chip by chip until the error is found?


    Could a bad memory card cause a halt of the complete system?

  • 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 between? Bad memory could cause a system to fail if parasites are introduced into the data bus, for example. My 3032 had a problem with such parasites. There may be other causes... but without schematics is difficult to search for weak points.


    Regards,

    Jaume

    When I tried to list all retro systems I have at home, the "The message is too long, must be under 500 characters" error appears! :lol:

  • Hallo netmercer - was meinst du von der Sachen???


    Da hilft erst mal überlegen und strategisch die Testschritte genau festzuhalten.


    Toshi - schade - was würdest du zunächst testen/ besser messen um einiges wieder in Gang gehen könnte.

    Ich erinnere mich -


    Anfang STATUS:

    a) die KISS RM mit 16 kB RAM lief ja in Betrieb

    b) die P2 startete gar nicht - da fehlten die 12V oder?


    Bis zum fast Total-crash? oder doch nicht?


    Bei den vielen Fragment Berichte - ist mir nicht eindeutig, was genau in welcher Reihenfolge von a) zu b) oder umgekehrt mit welchem Resultat getestet wurden.


    Aber wie ich schon geschrieben habe - das Problem nur KISS und/oder TA P2 Fachbeiträge nicht hier weiter zu behandeln möchte !!!!

    Toshi - wo sollen wir dir helfen - aber in einem richtigen thread, oder?

    Grüße

    helwie44

  • Hallo helwie44 ,


    verstehe das Problem mit dem CRT Controller in der P2 auch nicht.

    Wie Du weißt habe ich in meiner P2U einen TMS9937 (baugleich CRT5037) völlig problemlos in Betrieb gehabt.

    Kann mir beim besten Willen nicht vorstellen warum die 16K RAM Karte deswegen sterben sollte.


    Allerdings war der CRT5037 aus @Toshis defekter P2 und die Funktionsfähigkeit damit unbekannt. Gab es da nicht so eine alte Bastlerbauernregel, daß man eventuell defekte Chips lieber nicht in ein funktionierendes Gerät einsetzen sollte...


    Momentan geht es mir aber nicht viel besser. Meine P2U liegt immer noch im Koma und ich habe den Fehler auch noch nicht lokalisiert. :(


    Viele Grüße

    netmercer

  • Bastlerbauernregel, daß man eventuell defekte Chips lieber nicht in ein funktionierendes Gerät einsetzen sollte...

    Habe nach einem Weg gesucht, zu überprüfen, ob die CRT Karte - respektive der Grafikchip - der P2 noch funktioniert.

    Im nachhinein : Ja, es war blöd. Definitiv.

    Dachte aber die Bastlerbauernregel war "Stecke keinen guten Chip in ein kaputtes Board" oder so ähnlich.


    Ich werde jetzt alle Chips der RAM-Karte auslöten, sockeln und erst mal slabbi 's RAM Tester aufbauen um diese dann damit zu prüfen und dann das Netzteil der KISS überarbeiten. Vielleicht auch prophylaktisch alle Kondensatoren der KISS Karten tauschen, damit da nicht auch demnächst eine Bombe platzt. Vielleicht bekomme ich sie wieder hin. Den orangenen Rechner mag ich wirklich gern.