• [Article 6316]Troubleshooting Asteroids PCB (4)

    Problem solved.

    After checking  (as suggested in the VECTORLIST) the Vector Timer Circuit, with a particular attention to 74LS83 ( four-bit adder) at location M, I expanded my research to all the data flow from the ROMs to the XY Position counters. Everything seemed to be ok but paying attention to the scope I could see signal LOAD6  was different from other LOAD* signals. Replacing 74367 at locatio H6 the problem was solved.


  • [Article 6307]Troubleshooting Asteroids PCB (3)

    Ok, I spent a bit of time to understand what happened.

    I could solve the problem number 1, now all the screen is used. I just replaced a 74191 in F9 position. UNMDACY11 was always low.




    Now I’ve one problem only. The game starts, the TEST doesn’t show anything wrong but what I see is very strange. All DIP SWITCHES were in the same position so the language is SPANISH with 2 COINS PER 1 GAMES. As you can see the problem affects some asteroids (just one on the left ) and the alphanumeric messages.



    zoomed “2 FICHAS 1 JUEGO”


    as you can see the message moves downwards and “ASTEROIDS BY ATARI” is not shown.

    I’m quite blocked now because I checked all Y circuits from the output to the VECTOR ADDRESS COUNTERS…

    ROMs have been checked and vector RAMs replaced.

  • [Article 6300]Troubleshooting Asteroids pcb (2)

    Checking the counters I found a faulty 74191 in D9. Replacing it I can see something better:


    but the vectors seem to be “sampled” vertically. After a fast look I found pin 19 and 20 shorted of 74374 in B10 position.

    This is the situation now:asteroids pcb oo3

    There are 2 problems:

    1. 25% of the screen is not used
    2. all labels are corrupted

    the next picture shows better the problems



  • [Article 6277]Omega Race (2) :: Sound and Monitor

    Sound now works properly. I had to clean the speaker contacts.

    About the monitor:

    It is in very good shape.

    Plugging it to the cab I had the spot killer on and no lights on the neck.

    I cleaned all connectors but it was not sufficient. Then I realized that moving the cables I had some reactions and I checked the connectors solders and the red one on the main board connecting it to the HV unit has at least 5 pins interrupted. So 10 minutes with a solder and I remade the board like new.



    Assembling the monitor inside the cabinet and cleaning the yellow layer and the black cardboard I can say most of the job has been done…

    omegarace_1604 omegarace_1605

    Most of the job has been done. Now the back panel is missing. Actually I don’t remember if I have it somewhere in my garage or I have to remake it. We will talk about this next week.


  • [Article 6270]Omega Race (2) :: PCB – part 3

    Here the problems I had yesterday.

    1. BBU RAM S4: BAD
    2. V RAM2 J1 and or (L/M)1: BAD
    3. V RAM4 (J/K)1 and/or (N/P)1: BAD
    4. V ROM2 F1: BAD


    1 – It was related to a power problem. I can’t understand connecting the oscilloscope ground to the game ground the probe wire becomes hot. Anyway problem solved.



    2 – V RAM2: This was the most complex error. The analysis made yesterday had no success but considering now the problem was related to J1 and or (L/M)1 only I pointed my attention to the “Chip enable” circuit. After some tests I could see I forgot to rebuild the track between 7404 in position PR1 PIN 8 to 7432 in position R1 pin 10.


    3 – V RAM4: (J/K)1 2114 was faulty. I just replaced it.


    4 – V ROM2 F1: ROM was actually bad and I replaced it with a new one.


    This is the self-test result. I’m sorry I didn’t manage Z signal 😀 😀 😀


    so, PCB now is ok…


    What have I to do now?

    • No sound to the right speaker
    • Monitor (not working)
    • Back panel


  • [Article 6250]Omega Race (2) :: PCB – part 2

    Once cleaned all damaged parts I made photos of each chip position in order to always have a visual representation of the trucks behind the new sockets. I signed the IC position and it’s location on the PCB. Here some examples:


    Then I socketed and replaced resistors and filters.


    And then Kynar Wire!



    Plugging the board I had a good surprise because the game started BUT after few seconds the vectors hide for a while.

    Running the self test I have the following errors:

    • BBU RAM S4: BAD
    • V RAM2 J1 and or (L/M)1: BAD
    • V RAM4 (J/K)1 and/or (N/P)1: BAD
    • V ROM2 F1: BAD

    Actually not so bad.


    All the  RAMs/ROM (but BBU RAM) share the VECTOR ADDRESS BUS, from SMEM0 to SMEM9 controlled by 74157 in positions K3, L3, M3.


    MAIN ADDRESS BUS (MA0..9) and PROGRAM ADDRESS BUS (SEQA0..9) are connected to these 74157


    I can see BBU RAM (5101) uses the MAIN ADDRESS BUS too, so I’ll check if S4 pins 1, 2, 3, 4, 5, 6, 7 and 21 are correctly on the bus and if all lines arrive to 74244 in (P/N)6 (pins 3, 5, 7, 9, 12, 14,16,18). This will be the first test I’ll perform.


  • [Article 6237]Omega Race (2) :: PCB – part 1

    This was the PCB

    omegarace_1301So the acid made its job.

    The board had been socketed already


    But I realized the entity of the damages once I removed such those sockets!

    And I decided to dedicated a lot of time to remove all damaged parts


    This is the board now

    …even if some tracks have gone


    Now I’m keeping pictures place by place so resocketing the board I can check which track works and which not.





  • [Article 6207]Omega Race (2) :: Edges and T-molding

    This cab hasn’t a real t-molding. It is made just rounding the edges and painting them in black.

    After years all these parts were damaged and I had do be drastic to have a good result.

    These were the conditions before any action

    so I sanded all parts

    and I smoothed using a flatting paint and sanding again


    Internally I used a satin-black, glossy-black for the edges.

    and that’s all.

  • [Article 6128]Omega Race (2) :: Yet another Coin door


    probably if I summed all the time spend restoring coin doors I could reach years…

    Initial conditions. Not so good, sot so bad.

    First of all I removed all parts, Midway plate rivets included.

    Then I used the usual abrasive sponge (I can’t translate better than this) on metal parts and prepared a couple of new bulbs.

    Usual procedure for the frame and the main panel:

    1. removing the paint
    2. rust-fixing paint
    3. flating
    4. black paint

    This is the result, trying to give the original aspect


    Same for the panel…


    THE END:




  • [Article 6107]Omega Race (2) :: Inside

    As I told before the cab had some problems and needed to be reinforced. In several parts one of the side separated from the rest of the cab.


    So I spent a night with glue and metal parts trying to reassemble the cab.



    In the mean time I cleaned some parts

    After that I checked the electrical part.

    All voltages are ok in all steps:

    Before MT-88: 0k 220Vac

    After MT-88 and before MT-89: ok 125Vac, fluorescent lamps work properly

    After MT-89: ok

    After power regulator board: 5V OK, 12V for coin door and marquee ok, 12V for audio is 15V. I’ll check.








  • [Article 6076]Omega Race (2) :: Back side

    The back side has been quite complicated to restore.

    Edges were quite damaged and in general the MDF was compromised.

    First of all I removed all parts

    THis was the status of the edges (t-molding included but we will work on it later)

    omegarace_0404 omegarace_0403



    First of all I used wood putty for the bottom part and then I used waterproofing paint on all parts

    then I modeled both putty and edges with sand paper


    Then I used flatting for parquet in order to give back consistency to the MDF and then black paint.

    … last parts…

  • [Article 6026]Omega Race (2) :: Bottom…

    As usual I start from here.

    Bottom was curved due to the the 2 transformers weight.


    First of all I restored the foot supports even if I decided to not use them (I usually use castors under my cabs with European dimensions).

    1. I removed and cleaned the supports
    2. I removed most of the rust
    3. I combined the rust (protecting the support) with Neofer product
    4. Then I painted them with a protective chrome effect paint

    I removed, cleaned and made the same process to the metal profile.


    Then I pointed my attention to  the back castors.

    Then I used 2 wood panels. The first, smaller, to fill the curved part, the second to reinforce the structure.

    THen I reassembled everything and mounted the new castors instead of the original foot.


  • [Article 6012]Omega Race (2) :: Initial conditions

    Directly from US I bought this Omega Race few years ago. Unfortunately the cab has been damaged during the transport but it’s complete and this is enough to decide to restore it.

    I didn’t take pics when the cab arrived because it was covered by other cabs. anyway you can understand the conditions through these pics

    the grid picjed a knock
    the grid picjed a knock
    metal edges are dirty but in decent conditions
    metal edges are dirty but in decent conditions
    THis is a problem: edges on the back are completely "frayed" because of the umidity or I don't know what
    THis is a problem: edges on the back are completely “frayed” because of the umidity or I don’t know what


    the rest…

    this is the most important problem:

    the cabinet was splitting in two parts.


  • [Article 6003]ARCADEITALIA 2016

    Prima di intervenire su un cab è importante capire quali interventi fare. Può essere utile stilare una check list con i punti di interesse poi da sistemare nell’ordine più opportuno. Solitamente procedo come segue:

    1. Parte interna del mobile (legno, plastiche, metallo, …)
    2. Fondo
    3. Cablaggio interno e alimentazioni
    4. Monitor (pulizia e sistemazione)
    5. Parte posteriore e back panel
    6. Mobile esterno
    7. Coin door
    8. Comandi
    9. Scheda e Monitor (parti elettroniche)

    So che proceduralmente mettere in fondo la sistemazione della scheda può sembrare anomalo, ma dopo molti anni ho capito che se il gioco è funzionante la mia soglia di “restauro accettabile” si abbassa molto, quindi per evitare la tentazione di archiviare il progetto come finito e passare ad altro preferisco tenerlo non funzionante fino alla fine.

    Le parti di un cab possono essere identificate secondo diversi criteri; io lavoro su una matrice che prima di tutto seleziona le tipologie di materiali o tipologie funzionali:

    1. Legno
    2. Metallo
    3. Plastica
    4. Vetro
    5. Carta
    6. Comandi
    7. Cablaggi (rete, alta tensione, bassa tensione)
    8. Alimentazione
    9. TV
    10. Audio
    11. Gioco
    12. Eventuali altre parti

    Ognuna di queste categorie può riguardare l’interno o l’esterno del mobile. Questa differenza è fondamentale perché le parti interne non sono soggette a usura diretta e inoltre solitamente non sono a vista (a prescindere dal cardboard o altre poche parti)

    Tecnicamente ogni singolo punto identificato dall’incrocio di queste due liste potrebbero essere affrontate con tecniche, strumenti e metodi differenti.

    Ecco una sommaria matrice di identificazione dei punti di restauro.

    Oggetto dell’intervento



    LEGNO Side art

    Parte frontale

    Parte superiore

    Parte posteriore fissa

    Back panel


    Altre parti (pannelli ecc.)

    Interni invisibili

    Interni visibili

    METALLO Control panel

    Viti in genere

    Coin door

    Cash door


    Interno della gettoniera

    Cash box

    Staffe e sostegni

    Altre parti in metallo

    PLASTICA / VETRO T-molding

    Control panel


    Vetro anteriore

    Specchio semiriflettente
    CARTA Instruction card




    Altri comandi / FF

    sw e pot. interni
    CABLAGGIO DI RETE Cavo esterno di alimentazione Interruttore

    Filtro di rete



    Alimentazione TV

    CABLAGGIO BASSE TENSIONI Cab. basse tensioni

    Cab. altoparlanti

    Cab. video

    Cab. comandi

    ALIMENTAZIONE Trasformatori

    Schede di alimentazione

    TV Masse



    AUDIO Altoparlanti


    GIOCO Scheda / Schede