• [Article 6460]Imola GP :: Coin door and cash door

    Both in awful conditions…

    Actually I had no time to clean the coin door so I decided to replace it with another one I had. Original coin door will be stored for future uses. So I cleaned the new coin door and cash door painting their frames in black (glossy… probably matte should be better…). Then I cleaned and de-rusted all internal parts replacing what missing or broken. After cleaning I plated to protect metals.


    After that I reassembled all parts and remounted on the cab adding the locks.

    That’s all at the moment.

  • [Article 6441]Imola GP :: Wood (1)

    Side arts are in good general conditions. After removing the old side arts I had just cleaning.

    More peculiar the conditions of the front side. Probably something happened in the years and I found some damages. All the front part is vertically broken.

    So I used glue to repair the parts and wood putty to fill all splits.

    Then I used a white primer to give an homogeneous surface.


  • [Article 6419]Imola GP :: PCB (1)

    The game doesn’t work properly. This is the board:


    I can see there are other versions around Europe, like this one.

    The architecture seems to be the same but it uses different EPROMs and RAMs are located in a different position.
    The program seems to run correctly but graphics is corrupted.

    First of all I replaced a couple of resistors and one transistor but this work wasn’t related to the graphics problems


    As usual I replaced some components (with rusted pins) but I had no results. RAMs are on sockets so I easily replaced them.

    All ROMs have been compared with M.A.M.E. IMOLA GP SET-1 and all of them are correct.

    Actually I was wondering which kind of component is the blue one:imolagp1110

    I think it is a resistor network like this:


    but I’m not sure.


    So now I’m waiting for replacements. I’m concentrated on the buffers and in general on the data/address buses from CPU to video RAMs


    So I’ll continue to work on it once the DM81LS95N will arrive.


  • [Article 6398]Imola GP :: Score glass

    Score glass is in bad conditions.


    EPSON MFP image

    After a good scan I vectorized all parts and I reproduced it on a plexi


    This cabinet had been designed by “mike”, a famous graphic designer that signed a lot of Italian pinballs.




    This is the result compared to the original. Obviously the original marquee will be preserved into my archive.


  • [Article 6391]Imola GP :: Initial conditions

    Years ago, Wiz (www.tilt.it) gave me this IMOLA GP. Build in Imola (IT) by Angelo Arena (Arena Games) or Bacchilega (both from Imola). Actually I’m not sure because main Board has “A.A.”  and score board “BACCHILEGA” printed on.

    I shot these pics after  I removed most of the parts. Cabinet is complete even if graphics is compromised.

    First to do list is:

    • Monitor to be repaired (broken tube, modern Hantarex chassis)
    • Pedal: rusted
    • Coin door: broken (plastic) frame, missing parts, …
    • Cash door: missing lock
    • Speaker grid: ok, just dirty.
    • Monitor fame: ok
    • Monitor glass: ok
    • Score glass: bad conditions, some parts are missing, printing is removing from the glass
    • Side arts: both have missing parts, scratches everywhere.
    • PCB: not working
    • Power supply: original transformer is inside
    • Control panel: ok, just dirty

  • [Article 6358]Sprint One :: PCB recap

    My Sprint One PCB started to have some stability problems.

    Touching the big capacitors on the PCB I saw the liquid came out.

    Actually they were not in so good condition.


    I tried to find coax capacitors to replace them but it had been quite hard so I decided to apply one method learned years ago from radio-tubes collectors.

    First of all you have to cut the capacitor


    Then you have to empty it saving all external parts


    Prepare the new content using a new capacitor or a combination of capacitors.


    Fill the old shell and use hot glue to seal it


    Make it for all caps you want to refurbish



    Re-solder the new/old caps


    Done :)

  • [Article 6341]Tempest PCB: a new board

    I’m working on a Tempest PCB bought some months ago on ebay. It missed some PROMs and custom chips on the aux board.

    I needed a little bit to find all missing parts and I tested the aux board using my working main so I’m sure it works.

    So, plugging the boardset I can see this strange TEST screen:


    all “0” are on the same line… They should be on 5 different lines…

    Exiting fro the test the game resets.


  • [Article 6328]Major Havoc board (1)

    I’ve a not working Major Havoc board.

    Let’s go to have a look to this rare board.


    It has the “Quad Pokey” installed. In the same picture you can see the SN UR148



    First of all as you can see it is quite different from all other (vector) atari boards. Vector D/A circuit is more complex than usual.




    It has some “wires” and actually I dunno if these additional wires are factory modifications or not.

    As you can see in the 3rd picture and in the next one this board was dedicated to the prototype TOLLIAN’S WEB so I don’t know if the modifications are due to adapt the board to the final software release.majorhavoc08

    RAMs and ROMs have been verified and seem to be ok.



  • [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.