Taito Bubble Bobble Repair Log

Hi there,

I've a completely dead Taito board too, plug it in and nothing, no picture, no sound.

Edited by Cathaldub - 21 August 2014 at 10:31am

drevans wrote: I love these repair logs.  What I would love to see is more detail on how each chip is diagnosed as faulty. That's the bit I'm trying to learn more about.

Thread moved to Repair Logs :)

Cheers for the info, just tested those ics on my dead BB and IC44 SRAM is shorting on mine too so ill pull that and socket a new chip tomorrow, and see how I get on

Yup, fully dead, no display change at all when plugged in.

It was a sad day :(

Edited by Cathaldub - 22 August 2014 at 2:22pm

Nothing from the watchdog, looking at the bottom board pinouts would leave me to believe 5v and ground shorted , 6 on the roms(a78-09,10,14,17,18,20) on that board were corrupt when I read them in my programmer which leads me to believe the main fault lies primarily on that board. I'm pretty lost looking at the schematics though.

Edited by Cathaldub - 22 August 2014 at 7:13pm

I'm stumped on another project. I recently got a Bubble Bobble bootleg board and when I wired it into my cab, the game boots up into attract but won't take any credits and the screen is divided in two - the background images on the left and all sprites on the right. I have no clue what might be causing this. i'll try and attach some photos - thanks again!
http://s172.photobucket.com/user/karatechamp999/media/IMG_5629_zps2qchhhjr.jpg.html
http://s172.photobucket.com/user/karatechamp999/media/IMG_5626_zpsl4maftbu.jpg.html

I've jumpered JPA and JPB still no coin up - I think the test screen is supposed to show colour gradient in the middle of the grid but it seems to be black in the middle (although there are good colours in normal mode) and the grid is half off the screen to the left just like the title screen



well found a busted pin - fixed. - and a diode soldered in backwards - fixed - still the same issue though :( anyone got a lead on this??? its seems to be a pretty specific issue


Progress!!! ok, game coin-ups now (twas a gap in the cabs coin ground, so I just service switched it, even though the cab doesn't have a service switch) So now I can play, all the controls and player starts work - Only issue left is the screen -
Bob and Bub are confined to the very left of the screen, I can jump up the levels and even though bob stays in the far left, I can phantom move and interact with other sprites, (who also are stationary in other parts of the screen, except for up and down) , like enemies into bubbles and pick up fruit even though there is no VISIBLE movement horizontally
Both background and forground seem to be split as seen in the photos, intro screen is the same background to the left and forground to the right
Also I'm noticing (visible in the bubbles in photos) with sprites fall down the screen, there is an invisible horizontal line the scrolls with it that seems to run through the other sprites and text giving a scroll through effect.
- looking like one of the IC's or RAM has a fault, just not sure which might cause this, already piggybacked ls157's and ls283 with no success
- pin 11 of IC 97 LS374 was broken, I soldered it back, and checked for trace cuts, and cleaned between all the pins on the video PCB
????

after test mode grid (also half off the screen) see attached photo - not sure if this means it passes ram test because that part is off the screen.
does anyone know what it looks like if it doesn't pass the ram test? would I see something on this side of the screen?
also I checked voltages on all the chips on the video pcb and all are good

Anyone have a hunch here?!