bubbles issues

corky

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i bought a bubbles last week without a mpu board. well, it came today (thanks ken!). when i plugged it in, all i got was a bunch of red and blue vertical lines. no rug pattern, nothing. the three leds on the ar board are lit, but there is nothing on the display on the rom board. i played with the roms on the rom board and was able to get some sound out of the game (and a flashing "r" on the rom board), but no video. it also appeared to be playing this sound without going through the boot up process. thinking i may be onto something, i reseated all of the roms on the rom board. plugged it back in, still the same thing. anyone have any suggestions on where to start? crappy cell phone pic of the screen included.
 

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after messing with it i now get a semi rug pattern (but doesnt look like the traditional williams rug) and an error code "1E1" on the rom board.
 
Try recrimping the ROM cable. Most people pull the ROM cables by grabbing the cable and pulling. That will pull the wires out of the IDC connectors so fast it will make your head explode.

Here is a link to Arcade Solution's how to recrimp page. Ignore the first part and skip down the part about using the vise: http://www.arcadesolution.com/ribbon.html

ken
 
well, now i get a rug pattern followed by a "initial tests indicate rom 4 error" message. took a multimeter to the board and the voltage at the chips is only ~4.5v. time to rebuild the ps?
 
well, now i get a rug pattern followed by a "initial tests indicate rom 4 error" message. took a multimeter to the board and the voltage at the chips is only ~4.5v. time to rebuild the ps?

Wouldn't hurt, but you might start by cleaning your connectors and see if that improves the voltage.

What other voltages are getting? Like on the RAM chips?
 
The voltages on Williams boards should be checked at the RAM chips. They are the most sensitive to voltage issues.

picture.php


ken
 
im assuming you guys are talking about the seated ram chips on the mpu. those guys are getting ~4.93-4.99v. the mounted chips are the ones getting ~4.5v.

well, no more rom error. now, i get a rug pattern followed by "initial tests indicate all systems go" followed by a brief "high score table reset" followed by another rug pattern. this loop just repeats. the monitor is also kind of funky (random lines, blinky, minor waves - all sporadic).

any more suggestions?
 
Sounds like you are wiggling the ROM cable. See previous notes on re-crimping it.

ken
 
i replaced the ribbon cables for both the rom and i/o board. back to square 1 now. no rug pattern, just a bunch of vertical lines.
 
Dan, I think you're probably about ready to throw in the towel and sell it to me. ;) In all seriousness, I'm watching this thread with interest. It's gonna be great when you get it working!
 
Dan, I think you're probably about ready to throw in the towel and sell it to me. ;) In all seriousness, I'm watching this thread with interest. It's gonna be great when you get it working!

its definitely frustrating. 1 step forward and 2 steps back. what i thought was going to be an easy fix (as easy as popping in a board) is turning out to be a big pita. i cant wait to have it working either; i just want to play!
 
its definitely frustrating. 1 step forward and 2 steps back. what i thought was going to be an easy fix (as easy as popping in a board) is turning out to be a big pita. i cant wait to have it working either; i just want to play!

Do you have an EPROM burner? If so, you can start by pulling the EPROMS and verifying they are good.

The only thing you should need to get the game to boot, is the CPU and the ROM board. You can disconnect the SOUND and IO boards to test if you want.

If your EPROMS check out, and your voltage is pretty close to 5V, then you need to break out the logic probe and start looking at the CPU board.

Is the Watchdog barking? (if it's not constantly resetting, probably not).

What is the state of the CPU on pins:
40 (HALT)
37 (Reset)
35 (Q)
34 (E)
32 (R/W)

You can also check pins 8 through 31. You should see some activity on those lines (but not necessarily all).

Are you getting activity on the RAM chips? (Address lines and Data lines)?
 
thanks for the suggestions! i do not have an eprom burner, but i know someone who does. i bought a cpu board from ken (yellowdog) that was tested working the day it was sent out, so im almost positive the problem is somewhere else in the machine. ill try unplugging the i/o and sound boards first to see if that gets me anywhere. if not, it may be time to schedule a visit with the rom burner.
 
Fired up with just the mpu and rob boards plugged in. Still nothing. Would a bad Rom entirely prevent the machine from booting?
 
Fired up with just the mpu and rob boards plugged in. Still nothing. Would a bad Rom entirely prevent the machine from booting?

If it's the program EPROM that is bad, yes. If it's a graphic EPROM that is bad, the game should still boot.
 
There are a number of things that can go wrong with ROM cards. Normally the EPROMs are #1 on the suspect list, but there are seveal addressing chips that can go south as well.

What boards did you get with the Bubbles? I do take non-working boards as trade-ins against working boards. I do have a couple of tested and working sets of Bubbles boards on hand right now.

ken
 
There are a number of things that can go wrong with ROM cards. Normally the EPROMs are #1 on the suspect list, but there are seveal addressing chips that can go south as well.

What boards did you get with the Bubbles? I do take non-working boards as trade-ins against working boards. I do have a couple of tested and working sets of Bubbles boards on hand right now.

ken

i appreciate the offer ken, but now i am determined to make this mfer work. if im at the same point in a couple weeks, i may take you up on that.

i am so smrt. i never put 2 and 2 together that i can throw the bubbles boards in my robotron to see if i get the same issue. that may help narrow things down ::facepalm::
 
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