Qbert Battery mod and sound issue

BubbaK

Member
Joined
Jun 4, 2007
Messages
697
Reaction score
13
Location
New Jersey
I started playing with my Qbert again.. I rebuilt the sound board and upgraded the 2 caps on the main board. I also bought the battery mod kit from Arcadeshop, but I haven't done it yet. Someone else along the way had done some other battery mod and added a lithium battery to the board. I've attached a picture. My high scores are still not being saved all the time, so I want to do the AS mod with the NVRAM chips. I know I have to remove the diode at D2 and put a jumper in. When the other battery was installed, they moved the diode at D3 and took out the resistor at 340. Do I need to remove the lithium battery, reinstall the resistor 340 and reconnect diode D3 before installing the other chips?

Also, I was running through the sound test in the menu, and I have no sound on test #'s 16,29,30,31 and 32. I don't notice any sound missing during game play, but its probably been that way since I've owned this.

qbert%252520battery.jpg
 
If your doing the nvram mod all you need to do is clip the battery off. Some of the sounds in test mode are not there, perfectly normal.
 
Thanks Riptor.. So no need to worry about the diodes or jumper? Just cut the legs of the battery and replace the 2 nvram chips..

Do you have any substitute for the knocker or way to make it work? After the switcher, the knocker isn't working.
 
I think there is something you have to jump but I dont remember the details on it.
I found the knocker does not work well, if at all on 24v.
 
just clip the battery, the diode to the right of the missing d3 will provide the power needed for the nvram chips.
 
OK.. I'll give it a shot. The paperwork that came with the NVRAM chips says to remove D2 and put a jumper across it.

What is the voltage of the knocker solenoid? Is it 30vdc? Has anyone attempted to make a relay circuit to drive the kicker after installing a switcher? I can't imagine it being that hard to do..
 
Last edited:
Also, I was running through the sound test in the menu, and I have no sound on test #'s 16,29,30,31 and 32. I don't notice any sound missing during game play, but its probably been that way since I've owned this.

That is normal - do not worry about it.

Try changing out the two caps before you unhook the battery to see if it improves the high score save. Would be a good test and of value for us to know.

Bill
 
OK.. I'll give it a shot. The paperwork that came with the NVRAM chips says to remove D2 and put a jumper across it.

What is the voltage of the knocker solenoid? Is it 30vdc? Has anyone attempted to make a relay circuit to drive the kicker after installing a switcher? I can't imagine it being that hard to do..

Q*Bert runs it off of 30VDC. (However, the exact same coil is the knocker in all Gottlieb System 80 pins, where it is powered by 24VDC.)
 
Darren I dont think its an issue of voltage, more of an amperage issue. I dont believe the switcher delivers the voltage as fast as the linear and its only a momentary pulse.
You guys can debate it all you want but my tests show that these knockers dont work well on a 24v switcher. I tried a variety of switchers and a bunch of knockers including originals and brand new ones. I was going to sell a switcher kit just as arcadeshop eventually did. The weak knocker sealed my decision to scrap the project.
The only other solution would be to find a coil more suited for the 24v. It may take alot of trial and error but im sure you can find one that works better.
There have been a few guys who report their knocker worked fine on the switcher....FWIW. If anyone has one working(strong) on a switcher, post the number of the coil.
 
Last edited:
Riptor... I know you are deep into the qberts... what do you think about making a relay board using a 24vdc relay to output 30vdc? I was talking with an old timer electronics buddy of mine and discusing the problem with him. He felt pretty confident that he could come up with a circuit to make it work..

From what I have seen, the board supplys a constant voltage to the solenoid and switches the ground to activate? could a SSR work in this to handle the speed of the switch?
 
Riptor... I know you are deep into the qberts... what do you think about making a relay board using a 24vdc relay to output 30vdc? I was talking with an old timer electronics buddy of mine and discusing the problem with him. He felt pretty confident that he could come up with a circuit to make it work..

From what I have seen, the board supplys a constant voltage to the solenoid and switches the ground to activate? could a SSR work in this to handle the speed of the switch?

The simplest approach would be to add a 30-32v switcher and switch it with the 24v via relay. Did you mean SCR?
 
Solid state relay.. mechanical relay, either would work but you still need to step up the 24v to 30v. Remember, its already being switched with a transistor so I doubt a SSR circuit will help at all unless you increase the voltage. Maybe if you put some capacitors on there to store some extra juice. Another thought would be to increase the time of the knocker pulse.
The problem with the original design is the sound should have never been on the 30v line. I have had them running fine as low as 12v. The factory mod (amp replacement) piggy back board runs the amp (tda2002/3) at 16-18v.
If I were to look for a solution I would try to find a coil that fires on the 24v. I had planned on doing this but lost interest.
 
Last edited:
Swap the 74LS377 @ A10 mainboard. Im pretty sure thats your problem. VERY common issue.


Replaced the IC - no change - all sounds work fine except that one sound (qbert yelling as he falls off.) The sound works - but it's a straight 'ahhhhhh' instead of a 'AAAAAAHHHhhhhh'
 
Back
Top Bottom