Donkey Kong Junior board Sound Problem

ScumBum

Well-known member
Joined
Jun 18, 2008
Messages
5,240
Reaction score
395
Location
California
There is a very faint springy sound that plays constantly in the background . Its kinda like the jump sound . Now when I was examining the board alot of the chips had corroded rusty legs , alot of these chips were soldered in too . Is there a list of the sound chips and caps and what they are for ?

Its not the audio amp board because I was able to switch with a known working one and it was still there .
 
http://www.brasington.org/arcade/tech/dkj/

I replaced the lm324, 8035, and 4020 chip as described on braze's page and my dkjr sound is perfect.

Thanks for the link , thats a great resource ! What problem did your board have ?

After reading that tech page I'm thinking maybe one of the caps are bad in the jump circuit , at least I think that might be the sound I'm hearing .

I've replaced 74LS174 @ 3D , LM324 @ 7K and DAC08 @ 8K which has gotten the sound 99% there , just that faint noise is still there .
 
my jump sound was way off pitch. i didn't have the jump over a bad guy sound, my climbing sounds were messed up, and the music would come and go as it pleased.


I had to order the 4020 timer chip from mouser
 
Thanks for the link , thats a great resource ! What problem did your board have ?

After reading that tech page I'm thinking maybe one of the caps are bad in the jump circuit , at least I think that might be the sound I'm hearing .

I've replaced 74LS174 @ 3D , LM324 @ 7K and DAC08 @ 8K which has gotten the sound 99% there , just that faint noise is still there .

ScumBum did you ever get this fixed? I'm having the same issue -- freshly recapped audio board, the "jump" sound at game start seems to echo infinitely. The rest of the game sounds fine. FYI mine is a Donkey Kong, not a JR.
 
Last edited:

Thanks, none of these seem to describe my issue though? Maybe I'm missing it.

Edit: This page does, though. http://mikesarcade.com/arcade/repairs/dkong.html Awesome. :)

Mike's Arcade said:
Problem: Whirring sound all the time.

Sounds like the jump sound never completely cuts off.

Solution: replace transistor Q4 on the CPU board, a 2SC 1815

Anyone know where I can get this part? Think maybe resoldering will suffice?
 
Last edited:
Good to know, thanks. I actually looked for them on his site before but he doesn't carry "transistors", he carries "semiconductors" :p So I missed them last time I looked.

I wonder if I can put up with it until next time I need to place an order. $8 shipped for a transistor's sounding pretty lousy at the moment. :)
 
Thanks to mammyrat, the whirring sound is gone! If I crank the volume up pretty loud, I still hear some kind of oscillating sound, but it's definitely not the jump sound as before, and when the volume is at the typical low level I keep it at, I don't hear anything unusual at all. Replacing Q4 did the trick.

Thanks again, mammyrat.
 
Back
Top Bottom