Akai AX-60 problem with noise generator

patrickvf1976 · Joined: Aug 08, 2011 Posts: 135 Location: Gig Harbor

My Akai AX-60 has a problem with the noise generator - the noise generator's output has become extremely low all of a sudden and I can't figure out what happened. It was working just fine yesterday and I was able to make some nice thunder and swoosh kind of sounds. Now it struggles to get to a reasonable volume. Everything else works just fine. Any ideas what could cause this problem?

patrickvf1976 · Joined: Aug 08, 2011 Posts: 135 Location: Gig Harbor

So.. any suggestions, advice, anything? Anyone? Help??

patrickvf1976 · Joined: Aug 08, 2011 Posts: 135 Location: Gig Harbor

Still could use some help here. Any hints what to look for or even some schematics would do.

sneakthief · Joined: Jul 24, 2006 Posts: 504 Location: Berlin

http://manuals.fdiskc.com/flat/Akai%20AX-60%20Service%20Manual.pdf

first hit on google Razz

Either 1) the noise generator isn't working or 2) the circuit that turns off both noise generators for Noise A and B. 1 seems more likely.

page 40 says that TR4, TR5 and IC21 are responsible for the noise

On page 37, you'll find the noise schematic. It uses these parts:
IC21: BA715STD
TR4: 2SC 3330
TR5: 2SC 3383

Check along the signal path to see if you're getting noise. The schematic lists voltages next to the ECB's of the transistors - that's a good and easy place to start to see if either are blown.