I’m working on repairing an old Lowrey organ at the moment, and it turns out some of the frequency dividers are borked. You can buy replacement frequency dividers from the Organ Service Corporation for around $30US (the particular one I need is KS-5823), but since I need at least four of them, I’ve decided to make my own.
The easiest way to build them, I think, is using two 4520 chips (4-bit counters). This schematic needs double sided tracking. It’s ugly, and you could probably figure out some ways to make it better. (I at first accidentally got two 4518 chips - decimal counters - which would have had wrong frequency and duty cycle. Could be interesting to try, if you’re keen to replace them all…)
March 2nd, 2009 at 11:08 pm
hi there
i have a similar problem. dO YOU KNOW OF ANYWAY TO TEST THE 5823 AND WAS THE OPERATION SUCCESSFUL
MANY THANKS
JIMMY
March 5th, 2009 at 11:18 pm
Not really. I have an oscilloscope and just poked around to see where the signal was getting lost.
Before I had the oscilloscope I was using a pair of headphones that I had replaced the plug with an alligator clip that I clipped to ground, and a probe that I poked with. It kind of worked.
I have built one of this schematic and it works, but it’s quite large and a bit too unwieldy to really go in the IC socket. So I’m going to change it a bit so the PCB is perpendicular to the IC socket. _|_ sort of thing.
What sort of organ are you working on?
October 4th, 2009 at 3:56 pm
Hi, I’m doing the same thing as you are. Can you give me the full part number on the counter you are using. Also do you have the updated schematic of the _|_ type. as I would like to build this for my Lowrey co80. Any help would be grate! Thnaks, Russ
also what type of lowrey are you working on?
December 17th, 2009 at 10:05 pm
UPDATE! I DEMAND AN UPDATE!
August 8th, 2010 at 11:31 am
http://www.youtube.com/watch?v=lp_PIjc2ga4