The Pitchmaster SA-60 Guitar Tuner
Created 05/18/07
Last updated 01/19/23
By Paul J. Marossy
I was looking on eBay for "not working" guitar effects to repair and came across this intriguing relic from the past: the Control And Information Systems, Inc.
"Pitchmaster SA-60" guitar tuner. It was unusual and obscure, so I just had to buy it so I could check it out. It only cost $18 plus nearly $10 for shipping (boy it ain't
cheap to ship anything anymore). It appears that these were being manufactured around 1974-75. I don't know what happened to the company. It appears that they
went belly up in the sometime in the early 80s.
I discovered that it uses an interesting circuit, and supposedly this company had applied for a patent according to the sticker on the bottom of the unit. I tried to do
patent search but didn't find anything. Maybe it was good intentions that never happened, or maybe it was just a little "white lie"? We'll never know. Anyway, the circuit
uses a variety of IC chips - a MC1458 dual opamp on the input, a CD4001, a CD4030, a pair of CD4013s, an NE555 timer chip and a pair of EN2222 transistors in a TO-105 package.
I have never seen a 2222 transistor in that package, it's really old school! Another interesting feature is the six trimpots so you can customize it to other instruments.
Once it is working properly it's very precise, and is useful in setting intonation with that "open" and "12th fret" switch.
So of course, I decided that I have to reverse engineer it so I did my customary CAD drawing of it so I could attempt to generate a schematic for it, which at the time of
creation of this webpage I was in the process of doing. It's a bit hard to follow as it uses a semi-double sided PCB and I am not quite sure what some of these IC chips are
doing, so that complicates matters. Here are some pictures of it.
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This is the top of the unit. The enclosure is plastic. It was dirty and grungy looking, so the first thing I did was take it apart and clean everything, and I got rid of that sticker. |
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This is the bottom. Looks kinda rough but everything is still intact. I need to find replacement rubber feet that fit in those round indentations. |
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Here is a view of the circuit board. Battery arrangement is not the greatest... just a piece of foam wrapped around the battery which goes wherever you put it. Once the bottom cover is on it doesn't go anywhere though. |
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Here is PCB next to the enclosure. This thing is pretty big... measures 6"x3"x2" high. |
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It's big and quirky but it's kind of a cool forgotten relic of the past. I wonder how many of these things are still out there. |
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I thought I'd try something new to help with reverse engineering - a cardboard mockup of the real PCB. Lessens handling of the actual unit and it's just easier to deal with. |
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I lined up the pictues of the two sides of the PCB and glued them to a piece of a Triscuits box. |
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Then I poked holes so I could see where the tracks on one side of the PCB meets the tracks on the other side. A DMM helped me to verify where some of those tracks go under the IC chips. |
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Here I am at work trying to generate a schematic. I think I might ask for help on this one... |
In my usual manner, I just have to document some of these odd, obsure things to satisfy my own
curiosity. Hopefully sometime in the near future I will have the schematic for this tuner. If you have any info to contribute, please let me know!