Hohner String machines ~1974     Weight = 32 Lbs. (stringer w/cover) Number manufactured = ? MSR = $?

User Manual:
Reset Proceedures: N/A
Operating System code:
MIDI or other control protocol:
Software related Links:
Patches or knob settings:
Circuit Overview: below
Scematics/Service Manual: String Performer or Music Parts for other K series units
Common Service Issues/Tips: below
Parts Sources: Keys knobs semiconductors misc
Uncommon chips/modules used: MK50240 TOS chip, TMS3848 Dividers (used in some Hohner organs also)
General Info Links: Matrix Synth

Circuit Overview:
      Hohner made several string machines including a Logan with their name on it. (String Melody). There is also a string performer which looks cool but I have no information on it. Look online for photos. I have the simplest one, the 'Hohner String Synthesizer'. It's just a cello and violin volume and sustainer for each. Defeat switches for each and an ensemble that adds another footage above. Very warm. Standard divide down stringer with cards for each key to control contours. This is also known as the "K4" it appears however there is a wood grain top version and a version that appears to be larger. Maybe it has the power supply built in? It has the Hohner label on a black metal top. Anyway very nice sounding units. The 'String Performer' Hohner put up the service docs for above. The K2 is very similar to Elka Rhapsody 610 but uses different boards/parts to reach the same basic product.

Service Tips:
      The power supply was missing on my K4 with an impossible to find 15 pin (two rows with one missing as a 'key') Jones type plug. .087" wide pins by .034" thick. I had to retro a plug that works making individual pin sleeves from brass. The plug has four grounds in a row all tied together on one row, then an output pin, then another ground for the signal. Then another pin I don't know what does yet that also has a coax. inside I mean. And then the 'blank' pin on that side. Ok on the other side starting from the end opposite the blank pin (ie. next to the first of the grounds in the row we just covered) we have V- (-15V or so) then NC then V+ (12V), then another NC pin (no connection), then a 15 to 16V and another NC, then finally what I measure 18V that is independent. I seem to recall that one is the keyer. THey put it on a different supply to remove all pop I'm sure. Then the last pin is NC. ANyway so there are the pins in case anyone else ever runs into this again. A friend had a power supply from one that was internal but I put it in it's own box and it worked great. And just hard wired a 1/4" plug off the signal pin and ground. Anyway the typical stuff you would find in any divide down synth I'm sure.

I'd only have general parts (resistors, caps, transistors for these and occasionally the TOS. )
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