I recently got a Kawia K1r synth sound module. It would not retain program memory after unplugging, so I replaced the wired battery with a battery holder to make future battery changes easy. The synth worked fine, but still no memory retention. So I checked and found I had a bad solder joint on the holder. Fixed that, now memory is retained.
But... now for some reason I have no audio output on the rear jacks (left and right channels), but the headphone jack on the front does have audio.
With the help of some very good people at the Gearsluts forum I have been able to determine that the output muting transistors are not getting shut off. See the attached schematic of a similar unit (K1m). The two muting transistors are Q2 and Q3. Q4, as I understand it, is supposed to get turned on, and pull its collector low, and thus turning off the two muting Q2 and Q3. But I don't read any power at Q4. But then I don't seem to be able to read powr at several places that should show something. For example, where the ICs say VDD on the schematic I can't seem to get any voltage showing on my multi-meter.
Also, I don't get why on my multi-meter I get -34.4mV on one end of the fuse and -4.4mV on the other end. Surely this should be at least 5V or something? Of course, if I remove it the unit will not power on, so it's obviously working. Power is provided to the unit via an external 12V power supply (wall wart)
I would appreciate some assistance on this. A service manual is attached. See the K1m schematic.
Thanks.
Clay
But... now for some reason I have no audio output on the rear jacks (left and right channels), but the headphone jack on the front does have audio.
With the help of some very good people at the Gearsluts forum I have been able to determine that the output muting transistors are not getting shut off. See the attached schematic of a similar unit (K1m). The two muting transistors are Q2 and Q3. Q4, as I understand it, is supposed to get turned on, and pull its collector low, and thus turning off the two muting Q2 and Q3. But I don't read any power at Q4. But then I don't seem to be able to read powr at several places that should show something. For example, where the ICs say VDD on the schematic I can't seem to get any voltage showing on my multi-meter.
Also, I don't get why on my multi-meter I get -34.4mV on one end of the fuse and -4.4mV on the other end. Surely this should be at least 5V or something? Of course, if I remove it the unit will not power on, so it's obviously working. Power is provided to the unit via an external 12V power supply (wall wart)
I would appreciate some assistance on this. A service manual is attached. See the K1m schematic.
Thanks.
Clay
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