Hello everyone. Im having an issue with my JX-3P. When i select either the “edit write” or “sequence write” button, 1-16 of the patch buttons light up for about half a second and then back off. This problem also occurs when i try to select “load” under tape memory.
I took it apart and had a look at the memory protect switch and noticed a solder joint that had been completely lifted off the pad. after reflowing that solder joint i was able to press play on the sequencer with a single note being able to be heard. im still unable to write anything to memory without having those 16 buttons light up even after reflowing the bad joint on the memory protection switch. I also changed out the battery causing all previous patches that were on the synth when i got it to be erased.
any help would be greatly appreciated.
1 Like
Hello
The signal provided by the write enable switch runs from the DIN board through the jack board to the panel board. On the panel board this signal controls transistor TR14, which acts like a switch in the switch matrix. So the problem is either in the matrix or in the this signal flow.
To check the matrix:
Can you select Program group B and then coming from B the programs A5 or A13? If not, then the line SW4 is faulty.
Do the Bender, the LFO button and the bend range switch work correctly? If not then the line SW SC 4 is faulty
If both matrix checks are successfull, the fault is in the route from din board to the panel board.
Check the following places with a voltmeter, while switching the write enable switch to the both outer positions. Th voltmeter should change between 0V and something around 4V or 5V:
On the DIN board: Pin 4 of CN1
On the jack board: Pin 4 of CN4 and Pin5 of CN1
On the panelboard: Connection W40-R40 and Base of TR14
Attention: this drawing from the service manual shows the view from the component side. If you look at the mounted panelboard with the panel opened, then you have to think this drawing flipped vertically (TR14 is at the top)
Best regards
Florian
