Hello all, thanks for taking the time to read this. I am trying to revive 1986 metal Ensoniq ESQ-1.
I’ve created a video showing the current state of the synth. You can see it here:
When I turned it on initially, it did not make any sound and the screen was blank. Power cycling a few times resulted in a few characters on the screen, then a constant garbled tone from the machine after a successful boot of the OS. I can navigate menus and change setttings on different pages with the up and down keys. Pressing keyboard keys changes the tone coming out of the machine, but not musically. The pitch does seem to go down as I move down the keyboard. Changing settings such as the level of the overall VCA or the filter cutoff has no effect. I can see lots of different patch names and move between them, but the sound does not change. Trying to load sounds from tape mutes the constant tone. The volume slider does not make any difference when moved. Also, the value slider does not change settings. Cartridges are not recognized.
My first step was checking the power supply. The fuse at the bottom of the row of fuses had worked loose and was replaced. I checked all the voltages against the service manual. Everything seemed with the given parameters in the manual except the unregulated power which was 11.4VDC instead of 11.8VDC.
The internal battery is reading 0.03V, which is essentially dead. I’ve performed the soft reset accessed by holding the Record and Soft button 1. While reseting the constant tone is silenced, then returns. I’ve also performed the hard reset by shorting the ground of the battery terminal to C1. It did not seem to make a difference. Information for these routines was pulled from http://www.scoreforsale.com/html/reset_re-initialize.html.
I’m looking for advice on what to try next. I’ve got some experience building and repairing electronics. You can see my blog for an idea of where I am at: