Probably dirty sliders glitching out and changing parameters on you. My PG-800 does this a little. Thanks! Do you just spray some contact cleaner in there? Rubbing alcohol and qtips? I'm seeing lots of different suggestions across the internet. Cleaning pots is becoming a lost art, it seems. There ...

I've had "no output" situations that trace signal right up to the output stage volume control or busted output jack. I've also had (have) no output situations where there's no signal at the VCO, or s**t gets lost in a storm of fuzzy logic, etc. Upside is that the unit under discussion looks to have ...

Unless you yourself are looking to troubleshoot and repair this instrument, it would be reckless to purchase a synth in non-operating condition based on meeting a value or worth target. I mean, I'd probably buy it - but I'm sick in the head. I also don't charge myself $100 an hour for repairs, and h...

Jumbling patches.. what does the back-up battery read?

Anyway, good luck, they are cool synths and worth the effort to keep going.

Took a peek at the ESQ-1/ESQ-M service data, this is the page you're referencing, yes? https://i.imgur.com/LHunlyT.png Most of the numbers seem within acceptable ranges (except the display feed, which is all over the place). I do see a discrepancy with the unregulated +V to main board and what you l...

Forgive my ignorance, when you say "rails" you mean all the different voltage lines like the +5, -5, +12, -12 points? Yes, that exactly. Unloaded supplies can often run higher than when they're working in circuit. When you're measuring the higher than specified voltages, is that at the ICs being su...

Do you have an oscilloscope? Watching the rails upon power up (when it's doing the garbled thing) could guide you on this. Changing out the bulk caps is good stewardship, so while it didn't fix the issue it might prevent others down the line. I would continue to replace the smoothing caps on the pow...

I would suspect failing capacitors as my first directive, yes. Often caps will reform a little under use/DC charge (which could explain why you observe the issue clear up over time). If the garbled section is 30 seconds when turned on first thing and then that time shortens a bit if you turn it off ...

You have an MKS-50 listed in your gear, try that.

PG-300 (or similar) to animate the parameter changes predates widespread DAW usage.

Good luck!

The power LED going dim could very well be dried capacitors on the power rail, if you have the tools it would be worth checking internal voltages. Again, I'm not familiar with this particular model, but it looks like service data is available on the internet - so that is encouraging.

Sounds like you may have oxidization on switch contacts. Sometimes they come back to life with repeated exercise and use, 25 years is a long span though, so neglect may have taken hold.. If the switches remain reluctant to wake up and you are comfortable with opening the instrument up and exercising...

Gear like this this I tend to just plug it in and go. With the external power supply/wall wart if the PSU fails you can simply replace it. Do be mindful that Yamaha wants positive center on the power supply.

Because the method of removing and re-inserting all of the precious chips seems to me - amateur - quite dangerous... Funny story, I once purchased an Eventide H3000 in non-functioning condition at a garage sale. Opening it up and exercising all of the connectors and seated components was all it too...

I've never worked on a Pianet, but I have a passing familiarity with electromechanical pianos. I would avoid bending tines. Tine manipulation may result in tuning issues. If you can identify the pick-up and adjust its position you'd be better off. Again, I am not familiar with this exact constructio...

Update. 3.02 firmware acquired from monotanz, installed, no change. I went through several bouts of frustration with this thing, never reaching a solid conclusion until today. 1st hint: the boot hang has all LED except "transpose" lit. This indicates a failure in diagnostic cycle at the display (per...