Ensoniq Sq80 display

[nuketifromorbit]

I just picked up another sq80 and while everything on it works wonderfully the display will dim slightly from time to time. Is this a sign of the battery running out of juice or is the display itself slowly going bad?

[rhino]

if the whole display dims, not just a few characters, then comes back ok... check for cold solder joints where the +90 volts connects to the driver ICs. if they are all ok, then maybe the high-voltage inverter circut and/or xformer are failing. Let me find my schematic and i'll get back.

[nuketifromorbit]

Anyway the dimming really isn't a problem at the moment, and yes the whole display is dimming not just certain characters. Is it really necessary that I fix it? Would it be a bad Idea to wait till it completely fails? The schmuck who mailed me the thing did the worst job of packaging I've ever seen, I'm surprised this is the only problem. Basically while the lower portion and sides of the box had a decent amount of bubble wrap the top was only half covered. I'm guessing being thrown around by UPS could cause something like this? Oh yeah and thanks for the info, I've already checked out buchty's site and google to no avail.

Edit
Would replacing the Display controller with another from Buchty's site work, or would that just be a waste of money?

[rhino]

IMHO, the problem is power-related, not the controler. the 90-volt power comes from an inverter circut: the little transformer running at ultra-sonic frequency sometimes will literaly shake a winding loose.
also, now that you know the synth had a rough trip, check all connectors for being loose, or corroded.

[nuketifromorbit]

IMHO, the problem is power-related, not the controler. the 90-volt power comes from an inverter circut: the little transformer running at ultra-sonic frequency sometimes will literaly shake a winding loose.
also, now that you know the synth had a rough trip, check all connectors for being loose, or corroded.

The first thing I did was open it up, for the most part everything seems hooked up fine, but I haven't bothered to unscrew the circuit board that fits right underneath the display. I guess I'll eventually get around to it, but right now I can live with it. In your opinion how difficult of a fix is this? Is some one with very little soldering skill better off taking it to a tech?

[Anarog!]

I’m encountering the exact same problem here with an SQ-80 and wondering if you manage to fix it and if you did what the problem was? Would really appreciate you sharing your knowledge and expertise on this matter.

Screen is slightly dimmed in the middle and occasionally flashes bright, especially if VERY gently tapped (yes I know this is a very bad idea for this type of screen) after a while the screen comes up to full brightness and stays like that.

I’m not really sure but the fault I have described seems very indicative of a capacitor problem, then again it could be as simple as a connection problem, or possibly as bad as a failing screen.

Would really appreciate any help if anyone else would like to chime in.

[rhino]

Well, the old geezer was having a senior moment. Sorry for the bad advice: the SQ-80 and ESQ-1 DO NOT have inverters to generate the high voltage for the display. They use a voltage-tripler on the power supply. I was thinking og the Roland JX series.

[Anarog!]

Hi,

I’m having the exact same problem with the flickering when gently tapping the screen and everything, maybe I even brought the same SQ-80 *laughs* ... I would really like to fix this ...


I remember reading a whole bunch of stuff about the SQ-80 fluorescent vacuum display, how it’s prone to static discharge problems and I think I remember reading that if the screen has the above fault it’s failing. Then again I also read that the screen is bombproof and it’s always the electronics that fail.

Really appreciate some help on this guys.

Cheers in advance,
A-

POST SCRIPT: Ok fixed it... I had to take the display board off to replace a broken slider and on replugging it all worked, therefor I can say you should clean the metal pin connectors to the disply cables and see if it’s just dust and dirt before worring about electronics.