Reinard Synth#18 Ensoniq SQ2 Adventures: Keys not responding, Unobtanium and Overclocking

[@GonzoPhysics]

Excellent video. Really informative. Thank you! 🤙

[@construct09]

Thanks for your interesting video. I hope you find that IC, I'd love to see a follow up video!

[@tragicomixxxable]

Exelent knowledge, i thank you for this video!!

[@Alex-vb6uv]

Gruss Gott! Can you help me to repair the groovebox? I live in WIen

[@T-Cat-wy7ly]

Thanks a lot for this video - thorough and reliable information presented in an entertaining way! Have you thought about replacing the keyboard scanner (138065002B) with a micro controlller like an Arduino? As far as I can see it uses a 8x8 matrix for the keyboard and something like a 4x4 (or similar) matrix for controlpanel button scanning and LED driving. The Arduino Mini has 14 digital and 8 analog in/outputs so this should work to scan the keys and buttons and to merge this data to the data from the display controller. But it needs some 'programming experience' 😉

[@reinardsynth6581]

thx!! Yes, and actually I found a reference of Buchty (www.buchty.net/ensoniq/) thinking about doing this, but did not find any success story in forums or his web page... could be an interesting Arduino project indeed! You know what, I'll ask him! keep y'all posted...

[@rlgrlg-oh6cc]

Rainer Buchty may be able to help you. He has made a replacement for a different R6500 Ensoniq MCU.

[@aly.3921]

another great one thank u,,,what are your thoughts on why the scanner ic died?

[@reinardsynth6581]

I think -but cannot proof this- that something went wrong during the battery replacement by the previous owner... static discharge while handling the PCB??`did not find any clear indication of what happened. Other reports link to "soda spilled over the keybed" incidents causing the scanner IC to die; but i did not find any sign of a soda spil on the keybed...

[@dorianhernandez741]

I also have an SQ-2 where the LCD, backlight, and buttons work, but the sound is just a low frequency "hum". I am thinking it's the DAC, Op-Amps, and/or the Ensoniq OTISR2 chip (I hope not!). I'm looking in getting a new oscilloscope to do more troubleshooting, but I need the schematics for the SQ-2; do you happen to have them? I will look for an 138065002B and see if I get lucky; if I do will try to contact you ASAP. Cheers!

[@reinardsynth6581]

Schematics of the sq can be found here: audiopro.r-massive.com/Ensoniq/Schematics/Ensoniq%20SQ1%20%2832%20voice%29%20Schematics%20%5Blow%20quality%5D.pdf. The only difference with the 21voice SQ2 is the higget clock frequency of the OTIS and CPU and the addition of 1Mword of sample ROM in the SQ2 32 voice. If the front panel buttons work just fine it is not the key scanner at fault. Also check the ESP ans especially the -12V and +12V rails. And out of interest: with a scope See if there is as mich noise on the 5V rail as in my SQ2: 1V peak to peak…

[@dorianhernandez741]

@@reinardsynth6581 Thank you so much! I was able to get a copy after a free trial with SCRIBD (now Everand) last night, but I prefer the link you gave me (I should've known there was some SQ stuff in the R-MASSIVE site!). I have a hand held oscilloscope with which I am going to test the +/- 12V and 5V rails save the results to my PC. Do you have an email or something where I can send you the results?

[@dorianhernandez741]

​@@reinardsynth6581 Thank you so much for the link and the info on the key scanner; very much appreciated! I have a hand held oscilloscope so I am going to check the 12V and 5V rails and take a snapshot of the waveforms. Where can I send you the results?

[@reinardsynth6581]

@@dorianhernandez741 in a roundabout way: go to my eBay listing page and send a message: www.ebay.de/sch/i.html?item=135155293597&rt=nc&_trksid=p4429486.m3561.l161211&_ssn=reinardvanloo (one cannot send pictures in youtube comments...)

[@dorianhernandez741]

@@reinardsynth6581 Update: I found that the Philips TDA1441A is not getting -15V; C98 (tantalum cap) is internally shorted. The MC7912 supplying the -15V was getting pretty hot so that's when I found its output was grounded. Ordering parts today to replace all these and then some. I'll keep you posted.