The jacks in these units are old, and often are oxidized. I don’t recommend just spraying into the jacks, as many times the jack’s covers are missing, then you spread de-oxit throughout the machine. Remove the audio board, and Deoxit the jacks elsewhere and insert and remove jacks just after spraying several times. Then see if it’s better. The fact that you say it comes on after a bit makes me wonder if it’s something else. It may be helpful to post an audio file of the distortion… Since you say all channels have distortion, you should focus one Channel. Let’s say channel 1. You should get a 6012 DAC and SSM2047 pair or two for testing….and TL084 as well... If you simply put the new ICs in and distortion went away- that’s pretty telling. Now on to the troubleshooting checks... IC 20 and IC 30 and also IC51 on the I/O board belong to channel 1 (IC 2 and IC 3 also contribute- but let’s not go there yet only thing to check there is pin 16 on each have the proper +5V) It shouldn’t be above 5.1V - too much voltage or undervoltage can also create distortion issues in circuits, generally speaking. IC20 Pin 20 should be +10V IC20 Pin 17 should be -12V IC 20 Pin 14 is +VREF and 15 is -VREF IC30 Pin 10 should be -5V IC30 Pin 18 has indicators on the schematic of +12V and +10V - so not sure of this value, and don’t have an unit open to check it right now... IC30 Pin 13 is the outbound audio signal going to IC51 IC51 Pin 4 should be +10V IC51 Pin 11 should be -12V IC51 Pin 2 is from IC30 pin 13 IC51 Pin 1 goes through a 1k resistor and connects to the actual center pin of the jack. hope the detail is helpful. -T On Dec 4, 2015, at 11:17 AM, krikor kouchian krikorola@... [emax] <emax@yahoogroups.com> wrote: this may sound silly but try to plug and unplug several times the jacks on the audio outputs, it actually solved it for me cheers K Le vendredi 4 décembre 2015, Shawn Ward shawnjward@... <mailto:shawnjward@...> [emax] <emax@yahoogroups.com <mailto:emax@yahoogroups.com>> a écrit : > > > hi Ted > > so i took your advice and went over the sockets and IC legs on the output board with de-oxit and re-seated them > > I'm still getting distortion. its affecting all the outputs and all samples/voices so the problem must be the IC where they are summed > do you know which suspect ICs I should be focusing on in the output board? > I'm still trying to rule out corrupt sample data, but the problem is intermittent and there is no bad data messages on any of the banks i load > > I've noticed that sometimes i can load the samples with no distortion then after a while it kicks in > > > > > >> To: emax@yahoogroups.com <mailto:emax@yahoogroups.com> >> From: emax@yahoogroups.com <mailto:emax@yahoogroups.com> >> Date: Thu, 3 Dec 2015 16:43:49 -0800 >> Subject: Re: [emax] Emax distortion >> >> When you reseated the IC’s did you use DeOxit on the chips and the sockets? >> >> You can’t get the connector on the ribbon that’s soldered to the board on the one end, just so you know (I went looking for these just recently and can’t find them)…. >> You could try and DeOxit on the male side of the connector, also- although I haven’t heard of the ribbon being a common cause of noise. >> Usually it’s the ICs (they can go bad), the sockets, or the reference voltage being supplied for the signal being the problem. >> >> >> -T >> >> >> >> On Dec 3, 2015, at 2:08 PM, Shawn Ward shawnjward@... <mailto:shawnjward@...> [emax] <emax@yahoogroups.com <mailto:emax@yahoogroups.com>> wrote: >> >> >> I'm still having problems with distortion coming through all outputs on my Emax 1000 Keyboard >> >> >> I have an HxC drive installed and I've confirmed the samples are loading properly and not corrupt >> >> I've also re-seated all the ICs on the output board. >> >> >> my PSU rails are also showing stable -12.6v +12.6v 5.2v >> >> I'm thinking it might be a bad ribbon cable that connects the CPU board to the Output Board >> >> >> any tips to troubleshoot would be great! >> >> >> >> >> >> [Non-text portions of this message have been removed] >> >> >> >> ------------------------------------ >> >> ------------------------------------ >> >> Emax and Emax II User's Group >> ------------------------------------ >> >> Yahoo Groups Links >> >> >> > > -- http://www.krikor.fr <http://www.krikor.fr/> +33632199413 For Live&Dj bookings contact: cedric@... <mailto:cedric@...> [Non-text portions of this message have been removed]
Message
Re: [emax] Emax distortion
2015-12-04 by Ted Summers