electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
Live streaming at radio.electro-music.com

  host / artist show at your time
<on air> EdisonRex Edison's Electronic Review
Please visit the chat
 Forum index » Instruments and Equipment » General Discussion
JX3p-No sound-No front panel functions=could use some help p
Post new topic   Reply to topic
Page 1 of 1 [6 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
valvusmusicus



Joined: Nov 06, 2009
Posts: 56
Location: Bournemouth. UK

PostPosted: Sun Dec 09, 2012 4:50 am    Post subject: JX3p-No sound-No front panel functions=could use some help p Reply with quote  Mark this post and the followings unread

Hi All
I also have a fault on a JX3P
Hi all
Have a JX3P-all the power rails are correct-measured on the main PSU bd with the rest of the synth connected, and at each bd on the molex connectro-so power seems to be getting to the synth at the correct voltage.
The only problem is that the 7v rail sits at 9.4v, eith or without the synth power looms connected-could be relevant?? -but the switches dont do anything(accept memory switch 3 is permanantly illuminated) battery is a bit low-but this should not cause this problem,....should it??
The battery only backs up the memory-has no effect on the unit booting up..?does it?
Any thought


All the best
V
Back to top
View user's profile Send private message
Uncle Krunkus
Moderator


Joined: Jul 11, 2005
Posts: 4759
Location: Sydney, Australia
Audio files: 52
G2 patch files: 1

PostPosted: Sun Dec 09, 2012 5:57 am    Post subject: Reply with quote  Mark this post and the followings unread

I can tell you from working on my MKS-30 (JX3P in a box) that the "7V" line from the PSU is simply the input to the 5V regulator, and could be as high as 11V (in my case), and still be fine. When you trace it you'll find it only goes to the cartridge socket. I think it's used to "flash" the memory on those old cartridges. (EEPROMs) For the time, they were the most reliable way of storing and transferring data.

BTW If I were you, I would start by very carefully scrubbing the whole thing, to within an inch of it's life, with a hydrocarbon solvent, and a toothbrush. Laughing
Well, that's how I started mine, and it's a lot better than it was! Cool
I've done a lot more than that though,.... it can get quite involved. Twisted Evil Laughing

_________________
What makes a space ours, is what we put there, and what we do there.
Back to top
View user's profile Send private message Visit poster's website
valvusmusicus



Joined: Nov 06, 2009
Posts: 56
Location: Bournemouth. UK

PostPosted: Sun Dec 09, 2012 7:03 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks for that-I will give the boards a good scrub
I also notice that there ais a connection from PSU bd to main bd, thats not on the schematic, pcb overlay or anywhere in the service manual. its a wire coming from the output of the 5v reg on the psu bd and grnd to the main bd

On the PSU bd the connection is from accross D3 and c1. to the main bd accross c76-which I think is associated with the 74LS32 chip, which is IC53
Is this a mod? should I dis-connect it? Odd!!

Please see pics attached. The first one is the bottom RH corner of the main Bd and the second is the RH corner of the PSU board

many thanks

V


BD1.bmp
 Description:

Download
 Filename:  BD1.bmp
 Filesize:  8.51 MB
 Downloaded:  73 Time(s)


BD2.bmp
 Description:

Download
 Filename:  BD2.bmp
 Filesize:  8.51 MB
 Downloaded:  69 Time(s)

Back to top
View user's profile Send private message
valvusmusicus



Joined: Nov 06, 2009
Posts: 56
Location: Bournemouth. UK

PostPosted: Sun Dec 09, 2012 7:13 am    Post subject: Reply with quote  Mark this post and the followings unread

Cleaned the main bd thoroughly, there was some crap on the bottom right corner of the bd-now all the preset lights are flashing randomly-but when you depress the switches-they do nt respond. none of the other switches/LEDs function
Guess itstime to clean the switching bd??
Back to top
View user's profile Send private message
valvusmusicus



Joined: Nov 06, 2009
Posts: 56
Location: Bournemouth. UK

PostPosted: Sun Dec 09, 2012 12:31 pm    Post subject: Reply with quote  Mark this post and the followings unread

From info on another forum-seems there may be a fault around the DAC? will measure outputs/inputs/offsets, etc, tomorrow at work with scope
Will keep the post informed
Back to top
View user's profile Send private message
valvusmusicus



Joined: Nov 06, 2009
Posts: 56
Location: Bournemouth. UK

PostPosted: Wed Dec 12, 2012 4:02 pm    Post subject: Reply with quote  Mark this post and the followings unread

DAC circuit is fine-seems to output data well, not latched up or dead with no waveforms-any thoughts please?
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic
Page 1 of 1 [6 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » Instruments and Equipment » General Discussion
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use