Search found 72 matches

by Jacob Hunt
Tue Oct 27, 2015 11:35 pm
Forum: HELP!
Topic: OB-Xa Keyboard issues
Replies: 7
Views: 1178

Re: OB-Xa Keyboard issues

Solved it :D
U21 wasn't receiving data from the address bus on one of the pins, but the data was present everywhere else. Turns out there was a lack of continuity between E connector pin 33 and U21 pin 14.

I almost forgot how great this thing sounds :)
by Jacob Hunt
Sun Oct 25, 2015 11:04 pm
Forum: HELP!
Topic: OB-Xa Keyboard issues
Replies: 7
Views: 1178

Re: OB-Xa Keyboard issues

I suspected the connector heavily also, but have triple checked it for proper connection and continuity. No pins shorted, no lack of connection, seems to be working great. Tried pushing and pulling on it and other connectors and check solder joints for problems, no luck though. I can't tell much is ...
by Jacob Hunt
Fri Oct 23, 2015 10:16 pm
Forum: HELP!
Topic: OB-Xa Keyboard issues
Replies: 7
Views: 1178

Re: OB-Xa Keyboard issues

http://i57.tinypic.com/am6s81.jpg I've noticed that the second note triggered along with the first is always the note next to it in these columns. Example: E1 triggers E1, but also triggers C2, F1 triggers F1 and C#2, etc. I also noticed that 4 of the 8 columns function, so somewhere along the line...
by Jacob Hunt
Thu Oct 22, 2015 11:26 pm
Forum: HELP!
Topic: OB-Xa Keyboard issues
Replies: 7
Views: 1178

Re: OB-Xa Keyboard issues

J Wires all check out good, unless there's some type of J wire problem other than contact issues that could whack out the keyboard. Just yesterday one of the sections that worked quit, and a different section began working, a very odd and now moving around problem. Maybe some type of firmware error?
by Jacob Hunt
Wed Oct 21, 2015 12:52 am
Forum: HELP!
Topic: OB-Xa Keyboard issues
Replies: 7
Views: 1178

OB-Xa Keyboard issues

Hey everybody, I have an ob-xa in good functioning condition except for one thing- the keyboard is crazy! It triggers two notes at a time everytime, and large sections of successive keys do not play. I've noticed that these sections are broken into columns in the schematics, and feed into an ic U21....
by Jacob Hunt
Thu Jul 02, 2015 2:41 am
Forum: HELP!
Topic: Updating OB-Xa?
Replies: 1
Views: 496

Updating OB-Xa?

My OB-Xa is one of the older 32 program units, and was wondering if it would be possible to update it with a newer firmware. As I understand, the firmware is on the RAM chips, but I don't know a whole lot about that kind of thing.
Thanks in advance :)
by Jacob Hunt
Tue Jun 23, 2015 12:46 am
Forum: Gear Services & Other Goods
Topic: TDA0740 Wanted
Replies: 0
Views: 996

TDA0740 Wanted

My Omni has a group of notes all together that don't play, and I've heard the TDA0740 is the problem, but can't find one to try. If anybody has one to sell, let me know.
Thanks in advance.
by Jacob Hunt
Thu Feb 05, 2015 2:53 am
Forum: HELP!
Topic: Strange OB-Xa Problem
Replies: 3
Views: 764

Re: Strange OB-Xa Problem

Wow thanks! I'm glad to see I was looking at it backward, I guess it did seem a bit strange that It wasn't triggering even though it was :lol: Anyways, I figure you probably guessed from my lack of knowledge about the keyboard that I'm not too familiar with that kind of system, so looks like I'll be...
by Jacob Hunt
Wed Jan 28, 2015 3:26 am
Forum: HELP!
Topic: Strange OB-Xa Problem
Replies: 3
Views: 764

Strange OB-Xa Problem

My OB-Xa had the ribbon connector break that connected the keyboard to the lower control board.. Ok that was easy enough to fix and replace, but when I started playing it it acted as if the connector was never replaced. I'm missing several notes in groups across the keyboard, and it sometimes trigge...
by Jacob Hunt
Sun Jan 11, 2015 8:19 pm
Forum: HELP!
Topic: Minimoog now has a working keyboard
Replies: 15
Views: 2708

Re: Minimoog now has a keyboard but has a problem still

Got it :P Come to find out the Keyboard circuit also requires input from the 10v trigger to trigger the track and hold. Now with some finishing touches and adjustments this thing will be ready to go!
by Jacob Hunt
Sat Jan 10, 2015 11:34 pm
Forum: HELP!
Topic: Minimoog now has a working keyboard
Replies: 15
Views: 2708

Re: Minimoog now has a keyboard but has a problem still

Still scratching my head on this.. I noticed that my polymoog's keyboard behaves the same way at the output of it's pitch bar, so I imagine something is holding the last given pitch, and that something must have been bypassed on the Minimoog with the mods. I have the pitch buss output running into t...
by Jacob Hunt
Wed Jan 07, 2015 9:59 pm
Forum: HELP!
Topic: Minimoog now has a working keyboard
Replies: 15
Views: 2708

Re: Minimoog has no keyboard

And the trigger buss is working now!! My last problem to overcome is that whenever I let go of a key, the Mini reverts to playing the lowest F note.. It tracks pitch correctly across the keyboard and triggers notes pretty well (albeit a bit squirelly :D ) but it just doesn't hold on to the note that...
by Jacob Hunt
Tue Jan 06, 2015 9:15 pm
Forum: HELP!
Topic: Minimoog now has a working keyboard
Replies: 15
Views: 2708

Re: Minimoog has no keyboard (now it does!)

And it works!! The keyboard is sending the correct pitch! I just need to get the trigger buss working now. Here's a pic of my crazy setup. Those are boards from an old Kimball, and I have three buss bars from it and a 44 note keyboard. I stacked the boards and stuck the second contact into the guide...
by Jacob Hunt
Mon Jan 05, 2015 12:59 am
Forum: HELP!
Topic: Minimoog now has a working keyboard
Replies: 15
Views: 2708

Re: Minimoog has no keyboard

Well after weighing all the options, I've decided to use the pratt read keyboard. I'm connecting a second board to its electronics/contact assembly for use as the trigger contacts. It looks to me like for the pitch bar contacts a resistor needs to be wired in between each of them. Can anybody confir...
by Jacob Hunt
Fri Jan 02, 2015 2:18 am
Forum: HELP!
Topic: Minimoog now has a working keyboard
Replies: 15
Views: 2708

Re: Minimoog has no keyboard

I'm hoping it's as simple as routing some old wires back where they belong :D Haven't opened it up yet, so not sure what to expect yet. The odd thing about not being able to modulate with osc. 3 is that it mentions osc 3 control on the mod labels, but it appears as if it was left off, no amount of s...