TR909 issues

Post by **wiss** » Mon Oct 15, 2007 3:26 am

1. Snare control for snappy and tone are not responding
2. High hits manual do not respond but if controlled by midi they do
3. Clap just a real weak glitch
4. low toms just a glitch and the only control that works is the level

what can I do to bring it back to full health???

Altitude · Post by **Altitude** » Mon Oct 15, 2007 12:28 pm

Sounds like your noise source has gone to s**t. It feeds both the snappy and tone (it sounds like a tom right?) and is the basis for the handclap.

here is the schematic:

http://www.colinfraser.com/tr909/909noise.gif

Chances are its is a dodgy 4006 (Shift register it takes 2) or a 4070 (XOR Gate)

Cant help with the trigger though, look for loose wires or shorts maybe, if it triggers via midi it is likely an analog, not digital issue

Post by **Stab Frenzy** » Mon Oct 15, 2007 2:35 pm

wiss wrote:1. Snare control for snappy and tone are not responding
2. High hits manual do not respond but if controlled by midi they do
3. Clap just a real weak glitch
4. low toms just a glitch and the only control that works is the level

what can I do to bring it back to full health???

Oh no, it's turned into an ER-1!

Post by **wiss** » Mon Oct 15, 2007 6:52 pm

thanks Altitude

you dont happen to know where I can locate the plastic battery case?

Post by **nathanscribe** » Mon Oct 15, 2007 6:59 pm

Regarding the snare & clap:

Altitude is right I think, it sounds like the noise circuit had popped its clogs in some form or other. Open it up and with a scope check the output of (IIRC) pin 9 on the second 4006 in the pair... if that's a constantly changing pulse (ie, digital noise) then at least you're OK there. It could be a bad connection otherwise, but that's where my knowledge stops on the original (I built a clone). If one or both 4006s have gone, they're 14-stage shift registers, obsolete and hard to get. Good luck.

Regarding the trigger:

I second the above - if MIDI triggers it but the button doesn't, check the contacts and any wiring/connectors.

Regarding the tom fault:

the tom is made of a little attack noise (from the noise circuit, unfortunately) and oscillator sweep, so you should check the analogue side of the circuit.

It could be that a fault somewhere has blown back to the noise and bust a 4006. I had that issue with my clone. So I recommend making sure the other parts work without the noise, before replacing any 4006s.

Altitude · Post by **Altitude** » Mon Oct 15, 2007 7:14 pm

nathanscribe wrote:Regarding the snare & clap:
...

Lol, I think we are both pretty well versed in 909 noise problems

(Natanscribe helped me debug my clone when i had the same problem with the noise as he did)

The tom should sound with or without the noise (you can confirm this with the other ones) so there maybe something else going on there also

smallsynth · Post by **smallsynth** » Mon Oct 15, 2007 7:39 pm

Stab Frenzy wrote:Oh no, it's turned into an ER-1!

ha!

Post by **wiss** » Tue Oct 16, 2007 6:36 am

wiss wrote: you dont happen to know where I can locate the plastic battery case?

got one at radioshack..

Post by **wiss** » Tue Oct 16, 2007 8:42 pm

on the biggest board there is a cermic connector broken off on the "D3" in the section where its D1 D2 D3......what will this effect? I am starting to believe this is the high hats..

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Altitude · Post by **Altitude** » Tue Oct 16, 2007 8:49 pm

Here are the schems for the whole thing, look it up.

http://no-ho.com/909_schems.zip

if you cant figure it out, take a macro picture of the damaged area (and the noise while your at it) and post it here

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