RE-909 TR-909 replica

release

added IC11 and D30, D31, D33 to ORDERING

added info from christian about cabling

added gnd build notes from Christian, fixed an amount value

changed electrolytic capacitor in safety psu from 25V to 35V.

because its standard to have at AC Rectifier a safety range of multiplier 1.5 - 2

(for example an 18VAC is able to give after the rectifier a 28V-29V DC voltage.

regards Patrick 

added extra alternative options for 10k trimmers (clap)

fixed value in tape section.

new value R311: 820K (old value was 820R)

" Amp section "

fixed C143 voltage 47uF to 50V.

35V is fine too (comment Patrick)

advisory added for snare drum fix.

added info about cabling and errors in TR-909 service docs

fixed values in high tom, C95 and C97 were reversed

new value C95: 100nF

new value C97: 15nF

(just swap both capacitors, old value was C95 15nF & C97 was 100nF)

1

Snare Drum section - 

Revision.1

please download v.1.7 build documentation for details.

Service advisory: after building the snare you must place a jumper as shown in the pic below, this is shown without parts placed for clarify

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bigger picture from me - easier to find the place..

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17.Dec.2020

1.9 build guide

2

C95/c97 Tom section

Rev.1

swap both against each other

17 Dec. 2020

1.9 buid guide

3

Psu

REv.1

if you‘re using the Safety PSU do not connect pin 27 and pin 28 on the F3 cable, otherwise you‘ll create a ground loop.

17.dec. 2020

1.9 build guide

4

PSU - wrong routing

→ affects the memory

Rev1

change the 5.6V zener as shown here:

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17.Dec. 2020

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        • not released - not Confirmed

5

Noise floor - crosstalk

REV.1

from FB RE-909 group:

"Hello! Just wanted to share some good news about noise and crosstalk issues on RE-909. Pictured below is a Roland TR-909 factory mod with a wire that seems to reinforce grounding between C151 styrofoam cap in the hihat low pass filter and the common analog ground track where R236 is also attached. By doing the same mod in RE-909, pictured below also in the bottom of the board, cymbals crosstalk and digital noise leak into the hihats channel is eliminated, which fixes the last remaining issue in my build. I used a thick grounding wire to connect the lower pin of C151 to the double hole in the common ground track next to R236. This fix works perfectly on traffo PSU but I can’t guarantee it works on safe PSU (and preliminary tests show it doesn’t) because of the difference in ground routing. Otherwise, enjoy your digital noise-free, crosstalk-free RE-909!"

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6

Gate 

rev1-2

in case you hear the Gate signal of the SD in BD - you can try to connect a 1uF polar cap**  between GND and Trigger.  Measure with an scope to find the best value - maybe 470/680/820nF is fine too - or less.

15.may 2022

was posted in the RE-909 FB group on 10. may 2022

not tested by me, but confirmed by other people

7

MIDI BUG

rev.1 and 2

there's a failure in MIDI section

rev2_service_advisory_jan23.pdf

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8

Noise MOD

rev.1

only for rev.1 pcbs:

as described in the rev.2 guide, is there a extra trimmer for  the noise,

for rev.1 pcbs you should be able to cut a trace between 2 resistors and install a trimmer 

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9

jack IO

rev1

only needed in rev.1 (rev2 still has this fix) 

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2022

rev.2

1

Wiring

You can use the MTA100 system from TE connectivity for example or Molex Style Connectors with a pitch of 2.54mm

2

noisy/hiss

make sure to solder the potentiometer at all pins to have the correct ground - (the ground flow thru the outside pins / it act like a trace/bridge) 

3

MIDI OUT

measure the transistor HFE value for the switchboard Q604 - a gain of 350 should be fine.

otherwise it can happen that MIDI OUT doesn't work.

you can also mod the MIDI Out : http://www.colinfraser.com/tr909/909mods/909midi.htm

4

Transistor matching for gainstaging

It´s not important to match this trannys. it was very often discussed in the Facebook RE-909 group.

select the * S* Transistors to the same HFE to get a balanced gain on all voices.

check the schematics for more details, all are 603/945P Transistors

q12 in Bassdrum

q51 in snaredrum

q20 in Low Tom

q27 in Mid Tom

q58 in High Tom

Q71 in Crash

Q85 in HH

Q65 in Rimshot

Q37 in Handclap

Q33 Tom Noise - should be ignored or just use the same hfe as above

5

DAC assembly

use few millimeters height paper to get a correct alignment:

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6

mod

https://note.com/re_303/n/nd37b0d0ab809

"RE-909 MOD KIT" Build Guide｜Jun.pdf

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7

Tape Interface Section

the Tape Interface Section isn't required to build

8

Ba662 clone orientation

the ba662clone component side is at C58

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9

Q47 Q48 orientation of ZTX1051A

10

Q82 Q83 orientation

11

BA662 technology

MODE B Configuration is used in the 909

Pin 4+7 = GND

PIN 5 = -15V

Pin 9 = +15V

12

parts

low profile dual pin header for Switchboard and Eproms Crash and Ride (not Hihat)

DS1004-1X40F11

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13

green modding

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the LEDs should be with more brightness than the red versions.

17x N0G64L64 (square 2x3mm) 100mcd

4x N0G30L85 it has 70-200mcd

for 7x7 segment display you can use the original BOM version but in green = BC56-12GWA but its not bright, you can't use this under daylight or bright studio light.

in case you want more mcd/brightness:

OPD-T5621UPG-BW (available by tme.eu)

the Display is much brighter, the green is darkgreen color/tone compared to the BC56 version.

you have to change the Resistors 601 to 607 to 330R or more (680R is a good balance , not to dim , not to bright). You can use milled DIL Socket to test resistor values.

the only issue is the select switches - which is in SMT inside of the switches - please ask Andreas Kump - kumpronics.com

14

LED resistor changes

the 4511 can supply enough current as shown in the data sheets. but you should respect Ohms law and do the math before you simply change resistors.

its useless to swap resistors in case the display can't give more brightness as shown in the datasheet of the segment display

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15

Usage MIDI OUT

please pay attention to read the REVOLUTION v5 Firmware Manual.

MIDI OUT SYNC is by default disabled.

1

one or more Step LEDs are off, when you press a switch - a other stepswitch is active too

check orientation of the LEDs (look in the LED and compare it to a other LED)

check the diode orientation

when you have one LED - which never turns on - it can be a faulty LED - which is very rare - but it was happen on one of my builds and I spend 3hours to figure out a simple LED defect..

2

no voice out of one or more voices

check with a scope the trigger input and accent trigger.

option A: the Voice isn't triggered = no sound

check IC1-10 - swap with a other voice IC for easy testing. Use a Scope and look in the schemata where the trigger and ACC trig. must be available.

option B: output wiring or routing faulty= check with a scope at W5 the Audio signal.

nicetoknow: the AUDIO out goes from the VoicePCB to the multi jack board and then back to W6 and return to multi jack PCB. = failure source can be the cable there.

use a Frequencygen. and feed a signal to W5 to check the audio path to the Masterout, Indiv.Out., return path.