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 omg 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

Transistors

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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