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"Most 909s have v.1, I should know as I've owned 3 of these beasts.
The v.1 eprom causes sync IN issues with MIDI and DIN sync... in "slave" mode.
With the version 4 installed, ALL sync issues are fixed. Just search the web and read for yourself.
Again, this 909 has version 4... installed.
BOOM BOOM BOOM BOOM"
Inside a 909
I believe the Eprom v4 thing is a myth carried forth by sellers of this chip. Apparently the 909 is just picky with MIDI clock input when running as slave (the Roland service manual mentions some "glitch" with early ROM chips V1 though). Personally I use it as slave only with Sync in, no problems there. If you want a perfect fix for those milliseconds timing issues in many older pieces of gear, google innerclock systems (Australia), pretty good info there.
ReplyDeleteI have the original service notes dated Jun 15, 1984. There are only two versions listed, and no mention of a V4.
ReplyDeleteAccording to Roland:
"When synchronizing to MIDI clocks, there are glitches. TR-909 sometimes falls behind if STOP is pressed, then CONTINUE is pressed (this won;t happen when MIDI clocks are transferred between TR-909's). Software revision 2 cures this problem... To check if existing ROM is Ver. 2, the the power ON while holding down TRACK 1 key, and MAIN key 2 (BASS DRUM) will blink if version 2."
Have the V1 ROM! And I never had any problems of sync. My 909 is slaved via MIDI or DIN !!! No problem at all.........
ReplyDeletei've probably got fooled by 2 ebay 909 eprom v.4 sellers. i have tried to install two different ones, one from a guy in france and the other from switzerland, no one of these eprom worked proper. one eprom show wrong lightning details and the metronome button did'nt light when pressing it, i could'nt load the eprom demo ither with this one.
ReplyDeletethe other from switzerland looked like it was an original roland eprom but it could not load eprom demo or follow the slavesync when press continiue.
i will put my old v.1 back when i have the strength and time to do it.... this is not an easy job to change the eprom so thing once or twice before try this... i regret now doing this because i destroyed one lidpad for one of the legs for the eprom (needed to bridge this to make it work)
good luck!
I have a 909 that had the original V1 EEPROMS and it is nearly impossible to sync to incoming MIDI, except on the first go, as described in the manual.
ReplyDeleteI got V4 EEPROMs from a guy in Switzerland and this issue is fixed.
Installation of the EEPROMs is not a trivial exercise, as a lot of the traces are quite brittle and the new EEPROM needs to be soldered directly to the board.
The first ROM I received did not work, but the guy I bought it from quickly sent a replacement which worked just fine.
There is not enough room in my 909 to install a chip holder.
I have just bought a 909 apparently with V4 OS installed. It wont function properly. NO Reset when holding down tr.1 and pat.1 on power up, NO bank select, NO version display of OS on power up, NO total accent control, Crashes when changing the sync mode, I am not looking forward to finding out what has been done to the insides should this 909 have been badly soldered desoldered when the OS was changed. It Sounds great tho.
ReplyDeleteForget that myth. Read this Roland service bulletin #100236 dated Feb 6, 1985 about that upgrade available as Roland service part.
ReplyDeletehttp://www.synthfool.com/docs/Roland/Roland_Service_bulletins/Roland_TR-909_100236_02061985.gif