One of the first affordable digital drum machine with internal sequencer and 12 bits 25.641 kHz dirty samples from this era based on custom MB661107 exclusive developed by Korg. I made a full review years ago, you can read about it HERE
The DDD1 is not a very sought after drum machine, but it's still fun especially with sampler board
Sold as "not working" on local craiglist as "drumer macine" with stated "display not working, as IS"
UPPER: Ok the machine sounds and logic seems to be ok. LCD shows backlight, voltages are as they should be. Ohh look at that: Broken trimmer! Easy one.
UPPER way better now! as you can see. Then I noticed the buttons are not really working, it's quite common these days. The drum baby is also very greasy, I think previous owner tried to fix the buttons with some deoxit stinky green things
UPPER Disgusting work, greasy and sticky. A LOT of time to clean up that mess. A have to clean also the contact switches, opening is quite delicate, or just replace them.
UPPER quite all buttons needs replacement or cleaning.
UPPER On left side the corroded disk of tact switch. On the right once cleaned.
Upper: Also slider pots need cleaning. These are ALPS 10KB for data, and Logx2 for volume both 30cm. The input is also 10k but it's shorter, if you don't have the DBS1 sampling board, you just don't need it.
After replacing the CR2032 battery, just make a reset procedure:
HOLD YES AND NO, THEN SWITCH ON
UPPER: all working but one of the separate out (number 4) has a very very loud whining. In the schema both channel 3-4 are on the same opamp 4558 on IC30 (1/2/3 + 5/6/7) but it's marked a bit strange, they are quite similar "channel strips" so we can proceed in a kind of parallel testing.
Taking signal at 4051 multiplexer/demultiplexer pin15 the signal is quite right. The whining enters about C114. Electrolytic capacitors around are still good, they are innocent.
UPPER this is about the path of stuff to follow. Getting C118 out of circuit, the whining disappears taking signal on C114 oscilloscope shows the right waveforms now. Something ABOVE resistive array RA20 should be the culprit, I will try classic OPAMP test just to be sure and to restrict the selection to examine - oh it's double sided board TH, be gentle.
Upper. extracted the IC30 opamp, but It's good out of the circuit! I just have to inspect all the path: 4051 15 ra27 r120 c114 c113 r119 q10 r119 c112 ra20 c115 c81 c82 r96 r97 OPAMP IC30 in-6 in+5 out7 c67 r65
Ceramic capacitor 471 - 470pf was producing that whining sound. Now the unit is fully working on all outputs.
-DDD1 OS EPROM DOWNLOAD
-DDD1 User manual DOWNLOAD
-DDD1 service manual DOWNLOAD
If you like this page, just consider buying a sample pack :)
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