Hi there,
In the process of building the Yocto 2, I've finiched PSU, IO board, PSU busses, Noise, Kick Drum and sequencer parts needed for test mode.
Now when I switch it on, only 1 kick drum sounds on startup, and then remains silent. I've been probing araound a bit and found the trigger outputs (IC 112 & IC 113) were putting out trigger signals,
But I was wondering what type of output I should measure at the DAC-output (IC 118) and the accent buffers (IC 1, 2 & 110).
Hoping you could help me out here, thanks !
Yocto 2 makes only 1 bass drum sound on startup in test mode
A small follow-up after some more elaborate measuring:
Triggers from Trig-shift registers (IC 112 & 113) are working giving nice 5v 1ms triggers.
DAC seems to work, giving 13V at the output of the DAC buffer (IC6).
But this 13V is not getting through the multiplexers (IC 11 & 114).
Data is getting into the CD 4049 Hex-inverter (IC 3). Assuming that the 4049 is used as a Logic-level converter from 0~5V to 0~15V, it's not really doing that. A "low" (0V) on the inputs is converted to a "high" voltage of 15V, but a "high" (0V) on te inputs is converted to a "low" voltage of 9V, where I'd expect a value much closer to 0 V.
I've ordered some 4049's and 4051's for replacement (the Texas-instruments ones, as recommended elsewhere on this forum).
Triggers from Trig-shift registers (IC 112 & 113) are working giving nice 5v 1ms triggers.
DAC seems to work, giving 13V at the output of the DAC buffer (IC6).
But this 13V is not getting through the multiplexers (IC 11 & 114).
Data is getting into the CD 4049 Hex-inverter (IC 3). Assuming that the 4049 is used as a Logic-level converter from 0~5V to 0~15V, it's not really doing that. A "low" (0V) on the inputs is converted to a "high" voltage of 15V, but a "high" (0V) on te inputs is converted to a "low" voltage of 9V, where I'd expect a value much closer to 0 V.
I've ordered some 4049's and 4051's for replacement (the Texas-instruments ones, as recommended elsewhere on this forum).
Did you trying assembling the whole sequencer? When I assembled only the parts needed for voice testing (as shown in the assembly guide), I got a single faint bass drum “boom” at powering it up or nothing at all. Once I assembled the whole lower mainboard, everything was fine. Still have no accent, though.
Currently, only the parts needed to trigger voices in test mode are installed. And by looking at the schematic, that's indeed all you need to trigger voices in test mode. The rest is basically just shift-registers for controlling the Led's and switches. But I'll build that soon.
I did try forcing a positive voltage on the accent-input of the bass-drum, and that started triggering the voice. So the bass-drum voice works
So: voice is OK, trigger is OK, it looks like the problem is in the accent-section. And I suspect the 4049 to be the bad guy.
I'll post an update after replacing that one.
I did try forcing a positive voltage on the accent-input of the bass-drum, and that started triggering the voice. So the bass-drum voice works
So: voice is OK, trigger is OK, it looks like the problem is in the accent-section. And I suspect the 4049 to be the bad guy.
I'll post an update after replacing that one.
The promissed update:
The CD4049 was replaced by one ordered from Conrad, and that solved the problem. Now all the voices that are allready built trigger happily in Test mode.
The outputs of the 4049 now toggle between 4v and 15v instead of 9v and 15v, probaply good enough to get the 4051's to do their multiplexing-thing.
One weird thing though: it takes a good 10 seconds after switching on before the voices to start triggering. Is this normal ?
The CD4049 was replaced by one ordered from Conrad, and that solved the problem. Now all the voices that are allready built trigger happily in Test mode.
The outputs of the 4049 now toggle between 4v and 15v instead of 9v and 15v, probaply good enough to get the 4051's to do their multiplexing-thing.
One weird thing though: it takes a good 10 seconds after switching on before the voices to start triggering. Is this normal ?