sparx Posted October 13, 2012 Report Share Posted October 13, 2012 Are you sure MIDI is being sent out from core Port? Check this first. The unused inputs of the 74LS00, are they tied to ground? Regards S Quote Link to comment Share on other sites More sharing options...
EsotericLabs Posted October 13, 2012 Report Share Posted October 13, 2012 Are you sure MIDI is being sent out from core Port? Check this first. Yes but how? I don't have a midi 3/4 breakout box yet. Any other method? The unused inputs of the 74LS00, are they tied to ground? No they're not yet. Will do & let you know. Thanks for sharing your experiences! Quote Link to comment Share on other sites More sharing options...
sparx Posted October 13, 2012 Report Share Posted October 13, 2012 Get an LED to check the MIDI out. It should flash, have a look at the MIDI troubleshooting guide. Regards S Quote Link to comment Share on other sites More sharing options...
EsotericLabs Posted October 13, 2012 Report Share Posted October 13, 2012 Get an LED to check the MIDI out. It should flash, have a look at the MIDI troubleshooting guide. Regards S Did that and the LED is flashing. The core then must be working correctly. It is either the docking or the sound card itself. But also with the unused inputs of the 74LS00 wired to ground, no sound yet. I measured voltages on the docking board without sound card, which seem correct (input 4v98 high pulled up - out 1 & inputs 2a & B low 0V11 (NANDed) - out 2 high 4v43, pin 4 high. This seems correct to me. With the NEC XR385 board mounted pin 8 (midi out) is also pulled up to about 4V97 -> the xr385 has pin 8 as a midi thru. Supply voltage is 5V03 to be exact. What do you think about the hum when touching elco's on the soundcard? is it normal? I would expect the casings of these smd elco's to be grounded. Maybe I should reclamate to the seller of the sound card? Thanks again, I appreciate your help very much. Quote Link to comment Share on other sites More sharing options...
sparx Posted October 13, 2012 Report Share Posted October 13, 2012 OK, that's progress, these things are fussy with respect to the power supply, what are you using? There must be a seperate analogue and digital ground and they must only meet at one place, this is why I suggested using the GM Voice PSU as it is tried and tested. Have heard that the circuit won't work withour the Reset button/circuit, is this on yours? If bits were missing off the board it might be that. The first card I got was damnaged and the seller replaced it no problem. Stick at it, these things have great sound and one way or another we'll get you working. Regards S Quote Link to comment Share on other sites More sharing options...
EsotericLabs Posted October 13, 2012 Report Share Posted October 13, 2012 My PSU is still in two parts. One is a complete 5v 2a board from budgetronics.eu. See link 1). The second one delivers + and -12v at max 1A it is a Velleman kit 8042 see link 2. I was a bit afraid of 230 v so I wanted something ready made or reliable. Only later I found that the SNP has a fan connector t 15V and that voltage inverter IC' s exist. I planned to use the voltage inverter and a pair of 7812 /7912 with proper capacitors ( The velleman can be used for other purposes then) . If you re not from Europe: velleman is a prime supplier of electronic DIY kits The SNP feeds the core and the sound card with 5v through a small board with a double row header. Digital ground of the sound card is linked to the SNP ground. +and-12v is linked to the velleman of course. The velleman ground is connected t both digital and analog ground. This is the only place AGND an DGND meet. This also connects the two PSU'S grounds, otherwise they may be floating. There is a 3 pin header taking analog ground and audio L&R out to an audio jack on an alu piece of L profile. Now you ask, the hum on the elco goes away when I touch this profile. Maybe there is a ground loop? But then, why wouldn't the card function at all? And the reset on pin 26 has a 10k pull-up resistor to 5v and a 10uF electrolytic capacitor to ground. No button yet. When I got the board, everything was on. Only later the tiny SMD thing came off. I soldered a normal one in place. The black side of smd is negative, I found on the Internet. I hope this info leads to somewhere. If you see anything strange, please tell. If not I ll ask the seller for a replacement. Or I ll built a docking with a ready made board, vero strip board is nice, but prone to error in my hands... Thanks a million! In between I'm working on c chores specific for the Db60xg and more general for midi gear. I ll be happy to share them if you want them. http://www.budgetronics.eu/index.php?item=voedingsprint-5-volt-10-watt&action=article&group_id=39&aid=6955&lang=NL http://www.velleman.eu/products/search/?q=8042&search=Search Quote Link to comment Share on other sites More sharing options...
EsotericLabs Posted October 14, 2012 Report Share Posted October 14, 2012 Update: I also tested whether the midi signal gets from the core thru to the docking board. I soldered a led and a 100R resistor between +5V and the midi in signal line after the 74LS00 (closest as possible to the soundboard itself). This led happily flashed in sync with the led on the LPC1796. I also found that several designs have a 270R in the output lines (Others have opamp amplifiers). But still no sound.. I then connected Analog out to the ground of the 5V supply (it's an SNP0502 from Skynet in Taiwan) to see whether that makes a difference - No.. Now only a second digital ground wire is connected to the GND of the +/- 12V supply. I checked with the seller, he says boards were tested before shipping and that he will send tips to get it set up properly (but now he's asleep on the other side of the globe). In the meantime I improved the testing rig by soldering headers and connectors to the boards most frequently mounted and taken off again. My next step will be to wait for the ICL7662 voltage inverter IC and to build a +/- 12V with 7812 & 7912 & caps from the fan output of the SNP and a combined PSU header rail with +5/0/+12/-12V. Leaves more space on my board The velleman will make a fine lab PSU with adjustable voltages one day. I aslo consider build an output / input amplifier board with some opamps. Most schems have it and Mike also built one for input. But honestly, I don't see why this would help, but possibly maybe. If any of you have hints, please let me know. I think I have most of the common issues sorted out, but I'll be happy to have missed one in return for having this work.. Quote Link to comment Share on other sites More sharing options...
EsotericLabs Posted January 14, 2013 Report Share Posted January 14, 2013 An update on the DB50XG and NEC XR385 sound boards. I got it up and running with a GMVoice like docking board for the sound card and the output level shifters on the LPC17 side. I needed to connect both the M+ and M- wires to get it to work, so basicly a full midi out and midi in interface, apart from the DIN connectors. Now I'm working on mios based software for the XG and TB mode of the card, the voicing and the effect system, the QS300 user voices and multipart and drum setups. A crude and primitive 0.1 is working already, hope to get the effect section running before end of January. It will be a module (two .c and two .h) that can be integrated in any mios/scs/sdcard based application. Quote Link to comment Share on other sites More sharing options...
EsotericLabs Posted January 21, 2013 Report Share Posted January 21, 2013 No qs300 Voices on the NEC XR385 clones. http://launch.groups...r/message/33487 I programmed QS support but to no end.. If someone wants to test the beta software with a real db50xg, PM me. Quote Link to comment Share on other sites More sharing options...
EsotericLabs Posted April 17, 2013 Report Share Posted April 17, 2013 This is an update about connecting the DB50XG or clones to the Midibox core. Initially I had some difficulty in getting it running, but silly me forgot to wire the M+. I then followed the long route to conclude that a 74HC541 level shifter is needed to get the db50xg running. Not so: if you have a daughterboard on a GMvoice (or any compatible breakout board), just solder a 220R to the +5V of J4B and another 220R to the Sd (aka midi out) of J4B.This goes into a regular midi Din connector or header: +5V to M+ and Sd to M-. Works like a charm, no 74HC541 needed. The +5V output of J4B kinda does the level shifting, it is about pulling a current through the 6N138 on the daughterboard. This is cool as it frees up real estate inside a C64c case. I will have a SEQ V4 with built-in soundboard before soon!! Quote Link to comment Share on other sites More sharing options...
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