TK. Posted January 6, 2003 Report Share Posted January 6, 2003 Due to sporadic problems with the MIDI-In port of MIDIbox Plus I've decided to change the hardware although it (mostly) works perfectly. A user sent me his board so that I was able to search for the root cause - I noticed that the CNY17-II optocoupler from his MIDIbox sends much weaker signals to the PIC than those from my circuit. It's exactly what I had expected based on descriptions from other users (they had to tweak the 220 or 1.8k resistor). It seems that the manufacturs of this optocoupler cannot guarantee the specified characteristics, especially because users who bought the IC from the same distributor like me (Reichelt) never reported a problem. -> the CNY17-II will be replaced by a 6N138Since it's more difficult for me to change all the existing PCBs, I will create a new PCB with Eagle. This will allow you to modify the layout for your needs. I will also ask Mike for distributing premade PCBs of MIDIbox Plus in his shop, as I think that the design has still advantages compared to the MBHP; it's the low-cost solution.By this way I will also change the 74HC00 circuit (add a MIDI-In LED) and the interface to the LCD (additional read line improves the speed).More about the new PCB maybe in 2 weeksBest Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
Dave_Wheeler Posted January 6, 2003 Report Share Posted January 6, 2003 In addition to Thorstens proposal for a new Midibox Plus PCB, anyone that has used my PCB design will note that the board is layed out for the 6N138 so you should not see the recent problems.Thanks Again ThorstenDave Quote Link to comment Share on other sites More sharing options...
TK. Posted January 7, 2003 Author Report Share Posted January 7, 2003 Hi Dave :)you are right, with your PCB (midibox_plus_pcb_dave_v2.zip) the hardware changes can be accomplished with less effort. Only an additional wire between pin RC4 and the R/W input of the LCD will be required in order to get the upcoming (probably "final") firmware release running.I will put all current PCBs into a special archive - in respect to the work of the creators and as additional "source of inspiration" for people who want to etch their own board.Btw.: I just have finished the new layout and will get the PCB in about 4 days in order to test it. It looks expensive, but it isn't: the estimated price is about 7-8 Euro for a premade 10cm x 8cm board and it's also nice for DIY etching since only a single layer is used (and 9 bridges...)Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
d2k Posted January 13, 2003 Report Share Posted January 13, 2003 I rek so, if you look at the pic the red/pink wires (I count 9) will be the bridges to solder that'll save ya from using a dbl sided board...HTH...Dan Quote Link to comment Share on other sites More sharing options...
smitch Posted January 13, 2003 Report Share Posted January 13, 2003 thanks dan that helps. i seemed to have skipped over thorstens post Quote Link to comment Share on other sites More sharing options...
Guest sfx Posted January 17, 2003 Report Share Posted January 17, 2003 ???where can i find an old PCB's with CNY17-II Thanks in advance Quote Link to comment Share on other sites More sharing options...
TK. Posted January 17, 2003 Author Report Share Posted January 17, 2003 The old versions can be found here:http://www.ucapps.de/midibox/midibox_plus_pcb_dave_v2.ziphttp://www.ucapps.de/midibox/midibox_plus_pcb_shum.ziphttp://www.ucapps.de/midibox/midibox_plus_pcb_martin3.zipthey have been temporary removed from the website since they require some additional docs concerning the (slightly) modified hardware.Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
Sephult Posted February 13, 2003 Report Share Posted February 13, 2003 I have had a couple weird problems with my midibox plus before, I think it might have been due to the 7805 overheating, but I am not shure as to what it is yet. When I am controlling say 10 parameters, mixing in reason, I have had the box reset itself, but not all the time. Has anyone experienced the same problem? Quote Link to comment Share on other sites More sharing options...
TK. Posted February 17, 2003 Author Report Share Posted February 17, 2003 Hi,it seems that this is really an overheading problem. You can reduce the temperature by using a lower input voltage. It should be between 6V and 9V. Note: due to the law of energy conservation the 7805 has to transform the "unused" energy, which is linear to the voltage difference (input_voltage-5V) and the current load, to head. That means: than higher the current, than higher the input voltage, than more head will be produced.Best Regards, Thorsten. Quote Link to comment Share on other sites More sharing options...
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