ris8_allo_zen0 Posted August 28, 2007 Report Share Posted August 28, 2007 Hello everybody,I found that my brand new SEQ reboots after some random time (about 2-3 minutes) while I use it as arpeggiator, doesn't matter if using an external keyboard or the loopback port.I'm using the SmashTV board, 1 IIC, 6 EEPROMs and my custom "c64-keyboard" patch.Any clues?...Many thanks!!Enrico Quote Link to comment Share on other sites More sharing options...
MTE Posted August 28, 2007 Report Share Posted August 28, 2007 Maybe not enough power from the trafo....have it enough ampere.....and how many V do you drive the box ?Regards Quote Link to comment Share on other sites More sharing options...
ris8_allo_zen0 Posted August 28, 2007 Author Report Share Posted August 28, 2007 7.5 volts 1A to power all the above plus one LCD backlight (the other one broken and was temporarly replaced with another non-backlit). The 7805 has currently no heatsink and gets very hot with that backlight, that's why I don't want to use 9V.I also tried to modify the PCB to let the backlight use the unregulated supply, but for some error the same supply went also to LCD's Vd killing one of them. Now I reverted to original.However, I remember the Vd is stable at 4.86V. Quote Link to comment Share on other sites More sharing options...
MTE Posted August 28, 2007 Report Share Posted August 28, 2007 However, I remember the Vd is stable at 4.86V.You need clear,stable 5V for the MB-Circuits or MIOS will reboot ;)Give the 7805 a heatsink (he will be happy, and you too ;D ) and push up the Voltage to 9V, this I have all time on my circuits here and it works fine....if the trafo gets too hot, then u need a bigger one (1,5-2A is good choice)Regards Quote Link to comment Share on other sites More sharing options...
seppoman Posted August 28, 2007 Report Share Posted August 28, 2007 Does the SEQ also reboot when not in Arpeggiator mode? If not, it´s a software issue. If yes, it might be PSU-related.You could measure the current going into the box. But as long as you don´t push the backlight pot to the max, the 1A of the PSU can´t be the problem - a normal 7805 can take max. 1A anyway, so just make sure the box consumes less. But the heatsink suggestion should be the right way. The regulators have internal thermal protection and the output voltage drops when they get too hot. So keeping them at a temperature that you still can touch them for a few seconds is a good idea. But this is easier when staying at 7.5V - even if raising the voltage could help in some rare cases, the 7.5V can´t be the cause of the problem!Seppoman Quote Link to comment Share on other sites More sharing options...
ris8_allo_zen0 Posted August 28, 2007 Author Report Share Posted August 28, 2007 Does the SEQ also reboot when not in Arpeggiator mode? If not, it´s a software issue. If yes, it might be PSU-related.I did some other tests. In fact, it also crashes when not in Arpeggiator mode, unlike stated before. (last time it crashed I accidentally pressed Edit+GP2, which in fact does nothing special)Then adding an heatsink should be the solution. Thanks, I'll let you know.Best regards,Enrico Quote Link to comment Share on other sites More sharing options...
ultra Posted August 28, 2007 Report Share Posted August 28, 2007 i couldn't get mine to stay powered on 7.5v either. changing to 9v and adding a heatsink did the trick. Quote Link to comment Share on other sites More sharing options...
stryd_one Posted August 29, 2007 Report Share Posted August 29, 2007 Heh, first thing I thought was BOR... but I couldn't think of a reason that only arp mode would do that, so I stayed quiet... ::)Running off my variable PSU I have found 7.9V to be the magic number where no heatsink was required but voltage would not drop too low and BOR. You might need to go a bit higher depending on your peripherals.*BOR = Brown-Out Reset - When the power goes too low (a brownout) the PIC will reset itself. You'll probably know it if you see it, because it is very random, very sudden, and guaranteed to give you a bad sinking feeling in your gut when it happens the first time ;) Quote Link to comment Share on other sites More sharing options...
ris8_allo_zen0 Posted August 29, 2007 Author Report Share Posted August 29, 2007 Heh, first thing I thought was BOR... but I couldn't think of a reason that only arp mode would do that, so I stayed quiet... ::)I saw the problem in arp mode because I was drooling with that feature when I got the first crash :P*BOR = Brown-Out Reset - When the power goes too low (a brownout) the PIC will reset itself. You'll probably know it if you see it, because it is very random, very sudden, and guaranteed to give you a bad sinking feeling in your gut when it happens the first time ;)That feeling that suggests me I've worked hard for two months to have something that runs like Windoze :P but I see there's a good reason also for this symptom!Yesterday evening my Seq runned with an heatsink for an hour without problems, but I still can't touch it nor the 7805, they're hot like hell... possible? Best regards,Enrico Quote Link to comment Share on other sites More sharing options...
stryd_one Posted August 29, 2007 Report Share Posted August 29, 2007 I saw the problem in arp mode because I was drooling with that feature when I got the first crash :PLOLThat feeling that suggests me I've worked hard for two months to have something that runs like Windoze :P Oh, for me it was more like "Please let it start back up, please tell me I didn't just fry this thing". I was testing some code at the time, maybe it was a paranoid frame of mind ;)but I see there's a good reason also for this symptom!Yep, all that power needs POWER! ;D Quote Link to comment Share on other sites More sharing options...
seppoman Posted August 29, 2007 Report Share Posted August 29, 2007 That´s possible. did you change to 9V? did you measure the current going into the box? too hot to touch is not necessarily bad - I think the 7805 will work even at 80-90 degrees C. too hot to touch is already 50 degrees. But to be safe you can always use bigger heat sinks. If your case is out of metal, you could use wires between PCB and 7805 and mount it to the case.About the "higher voltage helps" again: the usual 7805s start working correctly at about 6.8V (DC!). If it doesn´t work with 7.5V, this can only mean a) thermal shutdown or b) the input voltage isn´t smoothed enough, so the 7.5V drops too much below 6.8V with each half wave. You can test this by measuring between 7.5V and ground (under load at the regulator) and using AC mode of the multimeter. that´ll show you only the ripple. If it´s more than a few hundred millivolts, b) is the reason. In this case a higher voltage does help but is only the second-best solution. Better is to use a larger capacitor to keep the input voltage stable. If you already have 2200 uF, try a 4700 uF or several parallel 2200uF caps. When using more than 500 mA, the bigger cap and heatsink solution is definitely preferrable - with a linear regulator, you always want to keep the dissipated heat within reasonable levels.Seppoman Quote Link to comment Share on other sites More sharing options...
ris8_allo_zen0 Posted August 29, 2007 Author Report Share Posted August 29, 2007 The measures surprised me: with the transfo set to 7.5V, the real output voltage was 10.8V!! and when set to 6V, it was 8.2V (both values under load).And the current drawn is around 0.25A. Isn't it too little to have a regulator+heatsink almost good enough to fry eggs while grooving? ;)The Vd/Vs voltage is 4.96V with 4 leds turned on, and 4.88 with 16 leds (soon I'll add the remaining ones). Is that OK?Yep, all that power needs POWER! ;DYou'd be happy to know that the power LED of the former-C64C (now "Commodoseq"?) now acts as beat indicator :DBest regards,Enrico Quote Link to comment Share on other sites More sharing options...
ris8_allo_zen0 Posted September 4, 2007 Author Report Share Posted September 4, 2007 No more stability issues ;) (see attachment)Best regards, EnricoIMG_2492 (Small).JPG Quote Link to comment Share on other sites More sharing options...
ris8_allo_zen0 Posted September 6, 2007 Author Report Share Posted September 6, 2007 Ops. I was wrong again :-[Sometimes the system go on for hours, sometimes it crashes at any time but only when I press a button of the control surface - now a key of the C64C - so I'm quite sure it's NOT a dissipation issue. Probably this unstability is related to the keyboard patch I made. Why? I'll try to answer myself in the next days...Edit: now I see it happens even when moving an encoder.... until now, however, it happens only with user interaction.RAZ Quote Link to comment Share on other sites More sharing options...
ris8_allo_zen0 Posted September 18, 2007 Author Report Share Posted September 18, 2007 The problem is still there, but now I have more hints.First, I can reproduce the problem by putting "high load": enabling gate on all steps of 3 or 4 tracks. In that condition it reboots very easily when I press a key.Second, it happens even without my mod. Since I don't have any "regular" buttons, I used the remote function to reproduce it.Third, I enabled the performance monitor (just to be curious). It shows values between 480 and 520 either at boot and at "high load", it falls down to 350 only when I use an encoder or button. Does it mean anything?Fourth, the Sysex at bootstrap says F0 00 00 7E 40 00 01 F7, like it was rebooted regularly.Fifth, doesn't matter if the IIC MIDI module is connected or not.Are these info useful?many thanksRAZ Quote Link to comment Share on other sites More sharing options...
ris8_allo_zen0 Posted September 18, 2007 Author Report Share Posted September 18, 2007 I noticed the bridge rectifier got very hot, but I didn't take much importance of this until now. Indeed it was the only component getting hot. I saw the voltage wasn't stabilized at all (4.8V dropping to 4.6V when some LEDs turned on).I replaced it with a pair of wires. (triple-checked the polarity)It works.YEAAAAAAAAAAAAAAAAAAAAAH!!! ;DWhy didn't think about it before?...Thanks for all the help anywayRAZ Quote Link to comment Share on other sites More sharing options...
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