Hello,
I’ve gotten everything all soldered up. I get a “Ready.” message on the screen. I get a message from midi out.
The two issues I’m having now are no MIDI in and
I’m using 6581s and getting 12.44v out of the IC sockets with a regulated power supply.
Does anyone have any thoughts on that reading? Could this also be affecting MIDI in?
Thank you,
Eric
Regarding MIDI In:
check 6N138 is installed
check shunts in JMI (and also JMO)
It’s probably one of these, if not, I’ll help more later (well, you can start by checking solder joints at JMI/JMO, the socket for 6N138, the DIN sockets etc.)
Regarding voltage:
I’ll assume you haven’t installed the 6581 yet.
12.44V is not too high. Regulated power supplies aren’t perfect. That voltage might drop after installing SIDs, but even if not, it’s fine, you won’t fry the SIDs.
Since the LCD is working and it boots, I can assume 5V supply is good, so the 12.44V would have nothing to do with MIDI In not working.
I checked the JMI and JMO solder joints, the 6N138 and DIN sockets.
Im still getting nothing sadly. I’ve also been through the MIDI troubleshooting.
I guess this could mean Im missing a soldering issue?
Hi did you ever resolve your problem? I seem to be having the same problem (midi in)… though I am using 6582a’s
Did you do all the MIDI troubleshooting here? http://www.ucapps.de/howto_debug_midi.html
Especially do:
TEST MIDI2: put the PIC out of the socket and loopback the MIDI IO ports at the Rx/Tx pins like demonstrated in mbhp_core_extract_io_loopback.gif. The core module has to be powered for this test! Repeat the loopback test of the previous chapter.
which is easily done by removing the PIC and inserting some thin wire (like a cut resistor lead bent into a U-shape) into the Tx and Rx pins.
Alternatively, leave the PIC installed, remove shunts from JMI and JMO and connect the MIDDLE pin of JMI to the MIDDLE pin of JMO. This disconnects the PIC from the MIDI In/Out circuits and loops-back the MIDI In signal to MIDI Out.
You need to get MIDI loopback working in order to prove the 6N138 is working, as well as your MIDI interface, MIOS Studio setup, drivers, etc. i.e. prove that the PIC is receiving MIDI but not actually working. If the 6N138 is not working then it is easily replaced (by me, if you can’t find one quicker yourself).
Cool I will have a look at this tonight, the diagram for this on the midi trouble shooting page was kinda hard for me to relate to the sammich.
I don’t have my unit in front of me, where are the Tx and Rx pins?
Any tips on removing the pic?
“Alternatively, leave the PIC installed, remove shunts from JMI and JMO and connect the MIDDLE pin of JMI to the MIDDLE pin of JMO. This disconnects the PIC from the MIDI In/Out circuits and loops-back the MIDI In signal to MIDI Out.”
this sound like the easier option (so I don’t damage the pic) would cut resistor wire held on to the pins work?
cheers mate! 
Thanks
Cool I will have a look at this tonight, the diagram for this on the midi trouble shooting page was kinda hard for me to relate to the sammich.
Designators (like R5/R6) are the same. Headers are slightly different, and it’s pretty clear which is the PIC and which is the 6N138.
I don’t have my unit in front of me, where are the Tx and Rx pins?
That diagram linked to in the previous post shows the corner of the PIC and which pins they are.
Any tips on removing the pic?
or if it is particularly stubborn,
“Alternatively, leave the PIC installed, remove shunts from JMI and JMO and connect the MIDDLE pin of JMI to the MIDDLE pin of JMO. This disconnects the PIC from the MIDI In/Out circuits and loops-back the MIDI In signal to MIDI Out.”
this sound like the easier option (so I don’t damage the pic) would cut resistor wire held on to the pins work?
It should, but it would be tricky to maintain while driving MIOS Studio. If you have thin bendy wire, cut two lengths, wrap each around the pin first, then twist together. Or use alligator clips to clamp on the middle pin (without shorting with the adjacent pins).
Cheers mate! LOL on the crowbar
Will let you know how I go.
Thanks again!
I was not confidant removing the pic, I went to jay car and asked for an ic pick yesterday when I ordered bought another 6n138 (just in case that was faulty) and the guy recons he never seen one??? I bridged middle pins of the jmo & jmi.
I did not see any mid fed back loop message?
Is this what I should have expected?
the CS was not connected if that make any difference?
I will perform led test, do the shunts need to be installed on jmo & jmi headers?
cheers
If you connect middle pins of JMI and JMO then yes, you should expect MIDI loopback… events going into the sammichSID via MIDI In should be echoed back out the MIDI Out.
Test your MIDI works by actually looping back the cable, i.e. connect MIDI In to MIDI Out, run some tests.
Run same tests using the sammichSID. If you don’t get MIDI echoed back then the problem is perhaps the 6N138.
I tried connecting the middle pins of JMO and JMI I wasn’t able to get a feed back loop with either of the two 6N138s that I have one of them
I know works for sure.
But what I did get is a HUGE list on the MIDI IN: menu of [17183.031] 80 00 00 [“” .032] 80 00 00 etc, etc.
I also get a blinking LED on MIDI in but not MIDI out.
Does this tell you anything Wilba?
Best,
Eric
@brogram: what are you using to test MIDI?
Do you get the same results when just using a MIDI cable to connect PC’s MIDI In to MIDI Out?
What is strange here is you say you got messages from the PIC, i.e. the “upload request” messages, so the sammichSID’s MIDI Out is working.
Try the short between JMI and JMO middle pins, but with sammichSID MIDI In disconnected. i.e. test if you are getting garbage data from the MIDI In circuit when there is no MIDI going into the sammichSID. It’s possible you have a bad solder joint (or short) somewhere in the MIDI In circuit, i.e. around the 6N138, the resistors, etc. perhaps the 6N138 has bad ground joint or bad +5V joint… perform the voltage check tests from the build guide again to check it is all good.
I just found a strange issue. When I insert a Midi Cable into {MIDI IN} the large ground pad for the DIN connector is shorted to the right round pad of J13 and this happens only when I use my MOTU Ultralight interface. Also the middle pad on J13 does not seem to connect with the large ground pad.
When I use my M-Audio MIDIsport uno it no longer shorts ground to the right side round pad of J13 and the middle ground pad on J13
still does not connect to the large ground pad. I hope this makes at least a little sense.
Also just found a short between 5V and Ground on 6N138… That should be it.
Victory! Thanks for the amazing help! I’ve never had so many problems on a build! Next time ill take it slow :sorcerer:
Celebrated too soon. Everything was looking great.
All LEDs did what they were supposed to. All soft wear loaded. The
Sid made noise and played with midi keyboard thought with the gate
constantly on. Then i realized the unit was getting hot and no
buttons were working and the knob as well. I opened it up and the
Sids were super hot along with the heat sync. I did voltage checks
on the control board and everything seemed to be tip top shape with
much better soldering than the bottom board and no shorts.
Deep breath. :hmm:
6581 SIDs get hot… not much you can do about that, apart from stick on some heatsinks if you want (see other threads for ideas). With a regulated 12V DC input (required for 6581!) then the heatsinks and ventilation should be enough. Perhaps warming up caused a nearly bad solder joint to go fully bad, or something.
One other thing to check… if you’re using a “high-power LCD backlight”, be sure use JBL set to 12V, shunt in JR4, and turn the brightness pot to half-way or less. You would not want JBL set to 5V, as this will only add more heat to the 5V regulator, which is under enough strain as it is, supplying those power-hungry 6581 SIDs.
“and turn the brightness pot to half-way or less”
Very important bit of advice 
cheers
Paul
I went over everything again and everything is still checking out fine with the top control board.
No shorts, all voltages are correct and all the soldering looks ace. But still the buttons and knob
don’t do anything… 
It responds to midi but it almost seems to be playing a song because any note I play will only trigger
some sort of a sequence in time with how I play the keyboard and has pauses and sometimes noise bursts.
:fear:
Were the buttons and knobs working at some point, and then stopped working entirely?
Did you already install the banksticks and uploaded the default patches? Just thinking perhaps it is set to a sequence patch and note events are triggering the sequence. From memory, the last default patch is Neo Zelda or likesuchas, and immediately after uploading the 128 patches, the “current” patch is the last patch. Or it could be set to some other patch. What is it showing on the LCD?
