I finally finished the MTC display for the Midimon. However, something’s going wrong with it. If you look at the photo you see that the display shows really weird things.
Of course I did some tests to find the fault, but no results were found:
I triplechecked all connections and possible intercourses with my meter.
I exchanged the HC595.
I took the HC595s off the sockets, applied +5V to the anode pins and grounded the segment pins to check if all connections are o.k. All the segments were lit as they should.
What is also strange is that the displays do not have the same brightness (as seen on the photo; display No. 7 is the brightest one). Even if I exchange them (they are mounted in sockets) the difference in brightness remains.
Could this be another software bug in the Midimon app?
oh…I forgot to mention: when there is no time code displayed on the LCD, on the MTC display all segments are lit with the exception of segment f (the upper left one), including the decimal points.
ok…here they are. Maybe the wiring does not look that nice, but as I already said I did check it with the meter. Segment wiring is done with Vero-wire; orange wires are anodes, black is ground, red is +5V, white is SO, yellow is SendClock and violet is ReceiveClock. Connection to the Midimon goes via ribbon cable; this was also checked with meter.
Therefore I reduced resolution for the following pics. Sorry for the waste of bandwith
Don’t sweat it bro, I’m just makin’ a joke No point in my helping you out here, nILS knows what he’s doing (in a big way!) so I thought I’d have some fun. Sorry to interrupt
now it works! After assembling another mtc board the fault was exactly present as before. But then after checking the midimon I found the source: it was the socket for the mtc display (sub-d 9 pin male). There was a connection where there should be none…
However, one thing remains: as you see on the photo, decimal points are not at the correct position. What is this?!
hey manticore, good to see your getting things done!!
im in the middle of finishing mine, not much more to do then its just doing the casework. i cant help regarding the software, but just xhange the pin wiring on the decimals one to the other, as yours has one each side of each segment display by the looks of it.
seeing yours makes me a little itchy to get mine finished , but i have to finish the gm5 midi module thats going to control it first!
once its all runnig and tested i can then get the casework done.
its nice for me to see another one built and done!
good luck for your housing; this mostly takes more time than the electronic side of a project.
Unfortunately the displays do not have two decimal points. It is a HP 3730 type; there is also a version with the dp on the right and they seem to use the same housing for both types. I studied the datasheet AND tried all pins - no dp on the right
Either I will have to live with this or must get some HP 3733 with dp on the right hand side. We will see…
yes, I know what you mean; however, only the left of the two decimal points has a LED inside, that’s what I meant. The right “point” is only used in the 3733 display.
Can you take some pics of the wiring?
No point in my helping you out here, nILS knows what he’s doing (in a big way!) so I thought I’d have some fun. Sorry to interrupt 
