my midibox sid freeze on startup when the din modules are connected

MIDIbox SID
1

hi everybody

i just finished my midibox sid (4sid) with complete control surface and everything is working normally .

the only problem i have is that it freeze on startup when the din modules are connected ( the lcd show a black row on the upper part )

if i disconnect/reconnect the din modules everythying work normally .

i soldered all the resistor and the unused chips are not stuffed on the last din .

if someone has an idea of what’s wrong that would make my day

thanks in advance

ps: it’s a v1 midibox sid

2

Hi,

and welcome. What kind of psu do you use?

3

hi thanks for the quick answer

i use the c64 optimized psu http://www.ucapps.de/mbhp/mbhp_4xsid_c64_psu_optimized.pdf

4

Please check the voltages at the first core when the problem appears.

C1:MCLR(1) - IC1:Vss(12) = 5V ?

IC1:Vdd(11) - IC1:Vss(12) = 5V ?

IC1:Vdd(32) - IC1:Vss(31) = 5V ?

Make sure that Sc on J10 coreboard is not connect to the sidboard. (only core with controlsurface)

Please check the value of  R1 (coreboard).

Greetings

5

C1:MCLR(1) - IC1:Vss(12) = 0,9v ??? c1 is the capacitor right ? what is MCLR ?

IC1:Vdd(11) - IC1:Vss(12) = 4,6v

IC1:Vdd(32) - IC1:Vss(31) = 4,6v

sc-j10 is not connected

r1 is 100 ohm

thanks a lot for helping

6

i have no idea why  but it’s working normally now !!!

7

Sorry, my fault.

It should be IC1 MCLR is on pin1 of the pic. If it works now, you can check if there´re any loosely cabels (bad connections).

8

thanks for helping midiboxxer !

i resoldered a few cables on the power supply i made months ago and it worked perfectly .

now i only have to make holes in the enclosure ( a c64 box ) for the plugs and my sidbox is finished .

but it’s alive already !

9

Congratulations, hope you post some pictures of your finished box.  ::slight_smile:

Best Regards

Markus

10

that sucks

i have that problem again !

everytime i power the unit up the lcd show a blackrow .

but if i disconnect/reconnect the din or dout my midibox boot normally

C1:MCLR(1) - IC1:Vss(12) = 4,6v

IC1:Vdd(11) - IC1:Vss(12) = 4,6v

IC1:Vdd(32) - IC1:Vss(31) = 4,6v

11

Your PSU is not strong enough, this causes the issue.

During Power-On, the PIC requires most of the power. For these 1..2 seconds the voltage probably sinks below 4.6V, and unexpected things will happen - or nothing will happen…

I would propose to try it without LCD backlight first, and maybe only with a single PIC (remove the slave PICs from the sockets) just to check if my assumption is correct.

Best Regards, Thorsten.

12

i tried without backlight and without the slave core modules but i had the same result.

i’m using the c64 psu with http://www.ucapps.de/mbhp/mbhp_4xsid_c64_psu_optimized.pdf

i checked all the soldering and it looks clean

thanks for helping

13

Have you the possibility to messure the current of your midibox with an multimeter?

14

hi

i’m not sure i understand the question .

i allready mesured the current on the core ic1 like you told me and i had

C1:MCLR(1) - IC1:Vss(12) = 4,6v

IC1:Vdd(11) - IC1:Vss(12) = 4,6v

IC1:Vdd(32) - IC1:Vss(31) = 4,6v

where am i suppose to mesure the current now ?

15

nobody ever had the same problem ?

16

Here some infos about measuring current: http://www.hobby-electronics.info/course/html/ch02s05.html

It helps you to determine, which part or module consumes most of the current. E.g., for a single core module w/o LCD backlight and without DIN/DOUT module I would expect a current drain of about 50 mA, with backlight maybe 150..200 mA - this can be measured at port J2 (if you are using the optimized PSU circuit) or at J1 (if you supply the core module on the common way). You need to disconnect one cable (use the +5V line), and insert the multimeter there as a “bridge”.

By connecting the DIN module, the current drain shouldn’t increase - if it increases, it indicates that there is a short somewhere around the 74HC165. This can be visually checked at the bottom of the PCB (search for soldering clumps, etc.)

Best Regards, Thorsten.

17

i tried to do what you said but i get a static 21 ma wich make me think i’m doin it wrong .

what do you mean by “bridge” ?

this is very frustrating i have a fully working sidbox that crash on startup .

thanks for helping

18

crashes on startup != fully working :smiley:

I had the problem with the DINs once. I had plugged the cable from the core to the DIN in the wrong way around… I’m pretty sure you checked that already though…

19

it’s fully working when i disconect/reconect the dins or dout .

sometime it boot normally after i made a “shortcut” with my finger .

if i don’t solve the problem i’m gonna add a switch but i hate to solve a prblem this way

20

it’s fully working when i disconect/reconect the dins or dout .

As TK said, if connecting the DIN modules increases the drawn current, then there is a short somewhere.

sometime it boot normally after i made a “shortcut” with my finger .

Where?

if i don’t solve the problem i’m gonna add a switch but i hate to solve a prblem this way

No, don’t do that :slight_smile: