Core trouble

Testing/Troubleshooting
1

My problem is that I connected my midibox to my computer last night for the first time to test it and i was getting no signals.

So i tested the voltage on the PIC and the Opto-isolator and got just under 4volts on all of them. By the way i’m using a 9v 500mA power source.

I then went on to the MIDI interface Troubleshooting:

test prog1- i have no idea what this is saying and can’t find any reference to it anywhere.

test core1- the core came from smashcore so i assume it does.

test core2- the core is a core_R4D so i figure it’s revision 4.

test core3- the solder points are beautiful.

test core4- i get 4volts for everything besides pin 20 on the PIC, which i get 2volts at.

test core5- all test @ 4v

test core6- looks good.

test core7- looks good.

test core8- looks good.

test core9- as far as i can tell this looks good.

test core10- skipped this because i’m getting 0 signals

test core11- skipped this because i’m getting 0 signals

test out1- this is where i think it shows what’s wrong, when i wire up an led to the end of the midi cord the way the image at http://www.ucapps.de/howtodebug/mbhp_core_extract_out_led.gif shows it doesn’t light up.

so i checked it with the middle pin as the ground and that lights up with the positive coming from both m- or m+.

test out2- i haven’t tried this yet but am willing too.

i have my midi cords wired straight to the core since i forgot to buy midi connectors when i ordered my boards.

i can supply pictures if that would help.

-Ajax

2

“Just under 4V” seems kinda low for anything to work really. You wanna have 5V.

So first find out why you only have 4V. Voltage reg dead? Hooked up wrong?

3

the PSU tests to 9v AC though, any suggestions on what to test?

i’ll give the schematic some look overs and try to figure it out but i haven’t done much schematic work in quite a few years.

or perhaps try a PSU with a higher mA?

-Ajax

4

i’m going through all the test again and i notice that i really didn’t know how to read my new multimeter when i was doing the first tests.

(it’s a sears analog multimeter)

so when i read it correctly i believe i get the following for the midi connection tests:

    *  TEST PROG1: SmashTV pre burned PIC.

    * TEST CORE1: the crystal looks to be good.

    * TEST CORE2: SmashTV core kit.

    * TEST CORE3: all solder points look to be very good.

    * TEST CORE4:

j2- 9v AC just under 4mA

j12- 9v AC 3mA

IC2-

pin 8- 9v AC 4mA

PIC-

pin 1- 9v AC 4mA

pin 11- 9v AC 4mA

pin 20- 9v AC 2.5mA

pin 25- 9v AC 4mA

pin 26- 9v AC 4mA

pin 32- 9v AC 4mA

    * TEST CORE5: all points are grounded.

    * TEST CORE6: midi polarity seems quite fine.

    * TEST CORE7: polarity seems fine.

    * TEST CORE8: R7 and R8 are both red red brown gold (220ohm).

    * TEST CORE9: as far as i can tell they are correct.

    * TEST CORE10: nothing coming through.

    * TEST CORE11: again nothing coming.

    * TEST OUT1: doesn’t light up at all.

yea, let me know what you think.

i think i’m reading the multimeter right, hope i am.

-Ajax

5

You should be testing DC not AC. If it reads >5.5VDC anywhere after the voltage regulator, turn it off quick!

6

ok, i’m going to give reading this damn multimeter one more chance before i go out and get a digital.

    *  TEST PROG1: SmashTV pre burned PIC.

    * TEST CORE1: the crystal looks to be good.

    * TEST CORE2: SmashTV core kit.

    * TEST CORE3: all solder points look to be very good.

    * TEST CORE4:

j2- 4vDC +250mA

j12- 4vDC 15mA

IC2-

pin 8- 4vDC +250mA

PIC-

pin 1- 4vDC 25-50mA

pin 11- 4vDC +250mA

pin 20- 2.5vDC 0mA

pin 25- 4vDC 25-45mA

pin 26- 4vDC 2mA

pin 32- 4vDC +250mA

    * TEST CORE5: all points are grounded. although i get 4vDV for all of them.

    * TEST CORE6: midi polarity seems quite fine.

    * TEST CORE7: polarity seems fine.

    * TEST CORE8: R7 and R8 are both red red brown gold (220ohm).

    * TEST CORE9: as far as i can tell they are correct.

    * TEST CORE10: nothing coming through.

    * TEST CORE11: again nothing coming.

    * TEST OUT1: doesn’t light up at all.

i’m pretty sure i’m reading it accurately now.

i have it set to DC V to read the DC V part of the range right?

and then i tested the mA with first DC 250mA then with DC 25mA if need be.

which all of this makes me think i need a higher power source.

and i just tested my power source for AC V and got 9-10 volts.

the PSU is a random one that i picked up at a thrift store.

the output is listed as 9V AC at 500mA.

-Ajax

7

i just test it with a PSU with an output of 9V DC @ 500mA and am getting all the same results.

-Ajax

8

i just test it with a PSU with an output of 9V DC @ 500mA and am getting all the same results.

-Ajax

what a surprise!

*

I would double check all the soldering joints, then when i am finished i would do it again.

I would double check all the components, values, position, direction, one by one, then when i am finished i would do it again.

go to * twice

then let us know if you ve found anything wrong.

Simone

9

“Just under 4V” seems kinda low for anything to work really. You wanna have 5V.

So first find out why you only have 4V. Voltage reg dead? Hooked up wrong?

I’d pull all the chips until you have that fixed.

10

so i’ve carefully pulled both the chips out.

then i looked VERY CAREFULLY over all my solder points, and they all look very precise and pretty.

i did this 3 times then went over all the close solder points with a small screwdriver to check for any short circuits.

after doing this i checked over all the components checking for right positioning and polarity.

everything is hooked up correctly compared to 3 different sources.

so now i’m checking the power circuit to try to find what component is killing the chain.

i shall post all voltages i get.

-Ajax

11

so the voltage stays the same up until it hits the 7805, it goes into pin 1 @ 9-10v and comes out of pin 3 @ 4-5v, which i believe is how it should be.

i also don’t really trust the accuracy of this analog multimeter, i tested the 9v DC power source and it said it was @ 8v.

the two theories i have on it is that either i’ve fried my optocoupler or my midi cables are wired backwards :P.

i’m using a Peavey midi cable sliced in half and wired straight to the board.

I just switched the polarity of the the midi cables on both the midi ports because how i understood it it wanted the red to the - and the black to the + on both ports, which seemed quite conspicuous to me.

but yea, i just switched them, threw the chips back in and am now getting midi signals :D!

i’m getting: 00000000549566 ms | SysEx: F0 00 00 7E 40 00 01 F7 on the midi in.

so now, i’m off to figure this out.

-Ajax

12

so now when i try to upload a program MIOSStudio sends the first line of code then receives nothing, the software is ported right and such, i have tested it getting info with an led on j13.

blah blah, i might of have too much wine to drink while debugging this.

i’ll give it another shot tomorrow.

-Ajax

13

Try to use the “edit” feature on the post. Easier to read than triple-posts.

so the voltage stays the same up until it hits the 7805, it goes into pin 1 @ 9-10v and comes out of pin 3 @ 4-5v, which i believe is how it should be.

After the 7805 it should be 5V ± next to nothing. 4.9V - 5.1V is okay. Pretty much everything outside of that means there’s something not like it should be. Maybe get a new (better, possibly more reliable) meter? You could measure the voltage in your PC (if you know what you’re doing). PC psus tend to be very precise on the 5V and 12V. If your meter drifts, you can blame the meter.

No midi out + fiddling with the cables sounds like a cabling issue to me.