Core working ... after grounging pin 1 of PIC

Testing/Troubleshooting
1

Guys,

The Core of my SEQ v3 is working. But only after i’ve grounded pin 1 of the pic for a while. When I power up the Core, I get nothing on the LCD. But after doing the grounding trick it starts up. I was able to load MIOS and the SW.

But I can’t see me doing this each time I want to use the SEQ. Any suggestions?

Cheers,

Tom

2

Hi Tom,

my first statement to this issue won’t help you, but I must highlight this: thats a very interesting observation! I will add the reset trick to the troubleshooting guide as an important experiment to check, if the core module is booting thereafter.

But before, the reason for this failures has to be found out of course. It’s propably a power issue - maybe your PSU doesn’t deliver enough current during power-on, so that parts of the PIC is not properly reseted?

I guess your LCD has a backlight? Did you already try to boot the MIDIbox without the LCD backlight connection?

Best Regards, Thorsten.

3

Hi TK,

Remember my MBHP_USB?

It was basically the same.

It only worked after I touched my PC-housing with one hand, and wiping over the copper-side

of the PCB with the other hand.

4

Have you checked the value of the resistor R1?

Are solder points in good condition?

What kind of PSU did you use? (transformer or a switching power supply)

How high is the voltage between the pins on J1 on the coreboard?

Have you meassured the voltage between these pins like discribed at the core torturial?

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

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

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

Hope I could help you a bit.

javascript:void(0);

WinkGreets

Markus

5

What kind of PSU did you use? (transformer or a switching power supply)

I also think, that is a good question.

If your PSU is a switched one it may be that you need some more current than the PIC itself to get the switched power supply working properly.

This may be your “trick” with the shorting of PIN#1 to ground.

In that case you provide some good current to the powersupply and maybe that’s why your core works after that “kick”.

So … is it a switched powersupply?

greets

Doc

6

Ok guys, thanks! it’s working now. I used my lab power supply, measured 0.02 to 0.03A and with this PSU it was working OK.

My other PSU, a typical AC/DC adapter states 0.5A, 6V. It’s an old PSU from a small radio, and this one worked fine for a Midithru box I’ve built.

Anyway, I now know what to do… build an interface :wink:

Cheers,

Tom

7

When powering the core modul with J1 you should have between 7 and 10V. 6V is a little bit to less. The voltage regulator on the core board needs the higher voltage for right working.

Greets

Markus