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IC4 1/0 Board burnt pad off pin 4.

Posted: Jul 15th, '14, 22:42
by guitarsucks
Hello there, I have had the misfortune of burning the pad off pin 4 of IC4 on the I/O board. I've socketed it and i had to desolder/resolder it.. unfortunately its gone. So i need to relink it to the proper point with a jumper. with all the rosin mess i can't see the trace lines on the pcb where they meet the IC and I can't find info on the IC in the original tr808 service manual as the yocto i/o is for the most part its own thing and . If anyone has that info or insight it would be much appreciated.

Thanks.

G

Re: IC4 1/0 Board burnt pad off pin 4.

Posted: Jul 16th, '14, 07:22
by vereggaet
Hi,

you can download PDF schematics here https://www.e-licktronic.com/en/attachm ... achment=46 or download Eagle files https://www.e-licktronic.com/en/attachm ... achment=39 and trace the lines.

Re: IC4 1/0 Board burnt pad off pin 4.

Posted: Jul 16th, '14, 11:42
by guitarsucks
Thanks for the reply,

I've got the schematics and the Main board PCB layout, I've been over them lots, IC4 (74HC595) of the sequencer section is there, but i can't find IC4 (6N138) of the I/0 board anywhere in the schematic. I must be missing something?

G

Re: IC4 1/0 Board burnt pad off pin 4.

Posted: Jul 16th, '14, 12:40
by vereggaet
Page 3 in the Yocto_IO_board.pdf..on the bottom by the midi in socket

Re: IC4 1/0 Board burnt pad off pin 4.

Posted: Jul 16th, '14, 13:38
by guitarsucks
Thank you, got it.

Seems like pin 1 and pin 4 (also indicated by the pinout in the 6n138 data sheet ) are not linked so i'm fine for that IC.

Now for more troubleshooting fun. I'll post my other issues R151 burns, wacky sequencer/ trigger woes in another post shortly.

Thanks again.

G