e-licktronic Forum

Hi,

Id like to share wit my exp. and ask for a little help.
I received broken Nava.
First thing to do was find short 5V to ground in seq.
After the few hours it was found (C614 was the cause). Cap was fine, but in some strange way that was a short problem. Removed, and another one cap was mounted - there is no more short in that section.
Another thing was lcd fucked up - another with nice cable was a solution.

And one more broken component was Atmega chip
Exchange and programmed with the newest firmware - works fine now.
Ive checked all ices nad vias and traces (few were broken also!!)
C155 and C45 were mixed polarity...
But I still get no clue why I cant get 5V on TP1!
It stoke on ~11V and nothing helps.
Could you have any help, pls?
I dont want to check rest of the instruments without proper +5V on that TP1 for obvious reasons.

Thank you

lukasz

short movie after init of firmware ->

Did you try to swap TL074P? Otherwise maybe a bad contact around TL074P? Did you check those film caps (C517, 518...)? Sometimes you also need to turn the trimmer (clockwise) pretty long until something happens...

Thanks for answering

Yes, I did it once before, but I think that will be a good idea to swap it once again (!). I dont trust this one enough.
I replaced that caps for new one, after the short was fixed.
Nothing changed after trimmer turning -> I know that clockwise turning until clicks appear trick.
There must be opamp or mcp failure I think now...
I will check this out and let know.

Thank you and cheers

It is not a TL... ;(

Did you try swapping the DAC? But yeah the problem could also come from the microcontroller.

Fixed - there was no connection between pin 2 (IC110), C169 and middle pin of trimmer.
5V is present rn.
I afraid of damage done...

Thank you for help!