OH NO! Core was in trouble with psu

Testing/Troubleshooting
1

i made a terrible mistake when i tried my optimized psu solution…

resulting the voltage for the core of beeing 9V instead of 5V!!!

(and no voltage regulator afterwards of course…) >:(

a few seconds later there was a loud crack sound, i mentioned a short bad smell and the lcd turns to an undefined state. :o

i switched off but too late. :frowning:

the pic was very hot, i did not feel any other hot part.

i’m in fear to possibly have burnt the lcd controller (2x40!). :o

is this possible?

wouldn’t the trannie be hot as well?

could it have damaged the opto? ???

any opinions welcome…

…under shock, it happens minutes ago and my MBSID sounded sooo sweet… :cry:

any opinions welcome

Martin :-[

2

i calm down a little bit and since this unhappy experiment shot down the 5V part of the psu (i’m soooo dumb) and it’s NOT the type you can open and simply change the fuse after such a malheur… i took the 7805 back into the circuit (cabled and with a heatpipe) and tested with a 18V DC psu i had laying besides.

after powering up my midi patchbay shows midi out after 2 seconds  :slight_smile:

(with another preburnt pic) (not THAT bad).

And i was successful in uploading mios and the sid app!!!

i’m a little bit frightened to connect the lcd again i must say.

But seems like everything’s working fine, even the bankstick…until now…reconnected the sid module, …no sound until now… :frowning:

3

Hi Martin,

looks bad for the SID - its very unlikely that it is still working (if you’ve luck only the 74HC595 are affected)

LCD: you can check this by connecting only ground, +5V and V0 (the contrast input) to the LCD. If you can see the black bars at the top (like after startup so long the display is not initialized), then it could be ok

Best Regards, Thorsten.

4

ok, the bar is working (LCD)…

sounds like the sid is broken. will try another one. and change the 595’s…

thank you

martin