aleph woes

sriegel

Member
2001-11-24 1:24 am
greetings all,
i've been trying to debug my completed aleph5 but still have no output, except lots of DC:(

here's where i'm at:

ps checks out fine at the rails

everything's fine up till Q4 , with around 9 vdc at r114 in one channel. but when i measure across c-e of q4 i get nothing. is this normal or is it a failed device? i'm still getting nothing across the load resistors (1ohm) on the output mosfet banks.

i don't know what else to try!

and why am i getting ~30vdc at the outputs??!!

hope someone can help this nearly hairless newbie,

cheers,
scott
 

sriegel

Member
2001-11-24 1:24 am
i found that i mis-wired the source and sense on the output hexfets and corrected this. now, i get around 0,5 vdc at the outputs, which is a vast improvement.

i still have 33 volts at the rails, everything the right polarity. but now i'm seeing almost no voltage across the zener on the +vcc rail.???? how can this be??

and i pulled and checked all the input mosfets and they are fine. all resistors are fine as well.

i also reheated EVERY solder on both boards.

i also checked my pcb layout against the schematic very carefully.
what the [email protected]#%$!( is going on here.?????
 

sriegel

Member
2001-11-24 1:24 am
no i dont have a diode checker with my dvm. is there another way to check? it seems that the zener coming from V+ may be inhibiting current somehow. it's the only device in the front end of the amp that i haven't checked, cuz i don't know how.

thanks,
scott