Made a idiot mistake, not sure what damage i have done.

[ats]

I replaced the 5 watt resistors (R78-R79) and filter caps on my 1998 Fender Hot rod Deluxe and all went well but i was not getting any channel switching or reverb so i traced it to a bad diode , replaced that and went to fire it back up when i took it out of standby , i saw the 1 watt R74 and the 1/4 watt R68 both smoke and burn , I quickly shut it down. WTF! I forgot to reconnect the ground wire from the PCB to chassis.  . I replaced those resistors i fried but it did the same thing as soon as i took it out of standby. Any ideas what else i may have cooked? oddly it didn't blow the fuse.

[shooter]

oddly it didn't blow the fuse.

gotta love a well  designed fuse protector circuit

you might have you hands full with this one, disconnect the +-16vdc @ cap n pull power tubes.  see if you get the +-48, 39VAC & 50V bias

[John]

I don't know the circuit, but that diode you replaced: is it oriented correctly? Those resistors you described, are they in the bias circuit? And I don't know why not having the PCB ground connected would fry anything; usually that just means there's nowhere for current to complete a circuit, so nothing fries. 

[tubeswell]

R74 is a supply dropper resistor between C33 and C35. You burn't this twice. My money is on C35 being shorted.


As to why R68 burn't? obviously too much current, but why there would be too much current at R68 is puzzling. Are you sure you wired it correctly?

[shooter]

that diode you replaced

which diode would help;

why R68 burn't?

my guess, it's some other number, maybe R78?

I'm way behind though, I'm trying to get from swapping L.V. R's that cause H.V. shorts

EDIT:
Is this a viable guess?

[ats]

Thanks for all the replies ! the two diodes i replaced were CR13 & CR14. I made certain they were oriented correctly. i went back over my work and made sure i didn't have a solder spilling over to another trace or anything, checked continuity on all the traces i replaced parts on. R68 is right between the reverb and presence pots it's defiantly the one burning lil 1/4 watt job.

I'm trying to figure out how to implement shooters suggestion of disconnecting the +-16vdc @ cap n pull power tubes.  and seeing  if i get the +-48, 39VAC & 50V bias.  I'm going to pull C31-33 & 35 and test them maybe they did short out.  Really embarrassing screw up i should know better than to rush to get something back together.

I'm really  hoping i didn't fry one of the transformers.  I'll see what i can find and report back.

[shooter]

implement shooters suggestion

I have a bad habit of NOT taking in everything, like the fact it's a pcb

I do think what you did in the lo volts section caused the HV problem,  you need to "get the load off" so you can power up without smoke, so maybe pull power tubes and see if 74 gets hot.

on pcb's a lot of times to "break" the circuit, you have to cut foil traces, sometime you can lift one leg.

[shooter]

Not to add to your list, but, it looks like there are 2 "safety?" diodes off the power tubes plates, CR4 & 5
might test those while you're ohming around.

[ats]

Thanks for all the help guys! Got it sorted out finally everything is working fine now! Turns out the lead of the 5 watt resistor (R78) was pushed forward and was making contact with the W28 jumper and causing the 4.7k resistor and the .1uf cap for the presence control to fry.  Whew! :)

[purpletele]

That will make you feel good for a while!