HEATHKIT SB 221 TROUBLE PLEASE HELP!

[hank]

I HAVE A HEATHKIT SB221 LAST NIGHT I TURNED IT ON AND THE TRANSFORMER STARTING VIBRATING & HUMMING THE METER LIGHTS GOT DIM AND THE RESET TRIPED I RESET IT AND IT WORKED FOR AN HOUR AND THEN DID IT AGAIN. I HAVE NOT TURNED IT ON ANY MORE.
CAN ANYONE HELP!
THANX VERY MUCH 73s
BEST REGUARDS HANK

 

[Beetle]

Sounds like a power supply troubleshooting party. If you don't have the manual, get it, and start there.

 

[cyclops1970]

I HAVE A HEATHKIT SB221 LAST NIGHT I TURNED IT ON AND THE TRANSFORMER STARTING VIBRATING & HUMMING THE METER LIGHTS GOT DIM AND THE RESET TRIPED I RESET IT AND IT WORKED FOR AN HOUR AND THEN DID IT AGAIN. I HAVE NOT TURNED IT ON ANY MORE.
CAN ANYONE HELP!
THANX VERY MUCH 73s
BEST REGUARDS HANK

Unplug. Lift off the cover. Bleed off the HV with an insulated shorting stick. Put both hands in your pockets. Look inside the power supply section...see any goop running out from the capacitors? See any carbonized diodes? Smell anything burnt?

Great thing about HV is that when something fails it usually does so spectacularly, so it's an easy troubleshoot...

At any rate, if the caps are original (even if there is no goop running out), I'd go ahead and replace them.

 

[Melee401]

yup
Put my vote on the power supply filter caps too

 

[Bionic Chicken]

Filter caps especially if they are original. If these need replacing it is a good idea to replace the rectifiers also. You can get anything needed at this link.

Harbach Electronics - Fans and Relays

REMEMBER THERE IS HIGH VOLTAGE PRESENT IN THIS AMP THAT WILL KILL YOU!!!!
If you are not familiar with servicing HV circuits please let someone who is repair it for you.

BC