Sunn Beta Lead - Resistor melted out - Can't figure out problem

[The Dude]

Yeah, there are 2 threads, but I think someone recommended that he repost in the SUNN forum, so not really the OP's fault.

[johnskoolie]

1. Disconnect the speaker and check its resistance.
2. Turn on the amplifier (without the speaker!). Do not supply anything to the input of the amplifier. All controls on the front panel to the minimum position. Check the main supply voltages. This is +40V and -40V relative to the chassis. Then check the power supply of the preamp +15V and -15V. If you don't know how to measure bipolar power supply correctly, read the Internet or books.
3. Check the output DC voltage - this is the output of the amplifier. If the amplifier is in good working order, it should be 0.

Hey just saw this. Thanks for the help! I will definitely do this tonight.

I put the parts back into the preamp and I tested it just to see (praying) if it somehow fixed itself with the resistor being put back in and everything moved around. Nothing. What is interesting it before when hooked up to a speaker it made this loud noise and now it doesn't. There is definitely a hum but nothing other than that. I had the amp on, and tested the speaker cable coming out of the amp - 33.33volts. It does have two speaker outputs so maybe thats the right amount?

I realized after I checked the speaker cable voltage that the reverb tank wasn't hooked back up (it's attached to the bottom metal casing and I left the amp open) - I am looking to see if that should affect the amp from working. I'd have to imagine it wouldn't but im not sure.

[johnskoolie]

Just out curiosity how many components did you remove from board? Each one represents a newly introduced variable to diagnosing the failure in the amp circuit.

I removed pretty much everything in the little area that the resistor burnt out and checked. All the values were correct now they are back in the circuit. That is whats kind of driving me nuts. I would understand if someone was blown and now that amp doesnt work, but I can find any piece that is damage (at least in the area that showed signs of the burn marks)

[johnskoolie]

Are there two threads open on this one amp? I mean come on man. Like Biden always clammers come on man!

Yeah my bad, I posted in amps and then someone directed me to post in Sunn specific area. I am brand new here. Howdy by the way! I am in Flagstaff, noticed it says you are from Scottsdale. I went to school at Desert Mountain (shea and 124th st)

[g1]

You measured -33V at the speaker output? If so, and you connected the speaker, it will probably have been killed.
Do not connect anything to the speaker output until you have repaired it and measure 0 volts there. Check if your speaker is now seized and check it's resistance with your meter.

[DrGonz78]

Yeah my bad, I posted in amps and then someone directed me to post in Sunn specific area. I am brand new here. Howdy by the way! I am in Flagstaff, noticed it says you are from Scottsdale. I went to school at Desert Mountain (shea and 124th st)

I get lost and can’t find anything in the supermarket. Welcome to the forum! Yeah I went to Saguaro high class of 97. I wished I lived here and then in flagstaff for the summers. Getting unbearable to live here at all in July.

[x-pro]

What are the supply voltages on the board? Of the available ones.