Peavey Delta Blues Question

[Cheeto333]

Hi all,

I'm attempting to fix my Peavey Delta Blues 115 and need some help. When I power it up, the preamp tubes and the pilot lamp light up, but the power tubes do not. There is no sound from the speaker, but I hear a buzzing from the circuitry. I checked both internal fuses and they are ok. I suspect that a jumper connecting the PC boards is loose. Unfortunately, the jumpers are difficult to access. I might be able to unscrew the knobs, jacks and mounting screws to get the boards off, but I wanted to make sure this is the correct next step. Anyone ever taken one of these apart?

Pictures can be found here(sorry for bad quality, I'll post better ones when my camera's done charging): Peavey Delta Blues - Imgur

Here's the DB115 schematic: http://www.freeinfosociety.com/elect...wPmOqks7zD3-sc

Thanks for any help.

[Cheeto333]

One of the jumpers near the fuses (JP510 I think) looks a little toasty, but it appears to be making a good connection. Here's a pic of it imgur: the simple image sharer

[Amp Kat]

It's possible that the heat could have heated up the connection and caused a cold solder joint. The power tube heaters are run in series so each tube drops 6.3 volts across it. If one tube is out they all go out. If one tubes heaters are bad it will kill the others. The two big resistors shown in the picture are used in the circuit so make sure they ohm out and make sure they are making good continuity to their respective circuits. The overall heater voltage is around 28 VAC and you should get that in the heater supply if the fuse is ok which is the white ceramic one. Make sure that fuse is not open and I like to get a good pair of magnifiers and check those jumpers out all the way across and with a continuity meter. If you take all the jack nuts off and the tube securing screws the whole PCB conglomeration will come out. You will have to bend the top board down to get it to come out so you will put more stress on the jumpers but you have to do what you have to do unless you can find a bad connection without taking them out. I personally think the problem is around those two power resistors and there is a bad connection but be as carefull as you can taking those PCB out and putting them back in and handle the jumpers as little as possible.

[Cheeto333]

Ok thanks I'll see if I can get the PCBs out.

[Cheeto333]

Fixed it! Jumper JP510 was not making a good connection, so I bypassed it with a piece of wire. The power tubes light up and I get sound out of the speaker!

Now let's hope it survives being put back together...

Thanks for your help!

[Amp Kat]

Ok good job ! and just be carefull with the boards and you are done.