Peavey Century 120 Bass Head Help

[kent007]

I got a Peavey Century 120 bass head off ebay; it was DOA. I opened it up and connected some loose wires and got the pwer light to turn on , but the signal is very low and very distorted. Can anybodu help? THanks.

[52 Bill]

I got a Peavey Century 120 bass head off ebay; it was DOA. I opened it up and connected some loose wires and got the pwer light to turn on , but the signal is very low and very distorted. Can anybodu help? THanks.

Welcome to the board. You should first contact Peavey and get a copy of the schematic for your amp. You may need it to figure this out.

Try plugging a cable from the preamp out into the power amp in jacks, or from the FX send to the FX return jacks, to see if the contacts are making a good connection.

Try plugging your guitar directly into the power amp in or FX return jack, and see what kind of sound you hear.

Pull out the back amp panel, and inspect the power amp pc board for burned or loose components. Make sure all of the plug in connectors that connect the board to the transformer and to the preamp board are correctly seated and making good contact.

Do you have access to a multimeter? If you do, then you should start taking voltage readings on the power supplies. There are 4 important voltages that need to be working, high voltage plus and minus for the power amp, and low voltage plus and minus for the preamp. Taking these readings will require you to work on the amp with the power on, so if you don't know what you are doing, or don't feel comfortable about doing this, then take the amp to a qualified tech.

[Gtr_tech]

Its more than likely a roasted output section. Sounds like leakey drivers/outputs to me.

[kent007]

Its more than likely a roasted output section. Sounds like leakey drivers/outputs to me.

Can you elaborate on the roasted output section? Where would the leakey drivers/outputs be and is that something that can be tweaked or would they need to be replace? I would love to have a working bass rig but this is by no means sentimental and I would rather get something else if this sounds like I maybe looking at a real costly repair.

[Gtr_tech]

Well if you have 1 or more leaky output transistors you'll need to replace them all as a set, don't try to replace just 1. THe driver section gets a little more complex. It doesn't sound like you have the knowledge or test equipment to diagnose this problem. You'd be better off to have it done by a decent tech...that way it will run reliably and you won't need to worry about it. If you just start replacing parts the cost will add up fast and you may do more damage than there was to start with.

[Enzo]

I'd agree, and not only that, but without doing it properly, you can instantly destroy new parts you install if other bad parts are not discovered first.