Hi,i got the circuit diagram of the soundguard protection u have sent, but the resistor(50w 5ohms) used in your circuit. in my circuit two resistors(25w 10ohms each) are used in parallel. so in my case what will be the wattage & voltage of the bulb. The bulb in my circuit is tube shaped. Please help.

are you kidding...so if you replace it and it burns up again what are you going to do?

Hi. Replace smd transistor T401 (i think) - code 50W - (BC337). Bottom PCI.

Blown poly switches????

"terribly owful " is not a descripption we can really understand. You need to describe whether the probllem is with the bass or treble speaker... lows/highs... The only suggestion we can give is to open the unit. You will need a LONG phillips screwdriver and remove all the screws in wells around the edges from the back and then gently separate the shell. Inspect for loose wiring. You don
t mention if you are using this as bi-amped or not which we need to know. This unit has the soundguard protection of the tweeter which consists of an automotive type lamp and a polyfuse. I would open the unit and see if there is a problem with the connections or possiblly a socket problem with the lamp as that would disturb the tweeter level. If you are bi-ampong this, then verify that swapping the speakers the problem is the speaker and NOT the cable or amp... Also verify the switch on the back of the speaker is properly set.

Let us use a bit of logic to resolve this... I have an Axiom but it would be a lot of screws to take out to get to the part... so let us think about this. The resistor value starts with a "1" and we know it is 5% tolerance (gold). we know the resistor burnt up with likely 5 volts on it... Value could be 1000 ohms, however the voltages present (12 volts max) would NOT have burned up a resistor of 1000 ohms. The USB area is mostly 5 volts and across 100 ohms is only a quarter watt... not enough to really burn up a resistor... First thing is to MEASURE that the resistor s open... in spite of being burned, it MAY still be OK... these resistors now usually either open or remain close to their value. The resistor ALSO may be a fusible resistor intended to act as a fuse... Is the resistor open or not? is it near a resistance with a "1" as the first digit? If it is not open I suspect it is not all of the problem. In that case, look for a burned circuit trace on the board. If it is open, then MEASURE the voltage across the resistor with the power applied. If you find 5 volts, then it MIGHT be a 10 ohm used to limit the USB current to 500ma. Get back to me with your findings... I have unraveled many of these things...

If an internal circuit breaker pops, something has failed. Even surge protectors do little to protect stuff unless they are high level types with filtering. Key thing: ALL your interconnected equipment MUST be powered from the SAME receptacle or power conditioner. Using multiple outlets can allow building "ground bounce" to rupture sensitive input circuits. Use of balanced lines avoids noise in systems.

There is a speaker protection network in most of Peavey speakers protecting the tweeter horn.

It consists of a Polyfuse (round disk about the size of a nickle or quarter, a resistor and an incandescent bulb.

Circuit can be found at: (go to last post attachment) http://forums.peavey.com/viewtopic.php?f=26&t=2260

Copied from earlier post I made for another.

For the MOST PART the lamp is NOT the primary path for the speaker current, the POLYFUSE is and is a low resistance until it is overdriven.

The bulb is a 12 volt bulb and is nominally 2.1 amps when used on 12.8 volts.

If this is in regards to the other problem mentioning 32 watts and 12.8 volts... this bulb is NOT 32 Watts, it is 32 CP or 32 Candlepower which is NOT Watts in general. The lamp is actually around 27 Watts when run at its ratings.

It is important to realize that the lamp and the resistor are there ONLY as a "soft" path when the POLYFUSE opens due to overcurrent. When the polyfuse cools, the lamp and resistors are effectively shorted by the Polyfuse and most of the current again flows through the polyfuse..

Here is a link to forum that someone has posted the soundguard protection circuit down the page:

http://forums.peavey.com/viewtopic.php?f=26&t=2168&view=previous

The 1156 lamp MAY have slightly different shapes but is an automotive lamp. If the bulb is blown, the polyswitch fuse is likely blown as well.

Probably the channel A went. If you are fortunate, the power supply is still OK. There are protection circuits for the speakers, however you MUST use speakers that are rated at over 400 Watts. If you use smaller ones, they can get blown. There is a weakness primarily on insulation for channel A and an arc between layers of a circuit board can wipe out several transistors and a zener diode and sometimes a metering resistor. Once this happens, have unit serviced before using it again as further damage can result.
ALSO PLEASE read my tip I posted on FIXYA regarding a grounding hazard when using Speakon to 1/4 inch speaker cables... essentially the barrel of the 1/4 inch jack of the A channel is the hot lead, NOT the tip for that channel.