Most guitar cabinets use high volume speakers, but it is possible to overload and damage them. Follow these steps to fix them.
Determine which speaker is damaged or broken. The easiest way to do this is to use a diagnostic CD and CD player to play various test tones through your speakers. Listen to each carefully and decide which is distorting sound, or not working at all.
Most guitar cabinets have a protective grill covering the speakers. Remove it with a screwdriver.
Carefully remove the broken speaker or speakers. Examine their cones and voice coils to see what exactly is damaged.
Repair a slight puncture or tear in a cone with a bit of tape or some light glue. Voice coils typically cannot be repaired, so if they are damaged, you will have to replace the speaker.
Before you install a new speaker, make sure you record the resistance, serial number and power handling data that's on the back of it. You will need to match this when you select a replacement driver.
Look online and at electronics stores to find the best deal on the speaker you need. Most guitar cabinets take 10-inch drivers that are rated at 100 watts or higher.
Before setting the new speaker in the hole, reattach or solder the speaker wires to the new speaker. Install the speaker into the cabinet using the old hardware.
Research the cost of speaker repair, as it may be more economical to simply buy a new speaker cabinet and sell the old one for parts.
Check the warranty on your speaker cabinet so that you don't void the warranty. Do not strip screw holes by tightening screws too quickly.