Take the cover off your amp and use a voltmeter to measure the voltage to the lamps (usually 6, 8, 9, or 12 volts). Also measure the diameter to the closest tenth of an inch. Inspect what type of leads (wire connections) the lamps have.
Then you can try to find a match at:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=64
You might also consider replacing the lamp with an L.E.D. White or blue are the cool colors. Use a resistor in series to drop the current to 10-20 milliamps. Use Ohm's law (R = Volts/Amps) to find the value of the resistor. For instance if you have 12 volts and want to feed 10 milliamps to the L.E.D. you would divide 12 by .01 and get 1200 ohms. Solder a 1200 ohm resistor in series and the L.E.D. will burn about half bright. A 600 ohm resistor will provide 20ma of current and full brightness for a std. L.E.D.
If the L.E.D. is not the exact right size, cut a small piece of clear or white heat-shrink tubing and slide it over and heat it with a hair dryer.
Buy enough lamps or L.E.D.s to replace all of the lamps. If one lamp goes, it is a good bet the other one(s) will go soon.
Then you can try to find a match at:
http://www.partsexpress.com/webpage.cfm?&DID=7&WebPage_ID=64
You might also consider replacing the lamp with an L.E.D. White or blue are the cool colors. Use a resistor in series to drop the current to 10-20 milliamps. Use Ohm's law (R = Volts/Amps) to find the value of the resistor. For instance if you have 12 volts and want to feed 10 milliamps to the L.E.D. you would divide 12 by .01 and get 1200 ohms. Solder a 1200 ohm resistor in series and the L.E.D. will burn about half bright. A 600 ohm resistor will provide 20ma of current and full brightness for a std. L.E.D.
If the L.E.D. is not the exact right size, cut a small piece of clear or white heat-shrink tubing and slide it over and heat it with a hair dryer.
Buy enough lamps or L.E.D.s to replace all of the lamps. If one lamp goes, it is a good bet the other one(s) will go soon.