I hve a a Fender/Pass Port audio system 150. Had a powersurge due to extended power cords and blew the fuse. I was useing it at a country wedding so extension cords were used. I've replaced the bad fuse. When I turned the system on it blew again. Can you help me?

The small fan or buzz noise you are hearing from your Fender 150 bass unit is likely due to normal wear and tear. Over time, components inside electronic devices can begin to wear down or become loose, which can cause the unit to generate noise. However, it's possible that the noise is being amplified through the speakers due to a grounding issue or other electrical interference.
Before attempting to open up the unit and clean it, try some basic troubleshooting steps to isolate the issue:

1. Try using a different cable to connect your PC or iPad to the Fender 150 bass unit. Sometimes cables can become damaged or worn, which can cause noise or interference.
2. Move the Fender 150 bass unit to a different location in the room to see if the noise changes or disappears. Sometimes nearby electrical devices or lighting can cause interference with audio equipment.
3. Try using different speakers to see if the noise is still present. If the noise disappears, it's possible that the speakers are causing the issue rather than the Fender 150 bass unit itself.

If none of these steps resolve the issue, it may be necessary to open up the Fender 150 bass unit to inspect and clean the components inside. However, if you're not familiar with electronics and don't feel comfortable working on the unit yourself, it's best to take it to a professional technician for servicing.
It's important to note that while the noise may be annoying, it's not necessarily an indication of a major problem with the unit. If the Fender 150 bass unit is still functioning properly and producing the sound you love, it may be best to simply live with the noise rather than risking damage to the unit by attempting to fix it yourself.

If this is an XLR style plug it is most likely a control port for something like an external mixer or effects box.

You are in danger of popping the amp. The Fender passport 150 would be capable of covering about only a 20 foot by 20 foot area. If your area is bigger than that, you need more power and certainly bigger speakers. I would NOT recommend the larger Passport systems as the speakers are too directive for what sounds like your use... also there are reliability issues.

Common problem, especially with the higher power version of this. These are very hard to work on due to the way they are packaged. Best to take it to a repair shop as either one of the amps or the power supply has failed.

You are saying the fuse blew out and then asking if there is a fuse??? That makes no sense...

Tripping on cords could do certain things but NOT likely to blow a fuse.

Tripping on cords OFTEN breaks the plugs on the cords or the jacks in the equipment. The power input jacks from those wall transformer power supplies seem to be very vulnerable to this. They often disintegrate OR break loose from the solder on the circuit boards rendering the unit inoperable.

In future, loop the cords through handles so they don't yank the jacks if somebody yanks the cord.

Likely an overload failure caused the protect light to come on, and then the fuse blew so all power is off... Do NOT replace the fuse as you will LIKELY do additional damage to components. Take unit in for repair immediately.
Note: These units are really hard to work on due to the way they are packaged.

Replace the fuse only once. If it blows right away, then servicing is required as continued replacement will likely damage more inside.

Most of thes have a fuse holder that is a part of the input power socket. There is a little rectangular panel adjacent where the cord connects with a tab that you gently pry out and carries a small fuse. Replace the fuse and re-install the carrier.

These units are very hard to work on due to packaging.

Yes you could do that. The preamp output is just a BUFFERED output of the signal sent to the power amp. And the power amp input jack is BUFFERED before driving the power amp. These impedances are neither high or low being in the 1K to 3K ohm range.

The jacks for BOTH are mono jacks so noise pickup is possible if long cables are used. The external effects unit should be well grounded and operate off the same receptacle as your Fender for system safety. Use SHORT audio cables to minimize noise.

ALL the signal will pass through the effects unit when used this way... HOWEVER the internal reverb will still be in this path. You can kill this by turning the reverb control to zero on the Fender.

If the fuse went, there probably is a failure. To avoid further damage, if you replace the fuse, put a 150 Watt lamp in series with the hot power wire. Make an adapter to do this safely.

The lamp will light instead of the fuse blowing and hitting the amp with a high current surge that could do more damage. If the lamp goes out, it is probably safe to operate.

I would recommend carrying a spare amp with you... These Passport systems are HARD to work on due to the way they are assembled.

This needs to go to the repair shop. The protect mode is turned on when either the power supply has a problem or one or both power amplifiers have a problem. These are often blown components.

These units are HARD to work on. To open you have to first remove then front panel before you can remove the back panel that has the power supply and power amps/heat sinks.

Compare repairs of these units to working under an automobile dashboard!

Hint: On startup, use a series 150 wat lamp to limit current while repairing. SInce these use a switching supply operating off the input line, use an isolation transformer for personal safety.