Crate Taxi TX15 battery full but dosent work

[siryo]

Hello everyone!!!!

Like title, I have a problem with my Crate Taxi TX15, the battery is full 13,3 V but dosent work, it swich on just if I put the cable of the power, but work bad couse it's like the battery was low, Im sure something it's broken in the PCB smaller, one where you plug in the power cord, maybe something it's burn, but I dont know what

hope someone can halp me, please.

thank u so much!!!!!!

[Enzo]

Start with voltages. Look at the power supply in the schematic. Is a good voltage coming out of that to the rest of the circuit?

[Jazz P Bass]

The battery has full charge but the amp 'doesn't work'.

Well that certainly narrows the problem down to everything but the battery.

As Enzo stated, check the power points on the main board.

If all is well, the list is still pretty long as to what is wrong.

Faulty output ic
Bad speaker.
Bad connection.
....................

Take it a step at a time.

TX50.zip

[J M Fahey]

On post #17 of http://music-electronics-forum.com/t17014/ Enzo posted the Crate TX15 schematic and PCB layout, under their code names.

The schematic shows a *fuse* between it and the main circuit (hint hint) and a 1N5401 3A diode between fuse and PCB .

Any of them open (suspect the fuse) and you have no power reaching the circuit as Enzo and JPB suggested.

And if the fuse blew , try to find why (I suspect a shorted TDA7240).

Good luck.

PS: where are you writing from?

[52 Bill]

How are you testing the battery charge? If you read the voltage with a meter it could read a 14 volt surface charge, which will fall as soon as a load is placed on it. Does the red charging led turn off? Try charging the battery for 2 or 3 days and see if it works any better.

[Jazz P Bass]

Good point.

These amps do not play very long on the battery (especially at high volume)

Not sure what the 'cutoff' voltage is where the amp will not function.

I have replaced a few of these batteries.

[Mick Bailey]

To test the battery without a proper tester, take it out of the amp and clip a 12v bulb across it say, a 21W car indicator bulb and see how long it holds up. You can work out how long the battery should last from its Ampere Hour rating and the load current. An old, sulphated battery will show full terminal voltage but discharge very quickly (as Bill 52 says).