Lepai T-Amp with TA2020

[whelibob]

thanks, for the help. so you think the tripath chip is now broken? i used 12V lead battery. adding a new output inductor with higher capacitance wont repair it anymore?

[col]

12v lead battery? batteries just charged can have voltage up around 14v. Do you have a multimeter? you should measure the voltage. I don't recommend connecting anything over 13.5v.

The constant ticking is the amp trying to reset itself. If you leave it like that it will burn out the chip. If you remove the zener, the little glass orange and black diode near the chip. It will stop the amp resetting. Then you need to work out which inductor is shorted. Follow Mike's directions:

"Try removing the zener diode between pin 18 (fault pin) and pin 11 (I think), and see if you still get ticking.

With the zener gone, try connecting an LED and 2k resistor between pin 18 (fault pin) and GND and see if the LED lights up."

col.

[MikeHunt79]

Originally posted by col
I might take out the zener too! Mike, did you replace it with a wire link or just remove it?

col.

I removed it and left it open circuit, it's not needed at all and I'm not sure why they put it in! Take a look at the TA2020 datasheet for the nitty gritty, basically the ticking sound is the amp trying to start up despite there being a problem, and the ticking can lead to a broken TA2020.

Originally posted by whelibob
thanks, for the help. so you think the tripath chip is now broken? i used 12V lead battery. adding a new output inductor with higher capacitance wont repair it anymore?

I could be the TA2020, it could be a short on the outputs where the inductors and diodes are, I'd remove the zener and wire up the fault LED if you've modded it already, otherwise I'd send it back.

[whelibob]

yes i measured the batteryvoltage, it was 12.5V. does anyone have the datasheet link, cant find it at the moment.
cheers

[MikeHunt79]

Originally posted by whelibob
yes i measured the batteryvoltage, it was 12.5V. does anyone have the datasheet link, cant find it at the moment.
cheers

www.kafka.elektroda.eu/pdf/tripath/TA2020.pdf

[col]

Mike, which side of the zener is pin 17 and which is 18? I think I might wire a fault led in and glue it to the front.

col.

[MikeHunt79]

Originally posted by col
Mike, which side of the zener is pin 17 and which is 18? I think I might wire a fault led in and glue it to the front.

col.

The zener goes from pin 11 to pin 18, if you can post a close up of the chip I can highlight it in photoshop for you.

i'll try and get a photo of mine with no zener, but I've only got a camera-phone so it may not work too well...

[col]

I'm sure you can get these in the UK:

http://australia.rs-online.com/web/s...duct&R=2335134

they would be much better than the originals.

col.

[MikeHunt79]

Originally posted by col
I'm sure you can get these in the UK:

http://australia.rs-online.com/web/s...duct&R=2335134

they would be much better than the originals.

col.

Yep there is a depot pretty near me, so I'll pick up a few next time I'm there, thanks.

I'm now trying to fit a nice allen & bradley pot to the amp as I managed to break the 100k volume pot while trying to remove the front...

[col]

just removed the zener and put a 2k resistor with led on the No18 pin. drilled a hole in the front between the tone controls to mount. So I now have a fault led

col.