Logitech z-680 amp repair

racerhoze · 28th September 2009, 12:51 AM

My z-680s seem to have taken their last breath. After stretching their legs with some good bass, the system shut off. I replaced the blown fuse with a new slow blow fuse and was greeted with a short (.5 second) hum and some sparks and smoke. What most likely failed, and can I repair it?

racerhoze · 28th September 2009, 03:07 AM

It appears that 2 of my transistors exploded...

pacificblue · 28th September 2009, 06:00 PM

That is not a transistor. It is a TDA7293 chipamp.

racerhoze · 28th September 2009, 07:39 PM

Quote:

Originally Posted by pacificblue

That is not a transistor. It is a TDA7293 chipamp.

Ah, excuse my n00bness. Anyway, can these just be replaced? Or is it likely that other components are fried as well.

racerhoze · 29th September 2009, 02:44 AM

Just bought two TDA7293s off ebay. I guess I will replace the blown ones and see what happens?

sasmit · 29th September 2009, 02:45 PM

It is highly unlikely that the TDA 7293 blew by itself..so before you put these new ones back in....please check the power supply and other psu components on the board...something is seriously wrong with them.

racerhoze · 29th September 2009, 05:31 PM

well I know in the logitechs, two of the chipamps are bridged for the sub.. Now I don't know how to tell which ones are bridged or not, or if that even matters.... And are there any newb diys sitting around for how to check my power supply? I have my multimeter here... But pretty clueless.

racerhoze · 1st October 2009, 05:37 PM

are there any components of my power supply in particular that I should be looking at?

racerhoze · 1st October 2009, 10:55 PM

So upon further disassembly, it appears that the sub is blown, sounds like the voice coil is destroyed. So Now I am going to have 7 TDA7293s and some of the other good parts from this amp... so who wants to help me build my first amp? Looking at the chip amps everyone here has built, has got me inspired.

jaycee · 1st October 2009, 11:44 PM

The PCB looks damaged - those blackened traces and also it appears there is a charred area under the chip. The components near those traces have almost certainly fried.

Furthermore, it is likely that the subwoofer speaker's voice coil has also fried (probably what fried the chipamps). Push the cone of the speaker in and out. If it is not smooth, and feels like it grates, the voice coil is fried.

Where did that large blob of solder come from?

I'm afraid I couldn't recommend attempting repair - the damage looks too great.

28th September 2009, 12:51 AM	#1
racerhoze diyAudio Member Join Date: Sep 2009	Logitech z-680 amp repair My z-680s seem to have taken their last breath. After stretching their legs with some good bass, the system shut off. I replaced the blown fuse with a new slow blow fuse and was greeted with a short (.5 second) hum and some sparks and smoke. What most likely failed, and can I repair it?

28th September 2009, 06:00 PM	#3
pacificblue diyAudio Member Join Date: May 2008	That is not a transistor. It is a TDA7293 chipamp. __________________ If you've always done it like that, then it's probably wrong. (Henry Ford)

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29th September 2009, 02:44 AM	#5
racerhoze diyAudio Member Join Date: Sep 2009	Just bought two TDA7293s off ebay. I guess I will replace the blown ones and see what happens?

29th September 2009, 02:45 PM	#6
sasmit diyAudio Member Join Date: May 2006	It is highly unlikely that the TDA 7293 blew by itself..so before you put these new ones back in....please check the power supply and other psu components on the board...something is seriously wrong with them.

29th September 2009, 05:31 PM	#7
racerhoze diyAudio Member Join Date: Sep 2009	well I know in the logitechs, two of the chipamps are bridged for the sub.. Now I don't know how to tell which ones are bridged or not, or if that even matters.... And are there any newb diys sitting around for how to check my power supply? I have my multimeter here... But pretty clueless.

1st October 2009, 05:37 PM	#8
racerhoze diyAudio Member Join Date: Sep 2009	are there any components of my power supply in particular that I should be looking at?

1st October 2009, 10:55 PM	#9
racerhoze diyAudio Member Join Date: Sep 2009	So upon further disassembly, it appears that the sub is blown, sounds like the voice coil is destroyed. So Now I am going to have 7 TDA7293s and some of the other good parts from this amp... so who wants to help me build my first amp? Looking at the chip amps everyone here has built, has got me inspired.

1st October 2009, 11:44 PM	#10
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	The PCB looks damaged - those blackened traces and also it appears there is a charred area under the chip. The components near those traces have almost certainly fried. Furthermore, it is likely that the subwoofer speaker's voice coil has also fried (probably what fried the chipamps). Push the cone of the speaker in and out. If it is not smooth, and feels like it grates, the voice coil is fried. Where did that large blob of solder come from? I'm afraid I couldn't recommend attempting repair - the damage looks too great.

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