Logitech Z-5500 Amp Troubleshooting - diyAudio
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Old 4th December 2011, 09:48 PM   #1
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Default Logitech Z-5500 Amp Troubleshooting

Hello to all.

Does anyone here have any knowledge of the amplifier section of the Logitech Z-5500 system (that is about as simply as I can put it)?

I have read through the entire "Hacking the Z-5500" thread a few times now and most of the focus there is surrounding the common faulty control POD issue and therefore solutions to eliminate the need for the POD.

I have what also seems to be a common fault as well (many similar unanswered questions), but cannot find any troubleshooting pointers anywhere online so far, hence trying this post here.

My Sub is dead, but the driver itself is fine (taken out and tested on external amp) as is the control POD and all satellite/centre speakers and their amps.
All wires trace (continuity) between the POD and the PCB inside the Sub and that is as far as my knowledge goes I am afraid.

Anyone know how I can "test" the op-amps or transistors or whatever other component/s in these Z-5500's is likely to go?
Would also be useful if someone knows which ones are dedicated to the subwoofer and what simple tests I can carry out to make sure that the amplifier section is at fault and NOT perhaps some other more complex issue?

Thanks for any help.

Steve
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Old 5th December 2011, 12:42 AM   #2
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Default Thread duplicated somehow?

errrr - no idea how this thread of mine has duplicated as I see it was posted twice and this was certainly not be me as after posting the original I have been away from my computer up until now.

perhaps a mod could delete the duplicate?

Steve
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Old 5th December 2011, 12:49 AM   #3
GloBug is offline GloBug  Canada
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Get out the multimeter start looking for power, work backwards from the sub.
Don't spend to much effort though. Check for a onboard fuse.
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Old 5th December 2011, 02:34 PM   #4
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Will do ... thanks - and will post back here if I find any anomolies.
If I can find an obvious dead component I will attempt a repair myself, but if it becomes a multiple component failure of sorts, then I guess I will have to throw in the towel.

Anyone ever had a fault in the amp sections that has been "easily" repaired and/or comments on the Z-5500 and typical component failure?

I know, I know ... how long is a piece of string, right?

Just hoping for a "pat on the back" from someone who may have had some success with electronic faults inside the sub unit I guess, as there appear to be zero comments on the WWW relating to problems that have been solved outside of the POD issue and blown drivers.

Steve
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Old 23rd December 2011, 03:48 AM   #5
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I've had the same issue thought it was my pod since everyone pods seems to be the culprit but its not my pod works fine after verifying that on another working unit its just that the unit keep blowing fuses after opening the sub realised two of the ics were burnt TDA7294 but everything else seemed fine (dont know exactly dont have a schematic sheet to verify)they were replaced now the sub unit powers on the pod but no audio is outputted from the speakers
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Old 23rd December 2011, 02:35 PM   #6
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Default z-5500 amp failure

Ok i have come across this thread "

Ok, i did alot of reading and the chip is an HCT139 wich is a demultiplexer, it is responsible for the mute and unmute of the amps and it is linked to pin 7 and 8 on the 15 pin D-sub connector. grounding those should unmute all the channels. so if you replace the burnt regulator and connect 7&8 on the connector to ground it should work fine. let me know how it goes. "

What the guys are saying basically i think is even after the Bunrt IC'S are replaced there is one particular that may need to be replaced hct139 since im assuming again (im not a technician) all the IC TDA7294 are in mute state and to unmute them all this IC HCT139 is responsible for that ........
can anyone verify
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Old 23rd December 2011, 02:51 PM   #7
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Default z-5500 amp failure

Ok i have come across this thread "

Ok, i did alot of reading and the chip is an HCT139 wich is a demultiplexer, it is responsible for the mute and unmute of the amps and it is linked to pin 7 and 8 on the 15 pin D-sub connector. grounding those should unmute all the channels. so if you replace the burnt regulator and connect 7&8 on the connector to ground it should work fine. let me know how it goes. "

What the guys are saying basically i think is even after the Bunrt IC'S are replaced there is one particular that may need to be replaced hct139 since im assuming again (im not a technician) all the IC TDA7294 are in mute state and to unmute them all this IC HCT139 is responsible for that ........
can anyone verify
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