Bose cinemate GS 2 - Page 1
Forum section: electronics / repair

author: funny718
author_rank: Contributor
timestamp: June 14, 2024, 02:37:05 am
content: This is my first project, and am probably over my head.So let me start with the symptoms so the system was working fine then one night while watching TV using the audio out connected to the Bose interface via a digital optical cable and the audio started popping and the sound was intermittently going in and out it was late that night so I turned off the system and didn't think much about it. Next morning my wife was playing a vinyl via the RCA analog cable and was working fine till she tried to raise the volume and I noticed it would not raise or lower then i tried to power off the system and it was just frozen. I then tried to reset the system by unplugging the power from the bass unit and disconnecting the db9 connector from the BOSE interface for about 30 seconds, connected everything back up and the BOSE interface light would blink 10 times like normal and when I tried to power it on nothing happens.I then went ahead and found the BOSE cinemate GS 2 schematic and trying to learn how to read the darn thing so I could begin to trouble shoot but not too sure where to start, but I opened the bass unit open and I found 2 boards I/O, DSP, plus the Bose Interface Module board. first, I unplugged the power then I started checking continuity between the BOSE interface module then the I/O board and then the DSP board making sure there was a connection between the pins which they seem to be all present. I went ahead and plugged the unit back in and still could not turn the unit on, so I started to test for voltages 1. BOSE interface module showed 3.3v the I/O board according to the schematics shows that there should be 3.3v on pin 5 of the J603 connection which is present. Next, I checked if the DSP board was receiving the 3.3v via the J602 connection and it was also present.so, I am at a loss of what I should check next visual inspection of the board and did not notice anything that looked burnt out either. I went ahead and left all the boards out of the unit and plugged the unit again and hit the power button and just like magic she came on I played music via the RCA connection and played just fine I then went ahead and tried to use the digital connection via the TV out and that was working as well, I went ahead and put everything back together and RCA was still working fine but the optical connection started with the same symptoms popping and the sound was intermittently going in and out and the system froze when I went to power the unit down, and since then I could not get the unit to start back up again.Thank you for taking the time and if you have any advice, please do share.I do have the schematics if needed

author: MathWizard
author_rank: Super Contributor
timestamp: June 14, 2024, 06:28:32 am
content: Does it sound more like digital noise, like something a glitch in windowsOS might do, or is it more like old radio's and doesn't sound like a computer game freezing ?Assuming the power is all working, and you have soldering gear, you could try and inject a signal to the output drive, and see if the audio ever gets bad.Try and find the overall output section, that drives the speakers. On a lot of newer stuff, it might just be big, multi-pin IC's, on a heatsink, maybe 1 for each speaker, or 1 for every 2-3 speakers. And then if you can find the input to that section, probably through some capacitor, you might be able to unsolder one side, and apply say a working MP3 player to it. Then let that play for ages.I downloaded some 7.5M zip file of schematics, with 11 files, I'll have a look at them, is that what you found ?Of the few digital audio things I worked on, the outputs from some DAC, then went to op-amps, and then onto the output power stage before the speakers.Try and find the RCA inputs, follow through to the output circuits. The whole thing will be controlled by microprocessors, and other huge IC's I guess too, keeping track of stuff and telling other IC's what to do.