Anyone fixed a Bose Wave Radio with no sound?

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I am repairing a Wave Radio Cd the old model and the problems were:
1- Hum at the speakers
2- Left Ch speaker only makes Hum and Noise while right speaker sounds
3- Aux input does not sound

I fixed all which was problems created with open traces because of the bad design ( the little holes in the back, only is need it the center holes, the extreme holes only produce problems because humidity, Salt that comes inside from this holes gets through the board provoking oxidation the traces and therefore lots of problems.

Now the last problem is too much Hiss coming from the left speaker, U600 works like an equalizer for this channel because left speaker is much different as the right speaker so they compensate with this equalizer circuit, I still have this problem but as I have dedicated 3 days completely of work making this repair as a training to understand the dogs on this Bose wave radios.
If anyone have fixed this Hiss please tell me, I'll be very appreciated
Thanks
 
As a new forum member I have some occasional electronics repair issues.

Right now it is a BOSE AWR1-2W clock radio about 25 years old I guess. It was given to me about 10 years ago and I quite like it.

It worked fine until recently when it started to “thump” when turned on and eventually the audio died completely. I guessed from some internet posts that the problem might be the main audio chip, TDA7374. Normally £8 or so off eBay but I ordered one from China for less than £2, including postage. Like the original, it is marked as made in Singapore!

WONDERFUL, it now works, BUT the clock now keeps time thinking it is on 60 Hz rather than 50Hz, so it advances by exactly 30 minutes every 36 minutes of real time. Not good for a clock radio!! So, question, is the timer function somehow governed by the new chip I installed, or have I disturbed something else??

Inside the set looks like new and I would very much like to get the clock back to accepting 50 Hz. The Bose set up guide on the internet (not the correct one I fear) says nothing about changing clock frequency, the device is marked 220/240vac and 50/60Hz on a label by the power connector.

HELP,!!
 
interesting company which performs repair service, maintenance and various mods:
http://www.condoraudio.com/wp-conte...adio-VoltageConversion-Restoration-Repair.pdf

Majority of the technical contents of this article was my original idea including my mistakes verbatim that I shared in private with the author starting May 2011. I didn’t give him any permission to use my information for commercial purposes.

I notified the author after finding his misdeeds. He eventually added a partial credit at the end of the article.
 
Ok, it is working on 50Hz now but I’m not sure why. All I did was switch off at the mains, remove the three back up cells (3 AA on this model) although removing one would have sufficed as they are in series, reconnect to the mains , then reinstall the back up cells. I am guessing, and this is a pure guess, it defaults to 60Hz if the back up is installed before connecting to the mains, but if the back up cells are not installed until after the mains is connected, it chooses 50Hz.

I don’t believe this, but as it is now working perfectly I am not about to disturb it.

The unit is now back to 100% operation and the 7374 chip from China via eBay cost me less than £2.

I rate it as being very well built. The remote control also still works perfectly.
 
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