Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

The Forum server seems to be much stable now although we are still rebooting it from time to time.
In fact, just rebooted.

Time to catching up with updating the blog.

Was back to 100% mechanical service mode but then 50/50 between mechanical and electronics for awhile.
Then, from the beginning of May, went back to 100% electronics.
Should be back to mechanical service mode from next week.

In between, compressed the right arm nerve again….
After the first injury last November, installed preventative measure but still happened again so made several modifications.

Couldn’t wright properly but fortunately, no signature required these days.
Normally, takes few months for the full recovery but the electronics service helped in shortening the rehabilitation process addition to the daily exercise.







Touched on this AMP briefly previously and now this is the extra detail for it.

Please don’t use this type of FET package on the Bose speaker AMP.






Someone tried repairing this AMP but not great soldering and wrong spec parts.

Resulted in short circuit between the IG power and the amp signal output through the metal cover.

Advised the owner to check the state of the speaker cone as I saw one similar example not long ago.








Initially, happy with the progress but during the thermal shock testing, found issue with the Bose IC U2.

Most likely caused by the short circuit mentioned above.

Basically, it was killing the SMD resistor and the C34.

So, after several feedback and talking with Heineken on here, decided to use the aftermarket U2.

Always nice having advice from Heineken.








Preferred using the gold plated IC socket but found out quite expensive in UK or US compared to Japan so directly soldered it instead.






After excessive testing, happy with the result so returned it to the owner.

Offered the option to replace it with my spare unit that will be built in the future in case of premature failure.



Have several dead AMP with burnt circuit board or issue with Bose IC U1 and U2.

Looked for the replacement aftermarket U1 long time ago to save Bose AMP but not available.

I already knew later spec Bose AMP uses different U1 for both the Front and Rear compared to the early spec ones.

After discussing with Heineken, he gave it a go with the later spec aftermarket U1 on earlier spec circuit board.

U1 controls the EQ, gain control, etc before passing the signal to class D amp U2 + 4 x FET.

The later spec board has lots of changes over the earlier ones so could result in different EQ, output level or even create new issues.

Still, wanted to try it by myself and already testing full set using my NSX so will touch on this in another post.



Kaz