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

While recovering from the sore hand, started working on long overdue electronics services for several owners/garages.

At the moment, I have 5 x Bose AMP, 1 x A/C CCU board and just received 1 x Audio Head Unit.
Addition to these, there is one NSX sitting in the garage and I need to find the time to carry out MOT on my NSX and MX-5.






One owner bought these Bose AMP from someone and sent them in for the refurbishment.
The owner was told that at least they were operational when they were removed from the car.

One of the AMP showed lots of rust and it even transferred onto the FET. Although being told that they were operational, didn’t want to power them up after seeing such amount of rust due to moisture getting inside the speaker box (how???) so carried out several measurements first.

Looked to be fine so finally decided to power them up and both AMP at least managed to drive the speakers.
Will work on them when I have bit more time.




3 x Bose AMP from another owner.


As soon as I opened the package, I smelt the burnt circuit board.
One of the AMP was already serviced by someone but only replaced the FET and not the leaky caps for some reason. Not sure whether the burnt damage happened before or after that service but at the back of the FET, the circuit board was burnt.

Fortunately, the excessive heat didn’t burn the surface mount chips at the back.

I normally don’t service any burnt circuit boards but the owner was happy to take the risk so going to first take some measurement and decide what to do.




1 x CCU board.

The very common failure mode of blower motor fan only operates when set at max speed.
There were several severe damages to the board and even one of the cap lead was already missing/dissolved before removing it.
Going to have fun repairing this board in this hot weather…..






The Alpine audio head unit. Some owners think that the OEM one is from Bose but it’s not.

As soon as I opened the lid, I found this.
Sticky liquid all over the place along the side case and bottom of the board.

The acid leaked so much that not only it covered the upper side but also caused so much damages to the bottom surface.
I can’t even see the label of the surface mount chip.

The caps are still leaking as we speak so considering the hot weather, decided to at least remove the leaky ones and looked into the extent of the damages…..

I think I can get this OP AMP 4560 but won’t know the state until I can get to the point to power the board up.