(Solved) Topping A90 Discrete Disassembly

[Dayman88]

Hello,
I am trying to take apart my A90 and I have take off every screw that I could find and it won't budge. Does anyone have any experience with this?

(Background with the problem)
So I am trying to take apart my A90 Discrete because it stopped working and throwing a code. So when it first started happening, it would click 6 times, going back and forth between 70 and 80 until it would just be stuck at "-2", where it wouldn't react to any input. I then tried to update the firmware, which was version 2.4. I updated it to version 2.8. This gave me the ability to actually mess with the settings, but it still clicked. It seems that the click only happens when it is on HPA mode though, and not in PRE mode. I still can't get any audio out of it though.

 

[amirm]

Did you pull off the volume knob. And are there two other screws on the bottom underneath the rubber feet?

 

[JSmith]

I have take off every screw that I could find

The ones circled are to secure the XLR in/outs;

Everything is straight forward, but after taking off the back plate you will need to figure out a way to easily disconnect the two ribbon cables coming from the rotary knob and display.

Worst part is to get the two screws from the front plate off, given that you'll need a very long and very thin screwdriver (the one from iFixIT is shorter and thicker, even with the longer adapter included).

Chances to damage the ribbon cables and/or to not be able to put everything back are quite high, so I strongly don't encourage anyone to teardown this device!

BTW, why drilling the top case for? I measured quite low temps on top, even after driving at insane levels two planars at the same time the temps were like around 40C. My Matrix HPA-3B was hitting 60C when I was driving two planars for testing.

Teardown thread here;

Topping A90 Discrete (A90D) - Teardown and personal thoughts

I found not many teardowns with this model, especially with the output transistors uncovered and with surrounding close-ups, so I decided to purchase one for myself (second hand) to pair it with my D90 MQA then write an article here on ASR. Looks like taking the PCB out from the case if somehow...

www.audiosciencereview.com

JSmith

 

[Dayman88]

Did you pull off the volume knob. And are there two other screws on the bottom underneath the rubber feet?

There are no extra screws underneath the feet and I don't see how I can take the knob off. I tried giving it a good pull, but that didn't work.

The ones circled are to secure the XLR in/outs;

View attachment 546429

View attachment 546430



Teardown thread here;

Topping A90 Discrete (A90D) - Teardown and personal thoughts

I found not many teardowns with this model, especially with the output transistors uncovered and with surrounding close-ups, so I decided to purchase one for myself (second hand) to pair it with my D90 MQA then write an article here on ASR. Looks like taking the PCB out from the case if somehow...

www.audiosciencereview.com

JSmith

Yeah I took off the screw for the Firmware update, thinking it was something that was hold the case together, and the usb port fell out. I realized what all of those screws were for, but I really didn't know what else to take apart after a while so I unscrewed them as well.
Thanks for the link to the tear down of this thing! It may help.

 

[Dayman88]

It's working now. I left it unplugged over night and it now it works. It seems that what ever was tripping the code just needed a long time to discharge.