ACA500Plus transistor blown

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Don't Panic. Please wash hands.

    Hello!


    I have an ACA500Plus I bought some years ago. I did not used it for years. Yesterday I decided to take it for a ride and unfortunetely a transistor blew up. I plan to fix it myself, it is component Q1 on the circuit board and It is near Aux Card Slot. I was using a 4gb Hitachi Microdrive, never had any problem, but yesterday I a connected my Amiga to a GBS-C Upscaller and noted that the system started to have what appear to be power supply issues and then smoke. Maybe unbalanced ground/circuit reference. Anyways I digress.


    Can you please tell me what is exactly component Q1 on ACA500Plus board for Amiga 500 (is it a bc850c transistor)? As I said it blew up, and I cannot see any reference. I suppose it is the same as Q2 or Q3. Q2 and Q3 are marked as "2GW" - this is manufacturer specific, so I can only guess.


    The card works, aux slot does not read anymore.


    I am seding attached photos.

    Thank you for your help in advance!!! Regards!

    Luiz Eduardo Giampaoli

    Q1 is a FET, type IRLML5203. This is available from different vendors, and to cover all of them, you should check that R6 is 1k - it's best if you just replace that as well if you're replacing Q1.


    Q2 my also be defective, as that's a low-side transistor that discharges the caps inside the CF card. This is a BC850C. It will pull the CF card power line to GND through R12, which is 220R.


    R2 (which also looks damaged) is the LED resistor for the CF card LED, and that's also 220R. All resistor sizes are 0603, and Transistor/FET packages are SOT23.


    Jens

    Hello Jens,


    Thank you! I will buy the parts. I found the BC850C and resistors here in my hometown Porto Alegre/Brazil. The IRLML5203 I am importing from China.


    I am mainly a software developer with strong interest in hardware integration and IoT, but electronics is basically a sporadic "hobby". Nevertless I will venture and try to fix it. I even bouth an Adonstar AD210 microscope.


    Wish me luck, I will keep the forum posted with the results wherever good or bad...


    Regards and thank you again,

    Luiz Eduardo Giampaoli

    Hello!


    I am writing this to provide a feedback: I am happy to say that I was able to fix the board. Now the aux slot works again, I was even able to update my ACA500 plus menu and installer.


    By the way: the new auto installer is very easy to use. I had't have used that yet until now.



    Thank you again,

    Luiz Eduardo Giampaoli