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Any hope left for the repair of this ?

 

Got the unit of someone who attempted to replace IC407 on their own. The board isn’t looking great. Just wanted the opinions of potential repair people better than myself
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the unit still turns on but of course gets stuck at initialising audio
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Daniel ZL2DTL/ZL4YOTA?
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Hello Daniel,
cleaning the existent pads using flux and desolder braid should be easy. Than check if the yellow capacitors are well connected, solder if not. (C431 looks like desolderd.) The ripped pad is for pin 21 and regarding to the schematics not connected to anything. So this should be no problem. Solder a new IC and it should be ok (if no other problem exists).
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73 Ludwig
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This can be fixed. ?The missing pad is no problem. ? Pin 21 has no connection. ?

Clean with flux and solder braid carefully. ?Inspect everything else under magnification and solder in a new pcm1804. ?This looks daunting but if you have good magnification and solder skills, it can be done. ?I’ve fixed far worse for other hams.
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good luck.
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73
Jeff Moore
W1NC
 

Hi,?

Cleaned with flux/solder braid but still a short between pin 7+8, and another crossing 10-13 remain. I imagine this was damaged when the chip was removed and scratched the board. However, and do correct me if I am mistaken, all of these pins are just grounded anyways so it should not be problematic??

I've never seen a QMX in quite this state, every time I have previously replaced these chips they have arrived to me with no repair attempted and it is time consuming but not beyond my ability to change. This definitely threw me off seeing the damage on the board.?

Thanks for the help all.?
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Daniel ZL2DTL/ZL4YOTA?
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On Sun, Feb 23, 2025 at 07:43 AM, Daniel ZL2DTL wrote:
still a short between pin 7+8, and another crossing 10-13 remain.
Daniel, that's fine. Please check the schematics for IC407. Pin numbers 1 to 14 are going at the left side top down und 15 to 28 at the right side bottom-up. Pins 7, 8 and 10 to 13 are all connected to GND.
You should find also a GND at pin 23 and 27 and a connection between pin 6, 9 and 22 all connected to VCC via L402.
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73 Ludwig

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