Electronics > Beginners
Beginners Road To Repair
don@cascadefellowship.org:
--- Quote from: CJay on June 26, 2018, 05:54:32 pm ---There are two connectors from the 'regulator' board to the main board, disconnect those and see if the short disappears.
I have a suspicion it won't.
There are two yellow blobs on the regualtor board near the jack inputs, they're tantalum capacitors, C29 and the other next to the QC sticker.
I would be desoldering those if the short doesn't disappear when you unplug the main board.
--- End quote ---
I have disconnected the two boards and the short remains. I've taken the 7812 off the board and the short remains. I'll pop the C29 and C46 capacitors off the board (testing after each one) to see if the short remains.
CJay:
If nothing else we may have isolated the fault to the smaller board so that's just made the problem a lot simpler to troubleshoot as there are far fewer parts on it :)
Hopefully it's one of the two tantalum caps.
If that doesn't sort the problem out then it would be useful to be able to see the track side of the board as well as a decent close up of the top side, it helps us as we can trace the circuit out then and make better suggestions :)
don@cascadefellowship.org:
--- Quote from: CJay on June 26, 2018, 05:54:32 pm ---There are two connectors from the 'regulator' board to the main board, disconnect those and see if the short disappears.
I have a suspicion it won't.
There are two yellow blobs on the regualtor board near the jack inputs, they're tantalum capacitors, C29 and the other next to the QC sticker.
I would be desoldering those if the short doesn't disappear when you unplug the main board.
--- End quote ---
I have removed both tantalum capacitors and the short remains between ground and output of 7812.
CJay:
OK, just spotted another tantalum (they're nasty little things prone to shorting out so they're the first place to look if you spot them), it's next to the leftmost switch, I think it's C32, lift that one.
Be aware they're polarity sensitive and will need to go back in the same way round. .
Can you post a pic of the track side of the board please?
don@cascadefellowship.org:
--- Quote from: CJay on June 26, 2018, 06:53:39 pm ---OK, just spotted another tantalum (they're nasty little things prone to shorting out so they're the first place to look if you spot them), it's next to the leftmost switch, I think it's C32, lift that one.
Be aware they're polarity sensitive and will need to go back in the same way round. .
Can you post a pic of the track side of the board please?
--- End quote ---
I've removed the third tantalum and the short remains. I did not pay attention to their polarity when removing them. I assume I can test for polarity? Here are the closeups of the board. I'll have to post them in three posts (two pics to a post). I just noticed something. Take a look at the ground pin hole of the 7812. There seems to be another component hole right next to it and they're both connected by solder (there was no component in this other hole).
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