Bad capacitor in plate amplifier.

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   Hi team.
I have a Mackie HD1801 subwoofer with a faulty amplifier module. The unit switches on as per normal, then produces volume for a while and then goes into thermal protection mode. I opened the module up and have identified a capacitor that seems to be arcing across the board upon start up. Some other points -

- The capacitor doesn't arc if you switch the power off and turn it back on within a short time frame (3-5 seconds). Is this because the capacitor is still holding a charge?
- The board is slightly burnt and the solder probably needs redoing.

Should I try re-soldering or do you think I need to replace the capacitor?

I am a novice at this sort of thing, any help appreciated!

Cheers

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partya Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 06 September 2013 Location: New Zealand Status: Offline Points: 112	Post Options Post Reply Quote partya Report Post Thanks(0) Quote Reply Topic: Bad capacitor in plate amplifier. Posted: 03 February 2025 at 1:34am
	Hi team. I have a Mackie HD1801 subwoofer with a faulty amplifier module. The unit switches on as per normal, then produces volume for a while and then goes into thermal protection mode. I opened the module up and have identified a capacitor that seems to be arcing across the board upon start up. Some other points - - The capacitor doesn't arc if you switch the power off and turn it back on within a short time frame (3-5 seconds). Is this because the capacitor is still holding a charge? - The board is slightly burnt and the solder probably needs redoing. Should I try re-soldering or do you think I need to replace the capacitor? I am a novice at this sort of thing, any help appreciated! Cheers
	Turn it up! Turn what up?

kedwardsleisure Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 20 January 2009 Location: Staffordshire Status: Offline Points: 5157	Post Options Post Reply Quote kedwardsleisure Report Post Thanks(0) Quote Reply Posted: 03 February 2025 at 9:44am
	looks like a dry joint. I would carefully desolder and remove the capacitor, examine the tracks on the other other side, clean everything up and refit it. The vibration shakes them loose, they're normally fitted with silicone sealant. Make sure it's discharged before touching it
	Kevin North Staffordshire

partya Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 06 September 2013 Location: New Zealand Status: Offline Points: 112	Post Options Post Reply Quote partya Report Post Thanks(0) Quote Reply Posted: 03 February 2025 at 7:17pm
	Thank you very much for your reply. I will try this fix and see how it goes. These subs have been good so are worth fixing!
	Turn it up! Turn what up?