Sinbosen d2 3000 amplifier repair

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   I am having a look at an amplifier from my friends rig. It is a sinbosen d2 3000 (chinese) type class d 1u amplifier. It has been faultless for years and defo delivered plenty of power into 2 or 4 ohms. It is specced at 3k at 8 ohms and 5k into 4 ohms, 7k into 2 ohms. It has previously run 4x 18" 1000w drivers no sweat and seemingly has endless headroom. 
Anyhow, it has blown an amp channel and I am not sure why. Suspiciously he has also blown a qsc pl4 on one channel around the same time powering the same ohm pukk 218s. I have tested all speakers and cabs with a meter for short etc and can find nothing amiss. I was expecting to find a short. 

I have inspected the board, it is a modular design and the power supply and one channel work.fine. the damaged channel has a visibly blown IXYS mosfet and a damaged 104j ceramic capacitor. The pcb is intact and undamaged. I have tested the mosfets with a meter and can find 2 that teet faulty. I am not an electronics engineer but have a basic understanding. What else is likely to have blown? What's the chance I replace the 2x mosfets and damaged caps and it works? 

Regards
Nathan

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Natedub Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 07 January 2013 Status: Offline Points: 135	Post Options Post Reply Quote Natedub Report Post Thanks(0) Quote Reply Topic: Sinbosen d2 3000 amplifier repair Posted: 11 May 2024 at 12:02pm
	I am having a look at an amplifier from my friends rig. It is a sinbosen d2 3000 (chinese) type class d 1u amplifier. It has been faultless for years and defo delivered plenty of power into 2 or 4 ohms. It is specced at 3k at 8 ohms and 5k into 4 ohms, 7k into 2 ohms. It has previously run 4x 18" 1000w drivers no sweat and seemingly has endless headroom. Anyhow, it has blown an amp channel and I am not sure why. Suspiciously he has also blown a qsc pl4 on one channel around the same time powering the same ohm pukk 218s. I have tested all speakers and cabs with a meter for short etc and can find nothing amiss. I was expecting to find a short. I have inspected the board, it is a modular design and the power supply and one channel work.fine. the damaged channel has a visibly blown IXYS mosfet and a damaged 104j ceramic capacitor. The pcb is intact and undamaged. I have tested the mosfets with a meter and can find 2 that teet faulty. I am not an electronics engineer but have a basic understanding. What else is likely to have blown? What's the chance I replace the 2x mosfets and damaged caps and it works? Regards Nathan

snowflake Members Profile Send Private Message Find Members Posts Add to Buddy List Old Croc Joined: 29 December 2004 Location: Bristol Status: Offline Points: 3443	Post Options Post Reply Quote snowflake Report Post Thanks(0) Quote Reply Posted: 11 May 2024 at 3:07pm
	can't advise on the repair, but have you also checked all speaker cables for a short?

Natedub Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 07 January 2013 Status: Offline Points: 135	Post Options Post Reply Quote Natedub Report Post Thanks(0) Quote Reply Posted: 12 May 2024 at 4:47pm
	Yes, thanks, first thing I did was get them to quarantine the cables and speakers tested everything with a meter and all is fine. They are now using it all with another amplifier with no issues. It's a bit concerning not knowing why.

Natedub Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 07 January 2013 Status: Offline Points: 135	Post Options Post Reply Quote Natedub Report Post Thanks(0) Quote Reply Posted: 12 May 2024 at 4:49pm
	From what I can gather it is internally identical to the CVR D3002

stitchie Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 12 March 2024 Status: Offline Points: 19	Post Options Post Reply Quote stitchie Report Post Thanks(0) Quote Reply Posted: 11 June 2024 at 2:32pm
	Have also been told these are very good amps, what model would people use to power 4x 18" 1000w scoops sub bins? anyone using one in Midlands area where it could be possible to hear it in action? TIA

HumbleDeer Members Profile Send Private Message Find Members Posts Add to Buddy List Registered User Joined: 04 May 2017 Location: Belgium Status: Offline Points: 35	Post Options Post Reply Quote HumbleDeer Report Post Thanks(0) Quote Reply Posted: 19 November 2024 at 11:57pm
	Check the respective opposite polarity transistors as well; check them both for shorts as well as damage to the body diode (the diode that runs antiparallel). Use the back of a small screwdriver to very lightly tap on any ceramic capacitors of the same type or purpose if they're a capacitor across the mosfets. See if any start to spontaneously fly apart of the likes. If not, just replace the mosfets and start the amp up with a current limiter in series. They generally protect themselves very well. The two amps blowing may merely be a coincidence until proven otherwise. I don't see anything being wrong that would not already be otherwise obvious to the user of the speakers.