Circle it next time.. near bottom of pic, just right of center.
Are you sure it was even installed normally?
Are you sure it was even installed normally?
Can you take a closer pic of just that area and possibly remove the mezzanine pcb on top board to get a picture of the same area on the top of main board?
Thanks, PapaZBill. Perry helped identify the part.
However, I have a whine coming from the PS transformer
However, I have a whine coming from the PS transformer
Despite whine is the amp working? Rails present, Class D switching , output?
Is the whining such that it would be audible, with the cover on?
Can you physically twist the transformer and whine changes or temporarily drops out? The transformer is firmly in seated, so this may not be possible, although the secondary windings will have some play.
One thought occurs to me C22-2nF may be drifting or slightly out of spec. This is the integrator cap that forms the sawtooth for IC20-UC3843 PWM. If it is too far out of spec or cracked it will cause P.S. mosfets to fail.
If you do change out C22 be sure to use COG/NPO rated sm.
Is the whining such that it would be audible, with the cover on?
Can you physically twist the transformer and whine changes or temporarily drops out? The transformer is firmly in seated, so this may not be possible, although the secondary windings will have some play.
One thought occurs to me C22-2nF may be drifting or slightly out of spec. This is the integrator cap that forms the sawtooth for IC20-UC3843 PWM. If it is too far out of spec or cracked it will cause P.S. mosfets to fail.
If you do change out C22 be sure to use COG/NPO rated sm.
Amp produces both rail and classic switching.
No, not audible when casing on.
As stated, the transformer is firmly seated.
Pushing and pulling on it doesn't change the whine.
What would u consider drift off spec? My readings are 3nf to 4nf.
No, not audible when casing on.
As stated, the transformer is firmly seated.
Pushing and pulling on it doesn't change the whine.
What would u consider drift off spec? My readings are 3nf to 4nf.
Did you test C22 out of circuit?
If you have an accurate LCR meter or DVM or if your not sure replace C22-2nF.
If you have an accurate LCR meter or DVM or if your not sure replace C22-2nF.
Yes, tested capacitor out of circuit.
I use a Fluke 175.
Unfortunately, none of the suppliers carry that particular value. If they do, I would have to buy it on Reel.
I use a Fluke 175.
Unfortunately, none of the suppliers carry that particular value. If they do, I would have to buy it on Reel.
I checked the BOM and found C22 is an X7R 0805 50Vdc 10%. Below are two links from Mouser. I may have misspoke about the COG rating for this amp. I have found that must of our amps are more reliable because of the COG rating for this cap.
https://www.mouser.com/ProductDetail/KYOCERA-AVX/08055C202KAT2A?qs=DPHdWjo8guMgcMFXuJBCTw==
https://www.mouser.com/ProductDetail/581-08055A202JAT2A
https://www.mouser.com/ProductDetail/KYOCERA-AVX/08055C202KAT2A?qs=DPHdWjo8guMgcMFXuJBCTw==
https://www.mouser.com/ProductDetail/581-08055A202JAT2A