I bought a Sony SA-WM500 subwoofer at an auction and it immediately blows its fuse. Both outputs of the STK404-140S show as shorted (pin 11 to 13, and pin 10 to 12). Before trying my luck on getting a reliable replacement part, I thought I'd ask here about my power supply measurements.
The schematic says to expect -58.8 VDC and +59.9 VDC. I read them at +/- 65.3 VDC. And the positive supply shows line ripple of about 50 mVpp (the negative is less than 5 mVpp).
The original STK404 spec gives +/-73V as the maximum supply voltage, with +/-51V recommended. Since these amps are known weak links, should I be concerned about driving them so close to the maximum and above the recommended? If so, is there any easy way to lower the supply voltage, which I believe is simply the rectified and filtered transformer output?
Also, does the larger ripple on the positive supply suggest I should replace that filter capacitor too?
Thanks for suggestions from those with more experience than me!
The schematic says to expect -58.8 VDC and +59.9 VDC. I read them at +/- 65.3 VDC. And the positive supply shows line ripple of about 50 mVpp (the negative is less than 5 mVpp).
The original STK404 spec gives +/-73V as the maximum supply voltage, with +/-51V recommended. Since these amps are known weak links, should I be concerned about driving them so close to the maximum and above the recommended? If so, is there any easy way to lower the supply voltage, which I believe is simply the rectified and filtered transformer output?
Also, does the larger ripple on the positive supply suggest I should replace that filter capacitor too?
Thanks for suggestions from those with more experience than me!