TA30320 & SMPS500R - help needed


2010-09-15 8:06 am
I got a TA3020 & SMPS500R from Connex. I connected the SMPS500R to the TA3020 Amp after removing the Bridge Rectifier and connecting Pin 1 to 2 and Pin 3 to 4 as in the instructions. The SMPS500R was outputting at +/- 60V DC.

When I switched on, there was a small spark. I checked the speaker outs with a multimeter & there was about 107 Volts AC relative to Earth on the speaker outs (this seems a pretty high & dangerous voltage). The TA3020 did not work at all. Hence I removed the heat shield and noticed that the Resistor R14 seem to be burnt. Further, there is now a short between AC1 and AC2 on the TA3020 power supply pins. Thus the SMPS500R goes into self-protection mode when connected to the TA3020.

The whole thing is assembled on a wooden board, no metal chassis. Is there something I'm doing wrong in the connections ? Any idea what has gone wrong with the TA3020 Amp ?

Please post some pictures, maybe can help to find the problem.
the SMPS500R has an Earth connection and is recommended to be connected for safety and low EMI. furthermore, there is a 10R resistor connected between the Earth and secondary GND which bring the GND potential close to the earh potential, and avoid GND loops. if the earth connection is not used, there is a very low leakage current < 1mA due to the Y capacitors and that's why you get ~100V AC when you measure the voltage between any point of the amp and earth. The primary side GND is completly isolated from the Earth or secondary GND, if it won't be, when you measure the voltage, will show you 220V AC or about 160V if you measure on DC domain. this is a dangerous situation, which must be avoided by keeping clear any primary section of the smps from secondary side, housing or any other wire which can touch the primary side. also, the SMPS must be earthed for safe operation.
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