JVC / Kenwood Transformer L07-3015-05

[Wooferhead]

I am looking for a transformer to replace the one inside my old subwoofer. I've looked it up online and found the model number L07-3015-05. However, the OEM model is discontinued. I am now looking for an equivalent model of transformer with the same design and spec that will work for my old subwoofer. Does anyone know anything about this transformer or its equivalent?

Here is the spec for my subwoofer:

Power Output: 150W RMS into 4 ohms / Phase Switching: Normal, Reverse / Supply Voltage: AC 110 V - 120 V / Power Consumption: 150W

 

[AnalogSteph]

Looks like with a bit of luck, there should be access to both ends of the thermal fuse which is the most likely part to have gone:

If so, you could attach a new fuse of appropriately lower rated temperature (I'm thinking about 73°C) to the outside of the xfmr with Kapton tape and connect it at S1/S2.

Transformers with dual split secondaries are generally special order. If yours is really toast, you may need to find someone to rewind it, assuming it's not potted to hell and back. Digging for a thermal fuse is generally possible but difficulty varies greatly depending on how deep it is buried.

BTW, the design of this sub scares me. They seem to be using 25 V rated filter caps (C611/612) on what has to be near enough 25 V, so I suspect the 63 V main filter caps are also going to get really close to their rated voltage. Secondaries might be 2x 35 V + 2x 18 V then. 2x 30 V + 2x 15 V may be the more sensible option long-term, especially if your mains voltage tends high.

If you manage to get the transformer repaired as outlined, make sure to measure the unregulated voltages (+/-VCC, +/-V). If your mains voltage tends high, the sub may need to live on a slight step-down or Variac. Using 25 V rated parts for C611/612 also seems irresponsible, these smaller caps are generally rated for peak, not working voltage. The big guys are probably 63 WV. (I have no idea why the voltages used to generate +/-15 V would even need to be that high. Usually you'd be using a 2x15 V~ transformer secondary for that.)

 

[Wooferhead]

Thanks for the info, AnalogSteph. Your diagram above shows a transformer 210-6415-120. Is it the same as the L07-3015-05 inside my subwoofer?