New here, but long time tech. Worked for an official Heathkit warranty repair station for more than ten years, long ago, then moved on up to Fluke, Tektronix, H-P test equipment repair and calibration. Now semi retired. But still have and maintain my own lab. My primary reason for registering here is to help keep as many people as possible from damaging their highly prized Heathkit W5M amps. As a repair tech for Heathkit in the 60's and 70's I replaced hundred's (you read that correctly hundred's) of power transformers in the W5M's. They did not take kindly to inrush current when first turned on. The repairs were done at Heath's expense. Along with replacing the transformer, there was an "OFFICIAL" Heathkit mod. to be added. It is by far the most valuable, and necessary, mod. to be done to these amps as it protects the power transformer from inrush surges. It consisted of placing a special, somewhat mechanical surgistor in series with the power transformer primary winding. If you own one of these amps, this mod should be checked for, and installed before you turn your amp on again, lest you take the chance of blowing the power transformer. I do not have the Heathkit part number for the surgistor, but may have a copy of the installation instructions. Also, I suspect that a more modern surgistor is probably available today. Ira.
