I installed the zener diodes today in my older non R model 275 watt ZW. The bottom line, it works great. My PW tenders and modern tenders sound just like they should, loud regardless of speed. Also no speed change when whistle is energized.
It’s not very hard to do; it took me about 90 minutes to do both sides. Well worth the cost and time.
I picked up my ZW at a show 2 weeks ago for $100.00 then I replaced the rollers, internal circuit breaker and now the diodes. It had a new AC cord.
All I have left to do is install four 8 amp circuit breakers and four TVS on the output and I’m done.
Greg
