[GreenKeys] W9DDD

[Jim W7RY]

Both of these TUs were designed and sold in the mid 1970s when the 
nominal line voltage was 120 volts. Just like today.

Not sure your theory holds up?

But perhaps.

Jim W7RY


On 2/20/2025 6:07 PM, Tom Hunter wrote:
> John,
>
> I don"t know which came first - the Heathkit HD 3030 or thr Flesher 
> TU-470.
>
> But they are absolutely identical to the extent that I took the power
> transformer out of a dead TU-470 and put it in an otherwise good Heathkit.
> It worked perfectly.  Both have internal loop supplies.
>
> Note: these old TU's don't like today's line voltages. That is how
> the transformers burn out. I have to run them on an eBay bucking
> transformer. They are very happy that way.  My FlesherTU-170
> runs noticeably cooler too. The bucking transformer was well
> worth the 90-some dollars.
>
>
> Tom   N3CRK
>
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