On Mar 15, 2023, at 9:15 PM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:

?

The fact that these 50-60 year old radios have continued running well on the parts that they were made from is a testament to their overall good design.?

Most of the problems appearing in these sets today are due to long-term ageing of the components.?

IMO, in most — but not all — situations, the original parts specs have served very well. When we replace an original part, most of us?will be long-gone before it will need replacement again.?

You won’t go wrong replacing like with like.?

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent from Proton Mail for iOS

On Wed, Mar 15, 2023 at 20:45, Rick WA6III <myr748@...> wrote:

Even at? 400ma (total) cathode current, those 15Ω cathode resistors (@200ma ea)? would only dissipate (I²R) about 0.6W

Since no one (ever) operates a T4X key down at 400ma , 1W cathode resistors would have more than enough headroom....

6JB6 screen current per tube would have to be over 120ma for the screen resistor to dissipate 1w.? Somehow I think the screen current is a fraction of 120.

Just looked on eBay and found 15Ω, 68Ω 1% 1w film type resistors for something like $3 and free shipping.

"10 Pieces 1 Watt 1% metal film resistors Over 200 Various Value YOU CHOOSE"

And if you want higher power ......

"10Pcs 5W 5 Watt Metal Film Resistor ±1% 0.1 - 91 Ω Ohm 0.1 R to 91 R 6*17MM"

Just do a search for the above text on eBay.

Cheers,

Rick

--

73/Rick

WA6III
*Every post is created using Linux