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Re: It'll never happen to me!

 

Hi Vic,

Remove one of the relay drive transistors and check it for reference as all on board will be from same spool.
If its is better then use that for Q90 and put a new one for the relay!

I used to do this for commercial rigs. Some rigs loose the PLL lock when they heat up and I figured the
gain in a loop was low. I just removed one from another stage and swapped them. Problem solved.

Raj

At 18/06/2021, you wrote:
Well, Raj, I just did that. I checked the Hfe of a 2N3904 with leads and it registered at 423, while the "3904" SMD devices only read 280, about the same as a 2N2222A, so I suspect this is another case of a supplier somewhere picking up any NPN and saying, sure, it is whatever you ordered! So I swapped the device with leads for the SMD and brought up the power a bit more, but it is still typically 30% or more less than it was before. A quick voltage check around the transmitter side showed all devices seemingly operating normally, although all were a bit lower than those listed in the spreadsheet on this site. That is because the main board is powered through a regulator and typically is less than 12v.

A curious observation is that the power loss is greatest on 20m, where before I had 9-12w out depending on the voltage of the source, and now it is down to 3-4w. 40 and 80 dropped from 14-15w before to 10-12 now and 10 from 3.25 to 1.5. I would have assumed an equal power drop from some common drive problem, so something else must be going on somewhere, although if I didn't have the old readings handy I would have probably thought this all looked normal.

=Vic=
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