[Elecraft] Common K3 failure modes???

[Geert Jan de Groot]

On 27/06/2022 20:39, elecraft-request at mailman.qth.net wrote:
> Four categories:
 > ....

I didn't want to start a flame fest, but I was trying to find what mods 
one should do as a preventive measure. Buying the input-diodes that fail 
on very strong input signals (discussed on the list) is one thing.
Protecting the LPA amplifier (the extra diodes) is a good and simple 
investment too - took me all of 10 minutes to install them.

Comments about the 8V regulator - I bookmarked these messages, assuming 
that an 7808 voltage regulator should be obtainable.
Thanks for the other comments - I think my radios are now in a 
reasonable shape against known mishaps.

Several other mods (like "gold pins") have been published and should be 
considered known.

Scarcity is another issue, and it's big. Elecraft often uses Microchip 
controllers in their radios (I don't know about the K4. but for older 
models this is true).
I have been trying to buy various Microchip processors for other 
projects and for many, stock has completely dried up with 
www.microchipdirect.com quoting availability end of 2023 for many 
popular devices. I don't know if Elecraft has had sufficient parts stock 
for their production, but it is likely that redesigns would be needed 
otherwise (Wayne has commented on this happening on the K4 a few times).

I wonder if the "last run of K3 modules" is also affected by this, 
explaining the long lead time on these modules.

Over the years there has been a mix of modifications, partially already 
solved in new production runs, etc. For instance, recently learned about 
the "hardware AGC" mod that I didn't know about - when I opened up my 
radio I found that the "modification" had been fixed in a later RF board 
revision and hence my radio already had this modification.

In that regard, I've suggested that Elecraft gives each K4 hardware 
modification a number, and to put a sticker inside the radio: "mod 01, 
02, 03, 05 done" so one doesn't need to investigate if a mod applies to 
a certain radio revision. I have not seen any hardware mods for K4 yet, 
so either they aren't happening (lucky!) or this is handled some other 
way. But, if you buy a radio second-hand, a sticker structurally showing 
what mods have been "done" would have been very nice.

Geert Jan