[Elecraft] K1 Manual Errata Sheet - add these?

[Don Brown]

Hi

I agree but remember the K1, K2 and most other Elecraft products have a self resetting fuse in series with the power line. This fuse will limit the current draw to about 3 amps if there any shorts on the circuit board. It would still be a good idea to limit the power supply or fuse it to a low value for initial tests in case in the unlikely event you had a short on the connector or somewhere between the connector and the fuse. I use a bench supply with a current limit adjustment when testing a new radio or when working on a radio.

As to D19 the reason it is there is to protect the PA transistor in case you transmit into an open circuit or mis-matched antenna. All Elecraft radios have very conservatively rated finals with appropriate protection. Although I don't recommend transmitting into high SWR conditions it is nice to know the radio will take a lot of abuse with no damage.

Don Brown

KD5NDB
  ----- Original Message ----- 
  From: Mike Morrow<mailto:kk5f at earthlink.net> 
  To: k6att at juno.com<mailto:k6att at juno.com> ; elecraft at mailman.qth.net<mailto:elecraft at mailman.qth.net> 
  Sent: Friday, July 23, 2004 11:52 PM
  Subject: Re: [Elecraft] K1 Manual Errata Sheet - add these?


  Jeff wrote:

  > Page 30, column 2, box 2:  Add "Do NOT use a power supply over [3?]
  > amps as any short on the board could vaporize a trace.

  A wise man would always use a fused DC power lead, not just for initial testing but also for normal operation.  If you ever develope a DC power short, such as a shorted D19 (zener across the final PA) due to transmitting without an appropriate antenna, you'll wish you had that fuse.

  <SNIP>