[Elecraft] KX-1 sudden decrease in power

[Albers]

When I was getting ready to check into Elecraft CW Net last night I hit the buttons to let the ATU do a quick check of the antenna and was stunned to see that the output power was only half a watt, even with the external 12V gel cell. Other observations:
- on my most recent trip I was getting 3 - 4 W
 - problem exists on all three bands
- external meter agrees
- I unplugged the ATU and installed the jumper - problem remains.
 - battery voltage 12.8 per KX-1's display
 - I exercised R4 to be sure it hadn't gone flaky on me. Output power varied smoothly, but still only .5W at max.
- I've done voltage checks on Q1, Q4, Q5 and Q6 as called for in the troubleshooting section of the manual, and all seem OK.
- Receive seems fine on all three bands

Anyone had similiar problem? Solution?
Any ideas?
73 Ray K2HYD
KX-1 #608