[Elecraft] K2/100 - INFO 080 - Happening intermittantly

[Bill Coleman]

I'm seeing INFO 080 happen intermittantly on my K2. I'll turn it on, and 
it will work fine for several minutes to a couple of hours, then I'll 
either see either "not inst" when triggering the noise blanker, or the 
SSB vox, or get INFO 080 when switching bands.

Here's the full story:

K2 #2548 - Options: SSB, AF, NB, 160m, 100 watt amp.

Just built the 100 watt PA this last month. Have been trying out the rig 
this weekend (CQWW Phone) in preparation for Sweepstakes phone. 

Rig works fine at first. After a couple of hours of operation, I get what 
appears to be an AUXBUS failure. I'll get INFO 080 when switching bands, 
or see "not inst" when activating a noise blanker or SSB feature. This 
persists for many minutes after turning off. Could possibly be 
heat-related. When it happens, I leave the radio for several hours, and 
it comes back up just fine when switched on.

Often the radio will appear to be working just fine right before the 
failure. Indeed, after one failed band switch, I continued to operate for 
several minutes on the same band. SSB operated just fine, even though 
pressing VOX in USB caused a "no inst" indication.

Switching the radio off and then on several times results in an INFO 080 
most of the time in this state. Sometimes the relays can be heard 
switching. Other times, they are silent. Sometimes two out of three tries 
give INFO 080, and the third appears ok, only to give INFO 080 later when 
switching bands (or to give "not inst" when activating some other feature)

When it failed the first time, I disassembled the rig and tried it again 
open on the table. Since the PA is the newest module, I disconnected it 
and cycled the power -- still INFO 080. I pulled out the Control board 
CPU and the RF IOP and re-inserted. Also pulled the SSB board CPU (making 
sure I put it in right. I've put it in backwards a couple of times 
before, and that will cause INFO 080 every time)

This last failure, I disassembled the rig again. This time I removed each 
module in turn. At one point, even with all the modules removed, still 
getting INFO 080 about two out of three times.

With power off, I checked the resistance between RF U1 pin 28 and Control 
board U6 pin 40 -- 938 ohms. Powering on, checked the voltage at each 
poin. U6 pin 40 read about 5.5 v. U1 pin 28 - 6.6 v. Even with all the 
modules in, this is the case -- U1 pin 28 will read about 6.6 v. Plugging 
in the 100 watt PA reduces this to 5.6 v. 

Tried re-soldering the socket pins for the IOP, and the resonator. Still 
no good.

Firmware:
* Control board - 2.02H (supplied with PA kit)
* IOP - 1.06 (I think)
* SSB - 1.07 (supplied with PA kit)
* PA - ??? (Don't remember)

Any ideas? I need a reliable radio for contesting -- I can't have the rig 
die in the middle of Sweepstakes! 

Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901