Don Wilhelm W3FPR gave the me answer for fixing my K2/100. He suggested I replace D16 and D17, as they may have gone bad without failing open or shorted.
It took a while to get the parts from Mouser. But these 1N5711 diodes were only $0.10 apiece. So, I bought 10 in order to have some spares.
Replacing D16 and D17 did the trick. I managed to test one of the diodes I removed (the other was destroyed in the desoldering process), and it showed a nearly correct forward voltage on my DVM, and about 3 times that value when connected in reverse. The diode action of the part was clearly compromised. A new part gave a low forward voltage, and an open when connected in reverse.
I suspect these diodes, and possibly the EL5146C might have been damaged by a stray static discharge sometime in the last year. Perhaps a good thing to have on hand -- although Don did indicate that 1N4148 diodes would work OK as a temporary substitute.
With the new diodes in place, the SWR Null Adjustment went well, giving a clear null down below 100 mV. More importantly, it read an SWR of 1.0 on all bands.
The rest of the alignment went smoothly, and the rig appears to be producing the correct power levels on all bands. Made a quick contact with HA8RM on 80m to confirm the rig is working again. I think it is cured.
Wednesday, September 12, 2012
Sunday, September 9, 2012
Fixing the Broken K2/100
Well, it's been slow going for my ailing K2. I put the tested U5 - 78L05 back in the board and cut pin 7 of U6. The KPA100 once again responded to the main K2.
I replaced U6 with a machine pin socket, and after waiting another week, I finally got the part from Elecraft.
With U6 replaced, I went through the KPA100 alignment steps. First problem was the SWR Bridge Null Adjustment. While I could get a clear null, the display never showed anything less than 1.1 SWR on 40m.
Next to the Power Calibration. This went fine as well, but when I checked the SWR on all the bands, I received a 1.8 SWR on 80m, and 2.6 on 160m. The highest bands gave a 1.0 indication, but most of the others were 1.1, just like 40m.
I double-checked my dummy load with my external watt meter. It appears they are 1.0 on all bands.
A bit after this, I did some full-power tests:
* 40m - K2 indicates about 70 watts (7 bars), but the external watt meter shows 100 watts
* 80/160m - K2 indicates about 50 watts (5 bars), and sometimes I get a Hi Cur warning. The external watt meter shows 100 watts, or perhaps a little more.
Something is obviously wrong with the power measurement circuits here.
Elecraft suggests that the D16 and D17 diodes are "half bad" -- that is they have been damaged enough to change their characteristics, but not enough to fail open or shorted. Next step is to replace them.
I just got the parts from Mouser this weekend. We'll try more repair work this week. It would be very nice to get the K2/100 up and running again. I'm guessing there might have been some damage from an electro-static discharge of some kind.
I replaced U6 with a machine pin socket, and after waiting another week, I finally got the part from Elecraft.
With U6 replaced, I went through the KPA100 alignment steps. First problem was the SWR Bridge Null Adjustment. While I could get a clear null, the display never showed anything less than 1.1 SWR on 40m.
Next to the Power Calibration. This went fine as well, but when I checked the SWR on all the bands, I received a 1.8 SWR on 80m, and 2.6 on 160m. The highest bands gave a 1.0 indication, but most of the others were 1.1, just like 40m.
I double-checked my dummy load with my external watt meter. It appears they are 1.0 on all bands.
A bit after this, I did some full-power tests:
* 40m - K2 indicates about 70 watts (7 bars), but the external watt meter shows 100 watts
* 80/160m - K2 indicates about 50 watts (5 bars), and sometimes I get a Hi Cur warning. The external watt meter shows 100 watts, or perhaps a little more.
Something is obviously wrong with the power measurement circuits here.
Elecraft suggests that the D16 and D17 diodes are "half bad" -- that is they have been damaged enough to change their characteristics, but not enough to fail open or shorted. Next step is to replace them.
I just got the parts from Mouser this weekend. We'll try more repair work this week. It would be very nice to get the K2/100 up and running again. I'm guessing there might have been some damage from an electro-static discharge of some kind.
Saturday, August 11, 2012
HK0NA
Delighted to find confirmations on LotW from HK0NA on Friday. Worked them back in late January and February on 160-10m, all three modes - CW, Phone, RTTY.
It's a great feeling to go from not having a country confirmed at all, to having them confirmed on nine bands and three modes. Kudos to the DXpedition team for uploading to LotW so soon after the event.
It's a great feeling to go from not having a country confirmed at all, to having them confirmed on nine bands and three modes. Kudos to the DXpedition team for uploading to LotW so soon after the event.
Friday, August 3, 2012
Broken K2/100
OK. At least I know what's wrong. It appears that one of the chips on the KPA100 fed by the 78L05 has failed and is drawing so much current that the regulator only puts out about 1 volt.
It isn't U1 -- the PIC chip that runs the KPA100. That one is at least socketed and was easy to remove and test with it out of the circuit. And it isn't U3 -- the 78L05 regulator. I pulled it off the board and tested it, it works OK.
It is either U4 -- the MAX1406C chip, or U6 -- the EL5146. My bet is on the EL5146. Now to order parts....
It isn't U1 -- the PIC chip that runs the KPA100. That one is at least socketed and was easy to remove and test with it out of the circuit. And it isn't U3 -- the 78L05 regulator. I pulled it off the board and tested it, it works OK.
It is either U4 -- the MAX1406C chip, or U6 -- the EL5146. My bet is on the EL5146. Now to order parts....
Monday, July 23, 2012
NAQP RTTY from Floyd County
Had a very limited time to operate the NAQP RTTY, due to other commitments in the evening.
During the IARU, my K2/100 had been acting up with an INFO 080 problem. I attempted to diagnose the issue further on Saturday morning, but no dice. I remove several boards, replacing them with Rework Eliminators, but the rig just seemed to get sicker. It refused to recognize the KPA100 at all, and even with it disconnected, the radio didn't sound right, and gave "not instd" on several options that were still installed. My K2/100 is a very sick radio right now.
So, I had to fall back on the venerable Kenwood TS-430S. I bought this rig new in the fall of 1985, and it has always given me reliable service. It was never designed for RTTY or computer control. (That being the role of it's successor, the TS-440S) But, an old rig is better than no rig, despite having to manually change bands in the logging software.
It was great to hear signals on 10m, and 15m open as well. Had a lot of fun S & Ping between stations. I tried several times to CQ on 20 and 15m, but only one station answered me. A few people I tried to answer CQed in my face. As a result, I'm contemplating moving the R7000 further up the hill, or perhaps hanging up some real antennas.
It seemed like conditions were generally good, just not a tremendous amount of activity. Still, plenty of fun. CU in the next NAQP.
Class: Single Op LP
QTH: GA
Operating Time (hrs): 3.2
Summary:
Band QSOs Mults
-------------------
80: 0 0
40: 1 1
20: 33 21
15: 21 19
10: 12 7
-------------------
Total: 77 48 Total Score = 3,696
Club: South East Contest Club
Comments:
Antennas:
R7000 at 3m high (10-40m)
80/40m trap dipole at 3-4m high (80m, 40m)
Equipment:
Venerable Kenwood TS-430S w/ AT-250 running 75-80 watts
During the IARU, my K2/100 had been acting up with an INFO 080 problem. I attempted to diagnose the issue further on Saturday morning, but no dice. I remove several boards, replacing them with Rework Eliminators, but the rig just seemed to get sicker. It refused to recognize the KPA100 at all, and even with it disconnected, the radio didn't sound right, and gave "not instd" on several options that were still installed. My K2/100 is a very sick radio right now.
So, I had to fall back on the venerable Kenwood TS-430S. I bought this rig new in the fall of 1985, and it has always given me reliable service. It was never designed for RTTY or computer control. (That being the role of it's successor, the TS-440S) But, an old rig is better than no rig, despite having to manually change bands in the logging software.
It was great to hear signals on 10m, and 15m open as well. Had a lot of fun S & Ping between stations. I tried several times to CQ on 20 and 15m, but only one station answered me. A few people I tried to answer CQed in my face. As a result, I'm contemplating moving the R7000 further up the hill, or perhaps hanging up some real antennas.
It seemed like conditions were generally good, just not a tremendous amount of activity. Still, plenty of fun. CU in the next NAQP.
Class: Single Op LP
QTH: GA
Operating Time (hrs): 3.2
Summary:
Band QSOs Mults
-------------------
80: 0 0
40: 1 1
20: 33 21
15: 21 19
10: 12 7
-------------------
Total: 77 48 Total Score = 3,696
Club: South East Contest Club
Comments:
Antennas:
R7000 at 3m high (10-40m)
80/40m trap dipole at 3-4m high (80m, 40m)
Equipment:
Venerable Kenwood TS-430S w/ AT-250 running 75-80 watts
IARU 2012
I had set up the K2/100 the night before and everything appeared to be working fine. Got into the shack just after 1200z, and when I went to change the antenna connection, it got a "not instd"response. It was pretty evident that the K2/100 is not talking to the KAT100. Tried switching the cable, turning the system on and off many times, still the same thing.
Soon I'm getting an INFO 080 error, which every K2 owner knows means that the main microcontroller can't talk to the other microcontrollers in the rig.
30 minutes into this, I still haven't worked a contact. It's clear that I have no clue what is wrong with the K2, so I go with plan B -- the venerable TS-430S. I bought this rig in the fall of 1985, just before Kenwood came out with the TS-440S. It's served me quite well. No computer control, though, so every band change is a manual event.
Worked about 5 hours, off and on. Conditions were OK. A bit sparse on 10m. 15m sounded good. I'm thinking I need a better antenna than the R7000. There were a couple of HQ stations who couldn't really hear me. Definitely more of a struggle to make contacts on phone than CW.
Soon I'm getting an INFO 080 error, which every K2 owner knows means that the main microcontroller can't talk to the other microcontrollers in the rig.
30 minutes into this, I still haven't worked a contact. It's clear that I have no clue what is wrong with the K2, so I go with plan B -- the venerable TS-430S. I bought this rig in the fall of 1985, just before Kenwood came out with the TS-440S. It's served me quite well. No computer control, though, so every band change is a manual event.
Worked about 5 hours, off and on. Conditions were OK. A bit sparse on 10m. 15m sounded good. I'm thinking I need a better antenna than the R7000. There were a couple of HQ stations who couldn't really hear me. Definitely more of a struggle to make contacts on phone than CW.
Operating Time (hrs): 5 Summary: Band CW Qs Ph Qs Zones HQ Mults ------------------------------------- 160: 0 0 0 0 80: 0 0 0 0 40: 0 0 0 0 20: 29 5 6 9 15: 48 17 11 11 10: 6 1 2 1 ------------------------------------- Total: 83 23 19 21 Total Score = 10,240 Club: South East Contest Club Comments: Antennas: R7000 at 3m high (10-40m) Equipment: Venerable TS-430S w/ AT-250 running 100 watts
Thursday, June 28, 2012
Field Day 2012
Somehow, I hurt my back. Well, I say somehow, but I know how. I over-did it at karate. It's hard when a 51-year-old man tries to keep up with the teenagers. Too much jumping and kicking, and I ended up in so much pain the Thursday before Field Day that I could barely stand.
Fortunately, I managed to get it under control by Field Day and work some stations from the Micro-shack. I started by putting the 80/40m dipole back up. A rope had frayed in two where it went over a branch. An hour's worth of work and that end was once again up in the trees. I spent some time raising the other end and managed to get it a couple of meters higher.
I used the Elecraft K2/100. The K2 is really designed for field day. It worked out really well. I borrowed a 12v deep-cycle battery from my camping trailer to operate class 1E. I did end up getting a Low Batt indication after about 3.5 hours, but I reduced power to 50 watts and continued one.
Conditions weren't great. I found nothing on 10m, very little activity on 15, which means everything was crammed onto 20 and 40m. At one point, I could not find a clear frequency on 40m CW -- there were signals every 200-300 Hz. It almost sounded like 160m during the ARRL 160m contest.
Managed to do a bit of running, but this one was mostly S & P. I must say that field day operating technique is significantly below the standard of most contests. There were several occasions where I was calling CQ, someone called, I answered, and they disappeared. It even happened a couple of times when someone else called CQ. I guess people got key (not mic) fright.
Took one break to take my wife out to dinner. About 0300z, my back had had enough of sitting and I had to pull the plug. Maybe next time, I'll be able to stay up a bit later and work more on 80m.
Two memorable contacts. Worked W4DOC -- the Atlanta Radio Club, with whom I have done innumerable field days. Also worked W8SP -- a club which my brother Ben, NJ8J, used to join for field day in WV. I had never worked W8SP before.
Call: AA4LR
Operator(s): AA4LR
Station: AA4LR
Class: 1E LP
QTH: GA
Operating Time (hrs): 5.5
Summary:
Band CW Qs Ph Qs Dig Qs
----------------------------
160:
80: 3
40: 119 5
20: 54 18
15: 10 3
10:
----------------------------
Total: 186 26 0 Total Score = 896
Club: South East Contest Club
Fortunately, I managed to get it under control by Field Day and work some stations from the Micro-shack. I started by putting the 80/40m dipole back up. A rope had frayed in two where it went over a branch. An hour's worth of work and that end was once again up in the trees. I spent some time raising the other end and managed to get it a couple of meters higher.
I used the Elecraft K2/100. The K2 is really designed for field day. It worked out really well. I borrowed a 12v deep-cycle battery from my camping trailer to operate class 1E. I did end up getting a Low Batt indication after about 3.5 hours, but I reduced power to 50 watts and continued one.
Conditions weren't great. I found nothing on 10m, very little activity on 15, which means everything was crammed onto 20 and 40m. At one point, I could not find a clear frequency on 40m CW -- there were signals every 200-300 Hz. It almost sounded like 160m during the ARRL 160m contest.
Managed to do a bit of running, but this one was mostly S & P. I must say that field day operating technique is significantly below the standard of most contests. There were several occasions where I was calling CQ, someone called, I answered, and they disappeared. It even happened a couple of times when someone else called CQ. I guess people got key (not mic) fright.
Took one break to take my wife out to dinner. About 0300z, my back had had enough of sitting and I had to pull the plug. Maybe next time, I'll be able to stay up a bit later and work more on 80m.
Two memorable contacts. Worked W4DOC -- the Atlanta Radio Club, with whom I have done innumerable field days. Also worked W8SP -- a club which my brother Ben, NJ8J, used to join for field day in WV. I had never worked W8SP before.
Call: AA4LR
Operator(s): AA4LR
Station: AA4LR
Class: 1E LP
QTH: GA
Operating Time (hrs): 5.5
Summary:
Band CW Qs Ph Qs Dig Qs
----------------------------
160:
80: 3
40: 119 5
20: 54 18
15: 10 3
10:
----------------------------
Total: 186 26 0 Total Score = 896
Club: South East Contest Club
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