[Elecraft] KXPA100 SN 707 Total Frustration with this Amp

[rldillon at aol.com]

Upfront this email is long and outlines the frustrations with this amp that I have never encountered with another piece of new Ham Equipment in my 27 years of being licensed.

First indication of Problem:

I received this amp on 27 Feb at 10:55 when the situation started. I unpacked the items and laid them out on the table with an anti-static mat in place. As I inventoried the items, I discovered that I had two back plates and no face plate. I started assembly of the amp and noticed that the hex nut for the RS232 (PC) connector was missing. I looked in the parts bag and it was not there either. I sent an email to parts at Elecraft and received a phone call asking to describe what was missing. I described in detail what was missing and received a promise that correct parts would be shipped.

Front Plate and hex nut were shipped via USPS on 3 March and received in WV on 5 March. I installed the front plate and then opened the small envelope with the hex nut. It was the wrong one. I sent another email to Parts at Elecraft with an attached picture showing that the part sent was the wrong one.

The correct part was shipped 6 Mar and received 8 Mar. I installed and hooked up the amp today (see comments below for todays adventure).

What has really caused the frustrations with this amp.

After the weekend ARRL Contest, I hooked the amp to the KX3 per the manual by setting Tun Power to nor and PA MODE to on. The amp immediately came to life. I adjusted the power knob and noticed that the power was now showing what the amp would output versus the KX3 power. There was station on 20 RTTY that I wanted to work so I set the output power to 45 watts which would drive the AL80B to just between 400 to 500 watts. Tuner after the AL80B is a Palstar AT4K into a Hexx Beam with an swr of 1.2 on 20M with tuner bypassed. I started up kcomm and entered the stations call. I heard the AL80B amp keying each time I sent my call. I tried several times with no contact with the station calling CQ. I keyed again and noticed that the al80B was only showing about 30-40 watts instead of 4-500. I immediately stopped sending call and exited kcomm, started the KXPA utility program and found the fault table. It showed several faults for hi swr of 99.9:1. How do you get an swr this high into an antenna with an swr of 1.2? I went back into the kx3 menu and turned off PA mode. I then set kx3 power to 10 watts and keyed with amp turned off. SWR showing on KX3 was 1.3. I turned amp on and keyed up with another fault for Hi SWR. I did work the station with my TS590, AL80B, Palstar tuner and hex with NO SWR problems!!

I tried more bands with the same problems. I downloaded the Beta Firmware and new utility and updated the firmware. Same problems and results. I swapped out the coax between the KXPA100 and the AL80B. Same results. I swapped out the coax that came with the KXPA cable package with a known good jumper to the amp same results. I bypassed the AL80b and Palstar tuner direct to the hex. Hi SWR faults. I tried dipole with Palstar same results. I added an LDG Auto tuner after amp with same results.

I reloaded ver 1.04 of the firmware and tried again same results. I also reloaded the beta a second time.

Today I hooked the amp back up after installing the correct hex and decided to try some more trouble shooting. Today with the PA Mode on and running the utility software, If I uncheck PA Bypass, which comes on with equipment turn on,  the PA Bypass comes back on. I can hear the relays clicking each time. If I change PA Mode so I can manually turn the amp off and on the PA Bypass works correctly. I changed the short piece of CAT 5 with a piece of fully shielded CAT 6. Did not make a difference.

I saw on the reflector an individual having problems with tuner retuning during a qso due to sensitive SWR . This is not my situation as mine does not have a tuner and is a kit version. I also saw where an individual had a problem using an LDG auto tuner. That is also not a symptom I am having as LDG tuner tunes fine when you use at least 5 watts or so to tune.

Any suggestions would be appreciated. I have totally lost any faith or confidence in the amp. As one of my friends told me it is probably time for it go away.

Rich, K8VE