70 mile an hour gusts of winds brought my antenna (Imax 2000) down. I keyed up my Madison and 350z for approximately a couple of minutes (in totality) without an antenna hooked up.
The pl259 into the antennas so 239 was ripped out of the coax (LMR 400.)
No smoke.
No popped or exploding capacitors.
No smell or anything out of the ordinary was noticed while operating the Madison and the 350Z basically without an antenna hooked up.
I hooked up the MFJ 1500 watt dummy load and to my pleasant surprise the Madison showed it's 2.5 watt DK and 13 watt pep (modulated.)
The 350z showed it's (normal) 125 watts DK and 500 watts pep (modulated.)
I let the Madison and 350z run for 45 minutes before I keyed and modulated them once again.
That's when I noticed I didn't get away without issue.
The Madison with the 350z in standby worked as it should.
Even after a 3 minute modulated key down it showed it's normal 2.5 DK and 13 pep watts with out any drop in output.
I took the amplifier out of standby and began to modulate.
After about 3 minutes (in totality) the amplifiers 125 DK and it 500 watt pep began to drop until the only output being shown on my MFJ 828 digital swr power meter was the Madison's 2.5 DK and 13 modulated (pep) watts.
I repeated the same test after shutting the Madison and 350z off for a half hour then turning them back on.
The results were the same.
The Madison shows no signs of damage no matter how long i key down and modulate.
On the other hand the Palomar 350z's 125 DK and 500 watt pep begins to drop down to zero output after modulating on and off for a few minutes.
I think it's important to mention that even when the amplifiers output reaches 0 and the only output shown on the MFJ 828 (swr/power meter) is the Madison's 2.5/13 Watts pep.
Even after the 350Z reaches 0 output it's relay is still activating when the microphone is keyed.
Those of you that are familiar with the Palomar 350Z know that there is a switch on the rear of the amplifier that allows the operator to switch between low (4 watts) and hi drive (50 through 100 Watts.) The switch bypasses the 350z's two driver tubes and uses the 50 through 100 Watts as the amplifiers driver.
Unfortunately the other two amplifiers I own are out for upgrades/repair.
From what I've written here in this post can anyone advise me as to whether they think it's the driver tubes that were damaged?
I was thinking about sending the amplifier out.
But after a bit of contemplating I thought I might save myself a few dollars by testing the 350Z with the switch in the high drive position.
The low position on the 300a which is one of the amps I sent out could easily be set for about 70 watts output.
If it is indeed the driver tubes I should see full output on the 350z with no drop down in the amplifiers output, correct?
If the problem still exists while driving it with 70 Watts what should I assume?
Could I have damaged all 6 tubes?
Or could I be actually looking in the wrong place when considering the damage to the amplifier?
If this test is not advisable please let me know?
I will wait until the 300a comes back and test the 350Z with the 70 watts driver unless those of you in the know advise against this testing.
Any ideas from my description about the way the amplifier quickly loses its output and eventually drops to zero output as to what damage could've been caused to the amplifier by operating it with no antenna?
Any information or advice as to what I should look for with the amplifiers covers (top and bottom) off that might coincide with the total loss of the amplifiers output after a couple of minutes of operation? Thanks.
73
PS. I do not have a tube tester.
The pl259 into the antennas so 239 was ripped out of the coax (LMR 400.)
No smoke.
No popped or exploding capacitors.
No smell or anything out of the ordinary was noticed while operating the Madison and the 350Z basically without an antenna hooked up.
I hooked up the MFJ 1500 watt dummy load and to my pleasant surprise the Madison showed it's 2.5 watt DK and 13 watt pep (modulated.)
The 350z showed it's (normal) 125 watts DK and 500 watts pep (modulated.)
I let the Madison and 350z run for 45 minutes before I keyed and modulated them once again.
That's when I noticed I didn't get away without issue.
The Madison with the 350z in standby worked as it should.
Even after a 3 minute modulated key down it showed it's normal 2.5 DK and 13 pep watts with out any drop in output.
I took the amplifier out of standby and began to modulate.
After about 3 minutes (in totality) the amplifiers 125 DK and it 500 watt pep began to drop until the only output being shown on my MFJ 828 digital swr power meter was the Madison's 2.5 DK and 13 modulated (pep) watts.
I repeated the same test after shutting the Madison and 350z off for a half hour then turning them back on.
The results were the same.
The Madison shows no signs of damage no matter how long i key down and modulate.
On the other hand the Palomar 350z's 125 DK and 500 watt pep begins to drop down to zero output after modulating on and off for a few minutes.
I think it's important to mention that even when the amplifiers output reaches 0 and the only output shown on the MFJ 828 (swr/power meter) is the Madison's 2.5/13 Watts pep.
Even after the 350Z reaches 0 output it's relay is still activating when the microphone is keyed.
Those of you that are familiar with the Palomar 350Z know that there is a switch on the rear of the amplifier that allows the operator to switch between low (4 watts) and hi drive (50 through 100 Watts.) The switch bypasses the 350z's two driver tubes and uses the 50 through 100 Watts as the amplifiers driver.
Unfortunately the other two amplifiers I own are out for upgrades/repair.
From what I've written here in this post can anyone advise me as to whether they think it's the driver tubes that were damaged?
I was thinking about sending the amplifier out.
But after a bit of contemplating I thought I might save myself a few dollars by testing the 350Z with the switch in the high drive position.
The low position on the 300a which is one of the amps I sent out could easily be set for about 70 watts output.
If it is indeed the driver tubes I should see full output on the 350z with no drop down in the amplifiers output, correct?
If the problem still exists while driving it with 70 Watts what should I assume?
Could I have damaged all 6 tubes?
Or could I be actually looking in the wrong place when considering the damage to the amplifier?
If this test is not advisable please let me know?
I will wait until the 300a comes back and test the 350Z with the 70 watts driver unless those of you in the know advise against this testing.
Any ideas from my description about the way the amplifier quickly loses its output and eventually drops to zero output as to what damage could've been caused to the amplifier by operating it with no antenna?
Any information or advice as to what I should look for with the amplifiers covers (top and bottom) off that might coincide with the total loss of the amplifiers output after a couple of minutes of operation? Thanks.
73
PS. I do not have a tube tester.
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