Hi folks,
I have an opportunity to buy a used LK-500 from a local friend who will let
me play around with it for a while before I decide on buying it. I haven't
seen it yet. I'm not sure about the model number, but I think it's the ZC.
It has (3) 3-500Zs, QSK (vacuum relay?), a separate (very heavy) power
supply that sits on the floor and venier tuning. Original cost was about
$1500. Don't know the exact purchase date, but I suspect it was over ten
years ago, sometime between 1985-1989.
Until a day or so ago, the amp sat on a desk and had not been turned on for
3 1/2 years, while my friend and XYL were estranged. They're back together
now (an amazing story in itself) and he tried turning on the amp the other
day, without the benefit of a Variac or other cap rehab assistance. The
second he flipped the switch, he heard some spitting and cracking coming
from the RF deck (not the power supply), so he immediately switched it off.
The amp was in standby at the time. He thinks it might have been spiders and
webs getting zapped by the HV. He's going to pop the cover in the next day
or so and see what's going on in there. He refused my assistance, so I urged
a few safety precautions on him.
Any opinions on the noise? When I get my hands on this thing, what other
trouble signs should I look for in both the RF deck and the power supply?
Even if the amp is in decent condition, I'm not sure it's going to meet my
needs. This will be a second amp for my single-op two-radio contest setup.
I'm already using an 87A and an SB-221 (w/10M and Rich's QSK mod), both of
which work fine. There are only three reasons for replacing the SB-221:
quicker QSY, legal limit output and 160M coverage (but no antenna yet on
that band.) My friend says the venier tuning on the LK-500 is very
reproducible, and I have to believe that it will be better than the SB-221.
Agree or disagree? As for power, he says he only got 1300 watts out with an
FT-990 at 100 watts. He didn't think amp input SWR was high. My FT-990 will
do 100 watts, but my 1000mp will only do about 90. I saw a post on deja-news
indicating that it takes 135 watts to push the amp to 1700 watts. Sounds to
me like I may only gain a couple of hundred watts output in this swap.
Opinions?
Now, what about reliability of this amp? Since the company is kaput, are
there any good parts sources?
Finally, assuming it's fully operational and has full output from the tubes,
what's a fair price for this thing?
Thanks for any help,
73, Dick, WC1M
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