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Lafayette KT-135 EXPLOR-AIR radio
kit |
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| Here's a video I made by
request. Keep in mind that while tuning the radio
you don't do it as crudely as what is portrayed
here. Tuning a regen radio takes patience. |
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Another
KT-135 |
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This kit was built by 12
year old Art Auch in 1969. I purchased it from him
in 2015 because of the pristine front panel and
knobs. It was intended to be used for parts, but
after emailing Art a few times I decided to repair
it instead.
According to Art, he listened to it for about a
year, then put it in the closet. When he got married
and got his own house it was moved to a shelf in a
closet in a spare bedroom. Years later, the spare
bedroom became his daughters room. While his
daughter was in college she needed some extra closet
space. After 30 years the radio came down from the
shelf!
Art's wife asked him where he wanted to store it, so
he decided to sell it at the next yard sale. A few
days later he checked on ebay and saw one up for
auction. He put it up as a "Buy It Now" auction and
three days later it was in Andrea's kitchen. |
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This radio seemed to be very
carefully constructed. Art said his dad, who worked
for IBM and had built a Heath Kit Hi-Fi, showed him
how to solder. His connections were so good I had a
tough time undoing them as I repaired the radio.
Notice that the big rectangular resistor connecting
the two tube sockets on the right is missing.
Lafayette used such crummy sockets with these sets
that the pins broke right off. I replaced both
sockets, then later had to replace the socket on the
left because a pin broke off while I was messing
with it.
It took a hot iron, two types of needle nosed pliers and some
wire cutters to undo 12 year old Arts' connections. |
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Darn good connections for a 12 year old!
The actual control is only about an inch and a quarter in
diameter. |
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Here's how it looked when the repairs
were completed. It works very well.
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NEAR DISASTER |
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Across the street from Art,
on Westview Terrance in Poughkeepsie, NY, was a kid
named Peter Denison. Not only were Pete and Art good
friends, but both their dads worked at IBM. Pete had
a KT-135, though he doesn't remember if he got one
first and Art saw it and wanted one, or if it was
the other way around.
Pete put his KT-135 on a bookshelf. One day he was
climbing up the bookshelf to get something out of
his closet, the shelf came down, and so did Pete,
right on top of the radio, which didn't have a
cabinet! Miraculously, he wasn't seriously
injured, but the radio didn't fare well. He took it
to Lafayette, and for a small fee they fixed it as
good as new. He stated that he was amazed at all the
things he could hear on it.
Unfortunately, a half century later he doesn't
remember what became of the radio. |
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REDISCOVERING MY ORIGINAL KT-135 |
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Inside the cabinet of my original KT-135 is a sticker with the address
of our old house.
2438 75th Ave
Philadelphia, PA 19138
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All I had of my original KT-135 was the empty cabinet. The
cabinet was in a box shared with a steam engine I
got for Christmas when I was a kid. We moved in 1974
and I boxed all my stuff up. Our new house was
smaller and there was no room for any hobbies, so
all the boxes of stuff ended up in my grandparents
basement. When I got married and bought my own house
I retrieved the boxes, but I don't remember ever
finding the KT-135. What happened to it? |
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By 2015 I hadn't seen the
radio in over 30 years. We had moved twice after I
was married, packing everything up and transporting
it to our new houses. Eventually we ended up in West
Point PA. The kids grew up and moved out and I got
divorced in 2007. (As if you can relate an entire
lifetime in one sentence.) From time to time I'd
look for the radio, but never found it. In 2010 I
met Andrea. In 2015 Andrea and I started a
systematic search of the house in West Point for the
radio.
There's that joke where somebody asks you
where you found something you were looking for, and
you reply, "The last place I looked."
Well, we found the radio LITERALLY in the last place
we looked - because there was no place left
to look! After searching through every conceivable
place in the house and coming up empty handed, we
started looking in the garage. It was found under a workbench, in a box in the corner, under
a pile of other boxes. It was the very last box on
the bottom. We opened every box till there was only
one left. If it wasn't in that last box, then it was lost
forever.
"Then
they did open the last box and Behold! The radio was
revealed unto them. And the radio was withdrawn from
the box, and their joy could not be measured. Then Mike spake unto Andrea,
saying, 'Let us take this then to your house in the
land of Gwynedd, that we may photograph it.' And it
came to pass that they did tarry not, but brought
the radio into Andrea's house in the land of Gwynedd,
and there did they photograph it." - Galoshes
12:14 |
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| My KT-135, initially
completed January 24, 1971. |
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It wasn't in the cabinet
because when I got done with it, it no longer fit in
the cabinet. I added a doubly isolated, choke
filtered solid state power supply in 1972. Two 12
volt filament transformers back-to-back isolated the
AC. Filament voltage was then taken from the
transformers, so the 50C5 audio output tube was
replaced with a 12AQ5. My friend Joe Jones gave me
the choke and the wiring diagram for the 12AQ5.
(Pins 5 and 7 are reversed on a 12AQ5 vs. 50C5. A
12C5 would have been a perfect replacement for a
50C5, but he didn't have one.)
After being
baked and frozen over and over in the unheated
detached garage for 25 years, it worked perfectly
when we turned it on. (I turned it on again a week
later and the power supply filter capacitor failed.) |
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| The "improved" KT-135. The
speaker screws are rather long, but I think the
criteria was that they had to fit through the holes
in the front panel. Resources were limited at the
time. The headphones jack is
easier to get to, and the antenna binding post has
been replaced with an RS-259 coax connector. A coax
cable runs to the antenna tuning capacitor. The
chassis voltage is at DC "B minus" so you will
almost always never won't not get shocked on it.
On
the rear center sits the big filter choke. Behind it
are the two back-to-back filament transformers. It
even has feet on the bottom! |
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| I didn't have a dipole antenna in
1971. All I had was a wire that ran up the side of the house
to the roof. I would bend the end of the wire in half and
stick it into the coax connector. After we found the radio
in 2015 I added another antenna connector, because I STILL
didn't have a dipole antenna. |
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| Some of the QSL cards I
collected between 1971 and 1972, using the KT-135. |
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| For some reason, In 1971 I turned
the radio into a toaster on the back of the manual. |
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| Ironically, Lafayette actually
sold a toaster. |
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| This one was restored in 2022. |
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| It was originally built by a kid
named Donald MacIver sometime between 1960 and 1964. |
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| It came with a TELEFUNKEN 12AT7.
It's worth more than the radio. |
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| Click for full size. |
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| Before and After. Proof that
I can solder better than Donald MacIver when he was 12. |
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