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.

 
Another KT-135
 
Lafayette KT-135
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.
 
Lafayette Explor-Air KT-135
 
Lafayette Explor-Air
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.
 
KT-135 bandswitch
Darn good connections for a 12 year old! The actual control is only about an inch and a quarter in diameter.
 
KT-135 chassis
Here's how it looked when the repairs were completed. It works very well.
 

 
NEAR DISASTER
 
Falling on KT-135
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.

 
REDISCOVERING MY ORIGINAL KT-135
 
2438 75th Avenue
Inside the cabinet of my original KT-135 is a sticker with the address of our old house.
2438 75th Ave
Philadelphia, PA 19138
 
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?

 
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
 
KT-135
My KT-135, initially completed January 24, 1971.
 
 
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.

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.)
 
KT-135
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!


 
Antenna connector
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.
 
 
 
QSL cards
Some of the QSL cards I collected between 1971 and 1972, using the KT-135.
 
For some reason, In 1971 I turned the radio into a toaster on the back of the manual.
 
Lafayette toaster
Ironically, Lafayette actually sold a toaster.
 
 
 
KT-135 from Kutztown, PA 2022
This one was restored in 2022.
 
KT-135 from Kutztown, PA 2022
It was originally built by a kid named Donald MacIver sometime between 1960 and 1964.
 
TELEFUNKEN 12AT7
It came with a TELEFUNKEN 12AT7.  It's worth more than the radio.
 
KT-135
Click for full size.
 
Before and After. Proof that I can solder better than Donald MacIver when he was 12.
 
 
 
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