Saturday, October 30, 2021

YAY! The KLH Model Thirty Four is Out the Door..... and other things

 I finally got this thing finished, and it fought me most of the way.

"It's Taillights", as my car buddies used to say.

Here it is, happily spinning a Decca 78 RPM record of The Andrews Sisters singing "Dancing Cheek-To-Cheek".

It had an issue with the audio randomly dropping out, and it required doing a whole lot of soldering work.

This is what KLH called their "Modular Series", and consisted of half-a-dozen or models like this one. Some had FM, others had FM Stereo ("Multiplex" in dayse of olde...), and still others included AM radio. These were produced after Henry Kloss had left the company, and it was purchased by Singer Corporation. Yep, the sewing machine people made stereo equipment.

It's called "Modular", as all the individual functions plug into an "Interconnect Board", very similar to a "Motherboard" in your PC.

This is the Interconnect Board with most of the other sub-assemblies pulled from it.

And it fits in the chassis, thusly....

The Power Amplifier / Power Supply board is still plugged in in the above picture, as this was when I was doing the "Triage" phase after "The Colonel" first dropped it off.

If you look at the first pic of the ICB (InterConnect Board), you'll see some white things with what look like dark lines on them. The "dark lines" are the male pins in the ICB, which are soldered to the back of the board. There's a female mating connector which slides over the vertical pins, connecting the sub-assembly to the ICB.

This is a mated set, where the Power Amp board connects to the ICB. You can see the vertical pins protruding through their mating connector on the Power Amp board where the grey cable crosses between them.

There's a total of 75 pins, and another 75 "sockets" that mate to them. About half of the 150 total connections weren't soldered very well fifty years ago, and temperature cycling, vibration, and moisture finally got to them, causing open circuits, and intermittent circuits when the board or connector was flexed.

I removed the solder from all of these connections, cleaned the parts, put fresh flux on them, and resoldered them. ALL of the other boards had many "iffy" solder connections, so those were treated the same way.

All-in-all, I reworked around 200 connections, which helped quite a bit. The last thing driving me bonkers was the Mode Select Switch. It would not pass the left channel from the FM stereo, and I started wondering about finding a switch. Repeated cleaning didn't help, so I resorted to Extreme Measures. I submerged the board in denatured alcohol, and cycled the switches back-and-forth a few dozen times. After drying the board off and re-lubing the switches, it worked.

The Colonel was astounded at how nice it now looks, and amazed at how good an old 78RPM record sounded on it.

I found out he was just going to use it to "preview" his collection of about 1000 78RPM records so he can pick the ones he and his wife like, and load those into a huge Wurlitzer Jukebox they own. Since most of the records they own are in the "Less Than Pristine" category, and he's not concerned about tracking force, I maxed it out to 5 grams. That's a Metric TON of tracking force in the 33-1/3 LP world, and I advised him not to play any 45's or 33's on it, as with that much tracking force, AND a 78RPM stylus (bigger tip in it), it could easily damage the record.

So, happy "customer", and when he saw the parts total, he said our agreed upon price for the job was too little, and gave me an extra $50.

I might some work out of this, and I might not, but it felt good to see how happy he was, and we saved an item from the landfill.

Got the snow tires on SLW's car today with the help of my son, which cut a 2-1/2 hour job for me by myself down to about an hour. He was running the jack and moving the tires in an out, and I ran the impact, took the summer tires off, put the snows on, tightened the lugs, and let him do the final torquing down to 80 ft-lbs.

Then we finished the Halloween decorations for Sunday night's Trick-or-Treaters. Got the smoke machine set up, put in a bunch of sound-activated lights, ghosts, and cackling witches, added some black lights and a projector, and tested it.

And I'm beat.....

Hope y'all have a Blessed Sunday, Halloween notwithstanding.......


  1. Happy Halloween and a Blessed Sunday to you and SLW!

  2. I'm happy that the old box was restored. You're a wonder, DRJIM.

    And then you did everything else.

    Scare the little ghosts and goblins when they show up demanding candy!

    1. Just glad my son helped me with the tires. Cut the time to less than half of what it usually takes me!

  3. 80 ft lbs? Might I suggest a stop at a pawn shop to purchase a breaker bar and appropriate sized socket? Stow in the boot. The first time you need to put on the spare will be on Hwy 14 near the top of Cameron Pass in a blizzard. You will thank me.

    1. Yup. Got one in the trunk. Learned that lesson the hard way back in Illinois....

  4. Agree with WSF. Personally, I never cared for the KLHs. I got an early Empire 298 and never let go of it, until I got out of audio completely.

    1. It was definitely "Built To A Price". Phenolic circuit boards of so-so quality, tin-plated connectors that corrode, and terrible soldering.

    2. That was something I learned early, thanks to a tour in Japan and visiting a plant that built amplifiers. The better the tolerances, the better the nameplate that went on the front...

    3. Yep. Much of the stuff Radio Shack sold in the 70's was "Famous Maker", but that's no guarantee of quality.

      I worked at a Radio Shack store over the Christmas season one year to help a friend out. I was astounded at the markup on some of their items, even their "high end" stereo gear. I had a customer come in one evening, and he wanted to buy absolutely the BEST stereo he could get. When he said money was no object, I told him to go down the street to the Wurlitzer store who sold equipment made by Marantz, Macintosh, and Fisher. He thanked me profusely, and said I was the first honest salesperson he'd ever met.

      Boy, did I get chewed out by my store manager!

  5. Reminds me of the old Zenith TVs that had the plug in circuit board modules. I can believe the solder issues on those style pins, especially if the motherboard wad on the thin side and they were soldered one only one side.

    1. I think RCA used something similar. Had a friend with a big RCA console color TV, and I had to swap a couple of plug-in modules in it for him.


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