The Ides of April

Yesterday was Tax Day, and also the Ides of April. The month of March gets all the publicity, thanks to William Shakespeare and some guys in the Roman senate. April’s Ides are not quite as celebrated.

Of course we’re starting with puppy pics! This was taken by a very nice woman after I took the guys for a longish walk in the wilds of Heritage Park, our first time on the Ravine Run trail. The pups were fairly tired afterwards, which was the plan. I seem to be getting into slightly better shape.

More on the Zenith

When I was growing up we had Revere Ware (TM) frying pans, which had a layer of copper on the bottom for better heat distribution. Every month or two we got out the copper cleaner and shined up the bottoms. They would stay bright for a few days and then they tarnished again.

I knew all of this, of course, but somehow I’d forgotten in the intervening decades. Shiny clean copper loses its shine after a few days, so all that beautiful shine is back to dull and dark. Fortunately a little more Penny-Brite cleaner does the trick quickly. I then gave it a coat of JAX Tarnish Preventer. I haven’t used this product before, so we’ll see how it does. It was easy to apply.

Here’s an earlier shot before disassembly. This is the front end of the brace that stabilizes the upper end of the tuning capacitors. There are (or rather were) soft rubber shock mount grommets that isolate the brace from the capacitors. Well, in this picture they are still there, but time has deformed them. They didn’t used to be all squashed and oozing out from under the washers.

The hard sleeves inside are intact, and I’m making new grommets with silicone. If I needed two dozen I’d make a mold and cast them, but here I just need three so I’m making them up from scratch. Here I’ve made silicone washers which I’ll extend with cylinders that fit into the big holes in the brace.

The Pioneer CT-F1000

I got the replacement FF/REW motor sleeve and the new tires. I got them all installed, and the spindles turn as expected… except that they aren’t driving the tape. The word “frustrating” comes to mind.

The two parts in the middle are the ones that made a bid for freedom earlier. I found the spring, and I determined that the spring I had used in its place was perhaps a little underpowered, so I put the original spring back in. It didn’t solve the problem.

I also found that the spindles are loose on their shafts. They should fit really tightly. I disassembled them and glued them on with some really cool adhesive called Tech Bond that lets cyanoacrylate bond metal to plastic, something it usually doesn’t do very well. It didn’t solve the problem.

Eventually I found my way to the clutch in the assembly shown above. There’s a fiber disk that usually transfers the power from the motor to the spindle but intentionally slips when the tape stops. I found that it was slipping too easily.

The answer was a solution of violin rosin. Most electronics techs don’t have this lying around the shop, but most electronics techs aren’t hurdy-gurdy players, which is why I have it. Just a drop of rosin fixed the slipping.

I put the transport back in the deck, and for five glorious minutes the transport did what it was designed to do: play, stop, pause, fast forward and rewind. Then it stopped. I set it aside until I could come up with a plan to figure it out. If I was a film noir private eye I’d have retired to the bar and ordered a double shot of bourbon.

The KEF Reference 103/3 Crossovers

The KEF Reference 103/3 speakers were produced in the late 80’s and early 90’s. Their crossovers were unusually robust, with all electrolytic capacitors. The electrolytics were past their useful life, and I replaced them for the customer.

Here’s one of the customer’s speakers. He was very happy with the results. (Photo credit is his.)

pair of crossovers
bipolar electrolytic
capacitors: done

The 65 Amps Ventura

This amp’s designer had a good idea about physically isolating the first two tubes from the chassis, but it isn’t well suited to trading out tubes frequently to look for the right sound. The socket in the middle suffered a failure.

After trying out a few ways of maintaining the isolation mounts, I settled on replacing the sockets with some vintage ones I had.

Here’s the amp working again. While I had the amp out, I noticed that the output transformer, the one on the right, is a bit wobbly. The mounting strap is too thin and small for the mass of the transformer. I flattened out the strap and added a reinforcing washer.

broken tube socket
removed shock mount and replaced
tightened transformer

The Aiwa Turntable

This was a really quick and easy fix. The belt fell off. I put it back on.

turntable platter
not turning around at all
reinstalled the belt

The PSB Subsonic 5i Subwoofer

This subwoofer amp’s SMPS (switch mode power supply) is not functioning. I went through the first round of replacing the choppers, the FETs (field effect transistors) that switch the high voltage DC on and off at very high frequencies to make AC that gets run through the step-down transformer. It didn’t help.

The next step was to remove the glue. When it ages it becomes conductive, so I removed it and replaced the capacitors. That solved the fault.

Subsonic 5i
dead switch mode power supply
new caps and choppers

More Soon

The puppies are not exactly a productivity tool at the moment. If you’ve been waiting for a long time, trust me when I say that I really would like to have your device done and back to you. I’m working on it. Oh, and the Motorola? What’s happening there? There’s so much stuff in the shop that I can’t get to the Motorola… which is why I’m working on the stuff so that I can get to it.

Take care, folks. Back with you soon. I’m out of room for more puppy pictures, so I might post a supplement.

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