Sony / Tektronix 326 Oscilloscope
This little 1970's scope is newer than some of my other test equipment, but still has some age on it. It has no ICs, but a lot of Sony transistors. It's a 10MHZ dual channel scope with a 300ns delay line built in. It has a Ni-Cd battery pack and can also run from external 12 VDC as well as 120VAC. The inputs for the scope are on the left side.
I picked it up at a hamfest for not much money due to its condition, but it did have a trace on screen when I bought it. The trace lasted until about the time I got home and then faded away. It was there just long enough to convince me to buy it. After opening it up and seeing how butchered the power supply was, I'm amazed it ever had a trace at all.
I picked it up at a hamfest for not much money due to its condition, but it did have a trace on screen when I bought it. The trace lasted until about the time I got home and then faded away. It was there just long enough to convince me to buy it. After opening it up and seeing how butchered the power supply was, I'm amazed it ever had a trace at all.
This is how it looked when it came home.
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Another view of the front panel and the crud all over it.
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The NiCad batteries were covered in potassium carbonate. But they cleaned up well and still hold a charge. The batteries lasted a few months until I forgot to turn off the unit one day and ran them down. A couple cells died so I replaced them all with new cells.
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At least the battery compartment was nice and clean. The old cells were a tight fit, but after replacing all the cells the pack slides in and out easily.
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The scope with the top and power supply covers removed
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Removing circuit boards for cleaning and repairs.
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The power supply has been removed to make repairs.
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The traces to the two current driver transistors for the flyback power supply were badly damaged (on middle PCB) and had to be repaired. In this photo the traces are being pieced back together and epoxied.
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Gold plated machined IC pins were inserted in the transistor holes. Most all the transistors in this scope plug into socket pins on the printed circuit boards. Not sure if the current driver transistors were in sockets originally but there was little choice due to the damaged traces.
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The original current driver transistors are very hard to find so I experimented with substitutes. A single SK9366 worked very well in the circuit so I used it instead of the original transistors because it was too difficult to mount the original TO-5 cans on the damaged board.
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more to come...
Page created 9/25/2019
Last edited on 12/07/2019
Last edited on 12/07/2019
