015-0058-01/Repairs: Difference between revisions
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The DC output connector is a Tektronix design that is unusually fragile. This complete power supply could probably be rather easily replaced by any common "wall wart" with an output of 18-25 V<sub>DC</sub>. The total current draw is less than 100 mA. If you do this, it would be best to replace the cord on the [[134]] with a modern barrel receptacle that accepts the existing connector on the end of the "wall wart" connector. This would eliminate the original, but fragile, Tektronix connector. You could also add a reverse polarity protection diode inside the [[134]]. | The DC output connector is a Tektronix design that is unusually fragile. This complete power supply could probably be rather easily replaced by any common "wall wart" with an output of 18-25 V<sub>DC</sub>. The total current draw is less than 100 mA. If you do this, it would be best to replace the cord on the [[134]] with a modern barrel receptacle that accepts the existing connector on the end of the "wall wart" connector. This would eliminate the original, but fragile, Tektronix connector. You could also add a reverse polarity protection diode inside the [[134]]. | ||
Unfortunately, there is no room inside the [[134] for a modern barrel connector receptacle, but inline barrel receptacles exist. | Unfortunately, there is no room inside the [[134]] for a modern barrel connector receptacle, but inline barrel receptacles exist. | ||
If you happen to have one of these power supplies apart, it might be worthwhile to add some series resistance to the primary, as Tektronix did to make their 230 V version. Add ~40 Ω for each volt that your typical line voltage exceeds 115 (or 230) VAC. This would help avoid transformer core saturation due to today's higher line voltage, and also reduce the power dissipation in the [[134]] pass transistor. | If you happen to have one of these power supplies apart, it might be worthwhile to add some series resistance to the primary, as Tektronix did to make their 230 V version. Add ~40 Ω for each volt that your typical line voltage exceeds 115 (or 230) VAC. This would help avoid transformer core saturation due to today's higher line voltage, and also reduce the power dissipation in the [[134]] pass transistor. | ||
Around 1995, I was passing thru Portland, OR and was able to visit [[Deane Kidd]] in his home. I asked if he had a [[134]] he could sell me. He had one, but had to build up a power supply for it from parts. I watched as he put together the one in the first two photos on this page. After I got home, I discovered that the transformer was open, so Deane had to mail me a replacement. In the process of adding all this [[131]]/[[134]] info to the Tekwiki, I also discovered that this supply really wasn't quite right: It should have had another plastic section at the bottom and a line cord. It was also missing the line input fuse, which I have now replaced. | |||
Revision as of 15:00, 31 March 2023
The DC output connector is a Tektronix design that is unusually fragile. This complete power supply could probably be rather easily replaced by any common "wall wart" with an output of 18-25 VDC. The total current draw is less than 100 mA. If you do this, it would be best to replace the cord on the 134 with a modern barrel receptacle that accepts the existing connector on the end of the "wall wart" connector. This would eliminate the original, but fragile, Tektronix connector. You could also add a reverse polarity protection diode inside the 134.
Unfortunately, there is no room inside the 134 for a modern barrel connector receptacle, but inline barrel receptacles exist.
If you happen to have one of these power supplies apart, it might be worthwhile to add some series resistance to the primary, as Tektronix did to make their 230 V version. Add ~40 Ω for each volt that your typical line voltage exceeds 115 (or 230) VAC. This would help avoid transformer core saturation due to today's higher line voltage, and also reduce the power dissipation in the 134 pass transistor.
Around 1995, I was passing thru Portland, OR and was able to visit Deane Kidd in his home. I asked if he had a 134 he could sell me. He had one, but had to build up a power supply for it from parts. I watched as he put together the one in the first two photos on this page. After I got home, I discovered that the transformer was open, so Deane had to mail me a replacement. In the process of adding all this 131/134 info to the Tekwiki, I also discovered that this supply really wasn't quite right: It should have had another plastic section at the bottom and a line cord. It was also missing the line input fuse, which I have now replaced.