I have recently acquired a 543 to add to my collection. From what I can see, it is similar to a 541A, with the addition of several more accurately calibrated horizontal magnifier positions.
I was not able to fully check it out before I bought it, but I did turn it on and saw that it has a trace. The serial number is 849, below the 950 which my copy of the manual indicates the factory mod to replace the selenium rectifiers with silicon diodes went into production scopes. Opening the side cover, I see that there is a circuit board loaded with top hat diodes near where the selenium plate rectifiers were located. I assume this is a 040-xxxx mod kit that was installed in a Tek service center.
For the purposes of documentation, I would like to know how the rectifier portion of the LV power supply schematic has changed. My manual (with green cover), has a modification section in the rear which gives the part numbers for the diodes and lists several low value resistors which became effective at serial number break 950. I assume the resistors were added somewhere in the diode bridge (output or input side?) to emulate the forward resistance in new (good) selenium plate rectifiers. But the mod section of the manual does not give the replacement schematic, so I don't know which resistor value goes with which diode bridge. I could guess by the numbering assignments, but a couple of the resistor designators do not line up with the diode numbering.
Also, the manual lists a part number for the diode as 106-056. Tek used 152 as the prefix for diodes, so what is a 106 number?
Does anyone either have a later version of the manual which shows the diodes in the LV power supply schematic that they can scan, or better yet, a scan of the schematic for the 040 mod kit for the 543 scope?
- Steve
