Re: Early 577 service manual needed.



    I did not realize that the preferred was the 10X10 which was option 10. This was the 8 X 10 1.25cm I do have a newer model that is the 10 X 10. Dialing in the amp was adjusting the horizontal and vertical amps for the CRT. Also getting them balanced.  It might be reading a little off due to it not being the better CRT. If i check the 177 on the other curve tracer it reads correctly so I suspect the resisters are fine. Though on this 177 half of the 22 Ohm current scene resisters were burned in half.


On 10/18/2020 1:20 PM, wrote:
Production serial numbers started at B010101, so B010124 is a production instrument, just a very early one. The suffix on the CRT part number designated different phosphors and graticule types. The preferred graticule for a 577 is 10x10 1 Cm centered horizontally. There is also a variant of this CRT that has an 8x10 1.25 CM graticule. Usable, but not the best. There is also probably a variant of this CRT with no graticule. Check the 154- RPR's on the vintageTEK website.

If by "dialing in the amps" you mean the vertical sensitivity on the higher-current ranges is wrong, check the high-current shunts, which are on a board plugged into circuit board in the 177 adapter. It's a piece of thin PCB material with scribe lines to adjust the resistances.

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