41CX schematics



#2

I already have the 41C schematics that can be found on the Museum CD set but i need the 41CX one in order to know the value of some small capacitors on the main board; where to find this information?

Thanks
Michel


#3

Now that you mentioned it, I was looking at the schematics also. It isn't accurate, the chip named "RAY 8024" isn't the LCD driver, is the power supply chip.

The schematics that I have is from a HP-41C. The 41CX may have another power supply design, but try to measure all discrete components and compare with the marked value on them (color-coded resistors and "cryptic" marked capacitors, you need to be familiar with that).

Old capacitors usually are the guilt.

Good luck!


#4

I just change the 2 electrolitic ones without resule. Now i want to change the tiny colorful capacitor near the coil but i don't know their capacity. It written on them :

a orange one : 471

2 orange : 352

one tiny blue : 1517

There is also a small but "long" metalic component glue on a spongious tape that i don't know what it is; if i do i will be able to try another one.


#5

>Now I want to change the tiny colorful capacitor near the coil but i don't know their capacity. It written on them :
a orange one : 471
2 orange : 352
one tiny blue : 1517

471 is 470pF

352 is (theoretically) 3500pF, but this is not a standard
value. I think it is rather 392, which is then 3900pF.

The rule would suggest the tiny blue one is 15*10^17pF but
this is nonsense, so probably better read it as
151 and a (not-well readable) letter, which stands for the
tolerance. Plausible might be J=5% or Z=-80%/+20% (!). The value is then 150pF.

Holger


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