Electronics > Metrology

IS that you FLUKE ... IS THIS ME....

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opa627bm:
I bought a used Fluke 731A on ebay and found out the battery exploded at some point and the pervious owner was trying to fix it but accidentally dropped the solder at back side resistor.
So I bought 2 7.2V battery pack, clean up the entire box and use the nail polish to fix the resistor.
But I am getting very high drift at 10V when either powered by AC or battery.
you can see one of the data log is the output and the other one is the reference. they both captured by 34470A.

I know later 731B have fixed a lot of the problem but this performance is no way fluke can sell it as a product.
Is that normal for the 731A owners?

alm:
Can you also show temperature in the same plot? The change is in the order of 10 ppm, and I believe the 731A (and 731B) were not super low tempco. The good news is that if it's temperature coefficient, then that can be adjusted to some degree. Search the forum on posts on the 731B.

I believe the main difference between the 731A and B are the resistors. There was also a change from the TI DH... refamp to the Motorola SZA263, but that occurred after the change to 731B. I have an early 731B in need of repair that still has the TI refamp.

HighVoltage:
When working correctly, the Fluke 731B is more stable than the 34470A.
The 34470A is not a metrology grade multimeter and therefore should not be used to gauge a reference voltage.

opa627bm:

--- Quote from: HighVoltage on September 17, 2022, 09:58:04 am ---When working correctly, the Fluke 731B is more stable than the 34470A.
The 34470A is not a metrology grade multimeter and therefore should not be used to gauge a reference voltage.

--- End quote ---

Cant afford any 8.5 right now.. the other 7.5 I have is a DMM7500...
also , does Solartron Schlumberger 7061 count as a metrology grade DMM?

opa627bm:

--- Quote from: alm on September 17, 2022, 09:22:28 am ---Can you also show temperature in the same plot? The change is in the order of 10 ppm, and I believe the 731A (and 731B) were not super low tempco. The good news is that if it's temperature coefficient, then that can be adjusted to some degree. Search the forum on posts on the 731B.

I believe the main difference between the 731A and B are the resistors. There was also a change from the TI DH... refamp to the Motorola SZA263, but that occurred after the change to 731B. I have an early 731B in need of repair that still has the TI refamp.

--- End quote ---
I dont have the room temp but it is pretty cold today in bay area, the logging was started last night , I think the delta is about 15C the entire day..

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