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## Inspecting the multimeter
This unit has clearly seen better days as the pushrods are gone and it looks pretty battered. But looks are not the reason I bought this meter, mainly the legendary performance of the 3458A are what I was after. Before powering up a used unit that's known to be faulty. It's always important to open it up and have a look, for fear of making a bad situation worse.
On inspection, there are some initial problems that are quite obvious, namely burnt resistors on the main A1 DC measurement board. These have been burned to a crisp, probably due to overvoltage. Looking at the schematics, these are two 10K resistors along the DC input path. Looking at the components, they appear to be CRF65 resistors, very similar to the CRF65. Luckily I had some resistors on hand that could function as a suitable replacement with some artistic creativity. Selftest afterwards reveals seemingly no issue with the DCV section, excellent!
On inspection, there are some initial problems that are quite obvious, namely burnt resistors on the main A1 DC measurement board. These have been burned to a crisp, probably due to overvoltage. Looking at the schematics, these are two 5K resistors along the DC input path. Looking at the components, they appear to be CRF65 resistors, very similar to the CRF65. Luckily I had some resistors on hand that could function as a suitable replacement with some artistic creativity. Some measuring around the input section for any other bad devices also made me inclined to believe all was in order.
Selftest afterwards reveals seemingly no issue with the DCV section, excellent!
![fix](3458-WorkLog/imgA.jpg)
![post fix](3458-WorkLog/imgB.jpg)