| Electronics > Repair |
| Please help to fix my Agilent 34401A |
| (1/1) |
| h4z4rd:
Hi guys! I've an Agilent 34401A DMM I bought it on Ebay. The seller didn't mention that it has a problem but he sold it AS-IS and it also was really cheap. About the problem: When I turn it on it shows an error message. The error #604 (A/D slope convergence failed). When it shows this error message I can't measure AC because it's all over the place. When it does not drop the error message it works good but most of the time it doesn't. I checked the solder joints and all looks good. I'd like to get some help to fix my DMM. What could be the problem? What should I check first? Thank you! |
| MarkPalmer:
Here is its service manual. http://literature.cdn.keysight.com/litweb/pdf/34401-90013.pdf Quoted from manual: A/D slope convergence failed: The dc section is configured to the measure zero state (MZ) in the 10 V range. This test checks whether the ADC integrator produces nominally the same number of positive and negative slope decisions (±10%) during a 20 ms interval. This problem most likely refers to the A/D converter IC itself, or possibly whatever is supplying power to it. -Mark- |
| Zapro:
My 34401a had this fault. After replacing almost all op-amps in the input, i found out that some zener regulators for U201 was faulty. And U102 too (and that cost me an arm and a leg) but replacing the chip and zeners fixed it. |
| vinovino:
What chip did you replace? U201 or U102? |
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