Dear all, I'm in Brazil. We have an old 421 gaussmeter with a MMT-6J04 probe. The probe is not working (421 shows the message "probe not connected"). I know for sure that it is the probe because I have try the gaussmeter with another probe installed on our VSM and the instrument works fine. We really need the probe working since we have urgent measurements to preform but if we buy one (and we will), it is going to take at least one month for the probe to arrive. I would like to give it a try fixing the probe. So my question is, is there an easy way to tell is the problem is a broken wire or is it is the eprom that was erased or is malfunctioning? The wire I can fix. Thanks
Post by Lake Shore Ogi on Sept 6, 2019 9:32:50 GMT -5
Unfortunately there is not much that can be done since the probes are permanently assembled/epoxied. You can inspect the wiring inside the connector shell to see if one of the wires somehow broke loose and check their solder connections. If the problem is within the probe stem or the Hall sensor at the tip, there is regretfully nothing you can do to fix it.
Post by Lake Shore Ogi on Sept 9, 2019 9:01:19 GMT -5
Hello! There is always a possibility for the EEPROM to fail but I don't think that we're dealing with this issue here. Please measure the resistance across [Pins 8 and 15] and also [Pins 1 and 9]. I'm guessing that one of the pairs is going to measure open in your case but normally they should measure between 2 and 4 Ohms. Best Regards, Ogi
Post by Lake Shore Ogi on Sept 10, 2019 15:14:43 GMT -5
I spoke to one of our engineers after seeing your response. The resistance appears perfect and there is no temperature sensor installed on this probe so that is fine too. He advised that this particular model does look into the EEPROM and your initial suspicion is most likely correct, which is that the EEPROM is dead. Regretfully, there is nothing "quick" that can be done. If we had the probe here at the factory, we would replace the EEPROM and re-calibrate the probe. -Ogi K.
Ok Ogi, thank for the reply. I'll talk to my boss here. Maybe we can send the probe to you for repair, but, depending on the price, we will buy a new one. Shall I contact your sales person to get a quotation? Mariano
Post by Lake Shore Ogi on Sept 11, 2019 14:37:57 GMT -5
You might be better off buying a new one because you'll pay a lot for the transit and customs import/export fees. This you can further discuss with our rep listed below, as they have handled this many times and will have better information than I do. If you have any other technical questions, please contact me/us at [email protected]