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I have no screen at all. The scope does not do a self test so I cannot get to an initial calibration. I did not copy the calibration constants and when I first powered the scope it ran a self test as normal and came up with the expected fail codes. When I tried to do an auto set, it started and then the screen went blank. I have no screen now when I power up. The fan works so I have some power. I will try to find the current sense resistors. Thank you for the replies, Rich
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On Wednesday, June 27, 2018, 6:20:09 PM EDT, Dewey Wyatt <kn4wddewey@...> wrote:
U664 is where the calibration constants are stored did you copy them to the new ram? If not you will need to do a complete recalibration. I went through a 2430a recently and bought a chip reader and writer to be able to save and copy the constants from one to the other. U360 holds stored waveforms and isn¡¯t as important as the u664. Hope this helps. Mine wouldn¡¯t boot either without writing the calibration constants to the new dallas chip. Even with auto setup it wouldn¡¯t boot after I copied the chips data all went well. Sent from Mail for Windows 10 From: RichR via Groups.Io Sent: Wednesday, June 27, 2018 5:53 PM To: [email protected] Subject: [TekScopes] Tektronix 2440 bad power supply? I recently purchased a 2440 with a 4000 code, battery weak. Everything else appeared to be working. That was the only fault code. I replaced the two ram modules with new. The original were obsolete (DS1235BWL-120) so I purchased DS1230-100+. When I first turned on the scope everything powered up and there were plenty of fault codes so I started a self calibration. It never completed the self calibration. The scope went blank. I was able to power it up only occasionally until it stopped completely. It no longer tries to test when it is powered on the only lights on are the three GPIB lights. The screen will start with some erroneous dots and then go blank. I have tested the low power board and have some readings that do not match the schematics The voltage reading according to the power supply overcurrent check page 478 of the manual do not match. The voltages on the side board are correct so I am not sure where to proceed. I have attached a - of the readings I got from the power supply. Any help is greatly appreciated. Thank you, Rich /g/TekScopes/files/015-0282-00/TEK%202440%20Power%20supply%20test/TEK2440%20Curret%20test20180627_12351992.pdf --- This email has been checked for viruses by AVG. |
