tek 2465b calibration - Page 1
Forum section: electronics / testgear

author: Jeff5341
author_rank: Newbie
timestamp: October 02, 2013, 12:54:53 am
content: Has anyone here gone through the Tektronix 2465b calibration procedure? I think the Dallas NRAM IC on the A% control board has lost its info.The boot up error code is "test 04 fail (03), sometimes (13). Attempting to do a recalibrate, I got to the step where I need A (2) ns marker signal. I don't have anything near that fast. Will skipping this part of the test result in a calibration error again? Also, the A5 board was functional when I removed it from a working 2465B. I Placed it in the scope I was working on with a known A5 board problem. That is when the cal error showed up. Placing this board back into the original working scope, the calibration error was still present! Wondering how simply moving the board from one scope to the next would have caused the test 04 fail to occur?Jeff

author: BravoV
author_rank: Super Contributor
timestamp: October 02, 2013, 01:00:03 am
content: http://www.ko4bb.com/Manuals/Tektronix/Tektronix_-_2465B_Oscilloscope/Tek_2465B_Calibration_Procedure.pdfAbove procedure shows this thing needs tons of high precision and expensive stuffs to cal it properly.

author: c4757p
author_rank: Super Contributor
timestamp: October 02, 2013, 01:51:31 am
content: Yep, you can manage with less expensive equipment for the 2445A (I did mine almost entirely with an HP 3325A fun gen) but I would not expect the same of the 2465B. Not at all.If you're getting checksum errors, I'd change the battery/RAM-in-a-box before bothering to cal it.

author: nanofrog
author_rank: Super Contributor
timestamp: October 02, 2013, 03:31:39 am
content: Those codes usually indicate the Dallas NVRAM is shot, though IIRC, bad hybrids can throw them out as well.Couldn't find a ROM dump that you could burn to a new one, so you'd have to replace the NVRAM and get it calibrated to get rid of the codes.Pushing A/B will clear the codes, but it will likely have a rather nasty DC Offset.

author: BravoV
author_rank: Super Contributor
timestamp: October 02, 2013, 03:38:08 am
content: For sure the cal is gone, but if you just want to make sure its working properly with un-corrupted NVRAM, there was a fellow did try to restore at his scope using other 2465B fresh nvram image and it works, read it here starting from here and up to his reply on the success result ->butmach's posts, and also I attached few copies of working 2465B nvram images, zipped in that thread.Hope this helps.

author: nanofrog
author_rank: Super Contributor
timestamp: October 02, 2013, 07:55:56 am
content: Quote from: BravoV on October 02, 2013, 03:38:08 amCouldn't recall the thread, and it didn't turn up under the search terms I used,so a big thanks for this.slburris's link allowed me to downloaded the one for mine, just in case (2445B FWIW).

author: Jeff5341
author_rank: Newbie
timestamp: October 02, 2013, 03:21:30 pm
content: Thanks for all the info ... I believe the NRAM has an internal lithium cell? If so, It is well beyond its average lifespan. I am considering purchasing one from the supplier in Greece. Did some of the calibration using my Rigol function generator, but sure wish I had the equipment to generate the fast pulse chain needed to proceed through all of the calibration steps.

author: madshaman
author_rank: Frequent Contributor
timestamp: October 04, 2013, 05:02:48 am
content: Get a used Tek 184, can prolly get cheap :-), it'll do your 2ns.