tek 2430 fails self tests - Page 1
Forum section: electronics / repair

author: m3vuv
author_rank: Super Contributor
timestamp: December 31, 2021, 05:42:54 pm
content: hi all i just got this scope with a bad nvram backup battery showing a fpp 4000 fail,ive now replaced the battery and get the following fails during the startup self test:6000 cksum-nvram* fail,any idea how to fix this?or what the cause is,i actualy used an 18650 sell at 4v in place of the original battery,so 4v not 3.6,i did connect the battery before removing the old one but had a wire come off so the nvram cal data would of got lost,is this just a matter of a recal?,if so how do i do it?,tia m3vuv.

author: m3vuv
author_rank: Super Contributor
timestamp: December 31, 2021, 07:31:01 pm
content: well ive fired this up againe for a nosey/conformation and now it passes all self tests,has anyone any idea why this is so ??

author: george.b
author_rank: Frequent Contributor
timestamp: December 31, 2021, 08:14:10 pm
content: Quote from: m3vuv on December 31, 2021, 07:31:01 pmI do not, but I'm interested in finding out, too. I have a 2430A with similar symptoms intermittently. I suspect there was something wrong with the PSU, which unfortunately just gave up the ghost on the primary side, so I'll have to get that sorted out first.

author: Testtech
author_rank: Regular Contributor
timestamp: January 01, 2022, 12:13:05 am
content: It has lost all it's cal constants. Download a service manual and perform the calibration steps, preceded by a COLD START.Note: This instrument CANNOT be operated for more than a few minutes with the case off, as it will cause destructive overheating of the CCD hybrids. You must direct an external fan at the bottom board.Also, recap the PSU replacing all the small electrolytic caps and the RIFA's on the mains filter.No special cal equipment needed, just a good DC source and square wave generator.Have fun!

author: m3vuv
author_rank: Super Contributor
timestamp: January 01, 2022, 12:59:35 am
content: yup i know about cooking the hybryds etc but i need to know how to self cal this ok,happy new year all .

author: bdunham7
author_rank: Super Contributor
timestamp: January 01, 2022, 01:09:22 am
content: The first thing to do is the carefully and thoroughly check all of the power supply voltages per the specifications which will list nominal voltages, tolerances and ripple limits.The next thing that I would do is to set it up to look at a 100MHz or so sinewave on both channels and let it run for an hour to make sure the CCDs are not faulty. If you see spikes and noise after a while, that may mean they are toast, in which case there's nothing left to do until you scrounge some up.

author: m3vuv
author_rank: Super Contributor
timestamp: January 01, 2022, 01:13:06 am
content: so what symptoms will iffy ccd's thro up? happy new year btw.

author: m3vuv
author_rank: Super Contributor
timestamp: January 01, 2022, 01:19:17 pm
content: well for some reason after power cycling this a few times with an 18650 cell fitted in a holder it now works fine,all self tests now pass!

author: med6753
author_rank: Super Contributor
timestamp: January 02, 2022, 06:09:56 am
content: Quote from: bdunham7 on January 01, 2022, 01:09:22 amYou don't even have to do that. A fried CCD hybrid will be in your face. It will consistently fail self-test and the affected channel will be unusable.Ask me how I know that?

author: m3vuv
author_rank: Super Contributor
timestamp: January 03, 2022, 08:41:48 am
content: all traces look fine on both channels so gues the ccd's are good,just need how to calibrate this thing but no luck here or on tekscopes groups io,as i said after replacing the nvram battery and power cycling it a few times all self tests pass now.73.

author: bdunham7
author_rank: Super Contributor
timestamp: January 03, 2022, 05:01:46 pm
content: Quote from: m3vuv on January 03, 2022, 08:41:48 amSections 5 and 6 of the manual--all of section 5 and starting at 6-25 if you don't want to read 6-1 to 6-24.https://w140.com/mmm/tek-2430.pdf