tds3000  look what happened - Page 1
Forum section: electronics / repair

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 22, 2016, 10:49:55 pm
content: Can anyone help with this:A TDS3000 oscilloscope was hanging when switched on and would just show the boot logo.I opened it up and tried disconnecting and reconnecting cables.I removed the cable from the inverter circuit to the display driver and switch it on hoping, it would go into some kind of diagnostic mode. However when I reconnected the cable and then power up the scope. I got two vertical stripes of the display and no boot display.See attachments.ThanksR_G_B

author: tautech
author_rank: Super Contributor
timestamp: June 22, 2016, 10:59:44 pm
content: PSU bad caps?

author: nctnico
author_rank: Super Contributor
timestamp: June 22, 2016, 11:14:28 pm
content: Seems like one or more cables didn't got connected properly. I also don't see why a device would go into diagnostic mode with the inverter cable disconnected

author: tautech
author_rank: Super Contributor
timestamp: June 23, 2016, 04:23:39 am
content: Quote from: R_G_B_ on June 22, 2016, 10:49:55 pmYou haven't given us a lot to go on.History:How long have you had it, has the fault just appeared or has there been indications that a problem was developing?Sure it's a display problem but why, PSU problem (always the first check), display driver, Display connections or software boot problem?Yeah, so you've done the mandatory fiddle but have you even checked the PSU is to spec, you don't say....and as it's a SMPS you'll probably need another scope. (ripple frequency possibly beyond your DMM range)Service manual:http://exodus.poly.edu/~kurt/manuals/manuals/Tektronix/TEK%20TDS%203000%20series%20Service.pdfI suspect (but not sure) there may be another connector behind the display that interfaces the cable from the Mobo to the LCD panel and it would be best to reseat this one too. I haven't checked the SM but it should show it as a part or in an exploded view.

author: SL4P
author_rank: Super Contributor
timestamp: June 23, 2016, 05:44:19 am
content: The two stripes ojn the display say the backlight inverter seems to be working - so what else happened?A data ribbon cable, or the inverter output touched something else... ? oops!

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 06:19:35 am
content: When the scope is switched on it was just showing the DPO logo and it would just stay there.So I tried disconnecting and reconnecting cables to try. To see if it was a faulty connection some how and to see if I could force it into a some kind of diagnostic mode. I disconnected the cable from the display driver and the inverter. And switched on the oscilloscopeAnd got just a grey screen. I then reconnected the cable and powerd up.This is all I did. And the display ended up as it is. Seems strange just removing a cable would do this. Nothing was shorted.

author: SL4P
author_rank: Super Contributor
timestamp: June 23, 2016, 06:24:51 am
content: I'd be looking <very> closely at the connections and PCB at both ends of the display ribbon cable, and the ribbon itself.Not much else with what we know.

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 06:54:55 am
content: Yes sorted the cable next to the inverter cable was not seated properly.Now I need to find out how to get off the stuck DPO boot logo. Can anyone offer any suggestions?R_G_G

author: lowimpedance
author_rank: Super Contributor
timestamp: June 23, 2016, 07:04:09 am
content: Not much of a suggestion but my work DPO4000 series scope failed in the same way a few years back, stuck at the boot screen. Being a work machine apart from checking the power supply was okay I was not going to start poking around the main board. The agent said it was a complete main board swap required and at $5300 for the repair, if it happens again the POS will go straight into landfill.good luck

author: tautech
author_rank: Super Contributor
timestamp: June 23, 2016, 07:55:46 am
content: There's a factory adjustment procedure listed on P74 of the manual that is entered during power on boot....could be worth a try to see what's in the menus within.There might even be an error log there that might point you in the right direction.

author: AndyC_772
author_rank: Super Contributor
timestamp: June 23, 2016, 08:33:42 am
content: Quote from: lowimpedance on June 23, 2016, 07:04:09 amThat's standard Tek procedure as far as I know. They quoted me stupid money like that just to change the NVRAM battery on a TDS754D; they wouldn't replace the module alone, but instead would swap out the entire processor board

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 09:49:18 am
content: Quote from: tautech on June 23, 2016, 07:55:46 amWhich factory adjustment manual is this?Is there a link?Any other considerations.The processor seems to run a little hot so it may be stuck in some kind of processing loop?

author: tautech
author_rank: Super Contributor
timestamp: June 23, 2016, 09:53:52 am
content: Quote from: R_G_B_ on June 23, 2016, 09:49:18 amReply #3 Service Manual link

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 09:56:33 am
content: Thanks tautechR_G_B

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 01:27:19 pm
content: Looks like i managed to force it to boot.I got a multi meter probe tip and ran it along the ram chips U540 & U550 while it was stuck in a loop and it pulled it out of the loop and the relays clicked and the thing boots.Next problem cant get anything to work what next and suggestions?ThanksR_G_B

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 01:29:13 pm
content: seems to also be displaying the correct date.The delay button is stuck on.R_G_B

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 02:20:09 pm
content: I'm guessing the the ram chips may need to re solderer to the board as it still getting stuck on the display and only when i run the multi meter probe along the chip does it boot?R_G_B

author: Anks
author_rank: Frequent Contributor
timestamp: June 23, 2016, 05:30:02 pm
content: When you say running the probe along them you mean individually or actually running it along them?

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 05:36:28 pm
content: Quote from: Anks on June 23, 2016, 05:30:02 pmactually running it along them

author: Jwalling
author_rank: Unknown
timestamp: June 23, 2016, 06:02:33 pm
content: Quote from: R_G_B_ on June 23, 2016, 05:36:28 pmJust hope that there isn't two pins next to each other called power and ground!Jay

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 06:09:45 pm
content: Quote from: Jwalling on June 23, 2016, 06:02:33 pmPoor IC design if it was that wayR_G_B

author: tautech
author_rank: Super Contributor
timestamp: June 23, 2016, 07:40:39 pm
content: Quote from: R_G_B_ on June 23, 2016, 01:29:13 pmThat needs be fixed ^^^Many DSO's use front panel buttons to enter/display states while booting, no surprise at all the boot is stalling.

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 09:03:18 pm
content: It boots the relays click disk drive check and then the front panel flashes.There is also the 1KHZ voltage on probe compensation.

author: tautech
author_rank: Super Contributor
timestamp: June 23, 2016, 09:32:59 pm
content: Have you found an error log in the UI?Is there any clues in that log to point you to the problem?

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 23, 2016, 10:12:40 pm
content: I looked at the service manual page 74I tiried the factory adjustment nothing seems to happen.R_G_B

author: tautech
author_rank: Super Contributor
timestamp: June 23, 2016, 11:24:14 pm
content: Please read R_G_BThis thread is hard work and I don't know why.You'll see the images in the OP have been looked at 100's of times and this thread is getting plenty of views for the short time it's been active.Your replies have been....well what can I say.....short.For those following along at home or for any that stumble upon this thread in the future it's going to be hard work too as finer detail for fault analysis is required.I hate seeing good equipment broken and while I may not have all the skills to offer the fixes I'll do my best to the point when another member with better skills picks up the challenge but we need more to go on.So please give us more to go on, use the Quote button so your reply is in context and doesn't have us guessing.You might be frustrated by your broken scope, I'm just as much by lack of detail in replies.Re-read the thread and edit for those following and those that find the thread in the future.BTW my signature has nothing to do with my willingness to help or suggested replacement preference, it is required by the moderators.

author: Jwalling
author_rank: Unknown
timestamp: June 24, 2016, 10:04:21 am
content: Quote from: tautech on June 23, 2016, 07:55:46 amIn the adjustment procedure, it calls out for a "Fast-rise generator 1 MHz repetition rate, 1 VPk-Pk signal, with <1 ns rise time" and suggests a Wavetek 9500 Oscilloscope Calibrator with one 9510 Output module. That's just a bit out of my budget! Is there a low cost alternative that someone knows of? Everything else I have.Jay

author: R_G_B_
author_rank: Frequent Contributor
timestamp: June 26, 2016, 09:52:25 pm
content: It is highly likely that the firmware is corrupt as the screen shows the the word Bug with a code.It won't load firmware from the disk drive so the only way is either hack the scope to gain access to the RAM where the firmware is stored.