54615B repair - no boot - Page 1
Forum section: electronics / repair

author: Iridium
author_rank: Newbie
timestamp: April 20, 2022, 06:18:41 pm
content: Hello,My oscilloscope HP54615B recently freeze during boot. Service manual :https://engineering.case.edu/lab/circuitslab/sites/engineering.case.edu.lab.circuitslab/files/docs/Agilent_54615B_54616B_54616C_Oscilloscopes_User_Service_Guide_.pdfThe supply seems to be ok (with or without load...), and the service manual just said me to buy another motherboard.... Not really usefull.In the 54615B, i found a NVRAM M48Z18https://eu.mouser.com/ProductDetail/STMicroelectronics/M48Z18-100PC1?qs=eb%2FRSZx1fMtLBqwnBmHVJw%3D%3D, with a retention time of 10 years.Can this component be the problem?Thank you a lot for your help, and sorry for my bad english.Iridium

author: m k
author_rank: Super Contributor
timestamp: April 23, 2022, 06:28:13 pm
content: Is "No module installed" a normal text?Is there any moment you can read the top line, is it steady?Manual page 4-34 step 5 has"logo and copyright text, followed by a graticule with text at top of the display"Your boot is clearly stopped very early.Maybe something is disconnected.

author: factory
author_rank: Super Contributor
timestamp: April 23, 2022, 06:47:00 pm
content: The module is an optional extra that fits on the back, there are several types for RS232 or GPIB connections and/or & measurement storage.David

author: Iridium
author_rank: Newbie
timestamp: April 24, 2022, 01:02:09 pm
content: Hello,QuoteYes, it's a normal text, already displayed.QuoteYes, the manual ask to check the low voltage, but all voltages are ok, and the fan is running.QuoteNothing disconnected (verified with my multimeter)Thank you for your time !Iridium

author: m k
author_rank: Super Contributor
timestamp: April 24, 2022, 07:05:22 pm
content: Disconnected can mean anything, like chips and cables but also stuff like bad solder joints.Are topmost dots random?Power on the machine few times and take pictures.Wait a moment before powering it up again.You should also find a way to figure out what is the true situation of the scope, it can stil be operational but with wrong picture.For that a 2nd scope is an obvious solution but any indication is enough.If topmost dots are not random then software failure is more probable.You're looking a CRT monitor and it has a picture so it's fine.Next in line is a display controller and it is outputting that picture just fine but it can also be totally independent so its input side is unknown.Rest are also unknown until you can prove otherwise.If probe calibrator is coming alive only some time after picture hangs it may be an indicator.

author: Iridium
author_rank: Newbie
timestamp: April 26, 2022, 03:29:07 pm
content: Hello,QuoteYes !QuoteThe calibrator output is set 5V. I can't use the frequency mode (2.49kHz output) because I have to select this mode with software keys; impossible without displaySome news : if I connect the module, the oscilloscope take more time before freeze, and the grid have enough time to be displayed (see attachement).Thank you !

author: m k
author_rank: Super Contributor
timestamp: April 26, 2022, 04:35:23 pm
content: Very good.You can do device inquiries through HP-IB.If they are answered you know the device is still operational, sort of.Is it normal that HP logo and grid are present simultaneously?Top line has one extra dot.Dotted line can also be a normal uninitialized situation you can't normally see.If your inquiries are answered try some measurements through HP-IB.Accuracy is not needed, you're just trying to find out how sane the scope section is.

author: Iridium
author_rank: Newbie
timestamp: April 27, 2022, 05:19:53 pm
content: Hello,I'm searching how to use the module (I never use this interface).QuoteYes, for a short time.

author: free_electron
author_rank: Super Contributor
timestamp: April 27, 2022, 05:50:48 pm
content: DEFAULTS LOADED your nvram is corrupted. empty battery

author: bostonman
author_rank: Super Contributor
timestamp: April 27, 2022, 11:06:02 pm
content: QuoteI'm curious, can replacing the NVRAM (or battery as I've seen some of these with battery access) reload all the information or does something need to be reprogrammed?

author: m k
author_rank: Super Contributor
timestamp: April 28, 2022, 09:05:23 am
content: Quote from: Iridium on April 27, 2022, 05:19:53 pmIf you have other modules available you can test them also.After first boot you get that defaults loaded or similar text but if setup memory is ok the text should stay away during next boot.Is there a real time clock, was it keeping up?Setup memory has obviously different sections for different settings, it's also possible that one part is ok and other part is not.Real time clock and setup memory are not necessary in the same chip but many times they are.If you have a serial port interface you can communicate with the scope using a simple terminal or emulator.

author: Iridium
author_rank: Newbie
timestamp: May 02, 2022, 11:10:25 am
content: hello,sorry for the delay.QuoteNo RTC foundQuoteI search for this.

author: Iridium
author_rank: Newbie
timestamp: May 09, 2022, 03:25:09 pm
content: Hello,After test, I can't access to the oscilloscope throught the external module.My problem seems to be the same as this video :So, I will try with another NRAM module...

author: merox
author_rank: Regular Contributor
timestamp: May 09, 2022, 06:46:47 pm
content: Quote from: Iridium on April 26, 2022, 03:29:07 pmMy 54200A behaved more or less the same than your 54615B, the culprit in my scope were corrupted/dying EPROMs.Had some new EPROMs burned, inserted them an the scope and it started working like nothing had ever happened.

author: bostonman
author_rank: Super Contributor
timestamp: May 09, 2022, 11:20:21 pm
content: QuoteDid you burn them prior with anticipation of them getting damaged or you found the firmware somewhere?If the issue with the 54615B is the same, I'm sure he'll be looking for the firmware.

author: merox
author_rank: Regular Contributor
timestamp: May 11, 2022, 03:22:11 pm
content: Quote from: bostonman on May 09, 2022, 11:20:21 pmI got my 54200A in non-working condition and searched for quite some time till I finally found the firmware online. The original source is long gone but I reuploaded them to KO4BB.But that won't help in this situation. I've searched for the Firmware of the 54600B series myself and couldn't find it anywhere. But I might have a similar looking scope at work, I'll have a look if it's the same - maybe I can dump the firmware of that one. I'll let you know in that case.

author: Runco990
author_rank: Frequent Contributor
timestamp: May 12, 2022, 05:41:48 pm
content: Replace the NVRAM or do the battery mod to it. Then run the built in calibration and the scope will be fine. I have done LOADS of these. The NVRAM battery is dead. Don't overthink it. Typical failure.The later series has the same problem now, but the battery is a button cell soldered to the main board, much easier to change.

author: bostonman
author_rank: Super Contributor
timestamp: May 13, 2022, 02:20:44 am
content: I have one of these and just curious how many NVRAM chips are on the board.I may buy some blank ones before they go obsolete so I have them for future needs (although the battery may die before I use them).

author: Fixed_Until_Broken
author_rank: Regular Contributor
timestamp: May 13, 2022, 02:31:49 pm
content: Quote from: merox on May 11, 2022, 03:22:11 pmI have a 54600B Do you need a dump of the ROM? I have a mini pro not sure if it can read the ROM IC that's in these. if it can I am happy to read it.