Agilent 16702 logic analyzer power LED  is blinking.  Does not start.  - Page 1
Forum section: electronics / repair

author: geshka
author_rank: Regular Contributor
timestamp: December 13, 2020, 07:23:18 pm
content: Hi experts.I have Agilent 16702 which is not starting - "power on" LED is blinking, buttons on the front panel are permanently lit, screen is dark. Seems like a POST is not passed.Are there any service manuals available? Any recomendations to check? Would appreciate any ideas ...Thanks.

author: james_s
author_rank: Super Contributor
timestamp: December 13, 2020, 07:57:56 pm
content: The first thing I'd check is the battery that keeps the NVRAM going, I don't know if it applies to this specific instrument but just a few weeks ago somebody had a HP oscilloscope of the same generation that had a similar fault and the cause was a dead battery.

author: geshka
author_rank: Regular Contributor
timestamp: December 13, 2020, 08:18:00 pm
content: Thanks.Just replaced battery. Did not make any better, unfortunately. I noticed there is a board between PS and LCD screen. It has a down there a LED that continuously gives two short blinks - looks like an error code?

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: December 14, 2020, 02:55:18 am
content: Any chance you changed the screen resolution to something the LCD can't display? I run mine at 1024 x 768, I think, on a big screen display. Anyway, the lcd does not turn on at higher resolution.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 14, 2020, 04:04:14 am
content: Since it's effectively a PC with LA hardware, you could try disconnecting the front panel devices and seeing if you can get the PC part to power up (external monitor, etc if needed). Since the motherboard should be an industrial one, there may be its own indicator for POST issues (maybe a connection for a buzzer or something) - I wouldn't expect that to flash lights in the LA hardware, but perhaps it's something with the interface card that is preventing it from booting.

author: geshka
author_rank: Regular Contributor
timestamp: December 14, 2020, 01:26:43 pm
content: Thanks for the responses.I did not change resolution ( maybe somebody did) . It was collecting dust in our lab storage for years, until somebody decides to "recycle" it. I just salvaged it from being crashed.About PC board and other stuff - There is a buzzer on board which is silent. Anyway, trying to boot it as a PC - this is cool idea. I will try. Thanks.

author: jmonette
author_rank: Contributor
timestamp: December 14, 2020, 01:39:26 pm
content: A 16702A is basically a computer. The first thing to check would be if the fans are sinning (you should be able to hear them). Then I would remove all the cards in the back and plug a monitor. Without those info, everything is possible!

author: geshka
author_rank: Regular Contributor
timestamp: December 14, 2020, 06:52:18 pm
content: Yes, fans are spinning. hard drive has initial kick (powered) but I cannot hear any booting activity. Exsternal monitor has some signal but it shows as out-of-range - no picture, just indication that there is a signal.

author: MarkL
author_rank: Unknown
timestamp: December 14, 2020, 08:23:16 pm
content: The power LED by default is blinking when the unit is first turned on. Late in the boot process, while various daemons are starting up, the LED is turned to steady.So, the only thing the blinking LED indicates is that your system has not booted. Not incredibly helpful.You could start with some of the basic troubleshooting steps, like checking the power supply voltages. There is a service guide that has some of that information, but it doesn't have any detail like schematics:http://literature.cdn.keysight.com/litweb/pdf/16700-97015.pdfCycling through different internal and external monitor settings is also covered in the above guide.I wouldn't characterize the 16700 system as a "PC", which implies an x86 and/or microsoft OS. It's a PA-RISC CPU architecture running HP-UX (Unix). The later 16900 series are x86 PCs running windows.

author: MarkL
author_rank: Unknown
timestamp: December 14, 2020, 10:22:21 pm
content: Also, if you're trying to use an external keyboard on the 16702, be aware there's an issue using non-HP/Agilent keyboards on these units. If you're trying to follow some of the monitor configuration procedures in the service guide, it will complicate things if the keyboard is not working.https://www.eevblog.com/forum/testgear/hp-16702a-mouse/msg374967/#msg374967

author: geshka
author_rank: Regular Contributor
timestamp: December 14, 2020, 10:24:24 pm
content: This is super useful , MarkL. Especially link to service manual.Thnaks a lot!!! will continue to troubleshoot