JTAG Interface / Boundary Scan Test at Panasonic/ LG / Samsung, etc.

[miette_Kruemelchen]

Hello,

Two years ago, I had the pleasure of participating in an online webinar hosted by XJTAG, which covered various aspects of Boundary Scan Testing.

https://www.xjtag.com

In circuit diagrams, such as those for Panasonic TV devices, I frequently come across JTAG interfaces on the mainboard (A-Board), which I believe could also be utilized for this testing.

I would be particularly interested in the possibility of integrating Boundary Scan Testing into our daily repair routines, especially if companies could provide BSDL files. This could prove to be an extremely useful tool for carrying out component-level repairs in our repair workflows.

Currently, in our day-to-day repairs, we often can only narrow down the issue to a specific area on the board.

I am curious if anyone has already gained experience with integrating Boundary Scan Testing into our TV repair processes. It would be very interesting if even smaller companies still engaged in repairs could access such repair systems. Or is this JTAG primarily intended for centralized repair facilities?

I look forward to hearing about your experiences and information on this topic!

Best regards,
Sven

[CaptDon]

Not sure I follow your thought process here. Typically on a board with a JTAG connector we are looking at the programming pins of an FPGA / CPLD something similar. When performing 'Boundry Scan' that is usually a first step in identifying what physical devices are attached to the JTAG chain. I am unsure how you would troubleshoot via the JTAG port? Perhaps custom code loads to generate specific voltages or waveforms for testing? But then you have to be able to replace the original data to restore normal operation?

[mianos]

Full jtag boundary scan is not just to load firmware. There are scan cells on every pin on the chip that can be used to test interconnectivity, in place, with everything else on the board. All major chips, like memory, bus controllers etc, can have a jtag interface for this. No need for so many pins on the bed of nails, it's all active.

[miette_Kruemelchen]

Hello "mianos" and "CaptDon",

Thank you very much for your contribution. JTAG is already a powerful tool, and the Boundary Scan Test is just a small part of it. However, in the service sector, it proves to be a significant asset for today's motherboards. As a television technician, I would wish for small businesses to have the opportunity to obtain the necessary files as well. I suspect, as mentioned earlier, that only centralized repair workshops have access to them.

Best regards,
Sven

[JimKnopf]

As a hobbyist i use TopJTAG and TopProbe with either a JLink clone or an Olimex Tiny-H for Boundary Scan. Usually, to load firmware/memory dumps openocd is sufficient.

For testing pins, i use a JTagulator (not always successfull).

Some bsdl files can be found at https://bsdl.info/

In case of repairs, i found my IR Camera, High Resolution DMM (i'm using a Keithley DMM 6500), Oscilloscope (i'm using a Siglent SDS2504 X HD) and an Logic Analyzer (i'm using a Hantek 4032L and Pulseview) more helpful than a boundary scan.