Motherboard Diagnostic/Testing - Hardware Options? - Page 1
Forum section: electronics / repair

author: eamondo2
author_rank: Newbie
timestamp: February 29, 2020, 07:00:56 pm
content: Hi all,So I've been lurking for a while but finally had a burning question to ask. I work at an electronics repair shop, learning the ropes as I go (no formal EE experience otherwise). We have been experiencing a lot of slowdown when it comes to testing customer's desktop PCs. The usual method is to do some surface inspection (bulging caps, bad connections, anything toasty) and then power supply/delivery tests. Then we get into the brunt of the time sink, swapping components one by one to find the culprit.The issue is that it's somewhat unfortunately expensive to keep enough revisions of modern PC hardware on hand to use for testing purposes. Modern CPUs seem to be dropping support for older socket types/controllers faster than we can keep them in stock, at least not at a reasonable enough cost for our size of operation.The question:I have seen a number of older Port 80h POST diagnostic add-in boards, usually just compatible with ISA/PCI interfaces for pulling diagnostic/stop codes from boards being tested. Not all motherboards have the built in LED segment display for getting such information.All the options I have found so far are either rather sketchy overseas options with less than stellar reviews, and no guarantees of compatibility or explanation thereof. I have seen some mention of USB2 being used as an access point for the common debug port through the controller, but I doubt that would be as compatible across revisions/controllers.Does anyone know of a dedicated tool that serves this purpose? If nothing else, just enough to see if the CPU/RAM/VGA is causing the boot failure. Barring that, is there any knowledgebase regarding poking around for common debug info ports/connectors on modern motherboards? I would imagine that while the factory in production uses a complex and specialized jig and test equipment to serve this purpose, there ought to be something similar to a JTAG serial port, or at least some way to read from port 80h across different motherboard revisions/specifications.Thanks in advance, I've been fiddling about with this for a while and haven't managed to get anywhere on my own. I had thought about using a logic analyzer or an arduino as an I2C or serial adapter for reading the information, but that doesn't seem to be supported as output on a lot of recent boards.

author: oPossum
author_rank: Super Contributor
timestamp: February 29, 2020, 08:13:41 pm
content: There are numerous tools that use LPC or ESPI bus to get the port 80 codes. The problem is that not all motherboard have easy access to those interfaces and those that do use a variety of connectors.An example of one of these tools:https://www.eltan.com/products/manufacturing-tools/327-lpc-post-serial.html

author: PKTKS
author_rank: Super Contributor
timestamp: February 29, 2020, 08:24:41 pm
content: There are today a number of PCIe boards as wellUsually it only works at the first PCIe slot due tothe enormous problems introduced by "Wintel" greedchanging things just insanely incompatibleNevertheless they all FIT. However the tip of the icebergis that BIOS vendors manage to keep pace with Wintelinsanity but the BIOS codes form a puzzle to decipherIn syntax even if do have a valid help CODE - chancesare you will have to parse the BIOS manuft tablerelate that to the "board manuf date" and check if validFrom my experience ? It is better than nothingworst case scenario as said you have LPT portBest case you have a PCIe board ready and the code will fitVery good for first evaluationCan not think of doing that without the codes.Paul