MHHAuto MB Star C4 Mercedes Benz Star Diagnosis SD Connect C4 Experience Sharing
There are so many kinds MB Star C4 SD Connect Multiplexer in the market, how to choose a good Star Diagnosis SD Connect Multiplexer? Below Autonumen.com share a Star Diagnostic SD Connect MB Star C4 Mux identify guide as following. This is sharing from MHHAuto forum, great Mercedes Star diagnostic SDconnect SD C4 tools experience sharing.
MHHAuto Thread: SD Connect C4 — avoiding garbage
I’m in the market for an SD connect C4 mercedes benz Star Diagnostic Tool and have been trying to spend my time doing some homework to avoid getting a garbage unit. I certainly can understand what a lot of people have been saying about the widely varying quality that’s out there. I am a EE and PCB designer, so I’m trying to make use of that knowledge to select the best unit that I can.
To that end, I’m going to share what info I’ve collected so far, and when I finally end up buying whatever unit I do, I’m going to do a full teardown on it and post the results here.
As another matter, I’ll openly post details on who I buy the unit from and impressions after receiving it.
Near as I can tell right now, there appear to be about 4 “factories” that make different units.
One thing I’ve been asking all of the sellers for (and I would encourage others to do the same) is photos of the actual MB Star C4 SD Connect unit (including PCBs) with a unique identifier in the photo to prove that the unit they say they are going to send me is the actual one they send me. Of course, some sellers immediately bail at this, but then you know who to avoid ahead of time.
In general, a lot of the components used in a Star diagnostic tool SD C4 Multiplexer are getting quite long in the tooth. Many of the parts are approaching 20 years of age. Thus, you stand a fair risk of getting pulls (used parts) and/or remarked parts on these.
In following posts, I’ll provide photos of what I can discern as differences between the MB Star Diagnostic SD Connect C4 units along with some commentary about whatever info I can provide at this point.
to, I’ve outlined some things I feel are important to note. They have a set of 4 analog switches on the PCB. In this photo, they are ADG426 from Analog Devices. I’ve seen some clones that use DG526CY from Harris/Intersil. The DG526CY, besides being completely obsolete, has an typical RDSON of 270 ohms vs 80 for the Analog Devices part. It also has a -55dB isolation vs -75dB for the AD part. In short, the AD part is just a much better mux. So with that said, I would insist on any unit I’m interested in using those.
A second thing you’ll notice is the use of can crystals where 4 pin variants were intended. This is just sloppy and cheap. There may also be issue with loading (and ultimately clock stability) depending on whether they matched the loading caps to the substituted crystal or not.