Bad ribbon cable in KOP

[annie1939]

I wanted to advise people that they need to check the ribbon cable that they got in their KOP. We had a rookie build at kickoff and nobody could get the wheels running except for one veteran team (F.R.O.G) . We finally narrowed the problem down to the digital sidecar or the cable. The NI rep there took a look and, sure enough, the ribbon cable connector was reversed. When he removed the connector and flipped it, the signal light came on and the motors started running and there was much rejoicing. There were three teams there that had not gone home in frustration by that point, but all of our cables were bad. The team that had gotten theirs working earlier had used a previous years cable.

Ann

[RyanCahoon]

Actually found a note about this on the FIRST website's control system page http://www.usfirst.org/sites/default/files/uploadedFiles/Robotics_Programs/FRC/Game_and_Season__Info/2012_Assets/DB37%20Ribbon%20Cable%20Assembly%20-%20Rework%20Instructions.pdf

Not sure how they would expect us to find this if somebody didn't already know the problem, though.

[Joe Ross]

At our rookie build day today, all 6 team's DB37 cables were reversed.

The FIRST instructions say to flip the male side. I think it's actually better to flip the female side, as it is more robust when squeezing in the vice. It was actually the female side that was backwards on the few that I looked at, also.

[vhcook]

Thanks for the heads up. I wonder what percentage of the cables out there are bad. I'll be checking ours the next time I get into the shop.

There is a somewhat vague note about this in the encrypted version of the KOP Checklist, not that we noticed it during the inventory:

Cable, DB37 Extension

flat cable - NOTE: MAY NEED REWORK. See
http://www.usfirst.org/frc/kitofparts

I also observe with some dismay that the KOP checklist that is on the kit of parts website right now does not have the note, and neither has a listed revision number.

[Paul62626]

Thanks for posting this, i will have to check Our team's when i get to the build site

[arizonafoxx]

Yeah that would have been nice to know about in the kickoff presentation or in Bill's Blog. I think many people do not have the opportunity to look online when they are at Kickoff workshops.

I got lucky that I found it while searching for the re-imaging tool but at first I thought the link was for if you break/tear the cable not that it may already be assembled wrong. Its a good thing I clicked on it anyway to check out the info.

[gzes]

Hi we just found that out and well when we flipped it the piece that holds the clips together broke:( where can we find a new cable? Or any suggestions to help thanks

[Joe Ross]

If you haven't placed a first choice order yet, there's a DB37 cable available
http://www.andymark.com/DB37-Flat-Ribbon-Cable-Kit-fc12-01-p/fc12-01.htm

Here's a few whole cable assemblies:
http://www.andymark.com/product-p/am-0500.htm
http://www.andymark.com/product-p/am-0504.htm
http://www.andymark.com/product-p/am-0672.htm
http://www.cablewholesale.com/specs/serial-cable/10d4-01203.htm

You can also get an equivalent for just the broken part from digikey or other electronics vendor. I think you can use your PDV from digikey for these.
http://search.digikey.com/us/en/products/A-DSF37LPXX-III-R/HMM37H-ND/924270
http://search.digikey.com/us/en/products/A-DFF37LPXX-III-R/HFM37H-ND/924261

[gzes]

Ok thanks alot

[CoachSally]

We received an email from our Boeing mentor regarding the reversed connector, and followed the pdf directions to repair this. However, the plastic clips that hold the plug in place both snapped off. Used a bit of hot glue to repair, but really don't trust this for a long lasting fix. Right now we are using last year's 37-pin cable connector. Does anyone know if there is an advantage (other than weight) to the ribbon connector?

[Al Skierkiewicz]

Sally,
Digikey sells the same type of connector and ribbon cable if choose to make your own. It can be done with a vise and a lot of patience.

[Cal578]

...Does anyone know if there is an advantage (other than weight) to the ribbon connector?

When we used the standard cable last year, it worked ok. The biggest disadvantage was that it tended to get in the way during assembly and troubleshooting. Our electrical team planned right then and there (during regional competition) to make our own cable for this year. We were excited to see the ribbon cable in the KoP. So you can imagine how disappointing it was that our cable was backwards. Fortunately, the team picked up on it quickly and was able to fix it before we had major problems or much time wasted.

Anyway, you'll probably have no problems using the old cable. Good luck!