RJ-45 Jack - Page 1
Forum section: electronics / general

author: MrRedHat
author_rank: Unknown
timestamp: November 09, 2014, 05:12:22 am
content: I have an RJ-45 jack that was on a PCB from an HP printer. Someone tripped over the network cable and tore it up pretty good. I was able to de-solder it from the PCB on the printer main board pretty easy, but I’m looking for a replacement. The part umber on the jack is RTF-134BB61F-HP. It has 1 row of 5 pins and then another row of 5 pins, and finally a row of 4 pins. I attached the best picI could of the jack. Is there any place I can find a replacement for this jack?

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 09, 2014, 06:44:15 am
content: Google reveals many sources of that jack. The problem may be finding someone who will sell you just one (vs. 10,000 of them)You may have to discover the manufacturer and beg them for a free "sample".OTOH it sounds like a pretty common jack, and you may find a generic one with the same footprint.

author: Kohanbash
author_rank: Regular Contributor
timestamp: November 09, 2014, 01:44:19 pm
content: HiIf you can not find the connector maybe you can put a RJ-45 plug on flying leads and solder the wires into the board.Also I have never seen a RJ-45 connector with 14 pins on it. Have others seen that?

author: Kjelt
author_rank: Super Contributor
timestamp: November 09, 2014, 02:03:29 pm
content: Quote from: Kohanbash on November 09, 2014, 01:44:19 pmNope but he should make a picture from below to show the pin layout because I can imagine that:Quote from: MrRedHat on November 09, 2014, 05:12:22 amThe last 4 pins are the two leds: 1 led green (+ and -) , 1 led orange (+ and -)Then two rows of 4 datapins which is normaland then probably on the far end another pin on both sides to mechanically fasten the metal can grounding pins which is a normal CAT6 RJ45 pcb female Jackonly the distances between the pins and rows differ per manufacturer.

author: MrRedHat
author_rank: Unknown
timestamp: November 09, 2014, 05:49:41 pm
content: I managed to get a better picture. It's manufactured by UDE.

author: MrRedHat
author_rank: Unknown
timestamp: November 09, 2014, 06:36:31 pm
content: I ended up buying a whole new formatter board for the printer. It cost $20 for the formatter board with shipping. I figured by the time I figure out the correct part, cost, it’s will probably end up being easier/cheaper to have done the formatter board.

author: Kjelt
author_rank: Super Contributor
timestamp: November 09, 2014, 07:00:33 pm
content: Weird it does have two rows of 5 pins, are there perhaps magnetics inside...

author: macboy
author_rank: Super Contributor
timestamp: November 09, 2014, 07:21:12 pm
content: Yes, it is big enough to definitely have integrated magnetics. And the last row of 2+2 pins are for the two LEDs that we can't see but I almost guarantee are there.

author: gxti
author_rank: Frequent Contributor
timestamp: November 09, 2014, 07:52:30 pm
content: Definitely a magjack of some type. They come in a few physical pin layouts but you have to be careful about how they're wired internally. If you find a datasheet for the original part, and compare it to ones on Digi-Key, you shouldn't have any trouble finding a compatible part.

author: Kohanbash
author_rank: Regular Contributor
timestamp: November 09, 2014, 08:01:36 pm
content: In the middle row with 5 can the fifth pin be a shield.So the row of 4 and the row of 5 next to each other are signal + shield. And then as others have said the pins on the edge are for the 2 LEDS,

author: MrRedHat
author_rank: Unknown
timestamp: November 10, 2014, 01:42:34 am
content: Is there any documentation that talks about the internals of magjacks? I ended up dissecting the one that I had and I found lots of little inductors inside. With some surface mount capacitors.My very limited electronics schooling tells me, these are probably filters to reduce line noise on the pairs. It appears that there are four rows of inductors with two inductors per row with two pairs twisted together.

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 10, 2014, 02:01:54 am
content: Quote from: MrRedHat on November 10, 2014, 01:42:34 amIf you use Google image search for "magjack", you will see dozens of diagrams showing the concept.The basic circuit and pinout looks like this....Note that there end up being only 3 pins for data in each direction, so likely some of the remaining pins are ground and/or maybe connection to the two unused pair(?)I wouldn't bet my life that is a Magjack. It seems rather on the small side.