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geekhack Projects => Making Stuff Together! => Topic started by: gustavQ on Tue, 03 June 2014, 17:06:40

Title: IBM Model M loose ground wire
Post by: gustavQ on Tue, 03 June 2014, 17:06:40
Hi everyone.

Sorry if i'm open a new topic just to ask, what I think is, a quick tip.

So, I was disassemble a model M and, I don't know if it was me, but I found a ground wire loose from the board.
I want to put it back in the right place, but I don't know where.

I took a picture to make it easy to show the problem.

(http://s29.postimg.org/xrxin6iqv/WP_20140603_002.jpg) (http://postimg.org/image/rqztq3w4j/full/)

Can someone show me the correct spot to re-solder the wire?

Thanks
Title: Re: IBM Model M loose ground wire
Post by: E TwentyNine on Tue, 03 June 2014, 17:15:24
J6.   No soldering, it should have a slide connector.

Similar to this (http://wiki.geekhack.org/images/c/c3/Keyboard-modelm-boltmod-pcb.jpg)
Title: Re: IBM Model M loose ground wire
Post by: gustavQ on Tue, 03 June 2014, 17:39:48
The ground wire with the connector is also there, but not in the picture. I have two ground wires, but one is loose. The board of my keyboard appears to be a little bit primitive compared to that one.
Title: Re: IBM Model M loose ground wire
Post by: E TwentyNine on Tue, 03 June 2014, 17:50:22
The other ground wire goes to the cable.  Check the cable for a broken wire.
Title: Re: IBM Model M loose ground wire
Post by: gustavQ on Tue, 03 June 2014, 18:10:46
The other ground wire goes to the cable.  Check the cable for a broken wire.

Sorry, but i'm not following you.
In this picture you can see that they are two separated ground wires.
(http://s15.postimg.org/reknsii9n/WP_20140603_003.jpg) (http://postimg.org/image/ox8wl8yd3/full/)
Title: Re: IBM Model M loose ground wire
Post by: dorkvader on Tue, 03 June 2014, 18:41:14
the one with the connector goes to the tab on the PCB. The other one sholud go to the cable, I think.

What M is it, specifically? (A lexmark?) I don't think I have one that new or I'd crack it open and check.
Title: Re: IBM Model M loose ground wire
Post by: rowdy on Tue, 03 June 2014, 19:37:31
There's a couple of pictures here (http://geekhack.org/index.php?topic=45962.msg965193#msg965193) of my cable while I was refurbishing a Model M (actually I ended up making a replacement fixed PS/2 cable for it).
Title: Re: IBM Model M loose ground wire
Post by: 0100010 on Tue, 03 June 2014, 20:03:35
The other ground wire goes to the cable.  Check the cable for a broken wire.

Sorry, but i'm not following you.
In this picture you can see that they are two separated ground wires.
(http://s15.postimg.org/reknsii9n/WP_20140603_003.jpg) (http://postimg.org/image/ox8wl8yd3/full/)

The thin black wire is part of the cable, the thick black wires spade connector goes to the end of J6.
Title: Re: IBM Model M loose ground wire
Post by: dorkvader on Tue, 03 June 2014, 20:39:41
It will probably still work without the ground wire attached to the cable, but it probably won't be FCC part15 compliant though.
Title: Re: IBM Model M loose ground wire
Post by: gustavQ on Wed, 04 June 2014, 03:37:19
the one with the connector goes to the tab on the PCB. The other one sholud go to the cable, I think.

What M is it, specifically? (A lexmark?) I don't think I have one that new or I'd crack it open and check.

Yes, is a Lexmark:
(http://s21.postimg.org/dbjsq8dmf/WP_20140604_001.jpg) (http://postimage.org/)

You are all right it is from the cable, I needed to strip a little bit of the cable to see the other end of the wire.
(http://s30.postimg.org/r508n3dv5/WP_20140604_005.jpg) (http://postimage.org/)

I'm going to fix this.
Title: Re: IBM Model M loose ground wire
Post by: rowdy on Wed, 04 June 2014, 05:37:45
Having stripped the cable, you've lost the strain relief that the gromit was providing.

Depending on your location, budget etc. you might consider replacing the cable.

Unicomp sell them (http://pckeyboard.com/page/Cables/ACable) for $15 - but maybe get someone else to confirm that this is the correct cable as there is no picture.
Title: Re: IBM Model M loose ground wire
Post by: gustavQ on Wed, 04 June 2014, 06:49:39
Having stripped the cable, you've lost the strain relief that the gromit was providing.

Depending on your location, budget etc. you might consider replacing the cable.

Unicomp sell them (http://pckeyboard.com/page/Cables/ACable) for $15 - but maybe get someone else to confirm that this is the correct cable as there is no picture.

When I was offered the keyboard the strain relief was already broken thats why I stripped the cable.

I'm going to do the PS/2 to USB mod anyway. I'm waiting for the material to do that, and in the meantime, I want to to check if the Keyboard is fully funcional. But I don't have the PS/2 to USB converter yet.