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DIY Read Channel Shorting Tool

Posted: Wed Aug 02, 2017 7:38 pm
by LarrySabo
I finally got fed up trying to short read channel VIAs using tweezers while madly hitting Ctrl+Z, so I just made myself a shorting tool. No way I was going to pay 35 Euros +VAT + S/H ($72 CAD) for a ready-made tool. Ten spear-pointed pogo pins cost me $22.24 CAD and 5 tactile push buttons cost me $9.00 CAD. I already had the Acrylic and the Bondic. I’ll make up others in various widths, as required -- it takes just 30 - 45 minutes each. If I make all 5, they will have cost me $6.25 CAD each.

Ugly as sin, but it works great! :)

Shorting tool on PCB.JPG

DIY Read Channel Shorting Tool

Posted: Fri Aug 04, 2017 11:54 pm
by Amarbir[CDR-Labs]
Larry ,
Sir this is good work but it will be better work if its longer ,BTW i have this for the work -> https://www.drtools.eu/en/product/23/sh ... nd-wd.html

DIY Read Channel Shorting Tool

Posted: Wed Aug 16, 2017 7:46 am
by RolandJS
Tell me more about your shorting tool, what it does and why -- I'd like to learn from you! :)

DIY Read Channel Shorting Tool

Posted: Wed Aug 16, 2017 8:17 am
by LarrySabo
@RolandJS, it's used to short the read channel on Seagate drives in order to get a F3 T> prompt in terminal. My understanding is that corrupted SA modules prevent normal drive start-up, so shorting the read channel prevents the SA from being read, forcing the drive to look to the serial port for instructions. Or something like that. ;)

DIY Read Channel Shorting Tool

Posted: Wed Aug 16, 2017 4:47 pm
by Jared
Yes, and with certain drives (namely Grenadas like ST3000DM001) you need to very carefully time when you short it during initialization. Too early, and it won't load part of the firmware needed to get terminal, too late and the drive gets stuck busy.

DIY Read Channel Shorting Tool

Posted: Mon Aug 21, 2017 10:32 am
by michael chiklis
I think you will be able to guess proper shorting time more easily if you use fingers instead using twizeers or switches.

Watch this video to understand how to do it
aluminium foil.jpg

https://www.youtube.com/watch?v=_Mrvo87WvF8

jump to minute 4 to find out directly how to do it.

DIY Read Channel Shorting Tool

Posted: Mon Aug 21, 2017 12:37 pm
by LarrySabo
Thanks for the video link, Michael. My incentive to build the tool had nothing to do with getting the timing right -- it was trying to get both tweezer tips to connect and stay connected as I started to hit Ctrl+Z. The spacing of the tips would change and one tip would become disconnected from the VIA as my focus shifted from the tweezers to the keyboard and screen then back again.

DIY Read Channel Shorting Tool

Posted: Tue Aug 22, 2017 11:32 am
by Jared
I tried the foil trick from this video a few times and never had much success with it. I've still found my tweezers to work best, but maybe because I'm just used to doing it that way.

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DIY Read Channel Shorting Tool

Posted: Fri Aug 25, 2017 9:23 am
by michael chiklis
Jared wrote:Source of the post I tried the foil trick from this video a few times and never had much success with it. I've still found my tweezers to work best, but maybe because I'm just used to doing it that way.


Did you put a little bit of solder on those points?
I suggest to use 60/40 solder that is better than free lead solder.

DIY Read Channel Shorting Tool

Posted: Fri Aug 25, 2017 9:32 am
by Jared
I did. In fact, even when I use tweezers I usually fill the points with a bit of 60/40 solder.

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