Thinkpads Forum

Regarding the famous X61(t) 266Mhz FSB mod, an issue of cutting through the motherboard trace comes up eventually (i.e. one got's to interrupt the motherboard trace that conducts the 7th pin of the clock generating chip to other circuits).

I'm concerned here, as my trial run attempts (involving a carpet knife and a scrap motherboard) didn't go well.
While cutting from a vertical angle, the knife blunted right away; besides, lots of force had to be applied to severe the motherboard trace (as per multimeter verification). Given that the PCB of the motherboard has multiple layers, I'd like not to cause a FUBAR situation here once i get to cutting the real motherboard.

Perhaps different of tools and/or a change of strategy are required. Care to advise?

The abbreviation of FUBAR stands for [censored] up beyond all repair.

I've had to perform printed circuit board surgery on a number of different types of boards over the years I've been in the electronics industry. What you need is the sharpest, smallest cutting tool for the job. That is usually an X-ACTO™ blade. There are many different versions, each designed for a specific cutting job. I've found that the #1 Precision Knife works well for the thin traces on a computer motherboard, along with the #5 Heavy Duty Plastic Handle for those times that I need to cut a wide ground line.

In order to prevent damage to the buried layer(s), you should NOT cut at a vertical angle, but instead angle the blade against the board (about 45 degrees). You should actually begin by scraping off the solder mask to expose the copper line. Cut the trace at TWO locations (1mm apart) and remove the copper trace between the cuts. It's usually very easy to lift the cut section from the board by getting the blade under the ends of the copper and twisting/rotating the blade. Verify with a multimeter that the cut ends on the board are more than 0 ohms.

ref: http://xacto.com/products/cutting-solutions/knives.aspx

Thanks for these instructions, Ray. They are well formulated and comprehensible.

Anyway, I went for a walk to my local electronics store, and they didn't have an X-ACTO scalpel available. So I took this Pro's Kit instead.
Once I get to actually cutting the PCB wire (still waiting for some preliminary hardware), I may get to go for one of these three options:
- Chickening out
- Cutting it and succeeding
- Cutting it and grandiosely failing, producing a giant paperweight in the process

Fun times ahead, fun times indeed.