L1 Bridge Connecting

SUMMARY: How to connect L1 Bridges on AMD’s Duron and T-Bird CPUs.

Changing the multiplier on AMD’s Duron and T-Bird requires two things:

1. A motherboard that allows multiplier changes;
2. A CPU with the L1 bridges connected.

Some CPUs leave the factory with all the bridges connected, so you don’t have to do it yourself. As of this date, only the very early AMD CPUs and some of the higher speed T-Birds leave the factory with connected bridges. In most instances, you will have to connect them yourself.

The First pic shows where the bridges are located on the CPU. It’s in the same location for Durons and T-Birds.

Looking closer at this section of the CPU, you will see that these bridges are very small. The cut is even smaller; it’s done with a laser and is just wide enough to break the connection. Your task is to reconnect the two legs.

Here’s an idea of size. In this composite shot, the top pic is a regular #2 pencil next to the L1 bridges. Do not use a mechanical pencil – many of the leads used contain plastic fillers that make them insulators, not conductors. Using a pencil is one option – we’ll discuss some others later. Now, sharpen the pencil to the finest point you can and VERY CAREFULLY connect the first bridge – it should now look like the middle pic.

Do the same to all four and is should look like the bottom pic. ABSOLUTELY make sure that each bridge is separate from its closest neighbor. If you inadvertently connect two bridges to each other, you could blow the CPU.

Once you’ve connected up the bridges, place the CPU into the motherboard’s socket and try to change the multiplier. You’ll know right away whether or not the bridges are connected.

Pencil is the cheapest, easiest and quickest way to connect the L1 bridges. Some have reported that the connection “wears out” over time and the bridges have to be re-penciled. The more permanent methods use conductive paint or a “Conductive Pen”; both of these methods are permanent but erasable with solvent – if you make a mistake, wipe it off with solvent and start over.

What’s pictured above are bridges connected with “Rear Window Defogger Repair Kit” paint. If you look at the grids on a car’s rear window, you will see thin brown lines painted on the glass. This repair kit contains conductive paint so that if one of the bridges is cut, you can reconnect it with this paint. It should be available in any auto parts store.

Don’t even try to use the brush they give you with the kit. I have found the best tool to apply the paint is the tip of a pin. Dip the tip into the paint, just putting on a small dab of paint, and connect a bridge. The paint usually dries very quickly, so you can’t linger too much. You can use nail polish remover as the solvent to wipe off any mistakes.

You can also get a Connective Pen that’s used to connect electronic circuits (e.g, Chemtronics CW2200MTP). It is used by electronic technicians to repair broken traces and is a silver based paint, much like the defogger paint. It looks like a pen and the tip is supposed to allow you to connect fine lines, but I still use a pin.

Michael Holaday sent me an email with another technique:

“I have what I think is a pretty slick technique of unlocking AMD’s bridges. I use the rear window defroster repair paint (keep reading, here’s the cool part). Just lay down one big thick blob covering all 8 pins; then scratch 3 lines through the blob like this – :|:|:|:. You now have 4 little blobs – the 4 bridges – that’s it – done! It seems to me this method requires much less time, effort, and dexterity than fashioning 4 very fine lines.”

And Simon Tan had this idea:

“Get 4 small strands of wire either from a speaker cable or whatever cable you can find that is stranded. Lay them over the traces and place a piece of scotch tape over it. Now you got yourself a very crude piece of trace tape that cost next to nothing.”

I’m sure there are more ideas floating around, so this is just a sample.

Email Joe