Low vs High Grade Circuit Boards?

Hello, I have been dismantling things for the last several days and have accumulated many circuit boards. I was wondering how to determine if the board is low or high grade?

I have been told look at the resistors - the smaller the better. Also, to look for gold-colored pathways.

I was recently told about the "see-through test" and was wondering how reliable it is. That is, holding the board up to a light source. If you can see through it, its low grade. If you do not see the light / BARELY any light, it is high grade. This all relying on the thickness of the board as a indicator.

Your thoughts? I plan to take everything back today and am hoping to maximize on them instead of throwing them all off as breakage.

Thanks for your time guys!

This thread is very helpful for sorting your boards.

http://www.scrapmetalforum.com/elect...rds-parts.html

Thanks for the link, the pictures really help! Any idea if the "light test" I talked about is accurate?

I don't know how accurate that is..never tried it myself. Here are some general characteristics of low grade boards:

Usually brown or tan on at least on side. <-- Best/easiest way to sort while you're learning.
Normally easily breakable.
Have large capacitors, resistors, aluminum heatsinks, transformers, and other material that isn't worth all that much per pound.
Very few, if any IC chips.

Once you get these out of the way, then you should have mostly valuable boards left.

Without going into much detail (you'll have to look up what these look like) here are the most valuable components of many circuit boards:

Gold plated pins, and connectors.
IC Chips
BGA's (Ball Grid Array) chips and Flatpacks
Visible gold plating on boards(Most of the time, gold plating doesn't continue under the solder mask, but it can)
PROMS
EPROMS - These have cool looking windows on the tops of them usually under a sticker.
It's late, and I can't think of anything else! There are other components that can be valuable too, but these are the ones to focus on for now.

Anyway, more of the above items give the board more value. Lesser value components decrease a board's value. The board itself has no value at all. It just holds together everything that does.

Originally Posted by ryanw

I don't know how accurate that is..never tried it myself. Here are some general characteristics of low grade boards:

Usually brown or tan on at least on side. <-- Best/easiest way to sort while you're learning.
Normally easily breakable.
Have large capacitors, resistors, aluminum heatsinks, transformers, and other material that isn't worth all that much per pound.
Very few, if any IC chips.

Once you get these out of the way, then you should have mostly valuable boards left.

Without going into much detail (you'll have to look up what these look like) here are the most valuable components of many circuit boards:

Gold plated pins, and connectors.
IC Chips
BGA's (Ball Grid Array) chips and Flatpacks
Visible gold plating on boards(Most of the time, gold plating doesn't continue under the solder mask, but it can)
PROMS
EPROMS - These have cool looking windows on the tops of them usually under a sticker.
It's late, and I can't think of anything else! There are other components that can be valuable too, but these are the ones to focus on for now.

Anyway, more of the above items give the board more value. Lesser value components decrease a board's value. The board itself has no value at all. It just holds together everything that does.

So pretty much, if its green odds are it is mid or high grade?

If anyone has a few boards of both grades laying around, take a moment and hold them each up to a light. I think it makes sense... high grade is too thick for light, where low grade is easier to see through.

Anyone able to confirm this as a reliable method?