Anyone know of one? I've googled it, but came up empty handed. I could really use a group of people who know schematics by heart, and could assist me with some designs I have.


-justin

One of the sites or lists on this page might be have what you're looking for:

http://www.ntu.edu.sg/lib/eng/eee.htm

Otherwise, I can suggest a few options:

1) Befriend an electrical engineering prof at a nearby university
2) Find a forum for discussing the category that your end product fits in, then find an electrical engineer on that forum
3) Ask an amateur radio operator (many have significant knowledge of electronics)
4) Call an applications engineer for whatever company manufactured the part that you're having trouble with
5) Hire an electrical engineer as a consultant. Warning: electrical engineering consultants tend to be extremely expensive. Having done some electrical engineering consulting, I can vouch that it is a very lucrative enterprise for the engineer

Jeff
BSEE

Justin,

One of my degrees is in Microwave Electronics. That'* not the thing in the kitchen, either. And my first 2 years with hp, I worked in Network Measurements Division, Microelectonics

What do you need?

lol .

I have tons of old motherboards [PII'* mostly] and none of them post. The reason of their demise, is a blown PSU.. I'm not interested in getting them to work, so I am going to desolder everything on it. What are the things that are going to be worthless, to help troubleshooting in the future go quicker?

Also, I have several sizes of resistors. I know how to tell their resistance by their colour codes, but some of the larger ones only have 5.2 ohms resistance, and some really small ones, have 5k ohms. I am guessing the larger the size, the more watts it is rated for? If this is true, how do you tell what is 1/4, 1/2, 1, etc.. ?


-justin

You're going to try to salvage a bunch of surface-mount components? Wow, that'* more ambitious than I would be. Even for the non-SMT stuff, it'* barely worth the time.

As a side note, I've encountered several motherboards that were "dead" but needed only to have a couple of electrolytic caps replaced. If you can see electrolyte leaking around those caps (they're the ones that look like cylinders), you might consider replacing them to possibly resurect the board.

I have looked into that, however there isn't anything leaking around them, and they have continuity, so I do not think they are the problem. I think it zapped the bios, but I am not sure.

Yes, I de-solder components off a board that was garbage, or useless. The only thing other than the usual stuff [caps, resistors, transistors, diodes], are a few little semiconductors.. that I have no clue what they are. One has the Motorola M, so I think it'* good. I've googled the numbers on them.. and unfortunately I cannot find anything on them. Oh well, they at least look cool.

Hardly worth it?? Dude, I am poor. Without getting this stuff for free, I would never be able to make anything more than a data cable for my TI-89.


-justin

You got an 89? who told you they rocked!!!!

lol.. you, Straitor

I have something that has defeated me, yes, something has defeated me. I have a graphics card, that has some useful stuff. That I want. Now, I can't find any solder posts, to actually de-solder. There is one chip on one side, and then another on the other side in the exact same location.. but they are different sizes, so what gives? I took some pics, but they suck, because my camera sucks in the morning.


I know it'* hard to make out, but what are those little rectangle things.. they are on every computer component I see.. are they switching diodes?


yes, that is a Geforce 3 GPU.


-justin

Justin, give it up. The P2 and higher mother boards run so crazy that they actually CREATE capacitance between the traces and layers. They have to design this in. And Jeff'* advice on surface mount components is sound.

The odds that you might get something off and replace it without smoking something else are extremely small.

And all that for a P2?

I told you I do NOT want the mobo to work. The only PII CPU I have is in use, and I don't plan on buying another. I just want the parts off the mobo. I just don't see a solder joint on that graphics card to desolder stuff, off of, to recycle. And I still don't know what those little rectangle things are. If you have any motherboard, or computer circuit board, they probably have one, about 1mm tall, and 3-4mm wide.


-justin