Alt./Elec. Prob, Tried so many things

Alright, I have an electrical problem with my 1997 Honda Civic DX.  It's not my battery (which is only a couple months old).  The whole thing started with my headlights starting to dim.  It seemed to do it mainly at night after the car had been sitting for a few hours, and in the morning, again after it had been off for several hours.  The dimming of course became worse with the use of accessories such as the air conditioner or stereo.  My check engine light also came on and it would dim also.  Around the same that all this started happening, my speedometer started going crazy, jumping up and down all the time.  So I'm getting ready to add some amps and planned on upgrading the alternator anyways, so I do what any cheap ass would do and I hop on ebay and order myself a 135 amp alternator from alterstart.  I get it, do the swap myself (this was my first time) and the only difference was that now my speedometer didn't work at all, absolutely no movement.  Check engine light was still on, and this alternator appeared worse than the original.  Now the car is useless.  So I pay 16 bucks to mail this thing back to alterstart in texas (after having a shop test it and tell me that it was bad of course) and they return it to me saying that they fixed it.  So I put it in again, and it still doesn't work.  I had previously charged my battery for a few hours, so the alternator appeared to work, until my car died at an intersection the next day.   

I have re-grounded my battery, and my engine.  My alternator grounds through the engine.

I have not ran a new positive power wire to my alternator, I plan on doing this once I fix my problem, but the stock one seems to be in very good shape. 

I have checked the brushes and the Diodes in my new alternator, they each seem fine.  I didin't know what to look for, or how to test a diode with my digital multi meter, but the brushes are still plenty long and are making good contact with the spinning metal rod, and the diode (I only say one in my new one, as opposed to three in my old one) looks fine.  It has no breaks or burn marks. 

The pulley is tight, and the harness plugged in.

Today I had the alternator checked by Kragen, it passed there machines test, but I got a second opinion from the alternator shop who had before said it was bad, and they said it worked, but the charge light stayed on.  In other words the machine said that it would work, but when I throw it in my car my battery light on the dash will be lit.  He said it could be a bad voltage regulator, which is built into the alternator.  Today I dissasembled the whole thing and didn't notice anything obviously wrong.  I have no experience with alternators, I worked as a car audio installer for about 10 months now, but not at a place that installs alternators. 

If nobody here knows of anything else I can try, I will have some choices to make tomorrow.  Alterstart claims no cash refunds, and the electrical shop says it'll cost 70 bucks to diagnose my electrical problem.  If it is the power regulator, they'll just tell me to get a new alternator.  If I want to send it back to alterstart for warranty repairs again, I'll once again have to pay for shipping.  Preferrable I would be able to isolate the problem, then say look, You pay shipping both ways, cause I already shipped it back once and you said you fixed it.  I just want to be able to say whats wrong with it, so they dont say its not the alternator.  Or maybe it isnt the alternator, but I dont know what else it could be.

Thank you for any help, and sorry about the long post. 

Unfortunately I have to agree with the alternator shop.  It sounds very much like a bad alternator or a bad voltage regulator.  A Honda shop with the right computer diagnostic equipment might be able to tell you for sure.  But it sounds like you did the right thing by trying to go for a larger alternator, but are getting hosed courtesy of Alterstart.  Tell them you are getting really pissed and you demand they send you agood alternator with a goood voltage regulator built in.  (they probably won't care, but it always feels better to yell and scream and make demands on retailers who are ripping you off.)

BTW, to check a diode with a DMM requires that you remove it from the circuit.  Set the DMM on the diode scale if it has one, or on the lowest ohms scale if it doesn't.  A properly functioning diode will indicate less than an ohm with the meter leads connected across the diode in one polarity, and an open circuit when you reverse the polarity (swap the leads position.)

OK so I called alterstart today, and explained the situation to them.  I got them to give me a new alternator altogether, and a 150A instead of a 135A, which is a $50.00 upgrade.  Plus they are going to pay shipping both ways to get alternator I have back, and get me the new one.  So I basically got about 65 bucks out of em, which doesnt even cover my insurace for the time I've been out of a car, but o well.  I'm happy I got something and soon this will all be over. 

I would just like to say that this has been my first negative online shopping experience.  I here people bashing online/ebay sales all the time, and they have there points, but I have never had a problem until now.  I have purchased thousands of dollars worth of products online, including a deck, amp, sub, 2 sets of speakers, a camera and a lens, and more, and this is my first regretful experience.