Component level repair (Was: Re: Setting up a VAXstation)

[Bryan Pope]

And thusly were the wise words spake by Liam Proven
> 
> Fascinating. The snag is, I know very little about electronics below
> the level of a broad knowledge of TTL, the rudiments of circuits and
> gates and so on. I have a bit of theory, no practice. I could not
> diagnose a faulty chip or anything; my troubleshooting consists of

All you need to start with is a logic probe.  Then for simple logic 
chips like AND, OR, NOT you would place the logic probe on the one 
or two inputs o see if they are high or low.  Then from that you 
would know what the output should be.  For chips that were a little 
more complex you would use the truth table from the datasheet for 
the particular chip to see what the output should be for each 
combination of input(s).

> Well, aside from 1 old Sun (SPARCstation IPX), the soon-to-arrive
> VAXstation, an Amiga and 2 STs and a QL, all my kit is Macs and PCs.
> The PCs range from a 386 to an Athlon XP, Macs from an SE/30 to a Blue
> & White G3/400MHz. So I don't run what most people here would consider
> "old hardware", I suppose!
> 

I know for the Amiga Commodore provided schematics...

> I am, a bit like Chuck, mainly a software person, but one who's
> competent with hardware to a basic level. I know bugger-all about
> electronics and while I regret that, I'm not inclined to fix it now. I
> just have an aesthetic appreciation for the way things /used/ to be
> done.
> 

I am also mainly a software person, but I am slowly teaching myself 
electronics because I would like to know how the "other side" works! :)

Cheers,

Bryan