Suggestions for VT103?

Tony Duell ard at p850ug1.demon.co.uk
Mon Dec 29 12:34:15 CST 2008


> So forgive my inexperience here -- but just to make sure I'm 
> understanding the changes I need to make -- is all that's necessary just 
> wiring up the address lines (18-21) from slot 1, to slot 2, to slot 3, 
> to slot 4?

Yes, but I think it's _twice_ on each slot (the Q-bus being based round 
dual-height boards). So a total of 8 points to link for each of 4 wires.

But it is just a matter of running wires between those points and 
soldering them down.


> 
> Also, just to satisfy my curiosity -- it's been mentioned by several 
> people that lead-based solder is necessary -- why is this?  (I think I 

Is there ever a good reason not to use leaded solder in homebrew stuff 
and classic computer repairs (neither of which come under any RoHS 
directives in the UK)?

It is a very bad idea to mix solders, the worst way, or so I am told is 
to use lead-free solder on a PCB that was originally soldered with leaded 
solder (the VT103 certainly was!) The resuling lead-free solder 
contaminated with a little lead produces a very poor, brittle, joint.

> have a spool of it somewhere that I liberated from my grandfather's 
> basement some years back, but I'll have to dig it up...)

This is electornic-grade resin-cored solder, I hope!. You can still buy 
leaded solderm at least in the UK, fortunately.

-tony



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