The General Approach to Computing - A Ramble

Tony Duell ard at p850ug1.demon.co.uk
Fri Apr 24 13:46:19 CDT 2009


> You can fix anything sold today if you want to spend a bunch of money for 
> equipment to deal with surface mount chips (BGA type equipment is not 

SMD, other than BGA, is not hard to do with simple-ish hand tools...

> cheap). You can get spare parts (or boards to desolder parts from) at a 
> recycler or ebay. Most people do not go that route because it is not 

Can you? I suspect the chances of finding the right ASIC for a PC 
motherboard, video card, etc is pretty remote. And I am told that if you 
desolder a BGA device, you have to 're-ball' it before reusing it, and 
the equipment to do that is even less common and more expensive than the 
reflow oven.

> economical and they don't have the skills or time to do it anyway. It is 
> also much easier to troubleshoot something that only has a few chips on it, 
> compared to the older stuff. I have an Atari 65XE in parts currently and a 

I disagree totally. It may be easier if you're just going to replace 
parts until it works (in that there are fewer of them to replace), but 
it's a lot easier to be sure a transisotr is working properly than even a 
TTL IC. And it's a lot easier to be sure a TTL IC is working correclty 
than to do the same for an ASIC where you possibly don't quite know what 
it should be doing ('Is this pin supposed to be stuck high, or is it a 
fault?'). Not to metnion the fact you can't probe the connections to a 
BGA IC.

> Commodore 1750 REU in parts waiting for sockets to redo the RAM. The 65XE 
> was broke when I got it and I want to fix it, it would be easier just to buy 
> a working one but I like to tinker anyway.

A friend was looking at one of 'my' scheamtics for an HP desktop and made 
some comment like 'Did you really have to include a schematic of the 
fan?' (The point being that I'd taken the brushless DC fan apart and 
traced out a schemeatic of the control circuitry). My comment was that it 
is a part of the machine I might have to repair sometime. And that a 
transistor is a lot cheaper than a complete fan (not to mention the fact 
that I am more likely to have a transisotr in the spares box).

> 
> I don't want to go back to the old days when machines were slow and 
> unreliable, when you had to fix a machine just to be able to use it.

It's odd, but I have many fewer problems with my classic computers than 
I've ever had using modern PCs. 

-tony
[...]

> doing support so the user does not have to. Don't expect the masses to want 
> to expend the time and energy into their commodity tools as you do to your 
> hobby.

I don't. I'd just like the chance to be able to carry on the way I think 
is the right way. Namely compoennt level repair. And that means I wish I 
could still buy real service manuals. And that I could buy spare 
components. I understand why I can't, but that doesn't mean I have to 
like it.

-tony



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