[Coco] Re: Let me introduce myself (GW/CoCo BASIC similarities)

[Richard E. Crislip]

Hello Gene

On 02/05/2006, Gene Heskett wrote:
> On Sunday 05 February 2006 04:47, Richard E. Crislip wrote:
>>Hello Gene
>>
>>Thanks for the reply, I am not sure what those caps are that you are
>>refering to, but I would guess that that would be my next step. I have
>>already removed and cleaned all the socketed parts (including the
>>daughterboard. No joy. So the caps seem like the next target. Could I
>>purchase them, cut the old ones off and solder the replacements on to
>> the place of the old ones? I'm not good enough and do not have the
>> equipment to desolder surface mounted components.
>
> No, that will take a soldering iron that looks like an overgrown set of 
> tweezers so it can hit both tabs of the cap at the same time.
>
> The only one I'm fam with is a GC thing, and needs a powerstat to turn 
> it down, it gets way too hot after 5 minutes at full voltage. Even 
> turned down, it can get the caps hot enough to explode them.  No real 
> damage though other than to ones nerves :)
>
> Since measureing those is a pita in circuit, investigate a gizmo called 
> a capacitor wizard.  Its a bit pricey at about $175, but it measures 
> the caps ESR at 100 kilohertz, the most important cap characteristic 
> for digital circuitry.  Anything over 1 ohm is suspect.  You absolutely 
> need one of those if you do service for a living.
>
> Also, if there is a commie 040 card in it, be aware that whoever made 
> that for commie put all those caps on it bass ackwards, so the failure 
> rate is 100% long before now.  They usually fail open, with now dried 
> leakage products all over the board under them, and which is somewhat 
> corrosive...  Gets into the board and eats inner traces in two where 
> you can't fix it, or shorts layers too.  And its crowded, very hard to 
> get the iron in there to replace them.  After about 5 of them on that 
> board I'm ready to shoot the neighbors cat or something.  It has IIRC 
> 14 of them.
>
> Absolutely the most piss-poor assembly Ijob 've seen in my 55+ years of 
> holding an iron in one hand.
>
> The german made 060 card is a far better card.
>
>Snip>

I have the german 060 card so that may be not a problem. I know this is an
off topic subject for this M/L but is there a site I can go to that would
have grapics to point those umbrys out? 

Regards
-- 
Cruising on AutoPilot                        |
        With an Amiga           ---o-o-O-o-o---  and a CoCo