[Coco] Blank PCB for EPROM-Based Cartridge

[Greg Law]

From: billg999 at cs.uofs.edu
Sent: Thursday, September 26, 2013 10:42 AM
To: CoCoList for Color Computer Enthusiasts
Subject: Re: [Coco] Blank PCB for EPROM-Based Cartridge

> I was hoping to do that with a number of the old carts I have
> but attempts to remove the old chip usually results in some
> of the lans lifting making the card unusable.  I suspect they
> were made as cheaply as possible and there was never any thought
> to re-purposing of them in the future.  :-) or in my case :-(

If the traces are melting, you're using too much heat and/or the soldering 
iron is taking too long to heat the tip. These are common problems with 
inexpensive pencil irons. Basically what happens is that the tip is 
initially heated to 750 degrees or so. When you touch the tip to a joint, 
the temperature of the tip drops significantly and it takes time to get the 
tip back to sufficient temperature to melt the solder. With fragile traces 
(specially those on densely-populated multilayer boards and cheap cards), 
the standard 750 degree soldering iron is way too hot and takes too long to 
melt the solder.

If you can afford it and think it might be worth the investment, you might 
consider investing in a temperature-controlled solder station with variable 
temperature and either a standard or a miniature pencil. The tips in these 
soldering stations have a temperature sensor so the control unit can better 
keep the tip at a constant temperature, even under load. The best part is 
that you can drop the temperature back to say 600 to 650 degrees when 
soldering or desoldering standard components. I personally prefer the 
smaller (miniature and/or micro) pencils, but this is a personal choice.