Re: Daystar Cache Speed

[Derek Morton]

I have found (at work) that if a GAL is overheated in the process of 
removal or installation the program can be corrupted.  Whether or not 
the device is actually damaged I cannot say as I discard any device 
which is overheated (rather than have it act quirky or fail prematurely 
in the field).  To program them you will definitely need at least one 
PLCC adapter.  As I mentioned, if memory serves, both 16V8 and 20V10 
devices are used on that card (although having it in front of you, you 
will know for certain) and the 20V10 is a larger device.

I cannot say whether a GAL is more sensitive than other programable 
devices such as (let's say) a PROM, but they are definitely more 
sensitive than hard wired devices.  As for a GAL getting warm...  It is 
possible that if the program became corrupted you could have had 
contention on one or more outputs, but realize that GALs consume a LOT 
of power (relatively speaking - even the quarter power devices), and 
the faster they run the more they use.

A PLCC device is just about the most difficult thing to remove you will 
likely find in an older mac.  The only thing which comes to mind which 
is more difficult would be a BGA package (and you would probably only 
see that in a late model NuBus video card).  The most effective way to 
remove a PLCC is to use a SMD rework station with the correct size LCC 
/ PLCC hot air tool.  As for myself, I have been soldering and 
de-soldering just about everything ever since 2M school in the Navy.

It is common to protect GALs as a means of preventing copying by the 
competition (or at least making it more difficult).  Where I work 
protecting GALs and programable micro-controllers is standard practice. 
 It is always possible to figure out the program in a GAL, but it can 
be VERY time consuming and tedious.

Whether or not it is worth your effort to play around with this project 
of yours is up to you to decide.  I too love the old Daystar 
products...  I am the proud (original) owner of an SE/30 specific 50 
MHz PowerCache.  A fine piece of engineering indeed!

Derek

--
Quadlist is sponsored by <http://lowendmac.com/> and...
Small Dog Electronics    http://www.smalldog.com   | Enter To Win A |
-- Canon PowerShot Digital Cameras start at $299   |  Free iBook!   |
     Support Low End Mac <http://lowendmac.com/lists/support.html>

Quadlist info:          <http://lowendmac.com/lists/quadlist.shtml>
 --> AOL users, remove "mailto:";
Send list messages to:  <mailto:[EMAIL PROTECTED]>
To unsubscribe, email:  <mailto:[EMAIL PROTECTED]>
For digest mode, email: <mailto:[EMAIL PROTECTED]>
Subscription questions: <mailto:[EMAIL PROTECTED]>
Archive: <http://www.mail-archive.com/quadlist%40mail.maclaunch.com/>
Using a Mac? Free email & more at Applelinks! http://www.applelinks.com