Sep 88 Letters
Volume Number: 4
Issue Number: 9
Column Tag: Letters
Lightspeed 3.0-Source Code Debugger 
By David E. Smith, Editor & Publisher
Lightspeed C 3.0
Kirk Chase
Anahiem, CA
Lightspeed C has jumped into hyperspace with their version 3.0 of their popular
C development system. THINK Technologies Division has upgraded their Lightspeed C to
version 3.0 due out by the time you read this. The new version is a significant
improvement in application development containing support for Inside Macintosh I-V,
68881 and 68020 code generation, precompiled headers, and a source level debugger!
The greatest addition to version 3.0 is, of course, the source level debugger. The
debugger has a source window that allows you to step through your code to see how it is
executing, either line by line or function by function. You can set break points that
are absolute or conditional. There is also a data window that will allow you to view and
modify the various variables and structures in your application. But, if source level
debugging isn’t enough for you, you can drop right into your favorite low level
debugger like TMON.
Sounds too good to be true? Well, there is a catch. Although Lighspeed C 3.0 will
run under System 4.2 or higher with the 128K ROMs, in order to use the debugger you
need 2 megabytes of RAM and run it under MultiFinder; it is also recommended that
you use System 6.0. The source level debugger is a nice addition, but it is not without
some price.
In addition to the debugger, there are some more goodies. There are precompiled
headers, Lightspeed C’s or your own, that speed up compilation. I was told in the
interview with THINK that to compile a program before with all the headers took
approximately 22 minutes; the precompiled headers reduced that to under 5 minutes.
Version 3.0 also includes libraries and inline code generation for the 68881 and
68020 chips for those who are programming for speed. Also, all the color object as
well as the rest of Inside Macintosh I-V is supported.
The upgrade is a nominal charge e specially if you already have 2 megs of RAM and
MultiFinder to run the debugger (obviously if you plan to run the debugger and need a
memory upgrade, it will cost you more). This version is a major breakthrough for
you developers, like I am, that like source level debugging.
Mac Power Supply History Reviewed
Dr. Ray A. Gaskins
Hampden-Sydney, VA
It could be argued that 1987 was the year of the power supply (analog board)
problem. Don Ritter, writing in MACazine, mentions the power supply in seven out of
twelve of his M.U.G. WRESTLING columns. MacTutor, in six of its monthly issues,
devotes more (and useful) words to it than any other publication. The Active Window
(Boston Computer Society publication) mentions something about the power supply in
three of its monthly issues. Perhaps not surprisingly, MacUser and MacWorld
mention the power supply in only one issue each.
The earliest reference to the power board problem that I have seen is one
mentioned by Ritter in MACazine (Jan 87, page 61). He references an article by
Howard Upchurch which appeared in the July/August 1986 issue of Apple Gram.
Upchurch blames the problem on two underrated capacitors and on the flyback
transformer. Other 1986 articles referenced by Ritter are a “bad power supply
board survey form” in which Apple admits to a power board problem with Mac Plus
upgrades. However, MACazine itself makes no mention of power board problem in
1986 (nor, for that matter, do MacUser, MacTutor or MacWorld).
Apart from recommending the removal of the heavy aluminum RFI shield mounted
across the top of the power supply board as a means of increasing air flow and reducing
heat, Ritter has little to suggest short of suing Apple. Instead he tells an endless string
of horror stories about multiple power board failures.
In my own fixed population of just over 100 Macintoshes, I have the full range of
Macs (1984-1988). I can remember two Macs out of this population that seemed like
characters out of Ritter’s horror stories. In both cases, replacing the video tube fixed
the problem. Therefore, my advice to anyone whose mac eats power boards (say, three
boards in six months) would be to replace the video tube (along with the third or
fourth power board). A symptom of this problem is a discoloration due to heat of the
four-pin connector that connects the video tube to the J1 connector on the power board
and a history of eating power boards.
I believe that there is some truth to the rumor that Apple felt that part of the
power board problem was due to the procedure being used to discharge the video tube -
you know, two crossed screw drivers. I have lost a couple of power boards because of
this and began not discharging the video tube for doing routine things not involving the
power board (e.g., replacing the logic board). My failure rate declined. Now there is a
neat tool for discharging the video tube that meets Apple’s approval and I use it
religiously.
In the 15 months prior to July 1987, I replaced 13 power boards. In the 9
months since then, I have replaced only 4. I attribute this to three things: Loy
Spurlock, Chuck Rusch, and Mysteray. MacTutor published long and detailed letters
from Loy Spurlock (March 87, page 4) and Chuck Rusch (June 87, page 13)
concerning the power board problem and what you could do about it (short of suing
Apple). Mysteray (July 87, page 17) wrote two long comments in MacTutor’s
Mousehole Report concerning the J1 connector on the power board - why it tended to
develop a cold solder joint, how to detect it and how to fix it. I am grateful to these
three people for their words of wisdom.
Since July 1987, I have had 10 power board problems that, prior to reading
Spurlock, et. al., would have meant 10 power board swaps. However, applying their
advice, I was able to save 6 of these boards by resoldering. The symptoms were varied:
(a) three had the classic thin vertical white line in the center of the screen,
(b) two had the shakes (screen jitter), occasional spikes and expanding/contracting
screen,
(c) three had horizontal lines across the top and/or bottom of the screen, and
(d) two had a faint vertical line just to the left of center.
Resoldering the four pins of the J1 connector fixed two (a)’s , one (b) and two
(c)’s. Resoldering two other joints that appeared dull under close inspection fixed the
other (b).
Resoldering had no effect on one of the (a)’s , one of the (c)’s nor on either of the
two (d)’s. (Rumor has it that the faint vertical line means that the power supply will
fail within six months.) Fixing six out of ten power boards by simple resoldering
isn’t bad. These Macs range from 128K to Mac Pluses. None had fans.
Using a jewelers eye piece (10X), I also examined the joints at J2 (9 pin
connector) and J4 (11 pin connector) on each of these boards. More often than not,
one or two solder joints on each end showed cracks. Resoldering these, although good
pr eventative maintenance, is usually not as critical as resoldering the four joints at
J1.
I looked at a couple of the replacement power boards and noticed that some of the
connections had been resoldered by hand, including the four pins of the J1 connector. I
couldn’t tell their resoldering from mine. The only difference was that they put on a
new paper backing with new double-stick pads. If you are careful in peeling back the
double-stick pad (use a plastic video alignment tool with a screw driver blade to help
peel it back), you won’t have much residue to clean off before resoldering and you can
restick the pad without applying additional glue.
What caused the cold solder joints? I believe that the explanation given by
Mysteray (loose video yoke connector) is probably correct. Therefore, I always
tighten this connector whenever I resolder the pins at connector J1. For a thorough
explanation of this, see Mysteray’s comments in MacTutor (July 87, page 17).
As far as voiding your warranty is concerned, after 90 days you are on your own
Referenced by (2):