Star Tech Journal

22
STAR*TECH JOURNAL/FEBRUARY 1 \)84
"Mr. Do!'s Castle" continued.
EPROM IA SCl - Unicorns; MDC - None;
HST - None; I - Unicorns.
EPROM M4- I Mr. Do! ; HST - none; SCl -
Shield door; MDC - none.
EPROM A3 - HST - All letters and back-
ground; MDC- Everything except "castle"; SCI
- Everything except shield and door, unicorns, Mr.
Do!, blocks, moveable ladders, "extra" monsters,
and points awarded for a dropped unicorn or
"extra" monster; I- same as SC 1 except for shield
and shield door.
VIDEO RAM B6·J6 and B7-J7
Let me explain how I came up with the data on this
section. Because these are not tested by the
program test, and most technicians don't have the
time to make a list like below for each new game,
and since the chips are also soldered in place, a
short-cut method of troubleshooting a video problem
is appreciated. In my setup I have the logic board
flat on a bench powered by a switching power
supply and an extension video cable so I can view
the video display directly in front of me. To
"freeze" the display to take my readings, I am
using a test clip with one side connected to logic
ground and waiting for the desired attract mode
display to appear, then connecting the "edge
connector" side of RS 1, which is the pause line to
the logic, to the test clip, which is ground. With the
display frozen, I use another test clip to connect to
ground momentarily ( one to three seconds, because
a longer time may damage the output of the chip) to
pin 14, the data output line of any of the sixteen
4164s. I then look at the display and write down
what the effect of grounding that pin 14 has on the
display, but using common sense you should
realize that two chips don't display the same line of
information on the screen. This means there are
observable differences between what each chip
displays. So there has to be an understanding and
nomenclature in the below descriptions to properly
promote identification of a possible bad chip.
This means we have to have a monitor which is
in good focus, proper color, and in a location close
enough to the observer so he can note subtle
differences. Secondly, the technician must be
reasonably assured that a problem is in one of the
4164s.
In order to get in agreement on color, we will
use the Mr. Dot's Castle display to properly adjust
color. Freeze the display as described above on the
Mr. Dot's Castle part of the attract mode and
adjust the monitor to display the below color
description.
The outline of the words "Mr. Do!'s" should be
reddish-pink with a white borderline. The rainbow
pattern which is scrolled behind "Mr. Do!'s" sh
ould consist of red, yellow, blue, and green stripes.
The innermost of the word "castle" should be
bright blue. The blue should be immediately out-
lined in white, then be shadowed by yellow and
then red, giving the word "castle" a standout
effect.
"Insert Coin" should be white as well as the
coins per play. "Universal" should be red and
1983 should be yellow. The screen or brightness
control should be adjusted so the background will
be dark, i.e., the same darkness as if the monitor
were off.
This logic board uses 128K of screen memory
which can be divided into two banks of64K bytes.
We shall label row B7 through J7 as the even row
of chips and row B6-J6 as the odd row of chips.
This nomenclature is in accordance with the
schematic. These chips are selectively scanned to
dump their memory contents onto the screen in an
even-odd fashion. Think of the two rows as being
brothers which work alternately in an even-odd
manner. Chip B6's brother is B7 and so on down to
J6's brother J7. These "brothers" handle the same
character( s) but display different lines of it. By
looking at the schematic we can further break
down the groups of eight brothers into a set of three
brothers and a set of five brothers. The set of three
brothers are B6-B7, C6-C7, and D6-D7. The
other five are DE6-DE7, E6-E7, F6-F7, H6-H7
J6-J7.
'
The first three groups affect just about every-
thing, but the last five groups control certain
characters. Keep this in mind.
Each character is broken into lines on the
horizontal axis as the monitor is vertically posi-
tioned. The even-odd display brothers will put
together a character. Using the list below and
discerning between which chips affect what
<:haracters, can narrow down your troubleshooting
time.
Let me remark here and now that if you have a
suspect bad 4164, you may easily find it with this
"The MPUs are reset
simultaneously by a
semi-sleepy watchdog.
"
guide and a little common sense. Does it seem like
five or six RAMs may be bad? Unless the board
was subjected to lightning interference, too high
Vee (+5) voltage, or excessive heat, it probably
isn't the RAMs, but maybe some support chip
around the RAMs, such as a multiplexer, latch, or
(horrors!) the custom function chip at F5 . Are
figures displayed at the "wrong" places, such as a
ladder where it shouldn't be? If so, don't look at the
4164s, but around the character ROMs H4-M4 or
the 8128 ROM at DE4, or chips associated with
these. Make sure the 4164s have active address
lines and enable lines. 4164s require +5 volts only
and shouldn't have as many problems as their three
voltage forerunners, 4116s.
If you are limited to working with the board in
the game (most ofus are), simply let the game get
to the desired attract mode and ground the pause
line (R51) to freeze the display so you can get
around front to look at it, or use a mirror if your
vision's good enough, to view scan lines.
The four attract modes are Mr. Do!'s Castle
(MDC), Instruction (I), Scene 1 (SCI), and the
(HST) High Score Table.
The HST is not affected by the group of five
brothers.
J6 and J7 (MDC) The rainbow pattern inside
"Mr. Do!'s" is affected and the word "castle" is
affected. J 6 will affect the topmost character line of
the red part of "castle" and J7 will affect the
second character line from the top. Let me say that
the whole word "castle" is affected but from the
above description I'm trying to narrow down which
RAM (J6 or 17) it is. I will follow this convention
below.
(I) None.
( SC 1) Key blocks are affected. J7 affects the
topmost line of the block where it joins the wall and
J6 the secondmost line.
H6 and H7 (SCI) Skull blocks and the shield
door are affected. H7 is responsible for the top line
of the skull block where it joins the wall, and H6 the
second skull block line from the top (MDC). The
rainbow pattern and the word" castle" are affected.
H6 takes care of the topmost red line of" castle"
and H7 the secondmost red line.
(I) The skull blocks are affected in the same
manner as the ( SC 1) description.
F6 and F7 (I) Faceless yellow and blue blocks
and unicorns are affected. F7 takes care of the top
line of the faceless blocks and F6 the secondmost
row.
(MDC) No effect.
( SC 1) Cherry blocks and unicorns are affected
F7 is the top line of the cherry blocks and F6 the
secondmost line.
E6 and E7 (SCI) Skull blocks, cherry blocks,
and Mr. Do! are affected. E7 is the top line of the
cherry blocks and skull blocks and E6 the second
line.
(MDC) The rainbow pattern in " Mr. Do!'s"
and the word "castle" are affected. E6 is the top
red line in "castle" and E7 the secondmost line.
(I) Faceless blocks, skull blocks, and "Mr.
Do!" are affected. E7 is the top line of the above
blocks and E6 is the second line.
DE6-DE7 (I) Skull blocks, faceless blocks,
and "Mr. Do!" are affected DE7 is the top line of
the skull blocks and DE6 the secondmost.
(SCI) Skull, cherry, and key blocks are affected.
Mr. Do! and the unicorns are affected. The
moveable ladders are also affected The top line of
all blocks are affected by DE7 and the second line
from the top of all blocks are affected by DE6.
The last group of three function very similarly
and will be described according to attract frame so
the differences will show up. This group of three
brothers affect background and characters. I will
describe what they least affect instead of what they
do affect.
(SCI)B6-B7 has the least effect on the faces of
the key blocks and skull block faces. B7 affects the
top line of the cherry blocks and B6 the second
from the top line. The shield door is not affected.
C6-C7. C7 has little effect on the moveable
ladders and little effect on the skull blocks. C6 has
more of an effect on the moveable ladders. C7 is
the top white line on the cherry blocks and C6 the
second white line from the top. The closed shield
door isn't affected.
D6-D7 The most notable difference between
these brothers and the other two pair is that the
shield door is affected and the moveable ladders
are not affected. D7 is the top line on the key
blocks and D6 the second line.
(HST) The differences between the three pairs
is too small and difficult to describe.
(MDC) "Castle" is the key word here. The
three pairs each do different things to the word.
B6-B7 affect everything in "castle" except the
white outline and the yellow shadow. B7 controls
the top bar of I in "insert" and B6 the second
segment under the top bar of the I.
C6-C7 These don't affect the red in "castle".
C7 is the top bar ofl in "insert coin".
D6-D7 These do not affect the blue center nor
the white outline of" castle". D7 lines up with the
top bar of the letter I in "insert".
The four programmable sound generators are
easier to troubleshoot than the video RAMs
(thankfully). Simply start a game and wait for the
music to begin. Next, pull the "pause" line low
(R48 edge connector side). The music will continue
playing while the pause line is held low. All four
generators will be active and produce sound. R9
sound generator plays the melody and low drum
beat-type sounds. P9, NP9, and N9 play the
repeated eight note sequence, with N9 playing the
upper octave, NP9 playing the middle octave, and
N9 playing the lower octave. A signal tracer can be
touched to pin seven of each chip in order to detect
activity. If you don't have a signal tracer, simply
lift one leg of all four resistors R55-R58 and
reconnect them one at a time during the music
mode to hear which one is not producing sound.
Output Resistor
Sound Generator
N9
R55
NP9
R56
R57
P9
R58
R9
I hope the above troubleshooting section helps
out in detecting and repairing Mr. Dot's Castle
Conversion Kits.