Star Tech Journal
Issue: 1983-March - Vol 5 Issue 1 - Page 19
STAR*TECH JOURNAL/MARCH 1983
19
Gottlieb's MA-400 Filter Board
Commencing with "Q•Bert", GV-103A, a Filter Board (AB) was designed to suppress radio
frequency emission which can cause electromagnetic interference.
The method utilized by Gottlieb (ferrite beads coupled with bypass capacitors), form low pass
filters. The ferrite beads surrounding the transmission lines are electrically nonconductive and
"absorb" magnetic flux. The higher the frequency, the higher the impedance (typically 100 ohms
above 30 MHz). The larger beads are utilized on lines carrying larger currents, such as power supply
lines and ground; the smaller beads suppress all other transmission lines. The output side of the beads,
related to the logic board, are coupled to ceramic high frequency capacitors that suppress high
frequency spikes to ground. Ceramic substrate capacitors were found to have the most desirable
effect.
Only the wires (signals/voltages) that penetrate the metallic shield surrounding the master
electronic board utilize the Filter Board. The large foil area on the Filter Board is a ground plane
which allows as small an impedance as possible.
Illustrated is a schematic representation of the resistive/inductive properties of the beads. Note:
Input to the Filter Board is any wire coming from the master electronic board.
Input _..,_~ '"'•'vVH-
''·\✓) r►
Part of Filter Board
(typical)
INTRODUCING
ENCORE RETRO·KIT .
from this:
Output
I
Troubleshooting Gottlieb's "Q*Bert" GG-111 System
The GG-111 logic board employs several jumpers that give the operator some troubleshooting leeway.
The two jumper posts are shorted together by a blue plastic-coated jumper terminal. These can be
removed by pulling upwards on the terminal.
Jumpers JP21 and JP22 are jumper options for the video summer. The video summer is the
arbitrator to set priority for either background or foreground. This determines whether the foreground
character will appear in front of or behind the background character. JP2 l has the blue terminal on it,
JP22 is bare. If there is a question as to whether a problem exists in the foreground or the background,
remove JP2 l. This will eliminate all foreground characters from the screen. By placing the terminal
onto JP22, all of the background characters disappear from the CRT. This will aid the operator in
determining what area of the logic board to concentrate his efforts on, either the background logic or
the foreground logic.
There are several groups of LSI on the GG-111 logic board that deserve some mention. J 1 through
16 are the Line Object Select RAMs. These should be suspected if either the wrong character appears
on the screen or if extra characters appear (i.e., a floating disk above Coily or all of the foreground
objects being identical characters). H 1 through H4 are the Vertical Position RAMs. If defective, these
can attribute to erratic movement of the characters and cause them to be positioned incorrectly on the
CRT. E 1-2, the Foreground Horizontal Position Register, will produce all characters at the bottom of
the CRT when faulty while E4, the Foreground Vertical Position Register, will move all the
characters to one side of the screen. E2-3, the Fore ground Object Select Register, can give rise to the
absence of several or all of the foreground characters.
to this:
Reprinted courtesy of Golllieb's technical newsletter, "On Target"
***
MOVING? QUESTIONS?
The address label on your envelope contains your subscriber account
number in the top left corner and the month and year your subscription
will expire appears at the far right.
If you have any questions regarding your subscription/account or wish
to change your address, we can more readily expedite the matter by
knowing your account number. (Computers, you know.)
Should you change your address, please send us your most recent
label, or a photocopy of it, and we'll update your account.
Place label from envelope here
or notify us of your account number
and old address.
Indicate your NEW ADDRESS below.
in less than 1 hour
Change any Galaxian'" or Pac-Man'" to Beezer'".
build a new look and new collections ..
The Do-It-Yourself Kit can be used to convert
other games to Beezer'" too.
INTRODUCTORY OFFER
Beezer'" Encore Retro-Kit'" .
. $745.00
ea.
BEEZER'" PC Board. Complete Control Panel-trackball.
button and wiring harness, Full Graphics·Marquee, View-
ing Window, Top to Bottom Side and Front Decals.
Beezer'" Do-It-Yourself Kit. .... ·$675.00 ea.
BE EZER~ PC Board, Graphic Overlay for Marquee, View·
ing Window.and Control Panel, 2 20" Circular Side
Decals.
contact:
Intrepid Marketing Inc.
Your name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Company _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Address
City/State/Zip
4984 El Camino Real, Suite 217
Los Altos, CA 94022
(415) 964-0943
(800) 872· 7200
TM - Encore Retro-Kit of Intrepid Mktg
TM - Beezer of Tong Elec.
TM• Galaxian, Pac-Man of Midway Mfg.
19
Gottlieb's MA-400 Filter Board
Commencing with "Q•Bert", GV-103A, a Filter Board (AB) was designed to suppress radio
frequency emission which can cause electromagnetic interference.
The method utilized by Gottlieb (ferrite beads coupled with bypass capacitors), form low pass
filters. The ferrite beads surrounding the transmission lines are electrically nonconductive and
"absorb" magnetic flux. The higher the frequency, the higher the impedance (typically 100 ohms
above 30 MHz). The larger beads are utilized on lines carrying larger currents, such as power supply
lines and ground; the smaller beads suppress all other transmission lines. The output side of the beads,
related to the logic board, are coupled to ceramic high frequency capacitors that suppress high
frequency spikes to ground. Ceramic substrate capacitors were found to have the most desirable
effect.
Only the wires (signals/voltages) that penetrate the metallic shield surrounding the master
electronic board utilize the Filter Board. The large foil area on the Filter Board is a ground plane
which allows as small an impedance as possible.
Illustrated is a schematic representation of the resistive/inductive properties of the beads. Note:
Input to the Filter Board is any wire coming from the master electronic board.
Input _..,_~ '"'•'vVH-
''·\✓) r►
Part of Filter Board
(typical)
INTRODUCING
ENCORE RETRO·KIT .
from this:
Output
I
Troubleshooting Gottlieb's "Q*Bert" GG-111 System
The GG-111 logic board employs several jumpers that give the operator some troubleshooting leeway.
The two jumper posts are shorted together by a blue plastic-coated jumper terminal. These can be
removed by pulling upwards on the terminal.
Jumpers JP21 and JP22 are jumper options for the video summer. The video summer is the
arbitrator to set priority for either background or foreground. This determines whether the foreground
character will appear in front of or behind the background character. JP2 l has the blue terminal on it,
JP22 is bare. If there is a question as to whether a problem exists in the foreground or the background,
remove JP2 l. This will eliminate all foreground characters from the screen. By placing the terminal
onto JP22, all of the background characters disappear from the CRT. This will aid the operator in
determining what area of the logic board to concentrate his efforts on, either the background logic or
the foreground logic.
There are several groups of LSI on the GG-111 logic board that deserve some mention. J 1 through
16 are the Line Object Select RAMs. These should be suspected if either the wrong character appears
on the screen or if extra characters appear (i.e., a floating disk above Coily or all of the foreground
objects being identical characters). H 1 through H4 are the Vertical Position RAMs. If defective, these
can attribute to erratic movement of the characters and cause them to be positioned incorrectly on the
CRT. E 1-2, the Foreground Horizontal Position Register, will produce all characters at the bottom of
the CRT when faulty while E4, the Foreground Vertical Position Register, will move all the
characters to one side of the screen. E2-3, the Fore ground Object Select Register, can give rise to the
absence of several or all of the foreground characters.
to this:
Reprinted courtesy of Golllieb's technical newsletter, "On Target"
***
MOVING? QUESTIONS?
The address label on your envelope contains your subscriber account
number in the top left corner and the month and year your subscription
will expire appears at the far right.
If you have any questions regarding your subscription/account or wish
to change your address, we can more readily expedite the matter by
knowing your account number. (Computers, you know.)
Should you change your address, please send us your most recent
label, or a photocopy of it, and we'll update your account.
Place label from envelope here
or notify us of your account number
and old address.
Indicate your NEW ADDRESS below.
in less than 1 hour
Change any Galaxian'" or Pac-Man'" to Beezer'".
build a new look and new collections ..
The Do-It-Yourself Kit can be used to convert
other games to Beezer'" too.
INTRODUCTORY OFFER
Beezer'" Encore Retro-Kit'" .
. $745.00
ea.
BEEZER'" PC Board. Complete Control Panel-trackball.
button and wiring harness, Full Graphics·Marquee, View-
ing Window, Top to Bottom Side and Front Decals.
Beezer'" Do-It-Yourself Kit. .... ·$675.00 ea.
BE EZER~ PC Board, Graphic Overlay for Marquee, View·
ing Window.and Control Panel, 2 20" Circular Side
Decals.
contact:
Intrepid Marketing Inc.
Your name _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Company _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Address
City/State/Zip
4984 El Camino Real, Suite 217
Los Altos, CA 94022
(415) 964-0943
(800) 872· 7200
TM - Encore Retro-Kit of Intrepid Mktg
TM - Beezer of Tong Elec.
TM• Galaxian, Pac-Man of Midway Mfg.
Future scanning projects are planned by the International Arcade Museum Library (IAML).