Main PCB Revisions - There are two different Dragon's Lair board revisions (A and C). Rev. A PCBs have a serial number below 6,000,
and rev. C PCBs have a serial number above 6,000. The rev. C PCB arrived when the transition was made from rev. D EPROMs (five chip set) to
rev. E EPROMs (four chip set). This is also when the transition from the PR-7820 to the
LD-V1000 laserdisc player started. The older rev. A PCB can be modified to use the
LD-V1000, and the newer rev. C PCB can be modified to use the
PR-7820. For instructions on how to perform these modifications, including details on the laserdisc player
communications, see the Dragon's Lair PCB Conversion Between PR-7820 &
Additionally, to see the multiple modifications that kept occurring to the design of the rev. A PCB during the game's production until the design was
essentially finalized near serial number 5,000, as well as detailed instructions for performing these modifications on early rev. A PCBs to achieve
their most stable condition, check the Dragon's Lair Rev. A PCB Modifications page.
Diagnostics ROM Package - To aid with PCB troubleshooting, Shaun Wood offers an improved
Diagnostics ROM Redo, which also contains the archive of the original, flawed Cinematronics diagnostics package.
EPROM Compatibility - Dragon's Lair uses type 2764 or 27C64 EPROMs or compatible, rated 250ns or faster (2764-25).
EPROMs rated slower, such as 300ns and higher (2764-30), have been reported incompatible.
National Semiconductor brand EPROMs have been reported incompatible.
Number of EPROMs - Avoid making assumptions about which ROM revision may be installed on a board based on the number of EPROMs present. Sometimes,
when operators updated the EPROMs from a five chip set to a four chip set, they would leave the 5th chip (now unneeded) in its socket. And likewise,
collectors who manually switch between Dragon's Lair and Space Ace may leave their 5th Space Ace EPROM installed while running
Dragon's Lair with four chips. Therefore, the presence of five EPROMs does not prove that it must be one of the five chip ROM revisions. Revisions A, B,
C, and D are five chip sets. Revisions E, F, and F2 are four chip sets. The Dragon's Lair Enhancement ROMs are four and three chip sets.
DIP Switch Updates in ROM Revisions E, F, and F2 - The following changes were implemented since revisions A, B, C, and D:
- The option to disable the joystick feedback sound is discontinued, and this DIP switch (B3) is now used to select the model of laserdisc player,
PR-7820 or LD-V1000. (The main PCB must also be correctly configured
for the player type.)
- The option for 4 coins per credit is discontinued, and this DIP switch (A1) is now used to increase the hard difficulty setting further to very
hard. Complete details are in the Dragon's Lair Walkthru.
- A setting of 2 coins per credit is not required for the pay-as-you-go setting to
function. Pay-as-you-go can still be used if the game is set for 3 coins per credit, and the price to
continue the game will also be 3 coins. However, the on-screen graphics will still incorrectly ask for
only 2 coins, both during the attract mode to start the game and also at the interruption points.
- In pay-as-you go mode, extra lives may be awarded after the interruption points only if the game is set to begin with 3 lives.
European Versions - Dragon's Lair was licensed to Atari for production and manufacture in Europe. The cabinet is very similar to
the Cinematronics release, but the hardware, including the laserdisc player, is totally different. Atari sub-licensed Dragon's Lair to Sidam
for production and manufacture in Italy. Most of the hardware for the Sidam version is the same as the Atari version, but the
cabinet design is completely different. Both the Atari and Sidam versions of Dragon's Lair
use a video overlay for the score and lives rather than the score display PCB that is used in the Cinematronics version. Click on the
following links to see pictures of the video overlay: Picture 1 | Picture 2
Interchangeability - Space Ace can be played in a Dragon's Lair cabinet by changing the laserdisc and the EPROMS
(and also ideally with the Space Ace control panel's three skill level selection buttons for "Cadet", "Captain", & "Space Ace").
Merlin MultiROM - Merlin replaces the original EPROM board used in Dragon's Lair and Space Ace. It
allows multiple game ROMs to be swapped by using the joystick and button. For more information, check the
Arthur PCB Replacement - Arthur is a replacement main logic board for Dragon's Lair and Space Ace. The
circuitry for the ROMs and the Space Ace annunciator are integrated onto one main PCB. For more information, check the
Monitor to TV Swap - If the monitor in your Dragon's Lair, Space Ace, or Thayer's Quest is not up to your liking, you can replace it with a
19" TV. The Monitor to TV Swap page will show you everything you need to know.
Volume Control Wiring Error - Apparently all Dragon's Lair and Space Ace main wiring harnesses were constructed with an error. Two pins are reversed
in the connector for the volume controls, shorting the right audio channel to ground and creating noise in the system. For the fix, see the
Dragon's Lair / Space Ace Operator Convenience Panel Pinout.
68705 Bypass Modification - An update for older rev. A Dragon's Lair / Space Ace PCBs. See the
68705 Bypass Modification page for more information.
Joystick Sound Volume Control Hack - Now you can adjust the volume of the joystick feedback sound in Dragon's Lair or Space Ace if it is too loud or soft
for your environment. See the Dragon's Lair / Space Ace PCB Volume Control Hack.
Engineering Mode - Engineering mode was designed to let the engineers playtest a scene without having to play through the whole game. To
learn more about this, see the Dragon's Lair Engineering Mode page.
Initialization - Ever wonder what all those characters are in the score display of Dragon's Lair while the game boots up? Check out the
Dragon's Lair Initialization page.
LD-V1000 Boot Switch - A simple inexpensive way to build a switch that issues a play command to the
LD-V1000 or LD-V1001. See the
LD-V1000 Boot Switch page.