Hercules Workshop

Featured Recondition Project : Coleco Electronic Quarterback

Tuesday November 23 2021 (2021-11-23) : Rob from Hercules Workshop
Featured Recondition / Repair Project :
Electronic Quarterback (1978) (Coleco)

NAME : Electronic Quarterback
MODEL # : 2020


We thought it might be fun to share a vintage recondition project with other enthusiasts who might enjoy following along as we repair and work on this hugely popular vintage handheld electronic game from 1978.

This game needs a lot of repair work but most of the issues are very common. The 9V snap battery connector is worn / damaged, there's no sound, power switch is shorty and the keypad has poor bounce back and can become unresponsive

We have a new message forum open Bits and Bytes - Recondition Project : Coleco Electronic Quarterback so everyone can share comments, tips or questions so we can all have some fun together reconditioning this nice vintage electronic game.

I'll keep updating this page as the project progresses.


The first thing we need to do is be able to supply power to the game. Some revisions of Electronic Quarterback have a DC power jack but this model doesn't so we'll have to replace the 9 volt battery snap connectors. Now you can get these at any electronic supply store or even in our online store Battery Connector, Snap 9V.

These are relatively simple to install, they usually give you more than enough length so you'll need to cut back the leads to about 12 cm (Figure 0).

Figure:0 - 9V Battery Snap Connector

Next you'll want to remove the old leads if they're still connected. The power connections are shown in (Figure 1). Now be careful not to remove the solder, there's components on the other side of the board soldered to these joints, just apply enough heat for the solder to melt and remove the wire.

Figure:1 - Battery Connections

Figure:2 - Cable Routing

Figure:3 - Printed Circuit Board

To connect your new wire leads, just reverse the procedure. Apply just enough head to melt the solder and connect your new wire, if needed you can add a little solder to the connection to strengthen the solder joint. Route the new wire leads through the eye at the bottom of the printed circuit board (Figure 2) and (Figure 3), this will remove any strain on the solder connections when someone is pulling the on the snap connector (otherwise the only thing holding your snap connector leads will be the solder joints).


The combined power and skill level switch (Figure 4) on the Coleco Electronic Quarterback is a DP3T slide switch (double pole three throw). It's actually wired and used as a double throw switch, the third switch position isn't connected and so works as an OFF position.

Figure:4 - S1 Power / Skill Switch - (DP3T Slide Switch)

This type of switch has three positions (or throws) and each throw controls two circuits (or poles). This switch S1 itself is mounted on the printed circuit board (Figure 5) just below the Run / Pass and Kick switch. There are four mounting posts attached to the switch housing and eight switch terminals (4x2).

Figure:5 - Power / Skill Switch S1 printed circuit board.

Align the four mounting posts on the switch housing with the holes on the printed circuit board and make sure the eight switch terminals are also aligned with their holes before firmly pushing the switch down and into position (Figure 6). Now first solder the four mounting posts to the board (to hold it securely) and then solder the eight terminals. Don't apply too much solder to the joints and only hold the tip of your iron to the joint and terminal for no more than 5 seconds, longer than that and you could lift the pad off the trace on the circuit board (Figure 7).

Figure:6 - S1 Switch Repair Replace
Circuit Board Mounting

Figure:7 - S1 Switch Repair Replace
Circuit Board Soldering.

The switch should now be mounted flush and soldered to the printed circuit board (Figure 8). The game is now ready to be tested by connecting a 9 volt battery and moving the S1 switch from the OFF position (the bottom position) to both SKILL 1 (middle position) and SKILL 2 (top position). You should see the LED display lights come on (Figure 9).

Figure:8 - S1 Switch Repair Replace
PCB Mounted

Figure:9 - S1 Switch Repair Replace
Tested Okay


There's a couple different styles of connectors Coleco used to connect the keypad to the main printed circuit board but they're all rigid metal conductors. I do have some replacement parts but I'm guessing most people won't have access to these parts at home so this is a neat work around. There are 6 connections that need to be made between the keypad and the main board (Figure 10).

Figure:11 - Keypad Connections
Main Printed Circuit Board

We're going to use hookup wire and connect them as pseudo jumpers between the keypad and main board (Figure 11). Just cut 6 short lengths of hookup wire, strip each end and tin.

Figure:11 - New Keypad Connectors

Solder the new connectors first to the main printed circuit board. You want to try and keep all the connectors roughly the same length and only about long enough so they can reach the keypad when it's right beside the main board. It will only need to be long enough so the keypad can flip over into position on the main PCB (Figure 12).

Figure:12 - New Keypad Connectors
Between Keypad and Main Board

You can now solder the new connectors to the keypad. It's easiest to do one at a time. Lay the keypad upside down next to the main board and and insert a connection, flip the board and solder. Repeat until you've done all the connectors. Don't worry about the wires not being as rigid as the original connectors, the two switches on the main board and eventually the game's chassis should support it.


The game we're reconditioning had no speaker when we opened it up and so it's not going to have any sound until we can connect a new one. We took a new speaker (new to this game anyway) from our parts shelf but you can also order these new from any electronic parts supplier.

The Coleco Electronic Quarterback uses a piezo electric speaker or buzzer to provide sound. The speaker is made up of a piezo electric ceramic mounted on a metal diaphragm (Figure 13). When a voltage is applied the piezo electric effect causes the ceramic to vibrate and produce stress against the metal diaphragm producing sound.

Figure:13 - Piezo Electric Speaker
Beige Piezo Electric Ceramic on Metal Base

There's a few different hardware revisions of the Electronic Quarterback, depending on the one you have the speaker may be connected to other (but equivalent) points in the circuit. However, regardless of the revision you can always connect to PIN 8 and PIN 9 on U1 (Figure 14).

Figure 14: U1 - DS75492N
MOS to LED Cathode Driver

Solder the connections to PIN 8 and PIN 9 on U1 (Figure 15). Be sure to leave enough length on the wire leads so they'll be able to reach they're mounting on the back of the game housing (Figure 16).

Figure:15 - U1 MOS to LED Cathode Driver
U1 is the IC in top left of image

Figure:16 - Piezo Speaker
Soldered to U1 PIN 8 and PIN 9


Coming Soon.....

We'll be completing our repair / recondition of this vintage Coleco Electronic Quarterback handheld game. Check back as we reassemble this classic game and make sure everything is working.


Click here to listen to a neat little audio clip.
(shall_we_play_a_game.mp3) Computer voice from the movie Wargames (1983)


We repair and recondition most Coleco, Entex, Mattel Electronics, Milton Bradley electronics and Tomy vintage electronic handheld and tabletop games. We offer a flat service rates that includes parts and there's no charge if we're unable to fix. Multi-item repair rates available.

For more information about our repairs :
(Click the below hyper-link)
Vintage Electronic Handheld and Tabletop Game Repair

SEND ELECTRONIC MAIL TO robert.osborne@herculesworkshop.net

Have a great day,
Rob from Hercules Workshop