These instructions regard the Texas Instruments vintage learning aids: Speak & Math, Speak & Spell and Speak & Read.
Modifications & Additions
Replacement: speaker grill foam
Battery compartment: Access Key
Battery removal: Pull-tabs
project box addition
Tools & Materials
Small screwdriver, small scissors, cheap scissors, plastic card, thick plastic tape or ribbon and glue, paper clip, wire clippers.
Step 1: Buying a Used Speak & Spell
Ebay is the main source for finding a speak & spell, other than chance encounters at yard sales and thrift stores. Take precaution in buying one from a new ebayer or anyone with a low rating. The questions to ask are: does it work, have you tested it, is there battery terminal corrosion, is the display clear and what is the cosmetic condition from 1-10. Most auctions will post if it works or not, so ask questions accordingly.
When the package arrives put in some batteries and turn it on. Play all the games and turn it on and off a few times. Make sure to inspect the keypad where children have doodled and scratched, to see if any traces are damaged. If its an original speak and spell, check that no buttons are loose. Leave the batteries inside the unit with the it off for awhile, later on try turning using on, look and listen for anything peculiar. Test out the 1/8 output, if its mono plug it in to a battery powered amp, if its stereo plug in some headphones. Last test is to power the unit with the AC/DC adapter.
After deciding to keep the learning aid, open it up. The screws should be really tight because it hasn't been opened since it was manufactured. Inspect the PCB, use q-tips and rubbing alcohol to clean any build up.
Next use rubbing alcohol to clean the exterior.
Step 2: Open It
1. Remove battery door and batteries.
2. Remove the two screws at the bottom of the back (these will be either philips or star [Torx] head). Set screws aside on your hardware magnet or some other safe place.
3. Spread case halves apart by prying with your finger inside the battery compartment.
4.With case spread a little bit, insert the lower of the four rectangular holes on the cases back and gently push the plastic retaining clips to the side. The case will pop open a bit as each clip is released.
5. Do the same with the two clips and set the back of the case in a safe place.*
- Ghazala, Reed. "Circuit-Bending". Indianapolis, Indiana: Wiley Publishing Inc., 2005. pg. 210
Step 3: Clean Out
After opening up one of these to see what the circuit board looks like. Inside of it the foam speaker grill has deteriorated. This thin piece of high-density foam protects the speaker from dust, debris and moisture. Grill foam is always discarded once its rotted because it makes a crumbly mess. The speaker cone itself is delicate and appears to be made from some sort of card.
Detach the speaker by gently releasing it from its plastic mount. Discard the rotted foam, and clean out its mess.
Step 4: Replace Foam
The foam ear pad is the right the material for replacing a grill cloth on a small speaker. The ear pad isn't much thicker than the foam sheet. It will also flatten out when pressed against the grill. The other place to scavenge foam would be in a motherboard box.
First take the ear pad and gently stretch it over the driver. Cut away little pieces of the ear pad where the plastic clips will hold the speaker. After those three clip areas are cut away, the driver can be locked back into position. To clip the speaker back into position, first Align the back posts with the speaker, then move to the middle posts and clip it in. Make sure the speaker wires arent going to be pinched when it is re-assembled
Step 5: Battery Compartment Key
The battery compartment is one of those inaccessible child proof areas. The manual mentions ways to open it with a metal key, coin or screw driver. A lot of these devices no longer have their door, do to opening them with metal tools. The card key became a better solution, its flexible and not rigid. The card works surprisingly better than any of the manual's methods!
Step 6: Battery Pull-tab
First place some tape where the pull-tabs should be installed to pop out the batteries. Measure out some tape or start with a long piece and cut it short after wards. The first measurement for the pull-tab length is 3 13/16, Cut a piece of tape 6 7/8 inch because it will be folded over and doubled up. Add a paper clip rod on one end and a pull tab on the other. The rod needs to be slightly larger than the width of the plastic tape. Make sure the ends of the tape don't meet up near either end of the pull tab. This will only work with thick plastic 1/2 inch tape and not 3m scotch tape.
Step 7: Project Box Addition
The addition of a project box is a clever way to modify speak and spell. All the mods can be in one area and can fill the entire box. The measurements for this project are dependent on what project box you use. If the front of the project box has a aluminum panel it will have to replaced with plastic. The box used on this speak and math is available from All Electronics.
Step 8: CLOSE IT UP
First tuck the speaker wire away from areas that could pinch it. Place the two halfs together aligning them at bottom screw holes, press it together till it snaps in place, Then close two middle clips and finally the top handle clips. Screw it back together and put the battery door cover on.