Broken Speak&****? Fear not!

[Tyler1144]

I found out how to workaround the burned out chips in broken speak& toys. Find where the kepyboard inputs to the board and force-boot it by shorting out the "Go" button's pins. It works believe me. Now since i burned mine out and found this workaround im very happy, now all i need to do is mount the Force "Go" pins to a pushbutton, and then the rest of the keyboard works again. Think of it as a jumper cable!

[Circuitbenders]

am i missing something here? Surely if it starts up and works fine when you short the pins on the board to correspond with pressing the keys on the front panel then theres nothing wrong with the the IC's.

That would indicate theres something wrong with the keypad, cable or connection block wouldn't it?

[Tyler1144]

Nope, its not the same pin that the "Go" button uses,

Its very strange, really. I push go and nothing happens, but then i short the pins where the keypad goes in, but to tell you the truth its not the "Go" buttons exact pins, its one of the pins next to it. You know how some pins have little metal streaks coming off of them? One of the first keypad pins goes to some unknown area, but when i touch that pin to the one on the right of it, the speak and read boots up and works perfectly.

Im baffled too

[Circuitbenders]

but if the whole thing works fine when you get it started so how can anything be 'burned out'? I'm not sure what you're trying to say.

How would shorting the GO pins get it to start up, surely the ON pins would be more useful there.  

The ON pins are the far left one and the sixth one in to the right, if you've got the batteries towards you.

[Gordonjcp]

I'm *guessing* here, but if there's a button scanned by the CPU that turns the thing on, there must be some way for the CPU to control the power.

Now, one way to do this would be to have a transistor that switches all the power, controlled by the CPU.  The CPU is powered but asleep until the ON button fires an interrupt, the CPU wakes up, and then turns on the switching tranny firing up the rest of the board.

I do have a broken Speak'n'Math here so at some point I'll draw out the power circuit.

[Circuitbenders]

In my experience the problem on dead speaks is almost always something on the power board, usually a knackered transistor.

What doesn't help is that you very rarely see two power boards the same. I've got four or five speak&spells with completely different power board layouts.

[Tyler1144]

Im sorry, i meant to say "On" not "Go"

and the whole thing does work fine, but only AFTER i short the 2 pins that turn it on. I havent looked too close at the board, but im pretty sure its not the exact same pins that turn it on via keypad. I know i burned it out, because i accidently left a loop/glitch on overnight (oops). And the next day it wouldnt even turn on and the speaker made a popping noise when i pushed "On"

But for some odd reason, the 2 shorted pins almost jump start it and force it to turn on, perhaps bypassing a fuse or circuit breaker or broken component of some kind? Its very strange, but i assure you it works, and not just on my speak and read, but all 3 of the texas triplets

[ne7]

can u take a piccy of where you are shorting and post it here?

[Tyler1144]

its the pins above the keyboard connector. Its one of the first few, i just put a piece of metal between 2 pins, i forget what exactly, but as soon as you connect them, it force boots the machine. Now i know the keyboard was hooked up properly, because screen segments lit up when i pushed buttons (skin oil doesnt go away easily)

Its a nice fix for "broken" speaks. Not only that, but since the keyboard is useless, you might as well use it to put switches in

[Ciderfeks]

Hi here, I know this is an old topic but I was wondering if anyone managed to get any more results using this method? More specifically which pins are we supposed to short? I have a broken S&S (blob of hot solder spilled on the power board and fried it) and would love to get it going again in order to finish the project....