V-Tech Talking Computer

[Doctor Bob]

Hey all, first time poister etc... I've been wanting to try circuit bending for ages, found this a great resource so far! Already came in handy to find out about V-Tech's notorious fuse issue. Saved it for a couple of hours anyway 
Amongst other things, I've gpt a couple of the V-Tech Talking Computers, both different models, one Grandstand and one My First (this one seems dead already.... will only click when you try and turn it on). This was my first project, and it's been fairly successful so far, got some crazy noises!

I'm  having one problem right now though... I can't find any kind of pitch resisitor! Is this inexperience, or is it not possible to mod some of the V-Techs in this way?

[Circuitbenders]

If theres no pitch resistor then it probably uses a ceramic resonator / crystal to set the closk frequency, all the better quality V-techs seem to.

Do a search for either term on this forum and theres some information on creating external timing circuits but its a lot more complex than just snipping out a resisitor and soldering in a pot.

[Doctor Bob]

Ok cool, thanks!
Will do some search and research 

[tinsolder]

hi out there,
my vtech  kiddy pc's have mostly a coil ,a small metallic cubic thing with apainted screw in it; and some 2 capacitors,the beige ones reading 104 or so. so what I idid for pitch bending was: I removed the capacitators (both) and added instead of them a old " air capacitator " ( the tuning thingy from older radios). but mine was about 3*3*8 cm big so i destroyed the housing a screwed all new together. maybe you can play around with different coils too. it's even fun salvaging older radios.

[kick52]

You can also remove the coil and replace it with a 555 circuit.
More info:
http://www.sailormouth.org/index2.php?pg=useosc.inc
http://www.sailormouth.org/index2.php?pg=vtech_pm.inc

[tinsolder]

hey kick,
did you tried this 555 oscillator? did it work? and what are the good values for resistors and capacitors, because i tried it but it never worked,thats why i added this huge piece of ancient radio times.

[kick52]

No, it seemed like a pretty shit bend so I didn't want to spend any more money on it. I *may* have fried it anyway, it used to keep crashing without any interaction, though it hasn't done that at all lately.