bending Vtech's talk and go farm rattle

[petersteven]

Hi,
I recently acquired this little one, full of promises. But i can't find any bending point on the PCB. I tried a lot of shortcuts but none of them seems to modify any sound. I can't even find the pitch resistor!
Please help me...

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DSC03662.JPG
Description:	The PCB of Vtech's talk and go farm rattle
Filesize:	5.74 MB
Viewed:	770 Time(s)
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[brock]

Hi and welcome to the forum.

I don't do any circuit bending but thought I'd give you my ideas as no one responded in two days. Unfortunately I don't see much promise there. You have a single chip on board under the epoxy blob, three inputs to select your sample, no sound modification signals. There probably won't be a pitch resistor as everything is digital and surely uses a clock internal to the chip. You might be able to do something by electronically controlling the switches with a counter or pattern generator if the switches are pre-emptive and cut off the sound selected when a different switch is selected.

It looks like you've been poking at the test points above R35-38. I suspect that is a test port but it might do something else. You could try removing the resistors to see if there is any change. If those pins look like inputs you could also try driving them with some kind of logic or even just apply power thru a pull-up to see if anything happens.

Brock

[AlanP]

Several of the larger resistors look to be zero ohm jumpers, and not resistors as such.

Have you traced out a schematic? That will give you a starting point.

[petersteven]

Thanks very much for your answers, I'll try some of your advices.