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Author Topic: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)  (Read 10791 times)

dislocations

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Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« on: December 02, 2011, 09:20:56 AM »

Can anyone help me out here?
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Dylan

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #1 on: December 02, 2011, 04:43:05 PM »

It should just be the resistor closest to the IC. If you still can't find it, it may use a crystal for the clock unit. In that case, you'll need to use one of the LTC1799 oscillator doo-hickeys.
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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #2 on: December 02, 2011, 05:59:20 PM »

don't the more expensive vtechs have those adjustable coils? I doubt this one has though, i'd say theres a resistor and you've missed it somehow. Sometimes v-techs have smaller boards coming off the main board that have a black blob chip and the pitch resistor on them.

I'm sure this has been discussed before for this machine, try doing a search.

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dislocations

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #3 on: December 02, 2011, 06:53:24 PM »

thanks guys........deffo no crystal. I'll take a second look!
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Bogus Noise

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #4 on: December 02, 2011, 11:28:39 PM »

There's loads of different VTech toys released under similar names, is this one you have?

Circuit Bent VTech Alphabet Desk Phonics

If so, then there are two circuit board types that I've come across! One is roughly square with regular components, and gives some good noises and a few glitch noise streams. The other is a small rectangle with SMD components. Couldn't get anything decent out of the SMD one. I can't remember clearly, but I think it was a crystal driving this one. I injected/replaced the signal with a couple of various oscillators, not sure if the 4011 worked, but if not the LTC did. Still, nothing worth drilling a hole in the front for!

There is a way to tell which circuit board you have before you buy one - check the number on the back.
For the big board, look for the number 17 (specifically on mine, 53-17000-002). The ones with 36 or 37 contain the smaller, pointless board. I think it's just those two digits that change and the rest of the serial number is the same - I just wrote down to avoid the 36 and 37!

dislocations

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #5 on: December 03, 2011, 07:52:52 AM »

Just checked.........it is a 17!!!!!! Will play and post results. Cheers!
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dislocations

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #6 on: December 03, 2011, 09:33:33 PM »

Thanks guys! Got it pitching like a bitch!!!!!!!
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tilde

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #7 on: November 22, 2012, 10:44:18 PM »

Hi

Where did you find the pitch resistor I've been searching and can't find it anywhere )-:

Thanks
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Bogus Noise

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #8 on: November 22, 2012, 11:15:10 PM »

Do you know if you have the big board or a smaller SMD board? Check the number on the back, if it has a 17 in it you'll have the good one, if it's the smaller board unfortunately there's not much that can be done to it! Have a look at my post a few up for more details.

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #9 on: November 23, 2012, 09:32:18 AM »

It's the big board-17.  I can find various glitches but not the pitch resistor. Does this use a crystal? If so any clues on finding/replacing it would be appreciated.
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Bogus Noise

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Re: Trouble finding pitch resistor (Vech Alphabet Phonics Teacher)
« Reply #10 on: November 23, 2012, 03:29:37 PM »

It's on one of the central two vertical solder point columns where the main CPU sits. The glitches are related to the pitch resistor too. The lick and prod technique should help you find it from here!