what's the part number of the chip?

[Haibo]

Hi,I try to repair my instrument, but I don't know the part number of the device U1 in the figure,could you help me? thanks.

 

[(*steve*)]

Do you have a picture of the chip in question?

 

[Haibo]

Hi,Steve
I'm sorry I can't give you the picture because the device is badly damaged, the only thing i know is that it is an 8-pin chip and the pin-6 output square wave whose frequency is 9.08Hz.
thank you.

 

[Martaine2005]

Hi Haibo,
What instrument is it?
Looks like an oscillator input to pins 2 and 3 with pin 6 outputting the frequency.
Some kind of multivibrator circuit?
Possibly an op-amp of some kind..

Martin

 

[duke37]

The device looks like an oscillator controlled by a 4MHz crystal (very common).
To get an output of 9.08Hz, you need a division of something over 440 528, not common and a lot in a little chip.

 

[(*steve*)]

a lot in a little chip

There are a number of mask programmable divider chips. One that I'm aware of takes the 3.something MHz colour burst crystal and gives you (from memory) 50Hz. (The datasheet says 60Hz)

 

[davenn]

There are a number of mask programmable divider chips. One that I'm aware of takes the 3.something MHz colour burst crystal and gives you (from memory) 50Hz. (The datasheet says 60Hz)

yup, and also a number of RF prescaler IC's that do this sort of thing eg. a MC12074 < --- just an example type different versions have different divide by rates


I have no idea what that chip in the above cct is ??

 

[GPG]

Got more of the cct?

 

[Colin Mitchell]

You could use a PIC chip and create the output yourself.