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SONY ICF 7600D oscillator crystal 150KHz -- unable to source for replacement

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mvs sarma

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While trying to help a friend (Thomas George) to restore his Sony ICF7600D radio, we came across a crystal 150KHz (cylindrical watch type) whose lead is broken by corrosion, and unable to source a single piece for replacement. It is an oscillator crystal across IC202, .at its pins 49 and 50.

I request for help and support.

thanks and best of 2017

sarma
vu3zmv
 

mvs sarma

Well-Known Member
the expected reply came and it appeared my apprehension was correct.
here is an extract.
"I am sorry to say that the frequency of 150.0kHz was only ever common in transceivers – as we are more industrial, we never ever produced this frequency. To even consider it today, our production would need project with maybe a hundred thousand pieces – we are therefore not able to help you.. .....Kind regards"
 

spec

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the expected reply came and it appeared my apprehension was correct.
here is an extract.
"I am sorry to say that the frequency of 150.0kHz was only ever common in transceivers – as we are more industrial, we never ever produced this frequency. To even consider it today, our production would need project with maybe a hundred thousand pieces – we are therefore not able to help you.. .....Kind regards"
Oh that is a shame.

But at least Golledge were helpful enough to reply to your enquirery.

But I think I gave you the wrong company name.

When I was at work we used to use all kinds of odd xtal frequencies, and there was one company that would supply the xtals of whatever frequency you wanted: we just filled in their specification form and three weeks later we had a suitable xtal and they were not that expensive either.

One of their engineers explained that, to them, one frequency was much like anoth (within reason) and only amounted to putting another frequency on the manufacturing job card.

On reflection, I now think that the companies name was IQD, or similar.

Do you need an xtal specifically, or do you just need a signal at that frequency, if that makes sense.

spec

UPDATE:

IQD are still going but they now seem to be a big company rather than a small flexible engineering company, but it may be worthwhile asking if they can supply your xtal: http://www.iqdfrequencyproducts.com/
 
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atferrari

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Hola Sarma,

Have you tried to find a non working one that you could cannibalize? Locally there is a lot of them but in working condition.
 
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alec_t

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JimB

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Would one of these be close enough?
I have just had a look at the schematic https://www.manualslib.com/manual/1004615/Sony-Icf-7600d.html?page=26#manual and the crystal seems to be the reference frequency for the PLL, so it needs to be 150kHz as near as possible.

I have been googling around and 150kHz crystals are not very common.
I have found some suppliers/manufacturers who seem to be only interested in lots of 1000 'nds.

If you cannot find a suitable crystal, how about building an oscillator which runs at a higher frequency and dividing down with divider chip, and injecting the result into the crystal connection in the circuit board.
Such an oscillator would need to be well screened to prevent the possibility of generating spurious signal up and down the tuning range of the receiver.

As a quick aside comment, I think that these small low frequency crystals are not made of quartz, but maybe some kind of ceramic.
A real 150kHz quartz crystal is big in comparison to a "watch crystal".

JimB
 

JimB

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If you have the space just hot glue a pic and output 150Khz out of a pin... The pic12f1840 has a very reliable osc..
A good solution, but, the frequency needs to be very accurate or the radio will not tune correctly.
Use a PIC with an external crystal which can be adjusted exactly?

JimB
 

JimB

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With a pic12f675... The internal osc is adjustable via the osctune register... If you place a pot on an ADC pin you will get really fine adjustment!!
Sounds interesting.
JimB
 

alec_t

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4.8MHz, divided by 32, will get you there. 9.6MHz crystals are in stock at Digikey (and no doubt elsewhere).
 

mvs sarma

Well-Known Member
Thanks for the concern shown for supporting me.

The crystal suggested by alec-t at Digikey appears good. The total cost to reach me at India would high. Thus I am thinking of giving a local us address where from a relative would return during March.there are few thoughts.

Thanks to jimB and Ian Rogers, for the PIC12F1840 suggestion, I was thinking likewise as I had few PIC12F510 dip. The space inside is dam limited.

The radio used UPD1706, a 4 bit micro-controller with needed software.software inside. The clock would have been defined as external crystal oscillator. But feeding external clock on the input pin of the clock pins will serve the need is to be seen.

I am also thinking of astable using 555 timer with 22K, 470K and 10pF, The frequency coolly working to 150KHz.
otherwise use hc4060 with 9.6 MHz and pic up 150Khz

Let me see how things go. thanks again.

regards
sarma
vu3zmv
 

atferrari

Well-Known Member
A 555, really?
 

mvs sarma

Well-Known Member
Yes atferrari.
I propose to use smd version. But only issue is the voltage available there is just 3.3V not 5 or 6V. May be I could try 7555 in smd and re calculate the values.

If you find any 555 calculator and enter the values I had indicated you can see the result is what Need.

thanks
sarma
vu3zmv
 

alec_t

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I don't think a 555 would be stable enough. JimB (post #10) reckons the frequency needs to be very stable.
 

JimB

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I don't think a 555 would be stable enough. JimB (post #10) reckons the frequency needs to be very stable.
A 555 would be OK as a "proof of concept", to see that the idea of injecting 150kHz into one of the crystal connections will bring the radio back to life.

But as far as I could tell, the 150kHz crystal is used as the reference for the synthesiser which determines the frequency that the radio is listening to, and so the frequency needs to be accurate and stable.

With the best components in the timing circuit, a 555 comes nowhere near to a cheap crystal when it comes to frequency accuracy and stability.

JimB
 

spec

Well-Known Member
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A 555 would be OK as a "proof of concept", to see that the idea of injecting 150kHz into one of the crystal connections will bring the radio back to life.

But as far as I could tell, the 150kHz crystal is used as the reference for the synthesiser which determines the frequency that the radio is listening to, and so the frequency needs to be accurate and stable.

With the best components in the timing circuit, a 555 comes nowhere near to a cheap crystal when it comes to frequency accuracy and stability.

JimB
Why not just build a 150Khz xtal oscillator using one of the schemes already described- it would be as easy as building a 555 oscillator.

spec
 
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