Monitor ovened crystal module? - UK Vintage Radio Repair and Restoration Discussion Forum

harrym1byt · 31st Jan 2009, 1:14 pm

Hi all,

I have the following unit which I am trying to reuse for a counter timer and I'm trying to work out the pin out and voltage specifications etc..

Monitor
7155-02
JF461871
10.000000 Mhz
84081756
54331

It has four pins on its base, two direct to the metal case, the other two insulated.

I did make initial contact via email with the US manufacturer and they did promise to look it up, but then despite reminders nothing more.

georgesgiralt · 31st Jan 2009, 1:25 pm

Hi !
IMHO, this is a 10.00 MHz crystal into it's oven. Crystal varies in frequencies as the temperature change. (frequnecy depend on mechanical dimensions, so if you heat the crystal, it will change dimension and then frequency).
So in order to stabilize the frequency, you put the crystal in an oven heated to a specific temperature. This way, when the oven has stabilized in temperature, the frequency is constant. (It may not be the same depending on the oven temperature, so you must wait for the whole set to reach the target temp before using the set)
So IMHO, two wires are for the heating resistor, the two others are the crystal wires.
You can check which are wich with an ohmmeter, I guess.
As to the target temp and the precision of the frequency, this would only be known when you get the spec sheet.

harrym1byt · 31st Jan 2009, 3:48 pm

I already knew all that, it is a 10Mhz crystal I need for the job, the only thing I'm trying to work out is the actual pin out of the device. My guess is one pin for input of the DC voltage, which has to be used for both the oven and the supply for the oscillator, then one pin for its buffered output.

All need to know is which pin is which and what input voltage it requires.

Thanks anyway.

Dickie · 2nd Feb 2009, 1:44 pm

Any chance of a photo? A number of manufacturers used standard pinouts for these things. Who is the manufacturer?

harrym1byt · 2nd Feb 2009, 5:16 pm

Quote:

Originally Posted by Dickie

Any chance of a photo? A number of manufacturers used standard pinouts for these things. Who is the manufacturer?

Monitor is the name of the US manufacturer - I 'll try to upload a photo a little later.

harrym1byt · 2nd Feb 2009, 8:17 pm

http://myweb.tiscali.co.uk/m1byt/OVEN2.JPG

View of the side of the case.

http://myweb.tiscali.co.uk/m1byt/OVEN1.JPG

View of the pins or base....

Note their are 5 pins, not 4 as I stated earlier - sorry for any confusion, I was relying on memory.

The two at the bottom of the photo are both connected to the case, with a calibration adjustment slightly above and between the pins. With three insulated from the case pins at the upper edge of the photo. I would therefore assume the three pins are - supply for the oven, supply for the crystal oscillator; buffered output from the oscillator. My guess would be that it needs 12v DC for the oven and 5v DC for the oscillator. All I need to know is which of the three pins is which and to confirm my assumptions with regards to the voltage requirements.

If it is not clear in the photo, the pin layout is symetrical.

Thanks..

Dickie · 3rd Feb 2009, 1:43 pm

Unfortunately I haven’t got any data that looks anything like your oscillator. In the absence of any other information I agree with your thoughts about pin functions. If you end up finding out by trial and error I suggest you apply 5V to each pin in turn via a current limiting resistor (100R or so) and look for a 10MHz output on the other pins. If nothing happens reduce the value of resistor and try again!

- A couple of comments. It’s odd to have two pins grounded rather than just one, and it looks very small for an ovened oscillator that's several years old.
Cheers,

harrym1byt · 3rd Feb 2009, 6:09 pm

Hi Dickie,

I don't think it is that old - my guess would be that the 84081756
translates to 1984, week 08, at 17:56 or 1,756th unit made in the day or more likely the week.

It was pulled from a section of modern multi-layer PCB, unfortunately chopped from the rest of the circuit, so no possibilty to trace the pins to the rest of the circuit for some clues. I have come across much smaller ovens than this one and the circuit I have in mind for this unit is designed for an optional oven which has smaller footprint than this one.

Applying some volts blindly to the pins was to be the next step, if I failed to find any better clues to the pinout. I have a rather neat modern bench PSU, where you can adjust the volts from 0 to 20v, and the current limiting from 1mA through to 5amps both metered to two decimal places.

georgesgiralt · 3rd Feb 2009, 7:04 pm

Just my 2¢ here, but will it be possible to open the device without destroying it ? This way you'll get the schematics and wiring ?

harrym1byt · 3rd Feb 2009, 7:39 pm

Quote:

Originally Posted by georgesgiralt

Just my 2¢ here, but will it be possible to open the device without destroying it ? This way you'll get the schematics and wiring ?

No, unfortunately it is very well sealed up.

31st Jan 2009, 1:14 pm	#1
harrym1byt Retired Dormant Member Join Date: Dec 2008 Location: Garforth, West Yorkshire Posts: 26	Monitor ovened crystal module? Hi all, I have the following unit which I am trying to reuse for a counter timer and I'm trying to work out the pin out and voltage specifications etc.. Monitor 7155-02 JF461871 10.000000 Mhz 84081756 54331 It has four pins on its base, two direct to the metal case, the other two insulated. I did make initial contact via email with the US manufacturer and they did promise to look it up, but then despite reminders nothing more.

31st Jan 2009, 1:25 pm	#2
georgesgiralt Hexode Join Date: Jul 2008 Location: Toulouse, France Posts: 406	Re: Monitor ovened crystal module? Hi ! IMHO, this is a 10.00 MHz crystal into it's oven. Crystal varies in frequencies as the temperature change. (frequnecy depend on mechanical dimensions, so if you heat the crystal, it will change dimension and then frequency). So in order to stabilize the frequency, you put the crystal in an oven heated to a specific temperature. This way, when the oven has stabilized in temperature, the frequency is constant. (It may not be the same depending on the oven temperature, so you must wait for the whole set to reach the target temp before using the set) So IMHO, two wires are for the heating resistor, the two others are the crystal wires. You can check which are wich with an ohmmeter, I guess. As to the target temp and the precision of the frequency, this would only be known when you get the spec sheet.

31st Jan 2009, 3:48 pm	#3
harrym1byt Retired Dormant Member Join Date: Dec 2008 Location: Garforth, West Yorkshire Posts: 26	Re: Monitor ovened crystal module? I already knew all that, it is a 10Mhz crystal I need for the job, the only thing I'm trying to work out is the actual pin out of the device. My guess is one pin for input of the DC voltage, which has to be used for both the oven and the supply for the oscillator, then one pin for its buffered output. All need to know is which pin is which and what input voltage it requires. Thanks anyway.

2nd Feb 2009, 1:44 pm	#4
Dickie Octode Join Date: Sep 2004 Location: St. Albans, Hertfordshire, UK. Posts: 1,478	Re: Monitor ovened crystal module? Any chance of a photo? A number of manufacturers used standard pinouts for these things. Who is the manufacturer? __________________ Regards, Richard, BVWS member

2nd Feb 2009, 8:17 pm	#6
harrym1byt Retired Dormant Member Join Date: Dec 2008 Location: Garforth, West Yorkshire Posts: 26	Re: Monitor ovened crystal module? http://myweb.tiscali.co.uk/m1byt/OVEN2.JPG View of the side of the case. http://myweb.tiscali.co.uk/m1byt/OVEN1.JPG View of the pins or base.... Note their are 5 pins, not 4 as I stated earlier - sorry for any confusion, I was relying on memory. The two at the bottom of the photo are both connected to the case, with a calibration adjustment slightly above and between the pins. With three insulated from the case pins at the upper edge of the photo. I would therefore assume the three pins are - supply for the oven, supply for the crystal oscillator; buffered output from the oscillator. My guess would be that it needs 12v DC for the oven and 5v DC for the oscillator. All I need to know is which of the three pins is which and to confirm my assumptions with regards to the voltage requirements. If it is not clear in the photo, the pin layout is symetrical. Thanks..

3rd Feb 2009, 1:43 pm	#7
Dickie Octode Join Date: Sep 2004 Location: St. Albans, Hertfordshire, UK. Posts: 1,478	Re: Monitor ovened crystal module? Unfortunately I haven’t got any data that looks anything like your oscillator. In the absence of any other information I agree with your thoughts about pin functions. If you end up finding out by trial and error I suggest you apply 5V to each pin in turn via a current limiting resistor (100R or so) and look for a 10MHz output on the other pins. If nothing happens reduce the value of resistor and try again! - A couple of comments. It’s odd to have two pins grounded rather than just one, and it looks very small for an ovened oscillator that's several years old. Cheers, __________________ Regards, Richard, BVWS member

3rd Feb 2009, 6:09 pm	#8
harrym1byt Retired Dormant Member Join Date: Dec 2008 Location: Garforth, West Yorkshire Posts: 26	Re: Monitor ovened crystal module? Hi Dickie, I don't think it is that old - my guess would be that the 84081756 translates to 1984, week 08, at 17:56 or 1,756th unit made in the day or more likely the week. It was pulled from a section of modern multi-layer PCB, unfortunately chopped from the rest of the circuit, so no possibilty to trace the pins to the rest of the circuit for some clues. I have come across much smaller ovens than this one and the circuit I have in mind for this unit is designed for an optional oven which has smaller footprint than this one. Applying some volts blindly to the pins was to be the next step, if I failed to find any better clues to the pinout. I have a rather neat modern bench PSU, where you can adjust the volts from 0 to 20v, and the current limiting from 1mA through to 5amps both metered to two decimal places.

3rd Feb 2009, 7:04 pm	#9
georgesgiralt Hexode Join Date: Jul 2008 Location: Toulouse, France Posts: 406	Re: Monitor ovened crystal module? Just my 2¢ here, but will it be possible to open the device without destroying it ? This way you'll get the schematics and wiring ?