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Old 26th Apr 2018, 10:50 am   #1
Brian of Romsey
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Default Pin-out for SEI Quartz Oscillator

Hi,

I realise this might be a bit off-topic, but I'm hoping that this is the right audience.

I have recently acquired an SEI brand quartz oscillator about which I'm hoping to get some information on the pin-out and the supply voltage. It is labelled as follows (with the bold text hand written onto the label):
SEI QUARTZ OSCILLATOR
QC. 1260
PART No.
FREQUENCY 94.808 MHz

SERIAL No. 721559
MADE IN ENGLAND
The case is 1.4" by 1.0", and about 0.4" thick. On the bottom there are four pins in a rectangle 1.0" by 0.5". One of the pins is clearly ground and is directly connected to the case, the other three are isolated. Below is a poor diagram showing the layout:

Code:
------------------
|  A          B  |
|                |
|  G          C  |
------------------
With G being the ground pin and A, B, & C being the other three. Pins G, B, & C show signs of having been soldered to in the past, pin A looks clean in this respect.

So, any suggestions about pin-out or supply voltage? I'm guessing that it will be a 5 Volt part with a full swing on the output, maybe TTL-like.

Thanks in Advance, Brian.
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Old 26th Apr 2018, 2:18 pm   #2
barrymagrec
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Default Re: Pin-out for SEI Quartz Oscillator

Frequency is a bit high for TTL I would have thought, more likely a sine wave or just possibly ECL in which case be careful as the supply may be -5.2 volts.
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Old 26th Apr 2018, 3:37 pm   #3
ronbryan
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Default Re: Pin-out for SEI Quartz Oscillator

If one of the pins appears isolated from the ground pin, when checked with a low voltage resistance test, it is probably the AC coupled sinewave output pin. The package may also have a second, square-wave output, as is the case with a 10MHz CQXL SPXO I have here.

Ron
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Old 26th Apr 2018, 4:27 pm   #4
G6Tanuki
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Default Re: Pin-out for SEI Quartz Oscillator

These were reported-on in April 1969 in Wireless World (see Americanradiohistory website).
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Old 27th Apr 2018, 8:54 am   #5
davidw
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Default Re: Pin-out for SEI Quartz Oscillator

The only data I can find is this for these Cathodeon packages.
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Old 27th Apr 2018, 10:22 am   #6
Brian of Romsey
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Default Re: Pin-out for SEI Quartz Oscillator

Hi G6Tanuki,

That's very helpful, thanks. Now I know it's operational parameters, I can go on guess at the pin out - there's only two possibilities after all. I'll start with +9 Volts on the pin diagonally opposite ground and look for the output as I wind the voltage up (watching the current).

Cheers, Brian.
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Old 27th Apr 2018, 10:29 am   #7
Brian of Romsey
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Default Re: Pin-out for SEI Quartz Oscillator

Dave,

Thanks for the Cathodeon info. Such a variety of pin-outs! Nothing like to standardisation of today.

Cheers, Brian.
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Old 12th Jul 2018, 10:20 pm   #8
Brian of Romsey
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Default Re: Pin-out for SEI Quartz Oscillator

Hi,

I finally got round to testing and sorting this oscillator. It does work (which is always a worry for second hand stuff from a radio rally).

At 9.0 Volts it draws between 3 mA and 8 mA on the pin diagonally opposite the ground pin. The output is a sinewave, centred on ground, with an amplitude of 2.9 Volts peak-to-peak when loaded only with the 'scope and 1.8 Volts peak-to-peak when loaded with 50 Ohms.

The pin-out, viewed from above (like normal chips are):


+------------------------+
| 4 = Ground ... Out = 3 |
| 1 = N/C .. 9 Volts = 2 |
+------------------------+


Strangely my bench PSU seemed unable to deliver a solid supply, loads of ripple - 840 mVolts! Even with a 47 nF polyester & a 470 pF polystyrene right across the pins the ripple only got down to 530 mVolts. Ah well, the output looked like a clean sinewave no matter what.

Cheers, Brian.
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Old 12th Jul 2018, 10:52 pm   #9
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Default Re: Pin-out for SEI Quartz Oscillator

Don't assume 9v just because some cathodeon oscillators were. They were competitors and each produced a very wide range of options. 12v was common, so were 6v and 8v.

Check pin 1 for diode + series resistor to ground. it may be a voltage operated frequency trim (also optional)

It's about 35 years since I last saw Dave Standring and the quartz folk at Times Mill. They were good people and they made very good stuff.

David
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Old 14th Jul 2018, 4:31 pm   #10
Brian of Romsey
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Default Re: Pin-out for SEI Quartz Oscillator

David,

I used 9 Volts because of what I read from the press release in post #4. I did actually start powering it up with 5 Volts and, because it drew only a few milliAmps, I felt happy winding it up to 9 Volts.

Cheers, Brian.
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Old 14th Jul 2018, 4:44 pm   #11
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Default Re: Pin-out for SEI Quartz Oscillator

That's good. These things were made to order and the datasheet was like a menu, choose the frequency choose the supply voltage, choose the temp range.... All the model number seemed to tie down is the package size.

David
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