Does anyone have a pin-out diagram for the above 12volt 5 MHz reference oscillator? (spec No FU00250) Usual searches only turn up 613A which seems to have a different base. This one 7 pin.

Hi Geoff,

I Have one of these but no diagram. Often these were made to a company's own specification. There is however a B7G base with it.  Going clockwise from underneath.

Pin 1 - Inner of a piece of coax. Presumably the output.
Pin 2 - Looks like it did have a connection as it has been soldered to but it was cut short
Pin 3 - Again cut short but with a capacitor marked 104M? Z5U63 other end to centre spigot
Pin 4 -  Longer red wire with rubber sleeve and twisted with black and green wires. Could be freq adjust. or +12V
Pin 5 - NC
Pin 6 - Green wire same length as black. Could be +12V DC in or freq adjust.
Pin 7 - Black also connected to centre spigot and to coax outer. Must be ground and DC return.

The wiring does not look very professional.

Hand written on the side is :-
350mA Start
170mA Stable
2V P-P 50 ohm
Sinewave

Looking inside
pin 1 white
pins 2 & 3 NC
pin 4 red
pin 5 green - not connected to anything inside
pin 6 blue with capacitor to case
pin7 case

So blue pin 6 looks like freq adjust.

I hope this helps. Please let me know if you get more info.

HNY
Paul G8AQA

Thanks Paul, that was very helpful. Pin 1 is the output 5 MHz which gives 2v P-P into 50 ohms with 12v on pin4 and ground /case pin 7. I did not attempt any connection to the other pins as this is sufficient for the moment.
73 Geoff
G4AKW

Geoff,
From the part no you gave (FU00250) this is the 5 MHz unit from the Pye/Philips HS400 high stability oscillator unit for quasi-sync PMR base stations.  Looking at the circuit, the pin config is as below.
1.  5 MHz o/p
2. Upper end of external 10 k pot
3. NC
4. 12 V
5. NC
6. Slider of ext 10 K pot i.e. adjustment voltage
7. Ground, 0 V and bottom end of 10 K pot

73
John G3UUT

Thanks Paul, that was very helpful. Pin 1 is the output 5 MHz which gives 2v P-P into 50 ohms with 12v on pin4 and ground /case pin 7. I did not attempt any connection to the other pins as this is sufficient for the moment.
73 Geoff
G4AKW