Weird XO clock start up problem

[Bill Fuss]

I have a spare Tent XO2 I'm getting ready for installation. I purchased a TCXO to change the frequency and plugged it in and it will not start unless you power up, pull the TCXO, then immediately plug it back in.

The TCXO vendor assured me they were 100% tested, and sent me a replacement. The new one does the exact same thing. The voltage is right on 5V and the original XO works fine.

I have to assume I was unlucky getting two bad units, unless something is going on that is beyond my limited knowledge of these clock circuits.

Anyone have any opinions or info I need to know.

Thanks all, Bill

 

[Andrew Eckhardt]

Can you link to the clock board circuit and TCXO datasheet?

 

[Bill Fuss]

Tent Labs has never released their circuit but I traced it out. The TCXO is naturally Chinese and has an industry standard pinout, I double checked that. It seems to run fine once you get it started.

There is 5v directly on the TCXO pin and the ground is solid.

 

[Andrew Eckhardt]

What happens if you just toggle the enable line on the TCXO after power up? How is the signal to that handled on the board? If there isn't any and the output section isn't just plain wimpy then it must have something to do with the supply rise time.

 

[Bill Fuss]

I'm looking at the data I got with the unit. It only uses 3 of the 4 pins. #1 pin is NC. Just ground, supply, and output. I fooled around with pin 1 but it checks infinity on the meter.

 

[Andrew Eckhardt]

Can you get your money back? It might be very stable once it runs but you really shouldn't have to kick start a decent clock.

 

[Bill Fuss]

The XO2 uses a basic 317 reg fed to the xo, I cant imagine it's current starved.

 

[Bill Fuss]

I should be able to, just looking for any other reasonable explanation. I appreciate your input and time.

Best regards, Bill

 

[Andrew Eckhardt]

I wish I could help out a lot more but you have Chinese parts and a mystery circuit.