[time-nuts] NTGS50AA Power supply

lists at lazygranch.com lists at lazygranch.com
Sat Feb 9 20:17:06 EST 2013


Are the two diodes really back to back? I have use two in parallel to enhance the time the diodes will conducting. Due to current hogging, the diodes will  effectively turn on one at a time.

-----Original Message-----
From: EB4APL <eb4apl at cembreros.jazztel.es>
Sender: time-nuts-bounces at febo.com
Date: Sun, 10 Feb 2013 02:08:17 
To: Discussion of precise time and frequency measurement<time-nuts at febo.com>
Reply-To: Discussion of precise time and frequency measurement
	<time-nuts at febo.com>
Subject: Re: [time-nuts] NTGS50AA Power supply

Nate,

I have it already connected to a 48 V supply according to the vendor 
instructions (fluke.l is a vendor with technical knowledge)and now I 
removed the PCB from the case that I furnished and found that my unit 
doesn´t have such bridge.  Instead it have a quite elaborate reversal 
power protection (a series diode, two fuses and a pair of back connected 
diodes which will blow the fuses if the power is reversed and the first 
diode fails shorted) so I think that there are dual supply models 
(according to my documentation) and single supply ones, as my unit 
appears to be.
Thank you for the suggestion to change the 1/2PPS to 1PPS by software,
I'll try it.

Regards,
Ignacio EB4APL


El 09/02/2013 17:54, Nathaniel Bezanson wrote:

> Open it up, you'll find a bridge rectifier as the first component on the incoming power.
> It's actually much easier to solder straight to the pins of that component, rather than trying to bodge something together that would poke into the backplane connector. :)
> I know there's a TSIP command for *other* units to change their PPS into PP2S (even second), so try throwing 8E-4E at this unit and see if you can change it the other way. Haven't had a chance to try it on the local one.
> -Nate-
> EB4APL  wrote:
>>                  Hello,
>>
>> According to a Nortel specification document (Dual Voltage Global
>> Positioning System Timing Module (GPSTM) OEM General Specification
>> Dataset Name: GSBW50AA), this GPSDO is dual voltage and can be powered
>> either from -48 V or + 24 V systems.  Mine is working from a 48 V power
>> supply but I´m afraid to test it at 24 V because the polarity should be
>> reversed and if my assumption is not true I can damage the unit.
>> Do you know if these units are dual voltage or my documentation refers
>> to other model?.  Has anybody operated it at 24 V?.
>> Another question, is there any internal 1PPS signal available?
>> Of course, my unit is of ebay - China origin.
>>
>> Regards,
>> Ignacio EB4APL
>> _______________________________________________

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