[time-nuts] Trimble T-Bolt Power Supply Question

Robert Atkinson robert8rpi at yahoo.co.uk
Sun Aug 14 14:35:11 UTC 2011


I'm with Bruce on this one. For my Thunderbolt I use a Power-One HTAA-16W (the bigger HBAA-40W would do too) open frame Linear 16W 5V @ 2A +-12V @ 0.4A each. While this does not appear to meet the +12V 0.75 warmup requirement for the thunderbolt, re-distribution of the load is allowed as long as you stay under the total power limit. These are classic linear supplies with 723 regulators ann 2N3055. Expensive new ($72 from Mouser) but available surplus (under several names, Condor, International power, same model No.). I pulled all mine from scrap (mostly specialist on one off) equipment. There are several on ebay USA starting at $20 BIN.
The problem with switchers (apart from noise) is load distribution. many rneed a minimum load on one output (typically 5V) to maintain regulation on the others. The Thunderbolt in unusual in having a high +12V requirement compared to +5V. A lot of switchers with a 0.75A +12V output will have several amps of 5V available. They can be quite stressed by maintaining the 12V output with less than 10% load on the main 5V output. 

Robert G8RPI

--- On Sat, 13/8/11, Bruce Griffiths <bruce.griffiths at xtra.co.nz> wrote:

From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] Trimble T-Bolt Power Supply Question
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Date: Saturday, 13 August, 2011, 20:31

I have used one of the Cisco34-0874-01 supplies to run a Thunderbolt for 
a couple of years.
It appears to work well.
However I haven't measured the resultant 10MHz output phase noise spectrum.
I am about to power another Thunderbolt with an open frame linear supply 
(723 regulators with 2N3055 series pass transistors) so in  principle 
comparison of their output phase noise spectra should be feasible (when 
I finish designing and building the required low noise post mixer preamps).

Bruce

paul swed wrote:
> Well I don't have a trimble.
> But my experience with cisco supplies is they come in a huge range of
> flavors.
> So I wouldn't be able to say one way or another. The larger ones require
> external connections and such.
>
> On Sat, Aug 13, 2011 at 9:38 AM, Richard W. Solomon<w1ksz at earthlink.net>wrote:
>
>    
>> I can assume from the underwhelming response that no one has tried to
>> use one of these ??
>>
>> 73, Dick, W1KSZ
>>
>>
>> -----Original Message-----
>>      
>>> From: "Richard W. Solomon"<w1ksz at earthlink.net>
>>> Sent: Aug 11, 2011 12:26 PM
>>> To: time-nuts at febo.com
>>> Subject: [time-nuts] Trimble T-Bolt Power Supply Question
>>>
>>> Has anyone used the Cisco Systems Power Supply (34-0874-01) to power
>>> the Trimble Thunderbolt ? I know there are other supplies out there,
>>> but I have one in the Junque Boxe and am curious if anyone has used
>>> one and how it performed.
>>>
>>> Thanks, Dick, W1KSZ
>>>
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