[hpsdr] Mercury questions

[George Byrkit]

Jim,
This wasn't in the BOM because it wasn't done by the manufacturing process.
There are some who may have added a heatsink (like the small, stick-on RAM
heatsinks, maybe), based on some old discussions on this list, to reduce the
temperature at U5, which is the ADC chip.  I'd try asking the person from
whom the board came initially.  Or it may be a Mercury EU?

There were similar discussions about changing the resistor values and such
on the LPU so that it could put out more current than originally, and often
had you replace the large resistors with 2 in series, standing up in the
air, to improve the heat dissipation there.  It is a Linear power regulator,
after all.

73,
George K9TRV

-----Original Message-----
From: Hpsdr [mailto:hpsdr-bounces at lists.openhpsdr.org] On Behalf Of Jim
Sanford
Sent: Saturday, January 7, 2017 10:16 AM
To: hpsdr at lists.openhpsdr.org
Subject: [hpsdr] Mercury questions

***** High Performance Software Defined Radio Discussion List *****

All:

I am helping a friend get an HPSDR going.  In comparing his Mercury 
board with my two boards, I see that one of mine has a heatsink on U5.  
My other board (purchased from TAPR years ago) and my friend's board do 
not have a heatsink on U-5.

I do not see a reference to a heatsink in the BOM.  Thermal imaging 
predictably shows higher temperatures on the devices without a 
heatsink.  (161F versus 150F or so on the heatsink.)

This was obviously added to my one board somewhere along the way.  Does 
anybody know when/why?

Specifically, should I be looking for heatsinks for the two boards?  If 
so, does anybody have/remember part number and source?

Or is this "nice to have" but not necessary?

Thanks & 73,

Jim

wb4gcs at amsat.org



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