[hpsdr] Mounting Munin T1 & T2??

[John]

Thanks for the offer Tim, but I have the straps that came with the 
kit.  They do seem pretty thick to bend so that they contact both the 
top of the transistor flange and the circuit board nicely.  I could 
make thinner straps out of copper foil and probably bend them or, 
maybe, buy some copper of the right thickness to fill the void 
between the top of the heat spreader and the straps I have.

Dick, what I'm trying to say is best described in the mechanical 
drawing of the RD100HF-1 data sheet available here:
http://www.mitsubishielectric.com/semiconductors/content/product/hf/sirfpowermosfet/siliconrfdiscrete/siliconrfdiscrete_lv4/rd100hhf1.pdf

The thickness of the flange is 3.3 +/- 0.2 mm but the bottom of the 
other leads is 4.5 +/- 0.7 mm above the bottom of the flange.  The 
problem I see is that when I make the four mounting posts for the 
circuit board so that the drain and gate leads are flush against the 
pads on top of the board, the top of the flange (source connection) 
is a considerable distance (nominally 1.2 mm) below the top of the 
circuit board.  I do not understand how the drawing on page 2 of 
Mounting the RD100HHF1
http://www.k9ivb.net/Munin2/Mounting_The_RD100HHF1.pdf
applies.  That drawing shows the RD100HHF1 flush with both the heat 
spreader and the top surface of the circuit board.  One of the 
pictures on your site shows the straps are flat and the other picture 
shows them bent, but the bent ones don't look as if they are bent 
enough to reach the top of the flange.

John, WoGN


At 03:51 PM 12/24/2013, Tim ORourke wrote:
>If you refer to wiki munin page you will see brass straps bent to 
>accmodete the raised mounting tabs. I can send you some straps if 
>you do not have a way to make them. Tim w4yn
>
>
>
>
>-----Original Message-----
> >From: John <radio at mediacombb.net>
> >Sent: Dec 24, 2013 4:09 PM
> >To: bob at llorenzini.com, "hpsdr at lists.openhpsdr.org" 
> <hpsdr at lists.openhpsdr.org>
> >Subject: Re: [hpsdr] Mounting Munin T1 & T2??
> >
> >***** High Performance Software Defined Radio Discussion List *****
> >
> >
> >Hi Bob,
> >
> >I don't think that document applies in my case.  With the transistors
> >I got with my kit, and with the four board mounting spacers made so
> >that the tops of the transistor flanges are flush with the top of the
> >circuit board, the other transistors leads are way above the level of
> >the top of the board.
> >
> >John,  WoGN
> >
> >
> >At 01:35 PM 12/24/2013, Robert Lorenzini wrote:
> >>On 12/24/2013 11:25 AM, John wrote:
> >>>***** High Performance Software Defined Radio Discussion List *****
> >>>
> >>>
> >>>
> >>>Transistors T1 and T2 in my Munin kit are made with the two thin
> >>>leads a considerable distance above the top of the mounting
> >>>flange.  When the four corners of the circuit board are spaced so
> >>>that the two thin transistor leads are flat against the pads on top
> >>>of the board, there is considerable distance between the bottom of
> >>>the copper straps and the top of the transistor flange. As
> >>>transistor hardware is tightened the board starts to bend and the
> >>>transistor leads lift above the pads on the circuit board.
> >>>
> >>>Has anyone else had this problem and, if so, how did you make it work?
> >>
> >>Your going to need to make custom spacers.
> >>
> >>http://k9ivb.net/munin2/Mounting_The_RD100HHF1.pdf
> >>
> >>Bob - wd6dod
> >
> >



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