[Skimmertalk] QS1R (Rev C) over heating?

[Alexander Ranaldi]

I placed some enormous copper heatsinks on my regulators and put the QS1R
board itself in a new enclosure with a built-in linear power supply and two
80mm fans running at ~2k RPM.  Seems pretty stable in that configuration. I
haven't checked the heatsink temperatures though.
Alex w2axr

On Fri, Jul 17, 2020 at 7:49 AM Dave <dave.g4aon at gmail.com> wrote:

> My QS1R failed recently. The fault was the 1.2V supply, which is fed from
> an L1117 1.2 regulator.
>
> Running the 1.2V rail from an external supply showed a current draw around
> 300mA when listening to a broadcast station with SDRMAX V software, but
> around double that current when running 7 slices with CW Skimmer.
>
> The original regulator, which uses the PCB as a heatsink, seems inadequate
> for the current needed by the Cyclone III FPGA. I tried an LM317 (TO220)
> regulator with a small heatsink, however the heatsink reaches over 90C
> running 7 x slices with Skimmer.
>
> Before I bolt the regulator to the case, has anyone  checked their QS1R
> for boiling hot regulators, modified theirs, or has mine an overheating
> fault? By the way, Skimmer works with multiple slices, as does the QS1R
> when used to listen “single channel” as in broadcast station listening.
>
> Thanks
> Dave G4AON
> --
> Sent from my iPhone SE
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