RE: [softrock40] Re: Ensemble Question
The problem is the resistor that helps drop the incoming voltage before it hits the regulator. I obviously messed them up because neither of them matches the schematics (R14 on one and R11 on the other).
Alan – W6ARH
What is the actual voltage of your 12V supply? Many are much higher, often up to 14V, particularly with small loads.
You do not mention which one of the Ensemble kits you are having the problem with.
There is some slight heating of the 78L05 5V regulator that is close to the power connector on all the current Ensemble PCB designs.
Measuring the 12V supply current with just the DC supply connected:
Ensemble RXTX - 27mA
Ensemble HF RX - 24mA
Ensemble VHF RX - 33mA, approx 230mW power dissipated in the 5V regulator.
The regulator on the VHF RX is the warmest, but you can leave your finger on it without any ill effect. Usually once things get up to 60 - 65C, then you cannot leave your finger on them for more than a few seconds.
My boards are run from a 12V gel battery. Perhaps if your DC supply is towards the upper limit, then the heat generated will be higher.
73, Bob G8VOI
--- In firstname.lastname@example.org, "The Silver Fox" <alan.r.hill@...> wrote:
> Has anyone noticed that the PCB gets very hot near the power input? I have
> two of them and they both are hot enough to burn you if you touch them. My
> other Softrocks do not appear to have this issue. I am using 12v input.
> Alan - W6ARH