cigarette lighter power

>Further experimentation shows me that though mostly this setup works,
>sometimes the R2 will still refuse to power up, sometimes emitting
>some beeps.  When NiMHs are put back in, all is fine except the R2
>springs to life without having to even hit the on switch.

The R2 returns to its previous state when power is applied.  If it was 
turned on when power was last connected, it will turn on when power is 
reconnected.

The beeps suggest a low voltage condition.  You should *not* have low 
voltage with this power supply.  What does a meter say the output voltage 
is?  Are there any poor electrical connections between the 3 V supply and 
the radio?  This includes the connections to the R2 battery terminals.

>So the LM317+1 resistor+1 diode as seen inside the converter is still
>not enough to fool the R2 every time...

It should be, if it's working correctly.  The output voltage should be 3 V, 
which is more than the batteries will provide.  What is the adapter's 
current rating?  Can it provide 150 mA or so without the voltage dropping?

>Though if we manage to power up, then all is ok.  I dare not try 4.5
>volts instead of 3 though.  Would "AA's hooked in parallel" as
>mentioned by others, help us get turned on? And once on they could be
>taken out of the loop?

I wouldn't try 4.5 volts; the R2 may not be designed to take that.  But 
there should be no need to use batteries or a big capacitor or any other aid 
to help "start" the R2, if the 3 V supply holds its voltage and there are no 
bad connections.  If I power my R2 from a 3V regulated bench supply, it 
turns on cleanly and reliably every time.  Find and fix the problem.

If the wire between the radio and the 3 V supply is more that a few feet 
long, you might want to put a moderate-sized capacitor right at the "fake 
battery" to reduce AC impedance - something like a 10 uF tantalum for 
example.  But, again, I've never done this, and I have no problems with the 
radio starting up.

>< but how do you connect the lighter socket to the icom ?
>
>I use an ugly electric tape and plastic dowels confection to press the
>wires onto the battery contacts.

You might try thumbtacks or some other form of metal cap for the end of the 
dowels, to provide a good large contact area for the R2's battery springs.  
A wire alone is pretty small.

        Dave 


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