[600MRG] ICOM R70 Receiver, continued

[Bill Cromwell]

Hi Frank,

I was going to mention the solution offered by Ed, KL7UW, to install a 
rechargeable battery to keep the memory. It will be slightly more 
complicated than just hanging a battery across the built-in memory power 
supply but not by very much. I have some schematics here as an example 
from a commercially built radio from Ten Tec if you can't find something 
closer to hand. The exercise keeps the battery and other parts of the 
radio from seeing one another. In your radio just hanging an appropriate 
battery across the memory supply might actually work. That supply should 
already isolate the backup voltage (and current). Maybe just a 'current 
limiting' resistor into the deal. The one radio I have with memories is 
down for repairs to the power supply (again). All the rest - including 
some solid state radio of not-too-old-age I just dial up the frequency 
(and mode) I want to use. The mechanical tuning doesn't need to be 
backed up and reliably power up on the last used frequency and mode <sly 
grin>. Having a few programmable memory "channels" available is a nice 
convenience, though.

73,

Bill  KU8H

On 07/01/2016 09:24 PM, Frank Lotito wrote:
> TKS for the suggestions guys.  It looks like the successor model, the ICOM R71 had a battery powered memory backup feature.  The R70, which is my model, did not have such a feature.  The R70 schematic does show two AC line operated power supplies. One of which is titled "memory." If there is a rechargeable battery shown on the schematic, I have yet to find it.  I can find no mention in the R70 manual of a back-up battery.
>
>
> Bill Isakson suggested that my receiver's loss in memory was due to the manner in which I was turning off the receiver.  He asked if  I was killing the line voltage to a power strip.  YES INDEED, that's what I am doing!  I guess if the AC line was live, and I turned off the receiver using the front panel power switch, the so-called "memory power supply" would be live. Thus on turn-on, the receiver would remember where it left off.  Mystery solved.
>
>
> However, in the interest of "safety," I will not discontinue the use of the "big kill-all switch" in my shack. I'll spend the half minute or so to redo the frequency and mode where I left off.
>
>
> Thanks again for your suggestions-
>
>
>    73 Frank K3DZ / WH2XHA
>
>
>
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