[sdiy] Effectron 3 / ADM 1030 schematic / battery

[Jim Coursey]

Hi Scott and Peter, thanks for the advice.  My preference is to not mess with the circuit (not having the schematic, etc), and I don't get the sense that whoever worked on this before changed anything significant.  (All the diodes and resistors match their marked designators, i.e. D100 is a diode etc.)  So maybe I'll try the Ni-MH first.  If I were to switch it to a lithium, which way do I orient the diode that replaces the series charging resistor?

Thanks,
-Jim




On Sep 18, 2011, at 12:11 PM, Scott Nordlund wrote:

> 
>> I have a non-functional ADM 1030 -- haven't tested it myself but since it was sold as broken and clearly a failed repair, I haven't bothered yet. It came to me with a dead battery attached to the outside, and a replacement battery in its place. One immediate problem I see is the dead battery has been identified as a rechargeable 3.6 volts (3 1.2v coin cells sealed in red plastic with solder leads). Probably Ni-Cad I assume, since it was from the 80s? The replacement that was soldered in its place is a 3.6 non-rechargeable lithium. Even if the battery only controls patch memory, I assume that using a non-rechargable in place of a rechargeable will cause problems elsewhere in the circuit. So before even bothering to turn it on I figure I at least have to get a rechargeable battery swapped in there (or alter the design to use a non-rechargeable, which is possibly over my head and pretty unrealistic without a schematic anyways).
>> 
>> My local electronics shop only had a Ni-MH replacement. I bought it but haven't yet installed it -- is it worth trying? Or should I be seeking out a Ni-Cad?
>> 
>> I tried emailing Deltalabs but never got a reply.
>> 
>> -Jim
> 
> You can use a lithium battery in place of NiCd if you replace the series charging resistor with a diode. NiCd batteries tend to leak and damage things so I'd prefer to replace them with lithium whenever possible. The lower voltage of lithium coin cells is usually ok too so long as they can supply the RAM chip's minimum retention voltage (to be absolutely sure, measure the voltage across the RAM chip's power supply pins when it's powered off, and compare it to the datasheet). 
> 
> I doubt that's a big part of your problem anyway, but just for general reference...
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