The PSU voltages available should be;
1) +12v regulated
2) +10v unregulated - this could range from around 8 - 12v normally
3) +5v regulated
4) -6.5v regulated
I dont have an SDS9 open at the moment so can't confirm what colour wire is attached to what output on the PSU. The regulated voltages should be close to those above - within approx .25 - .5 of a volt.
The +10v comes from before the LM323 voltage reg ( 5 volt reg) and from my knowledge is used (via a simple delay circuit) to provide a slight delay at start-up before the CPU can access the RAM memory.
The +5 is for the logic components (cpu etc) and the +12, -6.5 to supply the required voltage of 18v for the analog components.
If the +12 is low, this could cause a problem (including false triggering)
If the + 10 drops to low (to 5 -7v);
1) the output of the ram enable delay will be too low to provide the correct TTL signal requirement to enable RAM access reliably thus causing problems
2) This +10 also provides the input for the +5v regulator. The 78xx series regulators (as used in this supply) require between 7 - 9v input to operate correctly. If the voltage is too hi, the regulator will get hot and shut down. If the voltage is too low, the regulator will become unstable and not provide the specified output voltage.
Loss of +5v (for the logic devices) will cause all kinds of issues, most notably causing the CPU to restart randomly
--- In Simmons_Drums@yahoogroups.com, "sarsipri" <alfco@...> wrote:
>
> The voltage is 12.5 volt not connected. Should be about 9 volt (8.8), and drops to 6.8 volt. I changed it on another sds9, and the problem is in the power supply. I am not sure were 9 volt is coming from for the Brown wire.
>
> --- In Simmons_Drums@yahoogroups.com, "philmurr" <philmurr@> wrote:
> >
> > If you unplug the multi-way connector from the main board and measure the voltage at the power supply end, what do you get (on initial power-up and then after a few minutes) ?
> >
> > --- In Simmons_Drums@yahoogroups.com, "sarsipri" <alfco@> wrote:
> > >
> > > I have one SDS 9 with a power problem. The wire cable that goes to the mainboard, there is one brown wire with about 9 volt. After a few minutes drops to about 6 volt and all triggers go on. Can anybody check how much the output should be?
> > >
> >
>