Sirius Sportster 5- Will not turn on

SOURCE: power supply to Sirius Radio

yes, some sirius radios work on 5 volts, and some work on 12 volts. Your sportster replay is a 5 volt unit. If you trace that wire back, you will find a cigarette lighter plug with a transformer built into it, with either wires soldered to the terminals, or a female cig plug wired up behind the dash. Whatever sirius unit you plan on hooking up, I strongly reccommend using the transformer that it came with......however if you're willing to take a chance, it's most likely 5 volts.

SOURCE: sirius sportster sp-tk1, always displays "acquiring signal"

Same problem in RI too. Acquiring signal stays on the screen 24/7. My husband has the same Sportster. When I plug his into my car docking station, it works fine. When I plug mine in, it says "Acquiring signal". Does this mean my radio is dead?

SOURCE: Sportster randomly turns off.

I too started experiencing drop-out/unit lock-ups after two months.  After resetting to factory defaults,per Sirius phone support, without results, only pulling out power adapter would reset the unit.  I suspected a design problem with heat.  I wrapped the unit with a medical cold pack and got stable operation.  Given all the complaints I see on this web site, I suspect Sirius is well aware of the issue, and not addressing it appropriately.    

SOURCE: SIRIUS Sportster "Acquiring Signal"

Let me save you $30.00. A new antenna will not help, nor will cleaning the contacts. I just did both of those and it did not help. I have mine in the freezer right now cooling it down. Sirius told me that I should not leave it in the car because it gets to hot. They told me to buy another unit....

SOURCE: my sirius sportster ( SP-R2 ) satelite radio

did you try going into the menu and increasing the volume output