how does a sat box store frequency settings

[klegg]

How does the average satellite box hold onto its frequency settings when adminstered by the user...
I'm baffled as to why a sat box would reset itself back to factory settings, the RF board here doesn't appear to have any batteries onboard...
The question i have is what component (if it isn't a battery) ensures the board holds onto the settings its given ....
The only thing i can think of is that an IC may have an internal battery. The box is a Strong 4400 help appreciated

 

[Topper]

The standard method of storing such detail is to use an EEprom, or to make more of that an Electronically Erasable Programmable Read Only Memory chip. This means that information will only change when the information is written over or flashed. Sometimes they use a cheaper chip and hold the information by charging a capacitor up and feeding the chip, but capacitors do fail as do batteries. There probably are other methods but I am not familair with them, they are not as you correctly mention like a PC Mobo and have a Cmos chip backed up with a battery, but could be using a capacitor as mentioned

 

[klegg]

OK... Am i right to say the capacitor would be keeping the present settings until the sat box is powered back on thus restoring its max charge...Sat boxes must therefore be designed to hold settings for months even when not powered on. The discharge rate must be micro-amperes over that period, i'm guessing there isn't any other circuitry involved to prevent this cap discharging other than its associated CR network. CHEERS!

 

[Topper]

I suspect there are one or two user of strong stb's have alook in the workbench and soldering forum on this board if you haven't already found it
somebody may have already had a problem
http://www.satellites.co.uk/satellite/work-bench-soldering-station/

 

[Robbo]

Flash memory is normally used, and it doesn't need a capacitor as it in non-volatile.