Topic: 797 c2 Screen flickers

[Shotgun Slim]

When I power up my unit it flickers on and off.  Sometimes it will light up fine for a while then it is like the light goes out and all I see is faint dark image.  Then it may flicker and come back on.  It seems as though when I move the backlight to a lesser value it stays lit up better than at full power.  But then, this is also no guarantee it will "completely" power up and stay lit up. 

[Humminbird_Greg]

This could be a power related problem or the backlight circuitry may be in the first stages of failure.  Check all of your electrical connections to make sure that they are tight and corrosion free,  this includes the fuse, fuse holder and battery connections.  Get the battery it is powered from load tested as well.  If this does not show a problem, than you will need to contact Humminbird about getting your 797c2 unit serviced.

[Shotgun Slim]

Greg...after messing with it more.  I now notice a "low voltage" warning lighting up.  I have looked at the voltage setting and it appears to have voltage between 11.0-11.5 volts...from unit readout.  I also notice if I turn backlight setting down to near 0 the image will appear but just dim.  When I try to increase the backlight then it starts flickering or goes into that very dim mode with little to no lighting.  Does this make you lean to the battery or power to unit being the problem.  Or could it still be a circuit board issue.  I know it does the same thing even if battery is freshly charged.KAUDYE

[ITGEEK]

A freshly charged battery doesn't mean squat.
A bad battery can get freshly charged, but may not be able to
sustain any kind of electrical load.
Take a known good battery (maybe from your car), and hook it up
for a test.

[Shotgun Slim]

Ok..more info.  This unit has been hooked up for several years and just started acting up last year.  I don't fish very often..maybe 20-30 days a year.  I had it mounted in the dash by a professional and am not sure exactly where the power ties in.  I cannot get behind the dash, because of lack of experience.  I am pretty certain it is hooked up to main power for motor .  Trolling motor batt is separate.  I swapped the cables at the batteries at the transom and put all motor related power cables along with accessories...bilge..aereator etc to starting battery.  It does the same thing.  And this battery spends the starter like a top and easily starts motor.  Even when it may be cold and require longer cranking.  I am considering bringing it to regular boat mechanic as he knows how to get behind these dash panels which I don't.  I will ask him to wire direct to a known good batt to see what happens.  If the same happens once being tested directly to good battery I will send unit off to Humminbird.  May need Bird contact info.  Any thoughts? Thanks for any help....SLIM

[ITGEEK]

If the battery spins the starter on your main motor, then it has plenty of juice to run the sonar.

Humminbird customer service:1-800-633-1468.

[Humminbird_Greg]

You best bet would be to pull the unit and direct connect it with only its power cable to the battery.  I understand that you are not comfortable doing that so maybe you should just get the battery load tested and if it shows good, give the Humminbird CRC folks a call.