Digital guages (Yamaha) rigged on boat in 98 are getting power but are illegible.

[Toadfish4]

Do these gauges burn out over time? Both the speedometer and tachometer have become unreadable, motor cranks and runs fine.

 

[GA_Boater]

Welcome aboard.

Did both gauges start dimming or both go out at the same time?

You say you have power, but how much power? Digital displays will dim if the voltage is low.

Measure the voltage to the gauges and it should be over 12 VDC. Also it would be worth while to clean both the voltage and ground sources to the gauges.

 

[gm280]

I concur with GA_Boater's suggestions. Are the gauges reading dim or mixed up readouts. If they are merely dim, they are probably repairable. If they are mixed readouts, probably no so much...