Humminbird Side Imaging Forums
Side Imaging Forums => 798c SI => Topic started by: cjbfisher on September 23, 2013, 06:45:16 AM
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I had some trouble with my 798 cxi which was diagnosed as needing a new primary circuit board. Cutting a long story short, it couldn't be repaired, and it was replaced with a 798cxi hd. When I attach it to the auxilary power source to connect it to the PC, it works fine, but when I mount it on the base, it won't power up. I tried bending the pins slightly to make sure I had a good connection, but it didn't work. The battery is fully charged, and I'm getting 13v at the base.
Is there something different with the hd model that would be causing this?
Thanks,
Chris
P.S. I forgot to add earlier that I also removed the power cable from the base and plugged it directly into the unit without success.
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Did you check the voltage with the unit attached and powered up?
If you have a loose connection somewhere, the voltage could look fine without the unit connected and then drop seriously once under load.
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Did you check the voltage with the unit attached and powered up?
If you have a loose connection somewhere, the voltage could look fine without the unit connected and then drop seriously once under load.
Thanks for the reply Bob.
I can't test it under load, as I can't get it to power up at all. All of the connections are reasonably new, bound up nice and tight, and covered with heat shrink, so they shouldn't be able to work loose.
It doesn't make any sense to me as the unit powers up fine with the auxiliary power supply for the PC connection. That got me wondering if there was something different between the original 798 unit and the 798 hd unit that I now have.
Thanks
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No, there is no difference that would account for this. The 798ciX HD Si unit should power right up.
Did the original 798 unit work on this same power cable?
If so, has there been any changes made to the boat’s wiring since then?
Make sure that the polarity at the power cable is correct.
If none of this points to any problem then it must be a current issue so you will need to disassemble all electrical connections, re-solder them and reseal them again.
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Thanks Greg,
Everything is still the same as when the original 798 was working. I had a quick look last night after work, and found a possible weak point in the wiring. It seems that the fuse holder may be the problem. That kind of make sense, as it is the only place in the wiring that is not really well covered and sealed up. Hopefully I'll have a bit more time after work today to pull it apart for a closer look.
Thanks again.
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I managed some time to have a good look today. As I suspected, the fuse holder was the problem. Swapped it out for a good quality waterproof holder. Problem gone.
Thanks for your help.
Chris