How to replace 6400 fuse

NI0K

“Just remove the top cover and it’s right by the powerpole connector”. Except the filter board covers it! What is the procedure for removing the filter board?

AG4Q

I have the same question. Is removing the rear panel from the chassis the easiest way to get to the fuse?

NI0K

I got the job done. Here is what I did:
Remove top cover
Remove screws from ANT1 and ANT2 connectors
Remove screws from filter board
Unsolder wire from ANT2 connector
Using an L-shaped tool lift the corner of the filter board closest to the ANT2 connector
Pull the filter board away from the rear panel then raise the board to reveal the fuse

The fuse is a 30A ATO (mini blade)

KD0RC

No unsoldering is necessary. Remove the top cover with a T9 Torx bit. On the 6400, remove the two coax cables (very gently pull straight up) and make note of where they go back (LPF X2, RXA X7). Gently unplug the ribbon cable (PA X4). Remove the four phillips-head screws from the filter board. Remove the four phillips-head screws from the SO-239 antenna connectors. Gently ease the board back and out. The rivets holding the coax connectors can hang slightly on the mounting studs, so a little wiggling may be necessary.

Now the fuse is in plain view and can be replaced, if needed.

Put the filter board back in (making sure that all cables are accessible) and put all the screws back in only finger tight. Then tighten the SO-239 screws first so that there is no stress on the board. Finally, tighten the screws holding the board down followed by plugging in the ribbon cable and two coax cables.

I don't have an ATU or a 6600, so there may be more connections and another board to deal with, but I would think the process is generally the same.

I didn't need to change my fuse but did this exercise to understand what I need to do in the field should anything bad happen requiring a fuse replacement. My truck and camper both use this same fuse size, and I have plenty of 30 A replacements on hand, therefore I will never need to replace it...

Tim K9WX

One bit of advice for anyone trying this: the fuse in my 6600 is an mini fuse. It is not the larger style fuse used in RigRunners or other power strips common to the hobby. The terminology for these fuses is somewhat confusing and the 6600 hardware reference manual simply says, "The power input has a protective 30 Amp automotive “blade type” fuse inside the radio case." Make sure you have the right size replacement fuse on hand before you start. Here is a table of automotive fuse styles from Wikipedia. Lots of different ways of referring to the same fuse.

Tim K9WX

David Okay Patton

Cleaning the fuse blades and adjusting the clip springs on the fuse holder appears to have fixed a problem I was having with low power output. Before making the adjustment, I was getting less than 80W out on all bands, now over 100W at max power.

Al_NN4ZZ

Add a vote and comment to make this easier in the future...

https://community.flexradio.com/discussion/8028594/fuse-sd-card-next-hardware-generation-locate-them-on-the-back-of-the-radio

Fuse & SD Card - Next Hardware generation - Locate them on the back of the radio

Al_NN4ZZ

Jul 11, 2023

NEXT Hardware Generation idea -- Both of these items could be located where the user could access them easily. On my 6700 the fuse could be reached pretty easily after removing the cover. On my newer 6600 that is not the case. The 6600 manual says:

“Just remove the top cover and it’s right by the powerpole connector”. Except the filter board covers it!  It is not easy to get to the fuse and generally not recommended to try.

I had low voltage lockup problems on my 6700 and although the fuse was fine, the cause was corrosion on the fuse holder. No sure if anyone has seen that on the 6600 but it won't be easy for a user to check and correct.

An SD Card holder for the back panel could be similar to the way SIM cards are accessible on your mobile phone. Theoretically most of the corrupt SD card problems have been fixed but I still see users reporting the issue. Having the SD Card easily accessible would provide some insurance if that memory bug ever comes back.

IDEA: How about making both the FUSE and SD CARD easily accessible from the rear panel. It may not be easy to add this feature to the current hardware ( 6400, 6600) but it would be a great improvement for the NEXT generation. I'd pay the additional cost if it was an option on the existing hardware as well.

This change would make is easy for users to troubleshoot and replace both the fuse and SD Card. The change would reduce radio down time, shipping costs, and reduce support staff work load.

Thoughts?

Would you support this idea?

Do you think an extra $50 is worth adding to a $2K or $3k radio?

Regards, Al / NN4ZZ

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Regards, Al / NN4ZZ

al (at) nn4zz (dot) com

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