Kyocera A-910 Restoration & Information Thread

[tomand]

Kyocera FCL 05 modules:

After completing restoration of the phono / EQ PCB, I turned my attention to the notorious FCL 05 modules.
The FCL modules seem to have a dubious-at-best history among Kyocera owners, who claim failures relating to them. From static, popping, clicking, and even total shutdown of the amplifier via protection circuits! Well, I think I found the reason why... Any guesses?

Corrosive glue! That's right! The FCL module is actually just a modular PCB with a fancy red cover glued to it with... you guessed it. Corrosive glue.
Take a look at the following pictures to see what I mean.

Here is one of the FCL 05 modules removed from the phono stage. As you can see, it is not potted. The cover is simply snapped onto the PCB and glued into place

View attachment 2615436 View attachment 2615437

Here is the same module opened, revealing the internal PCB which houses a good few TO-92 transistors, as well as a couple resistors and diodes.

View attachment 2615440 View attachment 2615441 View attachment 2615438

And here is the main culprit of the notorious issues that people have with the FCL modules. The glue which was used to hold the ceramic-plastic covers onto the PCB.
In my case, the FCL modules worked perfectly fine as there was a conservative amount of glue used which meant none of it ended up creeping onto any nearby components.

View attachment 2615439

Here is one of the FCL modules completely rebuilt with new TO-92 transistors, as well as a complete reflow and deflux of the PCB. Reattaching the cover to the PCB was as easy as snapping it back into place and adding a small dab of super glue to each corner of the PCB.

View attachment 2615443 View attachment 2615442 View attachment 2615444

My FCL modules in the C-910 and B-910 are completely different, unless you cleaned them from the black resin they were embedded in (I wonder how) plus I don't know why they were so easy to open/remove the red plastic covers....

 

[Connor G]

Oh no worries at all, I wasn’t saying it for that reason. I am certainly a subscriber to your YouTube channel, working my way through your videos. I just found it funny that we are working on many of the same things around the same time. I did the L-07C, L-07C II, L-07Ms and L-07MIIs right around the same time and I just repaired a pair Sequerra Metronome 7s which I also saw in a video. Cools stuff. I’ve been long thinking about posting videos, but find it hard to find the time, especially now that I have twin toddlers, I applaud you. Maybe someday.

Dan

I feel you on the time front. Hardly any time recently for me to even listen to equipment. Sorry for the late response, just saw your post now…

My FCL modules in the C-910 and B-910 are completely different, unless you cleaned them from the black resin they were embedded in (I wonder how) plus I don't know why they were so easy to open/remove the red plastic covers....

The FCL modules in this 910 didn’t have any epoxy used inside. Guess I got lucky!

 

[tomand]

I feel you on the time front. Hardly any time recently for me to even listen to equipment. Sorry for the late response, just saw your post now…


The FCL modules in this 910 didn’t have any epoxy used inside. Guess I got lucky!

My FCLs are hybrid units printed on a ceramic base, many parts have been changed for the better, the units play brilliantly, outclassing much more expensive equipment