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NAIM NA-522 phono board problem

raysablade

pfm Member
I've removed my Naim NA-526 line boards from a NAC 92 and replaced them with NA522-4s I bought from e-Bay. These are recently serviced by WhichHat so I have no reason to suspect a fault in the boards themselves, but i can only get one channel to work (the right hand one as you look at the amp from the front). I've reinserted the line boards to confirm that there is nothing wrong with BNC's connection the main board and they work perfectly. The working phono board sounds great too, frustratingly better than my phono amp; the faulty side produces no distortion just a very faint sound through the speaker.

The seller has suggested re connecting the link cable on the main board but i was under the impression that this needed to be cut to use any type of output board on these amps.

Is there anything I should be trying, before giving up for now? The NAC92 is due a service so I can get it sorted out then, its just that i'd prefer to do that after Christmas.
 
Were the line boards working ok when installed? Assuming yes, either new cards are faulty or you broke something fitting them :)
 
Were the line boards working ok when installed? Assuming yes, either new cards are faulty or you broke something fitting them :)

The line boards worked before I fitted the phono cards and are back in place working fine now. Given the that the 522 cards had recent service, i think it is safe to assume that i've broken something;)

Its the first time i've tried to to install the 5** cards, it was more fiddly than i expected.
 
The 526 line boards do nothing more than connect the input and output together giving a straight-through connection without needing any power. It is possible that, on the bad channel, no power is getting to that 522 board. Possibly a fault on the NAC92 main board or maybe a damaged connector or dry joint.
 
The 526 line boards do nothing more than connect the input and output together giving a straight-through connection without needing any power. It is possible that, on the bad channel, no power is getting to that 522 board. Possibly a fault on the NAC92 main board or maybe a damaged connector or dry joint.

I've got some 523 MC cards i guess that they will provide a good test of the mainboard.

Update both channels are loud and proud through the 523 cards.
 
Yes, but turn the volume right down because they have more gain than the 522s! Corrected to 522 not 523!

If you have a multimeter it’s fairly easy to check if the motherboard is delivering power to the 5xx board terminals.
 
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Yes, but turn the volume right down because they have more gain than the 523s!

If you have a multimeter it’s fairly easy to check if the motherboard is delivering power to the 5xx board terminals.

I guessed 3 was the right volume and whilst it was loud it showed that both cards are receiving power so it is a fault in the 522 board itself.

Incidentally I've found that the plastic tips that come with caulking tubes are the perfect tool to retract the arms on the plastic clip that secures the board.
 
It could be that the faulty channel has the link wire CONNECTED. This would explain the faint sound from that side. It will also cause the amp to "motorboat" (the input of the MM board is connected to the output). Swap the MM boards over to test if this is true.

OK. You say the MC boards do work. Maybe the link wire has now disconnected itself? That is, it may be intermittent ...
 
It's quite easy to miss the vertical connectors on these if they're not aligned just right. But if you're still having problems we'll get them back and check them out fully for you.
 


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