AV 5103 - is it worth repairing?

[Albert]

Hi, I have a question - is it worth repairing a blown PSU?

[rowlandhills]

I've seen 5103s on eBay for less than 400 pounds, and they tend to go for the same price as Kairns, so I'd probably look at buying a second one to cannibalise for parts if no-one cones back with a good answer.

[LHB]

fatboy Wrote:Hi, I have a question - is it worth repairing? Not asking for a diagnosis or repair price but just, based on your collective experienice, does it sound like it's economically repairable.

I have a 2004 model AV5103 pre amp and very pleased with it I was too. It was bought second hand and worked perfectly for around 6 month then one day the power supply died. The semingly quite common case of the surface mounted diodes which make up a bridge rectifier overheating and burning out. I sourced a replacement and carefully tried to find out if the power supply was pushed or failed alone. Plugged in alone the power supply functions fine. The power supply connects to the bottom board (the one with analog inputs and outputs), it then passes power on to the upper board (the one with digital inputs and outputs) and also seperatly on to the front display board. If all boards are connected it powers but the power supply heats up quickly and badly. If you disconnect the upper board and leave only the lower board and front panel it powers up with expected errors (i.e. can't find upper board) but the power supply does NOT overheat. If You disconnect power to the front display and reconnect power to the upper board again no overheating. Basically when the front display and upper board are both connected there would appear to be a short circuit back to the power supply and to the bridge rectifier under the transformer.

Does this ring any bells with anyone? I fully intend to send it to an experienced Linn repairer but money is tight and I don't want to throw good money after bad. Does this fault sound like an expensive and probably terminal fault or does this sound like a more affordable failure of a component somewhere along the power rail. If it sounds like an expensive repair - e.g. the standard look and see fee to send it back to Linn is £400 - no disrespect but I may as well buy a second hand kairn and wait until times improve . Or does it sounds like an afordable repair and if so any recommendations of who to send it to?

The thread below has a lot of information about AV5103 power supplies overheating. I hope it's of some help.

http://forums.linn.co.uk/bb/showthread.p...974&page=1

[TomBK]

fatboy Wrote:Hi, I have a question - is it worth repairing? Not asking for a diagnosis or repair price but just, based on your collective experienice, does it sound like it's economically repairable.

Hi fatboy

To be honest...I wouldn't have a clou...

But I love mine, so I would suggest you'd try fixing the one you've got...lots of old-school people out there with the skills...I should think...

Tom

[Keltik Klown]

(2009-07-13 13:16)fatboy Wrote:  No one out there got any ideas?

Interesting to find these old posts. I now know a fair bit about what's going on with 5103s that fail in this way having had my own 5103 fail in the manner described -- and having subsequently performed an investigation, failure analysis and repair.

All the 5103 SMPSs I know about that have failed in this manner have been too badly damaged to be repaired. The PCB material under the diodes in question is very badly burnt, and in my case the solder pads and some of the inner layer tracking had completely gone from under one of the diodes.

I managed to source a replacement SMPS. Although the 5103 was working fine with the replacement SMPS fitted I was immediately concerned about the temperatures that were being reached in certain parts of the SMPS itself and the regulators on the top board.

However, having instrumented up my 5103 to determine exactly what was going on in these areas I'm now happy with it -- although it does run rather warm in some specific areas the temperatures are not excessive and I'm happy that it's working as designed.

[Zyklope]

(2010-01-21 00:29)Willi Murray Wrote:  

(2009-07-13 13:16)fatboy Wrote:  No one out there got any ideas?

Interesting to find these old posts. I now know a fair bit about what's going on with 5103s that fail in this way having had my own 5103 fail in the manner described -- and having subsequently performed an investigation, failure analysis and repair.

All the 5103 SMPSs I know about that have failed in this manner have been too badly damaged to be repaired. The PCB material under the diodes in question is very badly burnt, and in my case the solder pads and some of the inner layer tracking had completely gone from under one of the diodes.

I managed to source a replacement SMPS. Although the 5103 was working fine with the replacement SMPS fitted I was immediately concerned about the temperatures that were being reached in certain parts of the SMPS itself and the regulators on the top board.

However, having instrumented up my 5103 to determine exactly what was going on in these areas I'm now happy with it -- although it does run rather warm in some specific areas the temperatures are not excessive and I'm happy that it's working as designed.

Willi, seems like you are among the more skilled operators of the 5103s on the forum. I've got a separate posting here with a more fundamental question if you have time to look at it for me:

http://forums.linn.co.uk/bb/showthread.php?tid=5706

Don't want to bend any rules on this forum, but again, I'd appreciate your and Fatboy's thoughts.

Thanks in advance.

[Keltik Klown]

(2010-01-30 22:02)Zyklope Wrote:  Willi, seems like you are among the more skilled operators of the 5103s on the forum. I've got a separate posting here with a more fundamental question if you have time to look at it for me:

I certainly wouldn't make that claim myself -- I'll add some thoughts to the other thread.