Hi,

I very recently purchased a pair of Penta III type 6631.  They have been working fine since Sunday and I came home this evening and one has stopped working...

 It does not appear any particular event has occurred, I just switched on the beocenter and there is only one channel - checked the passives on the MCL and all fine.

I checked the powerlink cables, swapped them over, nothing.

 I dismanltled the amp assembly and I can't 'see' that any components have burnt-out - R73 looks like it has been getting hot in that the PCB is discoloured - but I removed the resistor and it tests fine.  Checked for dry solder joints and burnt tracks - nothing.

The light stays green.  The display works.  When a signal is first applied some sound comes through the speaker for 1/2 second at much reduced volume to the healthy unit, then dies away to a whisper...

Any suggestions from the wealth of knowledge around this forum would be greatly appreciated before I go and buy a new board!

I admit I have driven them pretty hard last couple of days, but they were fine this morning...

Thanks, Steve

In the button of the amp there are to fuses, (remove the sheild that cover DIN plugs ),- there are one fuse  for the amp and one for the display. It could be the reason why the amp are dead

 Notice that there are a reason why the fuses broke-  proberly old condensator or..or...

Buy instead  a new  Acustic Reality (B&O) ICEpower amp insted, its cheaper then a repair and  its sound much, much better and remember  that you can still keep the Penta display as normal.

 Then you will have a pair of speakers for the rest of you life. Penta sound very good  with a moderne amplifier

 Its very easy to change to a moderne ICEpower amp. Search how to do in the this forum.

 Look  at these price for ICEpower amp today, now they are gonna "cheap"

 http://arhifi.com/shop/default.asp

Thanks Bulgarien,

 No, I have checked the fuses and they are fine...

Do you have an idea which cap is likely to fail?  I was thinking of doing the upgrade you suggested in another thread...

ICEpower sounds interesting, will look into it and then probably have a heap of questions :)

 Still, for the time being I wouldn't mind trying to fix what I've got.  You can imagine my disappointment after owning for less than a week!

Steve

You can imagine my disappointment after owning for less than a week!

I think its okay,  becouce then you have to do the nessesary  and not wait and live with  bad and boring sound.

  The Penta deserves the best

Just take the next step, give you Penta new life and I promise that you will smile again.

 Penta sound great, but we have to help them on way..

Steve,it sounds like you might have a problem with the power relay contacts.If there is no sign of damage to the pcb,and the standby light does'nt glow yellow,it's probably not an amp failure.Try tapping the relay,if the sound comes on ok,there's the culprit!

Nick

Nick,

Sounds interesting, but wouldn't that suggest that the green light would not come on?  Also, there is some very low volume sound coming through.

I still have the thing in pieces, so I will certainly check the relay.

Steve

Bulgarien,

Thanks for your encouragement, but US$560 per speaker for ICE is um, not so cheap a fix for me right now - have to get over buying the Pentas first!

Steve

The standby supply is seperate.This is how the amp is powered up remotely.The relay connects power to the main amplifier.The contacts become burnt over the years.

Nick

I replaced a few capacitors in the amplifier circuit and fired it up - strangely at first the amp was behaving the same as before, a mere whisper coming through the speaker - then after a minute or so the volume began to fluctuate randomly through whisper to full volume and then it appears to have stabilised after maybe 5-10 minutes operation. 

 Do new capacitors usually take a moment to settle in like that?  I wouldn't have thought so...

Anyhow, I'm going to persevere over the weekend.

 Another strange effect is that when I adjust the balance control on the beocenter 9500 it works fine in the passive link rooms, but the powerlinked pentas will not fade to silence left to right... will double check cable connections (again) as it seems like crossed wires somewhere, but nothing has changed apart from the beolab failure and it was all fine before...

Anyone have any ideas?

Thanks, Steve