Hi guys...

Got a troubling set of pentas..

1st speaker) When connected with 8 pin powerlink...  (AMBER LIGHT)....and will give sound for say 3 seconds ONLY when switching between Auto/L/R on the mode switch...then goes off...then switch again..and it plays for another..3 seconds... NO DISPLAYS

2nd speaker) red light all the time....no sound no matter what we do.... NO DISPLAYS

 Ideas??

yeahhhhhhh..........

Hopefully I'll be able to answer questions like this when I actually pick up my pair this coming Friday, as I've never even seen them in person.  But for the 2nd speaker with the continual red light, have you checked the fuse?

Hey Austin...

I've downloaded the manuals....but as i'm on the short-bus....where is the fuse on the pentas???

gracias...

At the bottom of the tower, accessed from below behind a little cover held by one screw if I rememeber correctly.

Martin

I went through the manual......is there a Penta fuse??? That could be causing these problems???

Thanks..

I don't see anything about this in the service manual.....so...

To remove the thick plastic coating on the lower base of the pentas.....does it just pull off??

HI guys..

Got the amps opened up on the Penta II's.....a coil fell out (pic below)...and a dark, burnt spot on the board...(see pic)..

Here's a close up of the board that on the first Penta II..... Ideas of where to start would be greatly appreciated...

It's the C4 Capcitor that is bad.....what is that for???

Thanks !!

Don't know what it is for. Try replacing it, and while you're at it find out where the coil is supposed to go and put it back.

You probably also want to replace all the electrolytic capacitors.

Frank,

Slow down, my friend ...
Don't haste things. Look in the manual and find info there before assuming (wrong).
Of course, there is at least one fuse, and the Beolab Penta's have two.
One fuse is for the controlling electronics, the other is for the amplifiers.
C4 is clearly bad, not a surprise with that type of capacitor, I'm afraid, but the reason still needs to be investigated.
According to the schematics C4 is directly in series with a 10 Kohm resistor. This
tells the experienced technician that there DEFINITELY are other things that need attention.
The dark spots seens elsewhere on the board only confirms this.

The lose coil didn't even come from this part of the tower so there will be more to service before powering up again and don't just add mains to this thing. Power it up from a variac, not only for your own safety.
Don't get me wrong, Frank, but repairs like this are not some you can do "at the kitchen table". They are better left to a qualified technician one who has the proper instruments etc.
It will probably not be an expensive repair and it's always well worth the money spent to have it done by a pro.

Martin

Hi Martin...your input is much, much appreciated....

I understand....i've got an electronics guy now working on it.....(this stuff is all foreign to me).... he's experienced with micro soldering, caps, resistors...etc...but not at all with BnO...

Sorry for my haste....i've just got to translate all this to spanish for them...and it's dicy....

Yes..he told me tha the coil is from the crossover....

He has confidence that with direction he can fix what we need...and he's got all the instruments that a standard TV type repair man would .....have...

Again...the manual is good for me...(but im no electrician..) so i'm not sure even what to translate for him...

OH.....the RESISTORS are new and replaced...(but you can see that they were burnt before)......is what he's telling me...

Ideas for other things that need attention....as we begin to try to fix this thing..??

Great ! 

I'm afraid, I can't give you more hints without actually measuring about a bit.

Give the technician a couple of minutes to look at the schematics and understand the circuitry and he will know where to measure and what results to expect.

Martin

Hi Martin,

Strange...on the PCB 2....ours says 8001086....

In the book it says it should be...8001165......

Ideas..

Frank,

You should not concern yourself about the different part numbers of the boards.

As the capacitor C4 pop'ed it is likely that at least one or more of the following components will have failed:-

TR6 (BC548B) -- D6 could be short circuit -- D5 -- TR5 -- Tests these components

Also it should be noted that C4 is rated at 25 volts

Thanks Keith.....(yep..25 volt for the C4..got it...)

Also....they are going out for these now the BC548B's (x2) per speaker...

They don't list the D5 and D6 in the manual....can we just take the board to the parts shop?? Or do you have a reference for these...??  Strange, no??

THanks,

Keith

D5 & D6 are both IN4148 diodes

Just taking the board to a parts shop will not help you.

Thanks Keith.....he was ready to dis-mount them....he could see the 1N... but with your help....PERFECT !!!!

Also,....Keith....do you know the Diode codes for the D7 and R22.....??? They are not in the pdf file...

gracias..

Hi Keith...

On PCB 1........in the service manuals...they have no listing for....some resistors that look suspect..  can anyone tell me if these are correct....below...

R 65, R 66, .....150 k Ohms each yes??

and R 86..... 390 Ohms.. yes??  

Frank,

D7 is also an IN4148, this is a high speed switching diode made by Philips

R22 is a 680 ohm resistor

Yes, R65 & R66 are 150 K Ohm and are in parallel to give an effective resistance of 75 K Ohm. The reason they have done this is because resistors come in standard values, so the nearest value would be 68K or 82K.

These two resistors have a low tolerance requirements, so you should get at least 5% version. 5% resistors usually have a "gold" band around the resister if it is not written and "silver" for 10%.

Yes R86 is 390 Ohms..

Keith...i really appreciate your help.....!!

 I'll keep you informed on how things come out...

 

Also...since...we had 2 of the glued coils come off on the crossover board...

What glue / resin...do you use to stick it back on??

 

Usually something like two-part epoxy is fine.