Beolab Penta 2 type 6622 power issue

30 replies
pepps
Offline
pepps
GoldModerator
Posted March 22, 2014 at 19:36 GMT
#2199773

Dear fellows,

I acquired my first pair of Pentas yesterday. Mk 2 Beolabs. They're in excellent cosmetic condition - no rot!

The original mains cable is cut short and terminated in a plastic 'block connector'.
I phoned B&O in Bristol to check which fuse I should use in the plug I attach to the open end of the block connector - the guy on the phone said a 5 AMP fuse will be fine.

I plugged one of the Pentas into the mains with a 5 AMP fuse in the mains plug, no problem, the speaker's red LED came on and it sat in stand-by.
I plugged the other speaker in the same way, the red LED came on but immediately went out. I'm unable to get any life out of it.

After reading through some of the Penta-related topics on here I decided to check the fuses on the underside of the amp. These appear to be a little bit corroded (white powder) but seem to be in ok health.

Can anybody help suggest anything else to try?
The one Penta which is working sounds glorious and I'd love to enjoy a stereo set!

Kind regards in advance,

Julian

 

Location: Kent, UK

My B&O Icons:

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Beoplay-H95.png Beoplay-H95.png
Beoplay-E4.png Beoplay-E4.png
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Beofan for many years with a penchant for 1990s audio systems.
B(
Offline
Begbeo (archived2)
Bronze
Posted March 22, 2014 at 22:03 GMT
#2199774

Hi Julian, I'd check for cold solder joints, had a similar error and after soldering helped in my case.

regards

B(
Offline
Begbeo (archived2)
Bronze
Posted March 22, 2014 at 22:03 GMT
#2199775

Hi Julian, I'd check for cold solder joints, had a similar error and after soldering helped in my case.

regards

pepps
Offline
pepps
GoldModerator
Posted March 22, 2014 at 22:09 GMT
#2199776
Hi Begbeo,

Is a cold solder one with a powdery white coat over it?

The live/neutral leads look like that where the amp fuse and display fuse sit.

Location: Kent, UK

My B&O Icons:

Beovision-Avant.png Beovision-Avant.png
Beoplay-H95.png Beoplay-H95.png
Beoplay-E4.png Beoplay-E4.png
Beomaster.png Beomaster.png
BeoCenter-9500.png BeoCenter-9500.png
Beofan for many years with a penchant for 1990s audio systems.
B(
Offline
Begbeo (archived2)
Bronze
Posted March 22, 2014 at 22:35 GMT
#2199777

I'm not entirely sure but should not it be as you describe.
Try to remove all the white and solder again. It should help.
Can you make a photo and attach here.

regards

Jan

pepps
Offline
pepps
GoldModerator
Posted March 24, 2014 at 12:15 GMT
#2199778

Ok I forgot how frustrating it is to pop a photo up here. Basically I've swapped the fuses from the working Penta amp to the one which wasn't working.
When I plugged it into the mains the red LED lit once again but then went out after a second.

I'm going to go and buy some more fuses and try again.

As for spotting dry solder joints I'm slowly trying to work out how to take the front panel off - tis tricky.

 

Location: Kent, UK

My B&O Icons:

Beovision-Avant.png Beovision-Avant.png
Beoplay-H95.png Beoplay-H95.png
Beoplay-E4.png Beoplay-E4.png
Beomaster.png Beomaster.png
BeoCenter-9500.png BeoCenter-9500.png
Beofan for many years with a penchant for 1990s audio systems.
pepps
Offline
pepps
GoldModerator
Posted March 24, 2014 at 12:17 GMT
#2199779

Ha! I found the "add file" bit in my profile...excellent idea.

Here's the fuse photo.

Location: Kent, UK

My B&O Icons:

Beovision-Avant.png Beovision-Avant.png
Beoplay-H95.png Beoplay-H95.png
Beoplay-E4.png Beoplay-E4.png
Beomaster.png Beomaster.png
BeoCenter-9500.png BeoCenter-9500.png
Beofan for many years with a penchant for 1990s audio systems.
pepps
Offline
pepps
GoldModerator
Posted March 25, 2014 at 11:32 GMT
#2199780

Quick update: a short trek around north Kent revealed that the T40mA fuse is rare to say the least so I'm going to have to order some online.

Can't really work anything out until then sadly.

 

Location: Kent, UK

My B&O Icons:

Beovision-Avant.png Beovision-Avant.png
Beoplay-H95.png Beoplay-H95.png
Beoplay-E4.png Beoplay-E4.png
Beomaster.png Beomaster.png
BeoCenter-9500.png BeoCenter-9500.png
Beofan for many years with a penchant for 1990s audio systems.
Beobuddy
Offline
Beobuddy
BronzeFounder
Posted March 25, 2014 at 11:56 GMT
#2199781

If the 40 mA fuse blowns, then probably the 7815 or 7915 is shortened.

Location: Utrecht

Quite a challenge to achieve "Less is More" while having the Beovirus.
BO
Offline
bos00
Bronze
Posted March 25, 2014 at 11:58 GMT
#2199782

A 50mA fuse will do fine.

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