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ARCHIVED FORUM -- March 2012 to February 2022
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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022

 

Beomaster 901 refurbish.

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BO
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Halmstad, Sweden
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BO Posted: Sun, Dec 30 2012 8:50 PM

This thread actually starts here: http://archivedforum2.beoworld.org/forums/p/189/34354.aspx#34354

 

//Bo.
A long list...

BO
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Halmstad, Sweden
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BO replied on Sun, Dec 30 2012 9:10 PM

I ordered a capacitor & lamp kit from Dillen.

Arrived with good documentation.

 

Started with the three electrolytic caps. Originally they where 3300uF, these are 4700uF but that's only better. Since these where of snap in type i kept the original legs and soldered them together.

 

I glued them to the pcb whit hot-melt.

 

When doing a job like this on a working unit it's a good advice not to change too many thing at a time. I try to do thing in group not to many at the same time. If you change a lot and i doesn't work in the end, fault finding becomes quite difficult. A strategy the came to be proven wise.

 

Next a changed trimmers for 32V & Idle current.

 

In place.

 

Adjusting 32V

 

Adjusting idle current. Should be 25mA and 10mV over the 0,39ohm resistor.

 

More to come..

//Bo.
A long list...

BO
Top 150 Contributor
Halmstad, Sweden
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BO replied on Wed, Jan 2 2013 8:18 PM

Continued..

Resistor have to be unsoldered for measuring the idle current.

 

Now the orange ones.


Old ones and replacement.

 

The electrolytics changed.

Left the trimmers for the radio, 2R9 and 2R92 unchanged since I don't have the equipment for adjusting them.
.

 

Remove the wheel to unsolder the tantalums behind!
F

 

I didn't! It gave me some extra work!

 

I got the polarity wrong on a tantalum's which caused noises and cracks in one channel.

https://www.youtube.com/watch?v=75SdsBLq8

Changing the polarity corrected the problem

Next step will be assembly...

//Bo.
A long list...

BO
Top 150 Contributor
Halmstad, Sweden
Posts 728
OFFLINE
Bronze Member
BO replied on Mon, Jan 7 2013 11:06 AM

 

Assembled & testing

 

Lamps working

 

Hooked up to Beovox Penta, sound terriffic!

 

Thanks To Dillen for kit and good advice.

Next will be finding suitable speakers.

 

 

//Bo.
A long list...

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