Sign in   |  Join   |  Help

Two Beomaster 1000 projects

rated by 0 users
Not Answered This post has 0 verified answers | 1 Reply | 0 Followers

stefan89
Not Ranked
3 Posts
OFFLINE
Bronze Member

Dear fellow B&O enthusiasts, 

This is my first post on this forum so first a short introduction. I am Stefan, 32 years old from the Netherlands. I own several Bang & Olufsen products and love to keep the old ones working. I have two beomaster 1000 amplifiers, one from my father that I am trying to repair for him. However, I thought it looked so good in my house that I bought one for myself. However, they are both broken and I am not sure how to proceed with repairing them. Below, I give an overview of what I have already done and the symptoms. 

 

Beomaster 1000 no. 1 

With this Beomaster 1000, the right channel did not work and the left channel was very noisy. I quickly saw that a number of electrolytics were leaking, so I decided to replace all of them. The result was that the left channel sounded fantastic again while the right channel remained silent. I then started measuring at point K where the voltage appeared to be a stable 30V. Next, the voltage across resistor 678 turned out to be a neat 24mV. However, the value across resistor 678 was very different and could not be adjusted with the corresponding potentiometer. So I replaced and readjusted both potentiometers for the left and right channel. The left channel kept on sounding great, but the right channel still didn't produce any sound and the potmeter hardly had any effect on the value across resistor 754. My first thought now is that the problem must be somewhere in a transistor, but which one..... I did some measurements on the circuit board (see picture) and maybe someone knows what the most logical next step is?  Green lines mean that the value is correct according to the diagram. 

 

Beomaster 1000 no. 2

I recently bought this Beomaster 1000 together with a Beogram 1000. They both look very nice but do nothing at all. My first goal is to get the Beomaster working. The lamps do not light up and no sound comes through the speaker, also no noise. I started measuring at point K and over the resistors 754 and 678. The values were almost perfect but I adjusted them to 30V (point K) and 24mV on the resistors. But what should I look at next? At first glance, the Beomaster 1000 is in great shape, all electrolytics seem to be intact, only the lamps are really broken (blackened). What is a logical step to look at further?

I hope someone on this forum can help me further to restore these beautiful devices to their full glory. 

Greetings,

Stefan  

 

 


All Replies

stefan89
Not Ranked
3 Posts
OFFLINE
Bronze Member

I have fixed the issue with the second Bombaster 1000, it appeared to be a faulty on/off switch. It sounds really wonderful!! 

Page 1 of 1 (2 items) | RSS
Beoworld Security Certificate

SSL