ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hello to all,
First I want to thank the community for the posts and useful links, I've managed to save a beogram turntable with a dead motor last week
I'm working on a beomaster 1000 receiver from a friend with a dead right channel and with a faulty phono preamp.
After rebuilding the phono preamp, I changed the 2 big caps from the main board - 2000 uf 25v (2200 uf 25v), the big filter cap from the power supply 2000uf 50v (2200uf 50v) and a floating 400uf 40v cap in the main board (470uf 60v).
All was good, and after replacing the lightbulbs, cleaning the pots and switches and some work on the keys, tested the receiver, nice sound, both channels working, nice turntable amplification...
This morning, when I was preparing to reassemble the receiver, it switched off suddenly. It was the 800ma fuse from the power supply board that burned, a couple of burned fuses later I don't know what to do.
Any of you with experience of the BM1000 or similar systems had this problem? What should I check first? The filter cap?
I have the service manual and schematics.
Thanks in advance.
Rui
Resolved
It was the main AD149 transistor that was shorted.
Thanks
Good find, but go through the electrolytic caps, or just change them all, and check your idling currents and voltage feeds
Collecting Vintage B&O is not a hobby, its a lifestyle.
Hi, thanks for your comment.
I learned a lot from your posts - your Beogram 1000 repair is a must!
I replaced a few transistors in the motherboard that were dying (AC138), and I'm working on the caps. Its starting to sound good!
What are the values of the idle current and voltage feeds? - I can't find the information in the service manual.
Thanks!
Some manuals dont show it
I'm feeling dumb right now.
I can't find the point K, J and the resistor 734 and 678.
... help
If you have the repair manual with schematic they are there
Hum...
I have the schematic sure, I managed to find the resistance 678 (1K) but not the 754... Do you remember the location of the J, K and the resistances?
Sorry to ask, but I finally finished the recap and I'm eager to listen to it!
Maybe because mine is a type 2303?
I found this manual for 2302/2304 with different numbers.
The resistors 678, left channel, 754 right channel are 0.39 Ohms, the left channel resistor is connected to 2N5034/1, the other end of 678 is point J, which also is point K
That could be right I am looking at type 2316/17 schematics
Exactly,
I managed to check and tune the 30 volt (power supply section).
I don´t know exactly how to check the mA in the "AF No-signal current".