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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
It's been awhile, but I just got a Beomaster 3300. As usual if you get something for free there is always a catch
Anyway, this receiver doesn't want to co-operate and refuses to start up.
The standby doesn't light up, instead the bars of the FM fine tuning light up. That's all.
No button responds, No stand-by light, No sound. Only FM fine tuning bars. See attached picture
Fuses are fine. I could measure 33 volts on the power capacitors
Does anyone have a clue or can point me in a direction?
Thanks,
Richard
Anyone?
Is the 5V supply up for the processor?
Martin
Hello Martin,
Nice to meet you again.
I"ll measure it.
I could measure 5 volts on IC1.
We are talking about the small voltage regulator 7805 (IC1), which supllies 5 volts. This one measures correct.
Are the fine tuning bars an indication for a fault? I couldn't find it anywhere.
The tuning discriminators are driven by the tuner. The other lamps are driven by the processor board.Check all voltages to the processor board - measure the voltages on the processor board and make sure the ground connection for the board is fine.Check if the processor is running. If not running - check the reset signal etc.Martin
Martin, thanks. I understand.
I'll make all measurements asap and come back with my findings.
I checked the voltages of many measuring points.
In the reset part, there is TR35 and TR36. Both are about 4,5 volts too low ( 5,5V and 0,4V instead of 9,7V and 4,7V)
The rectifier gives 24 V, which is correct.
If I read the diagram correct, the only parts which could be defect are the 2 resistors R92 or R93, but most probably Diode D24 as the difference in voltage is 4,5 volt. This is just the voltage to the direct linked IC1
Can you agree with my reasoning, or do you have an alternative?
Thank you for pointing me in the right direction. I haven't replaced the component yet, but will inform you when done.
Check C55 and D24.Martin
I measured both C55 and D24, both are correct, when desoldered.
Next I measured for R92 and R93 about 35 Ohm, should be 56K and 82K
It seems the resistors are faulty?? Although it was the last suspect.
any suggestions?
Resistors won't fail that way.How did you measure them?And how did you measure C55 and D24?
I measured C55 and D24 by desoldering them.
C55--> 2,2uf
D24 --> OK
Resistors R92 and R93 in circuit. They start at 33 ohm, but slowly rise during measuring time. There is no fixed value. I don't get it.
Difficult to take a guess at without actually having it on the bench.The problem may be some place completely different.I suppose this is where the electronic repairers 3½ year long education and decades of experience has to take over.Where are you based?Martin
I live in the Netherlands. What I want to try first is replacing both Diode and Capacitor. What I heard, the components can act different in a powered circuit. When I power it up , I get each measurement a different readout on my meter.
Today I left my Beomaster at a repair shop for B&O equipment.They checked, but aftermore than 1 hour, they couldn't find the cause. I left it behind for spares.
Wrong choice of repairer.They don't know a thing about electronics.