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
Dear Members.
A very good friend of mine gave me a perfect 1900-2 Beomaster. He had it in box for 25 years and he even gave me all the documents of purchase. I cleaned it a bit and tried to test it but the only think i got as a s/by led on. The unit does not wake up. I have checked a lot of parts like the bulbs some test points etc, but no luck. The only bad resistor i found so far was a broken resistor 5R1 (1.8k) which is connected to the 5d1 (s/by led indicator). I would like to ask you If the beomaster can be activated without puting on the cover with the copper metals that guide to the buttons, maybe only by touching the pins with the finger.
Thank you very much for your advise.
Yes, you can touch the pins directly.Check IC9 and the two source selector ICs.If the two ICs have badly oxidated on their pins, replace them.And replace capacitors. There will be many bad ones in there by now.
Parts here:https://www.beoparts-shop.com/product-category/beomaster/beomaster-1900-2/
Martin
Thank you very much for your advise Martin. I have already ordered the caps as they should leaking the ics just incase and a rectifier. i hope it will work as it is really in perfect condition.
Hello again,
After i have replaced all the caps from the kit, the main bridge and the two selector ICs. Unfortunately no luck . The S/By led still remains and does not wake up. I have replaced the 5R1 resistor and still no luck. I was bit dissapointed but i do not want to leave it as the beomaster is in perfect shape. Any other suggestions will be more than welcomed.
Did you check IC9?What happens when you press a source touchpad? Does any light change? Relay click?
Dear Martin,
I have measured Ic9 on board and i have IC9b=14.1V , IC9e=14.7V, IC9c=0V These voltages occur when S/By led is on. Also reading the s/manual I have seen that after the touch is engaged I should have IL1,2,3 to light up through the current that passes fron 5R1 (1.8K which at the beginning was burned out). I have replaced it, But nothing is happening . Measuring all the bulbs (onboard i get 15Ω resistance) . Actually if i am not wrong the 1900-2 does not reach to the point of receiving orders as IL 1,2,3 remains off.
Some other measurements at S/By
TP 15=0.2V
TP 16= 15.2V
TR21 e=0V, c=12.74V, b=-0.78V
TR22 e=0V, c=13.7V, b=0.65V
TR27 e=23.5V, c=15.2V, b=23V
TR31 e=15.2V, c=0.47V, b=14.65V
TR32 e=0V, c=0.2V, b=0V
TR25 and TR26 all measurements 0V
Dear Martin!
I have replaced the relay and a blown diode and the beomaster has life again. It has perfect sound and all work except the two bulbs for bass and balance the fm5 and the volume control up and down.....Do you think the the two broken bulbs can affect any of the above problems?
Thak you
Hello,
An update.
The beomaster works perfect again. I have replaced the cd 4011 ic and the volume touch is ok now , i have adjust the no-load current, across the emitter resistors and plays perfect (it was working also before, but really hot in right channel as the voltage in the two test points was really different between the two outputs). I have ordered the lamp kit to replace all the lamps as two are burned out and i will place it in my living room . It was waiting 25 years in a box and now its back in business :).