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
I have two BG8000s, both are re-capped etc so I´m testing them now. They both work well in every way except for one thing: One of them doesn´t lift and return the arm at the end of the record in certain cases. It happens if the inner groove area of the record is too narrow, it seems. In that case the carriage motor just grinds away and the pick-up remains in the inner groove. If the area is broader, the arm lifts and returns normally.
I understand that the lift/return is activated when the carriage motor pulls more current. My reasoning is that the curcuit that measures the current isn´t sensitive enough.
Following that train of thought: Can the sensitivity of that curcuit somehow be increased or am I missing something?
The BGs are different types, judging from the number of mini-PCBs inside, but the type numbers are gone.
BR
Leif
I would suggest that the servo motor is not properly moving based on the optical sensor adjustment. Go through the procedure as detailed in the manual
Leif: I have two BG8000s, both are re-capped etc so I´m testing them now. They both work well in every way except for one thing: One of them doesn´t lift and return the arm at the end of the record in certain cases. It happens if the inner groove area of the record is too narrow, it seems. In that case the carriage motor just grinds away and the pick-up remains in the inner groove. If the area is broader, the arm lifts and returns normally. I understand that the lift/return is activated when the carriage motor pulls more current. My reasoning is that the curcuit that measures the current isn´t sensitive enough. Following that train of thought: Can the sensitivity of that curcuit somehow be increased or am I missing something? The BGs are different types, judging from the number of mini-PCBs inside, but the type numbers are gone. BR Leif
The two small, add-on boards are for settling (PCB 6) and uC control (PCB 7). The Beogram 8002 incorporated all of that into PCB 1.The won't affect the problem you are seeing. There was also a modification in later model Beogram 8000 units that added stability to the speed control by adding a flip-flop device (2IC3: HEF 4013 BP) in PCB 2. That also wouldn't affect your issue.
I have seen a couple Beogram 8000 turntables have a problem with stopping and return to the Standby position after playing a record.In both cases the problem was with the rubber servo belt. Try swapping the belts between your two Beogram 8000 units. If the belt is good then I would recommend looking at the position sensor signals on an oscilloscope. I posted what they should look like here.If the belt is the problem then I recommend buying a new belt from Beoparts. Those are guaranteed to be the correct belt for the BG8000 servo motor.
There are no adjustments on the Beogram 800x turntables for the end stop or run out groove detection as with the Beogram 400x. Of course the BG400x is an analog control system while the BG800x is a digital control system.
-sonavor
Thanks for the suggestions to both of you, now I have some things to work on that hopefully will solve the problem. I´ll try the suggestions one at the time and let you what the outcome is :-)