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
Hi Lee,
It took me several iterations in my Beogram 4000 adjustments to get the various tonearm events working correctly. In almost every case the problem came down to the position switches. Especially the ones on the moving tonearm carriage. The metal arms on the carriage assembly that activate the little position switches are very touchy. Make sure you check the height of all the activation arms as well as their horizontal position in the slide. The horizontal position setting of course sets where you want them to activate the switch. However, if any of the arms are at a different height from the others, it could disrupt or alter the activation of the switches. I ran my Beograms through several cycles with the metal arms removed so I could manually press the switches. Once I determined the switches all functioned correctly I focused on the activator arms and that was where my problems were.
-sonavor
Lee: I've finally got my Beogram 4000 up and running and it all seems to be fine apart from it often (more often than not) thinks there's a 7inch record on the platter when the platter is empty. Lee
I've finally got my Beogram 4000 up and running and it all seems to be fine apart from it often (more often than not) thinks there's a 7inch record on the platter when the platter is empty. Lee
The switch merely tells the electronics WHEN to look for a possible record.So the switch is apparently fine - but the record sensing is wrong in that it believes a record is present whenthe switch tells it to look.
Check the distance from platter to sensorarm.Check the lamp and its position in relation to the lens system.
Martin
Looks fine from here.It senses the radial streaks on the platter. You can see them as a pulse-train from the sensor and through thefiltering etc. at the main board.(You can also see, that exact positioning of the lamp and sensorarm height are essential for the signal condition).If no pulses comes through, the electronics assumes a record must be present.Somewhere this pulse signal is lost. Put a scope to the circuit and move things around a bit to get the best signal.
The small trimmer I think you are referring to is for adjusting the sensitivity of the record detection to account for vinyl records that are semi-transparent. So it makes sense that it would affect your problem. As Martin suggested though, it would be best to use an oscilloscope to examine the various points of the control signal and see what you have going on there. The service manual shows the expected signals and voltages.
Lee: How could one tell if the bulb was the earlier or later type?
How could one tell if the bulb was the earlier or later type?
You can't.But perhaps you can tell, if it has been factory fitted.
Lee:And can anyone recommend a good scope for these things that won't break the bank. I'm poor. Lee
Lee
I bought this one last year, until now working good, fast learning curve if you set your mind to it
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