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
Can anyone point me in the direction of the opto sensor lamp on the Beogram 8002 please? I've stripped the unit down but cant see where the lamp would be.
Thank you
Have you stripped it down with or without the assistance of the Service Manual?
As a Gold member, you have free access to the service manual here on Beoworld which should tell you all you need to know.
http://www.beoworld.org/manuals_view.asp?pid=307
Dave.
Hi Dave, I have used the manual for the strip down but can't locate the opto sensor lamp even in there. I cant fathom where it would be, there's not much of it after the strip down! Thanks.
Depends on which opto sensor lamp, we are talking about;There is one inside the sensorarm (the arm parallel to the tonearm) and another inside the tracking opto housing at the foot of the carriage.
Martin
There is also a lamp and two sensors inside the control panel.
sonavor
The tone arm fails to move inwards, so the one in the opto housing. I've removed the black cover but still can see where this would be.
It's at the foot of the carriage, not at the top.If you swing the tonearm (carefully) frmo side to side, you can see that a metal arm below decks swings along. This arm goesdown to the opto sensor and lamp.
Here's the deck at the moment - where should I be looking please?
https
https://onedrive.live.com/redir?resid=BC7961840C95EB32!9365&authkey=!AIf83ozNsx-_-ic&v=3&ithint=photo%2cjpg
Here is a picture showing the Beogram tracking lamp housing and adjustment screw. The lamp is inside that assembly. If you can, please post pictures of your Beogram in the Beoworld thread post. There is an "Options" tab on the Reply that allows you to browse to a picture on your computer and include it with the reply.
Here is another angle of the tracking lamp housing.
Hi folks, I've located the lamp (not sure how I was missing it!). Its working fine. I have adjusted the aperture screw a tiny bit at a time but without much success. Originally the tone arm would move in during play and then eject after a short while, now it moves in as before, plays a bit more, sticks on one part of the record for a few revolutions then ejects. The carriage just isn't tracking with the record in play.
Any other thoughts please?
Check to make sure you have a good belt for the tonearm drive motor. Martin can provide you with a correct one if you aren't sure about the one you have.
The photo control could still be a source of the problem. In the area where the tonearm will drop down and play a record, can you perform the "Aperture for Photo Control" procedure (Page 5-3 in the service manual)? When you run the procedure I prefer to disconnect the platter motor connector and manually turn the platter rather than brake the platter with your hand.Another procedure that you need to check is the "Manual << and > >>" (also on page 5-3).If those procedures check out good and the problem is not fixed you will most likely need to do a restoration of electronics (recapping, reflowing solder connections, etc.).
Replace the LDR.
Revisiting this repair one again after a break. I've cleaned the lens but still no joy, so LDR replacement is next. What is the specification please?
Many thanks
So I've now replaced the LDR (12-35k) and its still the same. I've adjusted the aperture so the light is getting through but no tracking of the carriage still.
I'm beginning to run out of hope / patience on this one now
Sorry to hear about the bad state of your Beogram repair. It is really difficult to follow where you are at with this project though. Can you describe what features do work and what doesn't work? Is it only the tracking that doesn't work right now or are there other things. With a complicated machine like this you have to work your way through the circuit to locate the problem(s). In disassembly and reassembly of parts it is really easy to break a wire or connection somewhere. When I run into this type of issue the only way out is to systematically go through everything (measuring signals, visually inspecting, etc.) until I find a signal that is out of sorts.
-sonavor
Thanks for the support Sonavor! In a nutshell this is whats happened in the repair so far:
I don't want to give up on her, but it's getting pretty close! I may have bitten off more than I can chew with this "project"
If Martin rebuilt your main PCBs then you can count on them being good. That should eliminate any electronic components on the boards. That leaves either some connection being broken or some component not on the main boards.The schematic snippet below shows the tracking sensor (highlighted in red) and the photo resistors in the control panel (highlighted in yellow). Both sensors feed the amplifiers for the tonearm drive motor. I would make sure both lamps and photo resistors are functioning. Also make sure the detectors highlighted in yellow have been adjusted to their correct output per the service manual.The other thing to check is the operation of tracking resistor (5R1 in red) at the P3-5 and P3-1 connector. Remove the top platter of the turntable so you can lower the tonearm where it doesn't touch anything and you can manually move it to make the motor track. You should be able to monitor the 5R1 resistor output, the IC2-5/6 amplifier input and the arm drive motor P1-1/2 to see what voltages are there (or not there) when the arm should be tracking. Also, make sure you unplug the Beogram between setups for measuring the signals and plugging/unplugging connectors.
Can you tell, if the tracking lamp is lit when the Beogram is playing ?
Thats for all the support! I'll check those components over.
The tracking lamp is lit when the Beogram is playing.