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
Hey everyone,
I have been working on fixing my father's Beogram 4004, and recently got to a point where I am not sure what to try next. So I thought perhaps someone more experienced than I could advise me on what to do.
The issue seems to be that the sensor arm does not recognize when a record is on the platter; and so it will not allow the tone arm to descend, even manually.
When I press START, the platter automatically starts to spin at 33rpm and the two arms start moving left towards the record. However, it does not see the record and it continues to move left until it reaches the end of its track and then it just moves back to the right and turns itself off. (note: it acts exactly the same with or without a record on the platter)
I'm assuming it is a problem with the sensor arm, though I am not sure how to go about fixing it. The end of the sensor arm lights up like it should, but it just doesn't seem to "see" anything.
Any help or suggestions would be greatly appreciated!
-Sam
if the sensor arm lamp is working, and the player does not drop the arm then you need to be looking at either the detector circuit or thereafter, as everything in the arm is more than likely working fine. Check for leaky capacitors or faulty transistors. If you want a diagram then upgrade to silver membership.
Got to go out atm but I am sure someone else will guide you through if you are up to the challenge.
When the deck is fully working, and only then, should you replace all the tantalum capacitors (kit available from member Dillen) and also trimmers and speed relay if that is on the board, as all these items are likely to fail in the near future.
Olly
Thank you for the advise, I will have to check those things you mentioned.
That being said.. I am not the most experienced person when it comes to fiddling with electronics like this so, if anyone has any tips for me they would be greatly appreciated.
Also, would a diagram be included in service/user manuals? I know I have them somewhere around, just can't seem to find them...
Yes these players often came with a full circuit diagram. Although it has to be said, this is not the model to be practicing on if you don't have a great deal of fault finding experience!
Find out how to test transistors with a meter on the internet. Also how to check for bad capacitors, especially leakage where tants are concerned. But really with this player you are best taking voltage measurements at various points in the circuit.
To be honest explaining these skills is really beyond the scope of these forums, but we can help you trace the fault if you make the initial effort to pick the skills up!
Thank you again, and yes I have been reading online about how to test capacitors and transistors like you mentioned. I would not expect anyone to put their time into explaining that part to me, of course.
What I was more interested in was any common problems people may have while trying to do this, so that I do not make those mistakes myself.
Also, yes I realize that it may not be wise for me to just start trying stuff out on this table. I will likely have a friend who knows more about circuits like this (though not specifically about Beograms) take a look and test things for me once I have determined the possible areas to check. Hopefully this will reduce the possibility of something going wrong due to my inexperience.
Still no luck finding the manuals, going to keep looking for now but if I can't find it then I will surely be upgrading to silver membership to get the diagram that way.
Thanks again for your help so far!
No probs, I enjoy helping, but it also helps to keep the site afloat by joining up so it is only fair we follow that route if no other options become available!
Yes, I'm glad that option is there. Even still, if I don't "need" to upgrade, I will anyway if I get my table fixed as a result from help here. I like to support things like this, especially when I receive the help I need; that way at least I'm doing my part to say thank you and to help it stay around for the next person coming here for help.
Step1: ... these players often came with a full circuit diagram.
... these players often came with a full circuit diagram.
Did they ?
I know that many Beomasters and radial Beograms did but I don't think, I ever found
a circuit diagram in a tangential deck.
Martin
Dillen: Step1: ... these players often came with a full circuit diagram. Did they ? I know that many Beomasters and radial Beograms did but I don't think, I ever found a circuit diagram in a tangential deck. Martin
Supplied in the documentation as far as I know. I have had several 4002 circuit diagrams and have passed them on to the new owners.
Regards Graham
Well I have one Martin!