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
Hello Everyone. My first post, but a very avid reader. My CDX loves you all.
I have a few questions about my Beogram 8000 that I have been trying to repair. I have read and tried everything I can find, but my 8000 still does not work correctly. I have done a full Recap and resoldered all the joints twice (Main MCU also). The arm movement has also been cleaned and lubed, arm motor tested, arm photo pickup system tested. I am not a novice to electronic repair and have tested all voltages with everything being in spec. Here is what I see.
The motor drive works fine when “Turn” is pressed, both at 33 and 45 speeds. Speed is right on with the new metal disk purchased from Martin (tested with Speed Strobe). However, when I press play the arm only moves over around 2-3cm and then stops and returns after a few seconds. If I disconnect the motor drive plug P4 on the main board and use play it works perfect (sets down at the right spot, mute relay works, tracks fine, and returns at the end). Left and right arm movement also works fine.
I will also say that if I unplug (disconnect and reconnect from an external switch) the power from the 8000 sometimes the display will read 33 only or nothing at all. I have also had times where everything works perfect for hours of testing until I reset the power and then it goes crazy again. Then I have a drink and sob.
Everything seems to work fine on its own, but when you combine the drive and tonearm controls the 8000 does not work consistently. Could it be the main Processor chip?
If anyone has had a similar problem or could give me another trouble shooting technique I would be very appreciative of their advice.
Thanks for reading and HELP if you can.
What you see is a CPU reset.Check the capacitor inside the CPU casing.Check that its negative pin is electrically connected to the metal case (ground).Replace the CPU socket.
Martin
Thanks for your reply,
I have replaced the capacitor inside the CPU casing and resoldered/checked the ground. I have resoldered all the CPU socket pins. Do you think the chip socket might be bad every now and then? Not a big deal to replace, but does the socket really go bad?
Thank you for the advice.
The CPU socket is known to fail, yes.It's a cheap component and it can fix many strange issues.
Hello Martin,
I will order a socket and give it a go. Get back to you after install. Early January with the holidays and all.
Thanks again.
Grant