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Beogram 4002 (Typ 5523) and 4004 (Typ 5526) Questions

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StanfordBeogram4002
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StanfordBeogram4002 posted on Tue, Dec 7 2021 6:50 AM

Hello,

I have two Beograms (one 4002 and on 4004). I went through each one, cleaned and lubricated the chassis and the tone arm lowering mechanism. Everything was working for both after this step. However, after removing the main PCB for each to examine the caps, remove the old transport lock bushing fragments, and add new thermal compound for the transistors with heatsinks, I have run into two issues. 

The first being that the Beogram 4002's motor will not spin - it is plugged into the correct port (the one closet to the front of the Beogram). The Beogram turns on and the tone arm works as intended, just the motor does not spin. 

For the 4004, the unit simply will not respond to any command from the control pad - I even checked the fuses (both of which are fine). I really have no clue with this one as it was working before. 

Does anyone have any suggestions? I am trying to learn to care and maintain these myself, but my knowledge of electronics is limited (I recognize that a tangential arm Beogram isn't the easiest thing to work on - that said I have made all of the service manual adjustments to a proverbial "T".) If you need more information/photos/video please ask!

Thanks!

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Spassmaker
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North Germany
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Hi

Beogram 4002:

Does the motor spin free when you turn it with your fingers?

As I remember the plug from the motor could be inserted in reversed position.

White should be in front of the Beogram

Red in the back.

Test / check following:

1. Take of the MMC pickup and store it at a save place, or put at least the pickup guard on the system, be always carefull

     with this delicate piece. No uncontrolled movement of arms, fingers or tools!!!!


I would try :

2. Turn the ribbed platter without the belt by hand and look what's happening when you press start.

    does the tonearm traveling until the end and driving back to it's home position?

    While this traveling inwards do you hear the speed switch relay?

3. Have a closer look for the power rail comming via 1R13 (10 Ohm) and TR 2 (Emitter around 8,5 Volt)

    Diode 1D13 and resistor 1R12.

4. check the polarity of C5, C8, C 10, C11 not always the printing on the PCB's are correct, compare

    with the service manual.

 

Beogram 4004:

Check rail voltages at first, check for broken connection wires.

 

Kind regards

Christian

StanfordBeogram4002
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Thank you for your response - I am waiting to purchase a multimeter. 

I did do some basic elimination work. There is a ground issue on the 4004 (I am assuming) as the two fuses were blown. I checked each external connection (the motor, the control arm, etc.) - plugging each connection into the main PCB (not screwed into the chassis and held up by my hand) one by one and then plugging in the unit to see if it would if it would blow the fuses. None blew the fuses. That said when reattaching the the main PCB to the chassis with the screw in the red area, the fuses instantly blow. That capacitor (C1) looks to be connected to the transistor IC1I.

Any ideas from that?

Ian

 

sonavor
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Hi,

I have both of those type of turntables fully restored. They are a couple of my favorites.
I recommend browsing these Beogram 400x restoration posts to give you some information to check yours with.  You can also send in your non-working platter motor for restoration if you don't want to restore the motor yourself.

-sonavor

Spassmaker
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Hi

I'm not really sure, but are there isolation mica washers underneath the 2 big transistors of the Mainboard even one underneath the big transistor (tonearm solenoid) mounted on the chassis?

Also isolation washers for the screws holding the transistors.

Have a look

Regards Christian 

Spassmaker
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North Germany
218 Posts
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Any progress so far?

Christian

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