[jfrancis49]

Hello All,

I was able to find a Beogram 4002 in practically perfect condition at a thrift store and have been doing a restoration on it. I have replaced all the capacitors, the old large carbon resistors, the TIP power transistors, oil infused the bearings in the motor, and torn down and cleaned and lubricated all moving parts. But when I tried to see if it would play a record for the first time, three things did not happen. It started an switched to 33 rpm but does not find a record on the turntable and does not switch to 45 rpm. It just continues towards the center spindle and then returns and shuts off. If you press the 33 rpm button the light turns on, but the 45 button does not turn on the light or activate the motor. I have looked at the speed selector circuit in the manual to see what components might be involved and need replacing. I had replaced both relays as well as the trimmer resistors for 35 and 45 rpm. So I looked at the manual and have now have replaced IC2, TR8 and TR17. I have a transistor tester and they seemed to be alright but I replaced them with new ones anyway.

I also have an extra control panel and keypad I could plug in so I know that the problem isn’t there. Because this Beogram was in such great cosmetic shape I had hoped a capacitor replacement and good clean might be all it needed. I can solder and use a multi-meter but that is the extent of my skills. Any suggestions about what else might be checked would be appreciated.

 

Thanks,

 

John

[Mark-sf]

First focus on it not finding the record. The lamp+Photocell handles this at the end of the fixed arm. Do you see the B&O logo at the end lit up? If not that bulb needs replacing. If you are, then the lamp’s and photocell’s alignment may be off. The black insert pulls out of the arm enough to allow it to drop down in most cases or you can remove the arm screws under the cover.

[jfrancis49]

Hello Mark,

Thanks for the reply. Yes, the sensor arm lamp is working and pushed as far down in the sensor arm cavity as it will go. I understand there is some circuit connection here for the fault I am seeing. At start the sensor arm is not finding the record and or switching to 45 rpm as it travels inward. But I was thinking that the 45 rpm button on the keypad though should also function by lighting the 45 dial and turning the motor when pressed.

John

[Mark-sf]

Only the 33 button will cause the platter to spin for cleaning purposes. Once you have the arm moved over and paused, then pressing the 45 button should change the speed and illuminate. Can you move the arm over using the Play button and push the Cue buttin to cause it to lower and begin playing. If that doesn’t work, there may be an issue with the solenoid circuit or its mechanicals. The area should go up and down with the Cue button at any point except rest.

[jfrancis49]

Hello Mark,

You were correct, the 45 rpm light does light up when I am able to use the cue button. And the solenoid does function. But the forward and reverse buttons don’t seem to activate those actionsn nor the stop button.

[Mark-sf]

There is a clear right-angled plastic piece that has black lines on it that moves with the tonearm There is a lamp in a black plastic housing that illuminates a photodarlington transistor. I would check that that lamp is working. If it is, the the transistor may be bad. The detection of those black lines are necessary to find the edge of the record, switch to 45 and return after playing.

[jfrancis49]

Thanks Mark,

I have an extra board with the photodarlington transistor on it so just switched out that board. No change, the sensor arm still does not recognize where the record set down position should be and does not switch to 45 rpm as it travels toward the spindle. So something may be amiss on the main board still.

[Mark-sf]

Assuming the LED is getting power, I would check that the collector of 1TR17 transitions from 0 to 20v when a black stripe goes by. BTW, the service manual has a troubleshooting flowchart for this specific issue.

[jfrancis49]

Hello Mark,

I do have the service manual and have looked at the flowchart. Don’t quite know how to follow some of the trouble shooting. I understand how to identify the different legs of a transistor, but not sure where to connect the other multimeter probe to. Afraid of shorting something.

I am currently traveling and won’t be back for a week.

[jfrancis49]

I thought maybe I should look at R88 and see if that should be adjusted. And that turned out to be the issue. Now all is working with the speed changes and set down, but I need to do some other adjustments. Balancing the tone arm is next. For whatever reason I have a hard time getting more weight forward to balance without it binding and pulling toward the spindle.

[Mark-sf]

Setting the tracking force is a 2-step process adjusting the counterweight for balance and the knob controls the force via a spring. When adjusting the counterweight it can get skewed by binding on one of its support slots. The same bracket has a V-support that the lift solenoid engages governing its cued alignment. Either of these can skew the arm.

[jfrancis49]

Hello Mark,

Once again, my appreciation. I seem to have an unexpected amount of trouble getting the arm to balance. I will give it a go this weekend.

[jfrancis49]

Hello,

I unfortunately had some health issues that slowed me down on sorting out the tracking force and arm balancing on my 4002, but I got back to it and hat is now working properly. I ended up taking the tonearm apart and lubricating it and then making sure it was not binding. I have adjusted the 33.33 and 45 rpm speeds and tried out a record. The record plays fine but I notice the tonearm is moving towards the sensor arm and plays at an angle. Is this a tracking sensor adjustment issue? They are both parallel to each other in the up and resting position. It sounds fine, but my other 4002 does not do this when playing a record.

This I believe is my last fix on this turntable.

 

John

 

 

[Mark-sf]

Glad to hear it is now working. Yes, if the arm is at an angle when tracking, that means the shutter is not properly adjusted. Please follow the procedure in the service manual and everything should be fine. If you find you are at the adjustment stop, then the shutter clamp around the base of the arm has been moved and can be mechanically adjusted to give you a new center point.

[jfrancis49]

Hello Mark,

Thanks for the reply. So if the tonearm is angled towards the sensor arm when playing, does that mean it needs to be set to be more responsive?

John

[jfrancis49]

Hello All,

I just finished adjusting the tracking sensor on this Beogram 4002 and outside of polishing some scratches out of the dust cover I hope it is completed. Thanks to Mark and his help and encouragement I was able to get a few stubborn problems worked out. The 4002 was in beautiful cosmetic condition but had a severely frozen tonearm and a non-functioning board. I was lucky I was able to replace some components and not have some serious trouble shooting.

John

[Mark-sf]

John, great to hear you were successful and the forum proved valuable. Enjoy!

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