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Hi all, I have an issue with my Beogram 4002 type 5524 and 5514.
The type 5514 was working perfectly, but i damaged the IR LED and the small photo diode on the other side of the perspex ruler. The tonearm won't drop or lift automatically anymore. All other buttons and tracking sensor are still working fine. I am sure this topic has been covered quite a bit in the past, but i cant find any articles on the specific IR bulbs and photo sensor. The IR bulb seems to be the original. Whereas the photosensor has three connections, with the third to the left removed.
Any help most welcome.
I have found those 4D1 LEDs are often burned out. Here is how I have replaced mine...here and here.
-sonavor
Thanks you for the very comprehensive links. I tried 5mm IR LED Infrared 940nm Light Emitting Diode Lamp Water Clear and SFH 300 -3/4 Osram Opto 50° IR + Visible Light Phototransistor 5mm. I may have caused more problems and damaged the circuit as when I turned it on the tonearm dropped each time I press the home/ stop button and now with no automatic drop at start 33 position. Occasionally the 45 clicks too when start is pressed.
perhaps the photo sensor inside the tonearm may have become damaged too?
Otherwise would the arm not drop even if the IR sensor was not functioning properly or is it because it is a looped circuit and they are both dependent on the other?
(Any idea of a modern replacement of sensor if ti is damaged?)
I was also curious that a visible LED (amber) is used, a type 5513. Should types 5524 and 5514 only use IR LED or can it be replaced by either IR or visible LED?
C
The important thing is to measure the signal that the sensor produces when the light source hits it to make sure it matches what is prescribed in the service manual.There are a number of links on the Beolover Blog for the various types of Beogram 4002 and 4004 turntables with regard to these funtions.Beolover does make a replacement lamp module for the fixed arm. I have used that part myself a few times. On other restorations I used an incandescent bulb like the original that I source from Martin Olsen of Beoparts (or optionally Dillen through the Beoworld forum). In all of the light sensor devices the position of the lamp is critical. Again, that is why measuring the expected signal that is produced is important...to know that the lamp and sensor are correct.
FYI...I just finished going through a Type 5513 adjustment (pretty much the same as your 5514) here. I show the replacement of 4D1 and the adjustment of the voltage output for 4IC1.
Sounds to me there are a number of issues going on here......may be a good idea to sort one at a time, the 45rpm clicking in on start up is familiar, I had this issue myself....I have also replaced the detector lamp and photo sensor, its tricky but can be done, cant find my thread but here's another...
https://archivedforum2.beoworld.org/forums/p/1632/13942.aspx#13942
Hi both, thanks for the advice. Really appreciated. Thanks for the links too
Just to recap I had a fully working 5514 and wanted to use the main board to get the damaged 5524
Working agin, while I fix/ replace the original main board. When adding a new IR LED to the arm position and arm position IR photo-resister, It caused some unknown problems.
When adding a visible LED to the it illuminates and now luckily When I press the start on either the turntable with a strong light overhead and turn it off the arm drops. If I shine an LED torch or phone torch near the sensor it drops and likewise if I shine at the end groove of a 33 it will lift and return to the home position. Less light is needed on the 45 for it to lift and return to the home position with light shone near the sensor.
*The sensor at the base of the tonearm doesn’t seem to work on the 5524 as the motor doesn’t move as it should when a record is played.
So with this is mind, does it appear that I am using the wrong LEDs to activate the photo sensor or maybe there’s there a damaged transistor or resister not allowing enough power to get the arm position sensor. I don’t have a stroboscope and have basic ability with the voltmeter.
Does anyone have a link or a known supply
A. for replacement sensor at base of the tracking arm?
B. Suitable replacement arm position sensor?
Thanks again
Did you measure the voltage of the 4D1 collector? You only need to use a multi-meter to measure the DC voltage. When the arm is advanced where a clear portion of the marker lens is in front of the the sensor (4IC1) you should have 5 VDC on the collector of 4IC1. If you don't then you use the trimmer on the main board (1R88) to increase the 4IC1 collector voltage to 5 VDC.
Thanks for your reply. Very useful.
*Update. I have now fixed the record tracking by tightening the aperture adjust eccentric screw re. Beolover blog.
https://beolover.blogspot.com/2020/06/beogram-4002-type-5513-going-through.html
I've tried this. There is no voltage reading when the positive terminal is placed on the collector of 4IC1 and no increase when trimmer 1R88 is adjusted.
Okay, it sounds like the sensor might be dead but it could also be a broken connection. Can you remove the sensor and test it?
Also, just to be clear, you had the positive meter lead on the collector and the negative lead on the Beogram system ground, right?
...and the 21 VDC supply voltage is good?
I’ve checked the voltage again and it fluxiates slightly in negative numbers.
No reading.
I’m not sure the sensor is dead as when I turn off an External LED Desk lamp the tone arm drops
When travelling From left to right. Also shining a phone light Near the sensor causes the arm to
lift at the out groove of the record
It sounds like the LED you installed is not bright enough if extra light from another light source will get the circuit to work. That being the case then the sensor would appear to be okay. The LED I have been using is a Cree C503B-AAN-CY0B0251. Other LEDs will also work but they have to put enough light on the sensor. Trimmer 1R88 adjusts the LED output. As I mentioned above, the service manual wants the LED level set where the voltage on the 4IC1 sensor collector is at 5V. You can see where that measurement point is on this post. Part way down the page where the DMM is measuring 5.023V. It is where the red test lead is connected.
Since the additional light sources are making the sensor work I would measure the sensor (4IC1) collector with the extra light shining on it. It should measure some value above 0 VDC. I am guessing your LED is too weak and the trimmer resistor 1R88 is unable to set it in a range that works.
I will get an LED like this and test it. Do you know if this would be a suitable photo resister replacement too as the one that i have has seen better days?
(The one on the turntable had three connectors and the previous owner cut off one and wired the two right legs to the solder pads).
https://www.mouser.co.uk/ProductDetail/OSRAM-Opto-Semiconductors/SFH-203-P?qs=K5ta8V%252BWhtbzn2tqknBCKA%3D%3D&vip=1&gclid=EAIaIQobChMItIGAl9D06QIVVeDtCh1iHAHgEAYYAiABEgIuu_D_BwE
That's a good question. I have never come across one that needed replacing. You can ask Martin Olsen (Dillen here on the Beoworld Forum) if he knows a suitable replacement part.
Okay, as I said earlier, it seems odd and unlikely that the sensor would go bad. Get a better LED to try then see how the sensor reacts.
It would help if you posted some photos of your testing. Where you are setting your probes for your measurements, etc.For this position sensor check you can do everything with the turntable platters (both top and sub) removed.
Hi sonavor,
Thanks for your input. The 5524 was working pretty much to spec and I was about to report back to you.
However the microswith on the right closest to the motor was faulty. The outcome of this is the stop button (SO) and slow > button don’t work.
All other commands are functioning.
Any ideas what transistor or diode would effect both of these functions but not the other control buttons?
Hi,
Have you verified the switches for those functions on the control panel are making contact?
Hi, I have rechecked the 5524 with a working main board from. All functions work,.
Update: The Slow > and SO buttons don’t control the motor but the > and SO buttons do activate the solenoid and lift the toenarm.
The Start button and slow < buttons activate the motor, so there is a problem with activating the motor in the other direction.
Do you have the service manual and schematic?
The ">" and "SO" signals do go to the same side of the tangential arm drive motor. So the failure does kind of make sense (that both of those are not working together).
Check the diodes in that circuit and the trimmer for the ">". It sounds like the transistors for that side of the motor control are working since you say the ">>" works.
Thanks for this.
I do have the manual and i've been looking at it. However i am trying to marrow the path of the fault down.
The > slow return button activates solenoid but not the motor
The SO operates the solenoid but not the motor.
I have replaced the trimmers.
I noticed charring to the board below two of the circular metal transistors. (Marked with red marker in image)
I replaced them for now with ones from a donor board. I have replaced two of the diodes on the signal path too.
I am hoping the problem is localised to the signal path. Perhaps one component could be responsible.
Your board looks pretty normal to me. I wouldn't think those transistors are bad. The ">>" works after all.
You replaced all of the trimmers. While that is fine you do need to run through the service manual checks for those.Did you perform the slow slide transport adjustment procedure where you set the voltage across the tangential drive motor (servo motor) to 3 volts for the "<" and ">" operations?
Adjusted to spec by measuring the motor voltage, right? Just making sure.
Compare the voltage at the junction of 1TR24, 1D46, 1D48 and 1D31 for the following operations ">>", ">", "SO" ...and when none of those operations are occurring but the Beogram is in play (i.e. "Play", "<", "<<"). -sonavor
Also, that area under the transistor looks like normal discoloration in the PCB due to heat from transistor. That is normal. Scorched would be black and there would likely be black scorch marks on the transistor casing.
Sorry, I looked at your photo more closely. That is pretty scorched under the 1TR20 transistor.
Do you have a transistor tester that you can check it on?
Struer :Just working through the the trimmers R 56 - 3v R57 - no reading So not sure signal is even getting to the trimmer at all
R 56 - 3v
R57 - no reading
So not sure signal is even getting to the trimmer at all
Well, that confirms what you are experiencing. R57 is for the ">" slow slide transport which you are not seeing working.
To be clear though. When you say no reading you mean no drop across the servo motor while attempting to adjust R57?That's why I would like to know what voltages you see at that node for (1TR24, 1D46, 1R92, 1D31 and 1D48).Since ">> Off" works, or does it? ... you should see a voltage for that action.
1TR23, 1TR24, 1TR25 and 1TR26 are managing the motor reverse direction. the high voltage side of that circuit is coming from a 21V rail. The base of 1TR24 is controlled through the ">" slide transport, the SO and the ">> OFF" signals. It sounds like your problem has to exist within that area.Since you see the tonearm cue up occur (solenoid disengages) then it appears you are getting 21V from the ">" switch through 1D29.Check between 1R57 and 1D31. What is going on there?
Okay, then from what you are saying none of the reverse direction servo motor functions are working.
That means the problem is in that area I mentioned earlier. Did you check the voltage levels you see at the one large node (1TR24, 1D31, 1D46, 1D48, 1R92)?
I'm not following what your measurements are.
Here is where I was asking you to measure and what the voltage at this point is for the various Beogram operations (">", ">> OFF").
The meter positive lead goes on the node the picture shows. The negative lead goes to ground (you can use the ground (black wire) of the reservoir capacitor if you are unsure of another ground.
Yes, where you have a couple of red marks on the solder joints. The base of 1TR24. I want to see if there is any activity there when ">" and ">> OFF" are pressed. Pressing ">" will route 21V through 1R57 through 1D31 to that node. On a working Beogram 4002 I measure 6 VDC at that node when ">" is being used and I measure 15 VDC when ">> OFF" is used.-sonavor