Mark-sf
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I would not accept a shipment where the platter and cartridge were not removed. Padding can help it survive without the transport screws engaged but an in place platter will likely cause damage. You are correct that the cord is necessary for arm movement as it goes around two pallets that are driven from the arm motor.
The base of TR45 should be adjusted to 27.2 which should give you 26.6 at the collector of TR48. If the base of TR44 is 29.2V and you still are seeing a drop to 22V then the speaker output voltage before the output cap can’t be 28v. Note that the positive side has an 100 ohm resister to isolate it where the negative doesn’t. You need to further investigate after TR47 for the current draw.
The 250-ohm trimmer and TR45 governs how much no load bias is applied to each base. It is mounted on the heat sink to sense temperature and also adjust the bias. It’s possible that transister is bad or the adjustment is too high. The circuit calls for a BC311 and since the bias is not separately adjustable for its BC310 mate its possible that your BC161 is a poor match. Sorry, but its been too many years since I worked on one of these.
Glad you got it sorted out as I was out of suggestions. First try the bias adjustment.
The diode is blocking current flow from TR48 collector to base of TR47 as it conducts in the other direction due to the higher voltage that is supposed to be on the base. Therefore, it cannot be bypassed with a jumper.
You say there is 0 volts on the anode, is it the same at the collector leg of TR46 and the base leg of TR47? If you power down, what is the ohms reading to ground from the anode for each channel?
It’s possible you have a broken trace at the anode of the diode. Try a jumper from it to the base of TR47 and the collector of TR46. Don’t know what else to suggest based on what you are reporting.
You misunderstood my suggestion. If the voltages are not as specified in the schematic the transistor will not turn on even if it is good. What are the actual base and emitter voltages?
It sounds like TR46 is not being turned on. Are the voltages on its base and emitter as per the diagram?
I just did some more troubleshooting, The tracking force seems to be right, 1,19g (measured with a jewelers scale). It randomly skips/repeats the groove, maybe every 20-30 seconds. I can’t see any obvious reason why and the tonearm seems parallel to the sensor arm the whole time, even when it skips.
I would remove the platter and press play without the record. Once the arm drops, I would tap it just enough for it to start progressing in. This way you can observe where or when it may be hanging up.
As to your standby problem, I would try running the TT without connecting to the Beomaster and seeing if it still stops.
Since this occurred when using the turntable and the FM still works I would check the solenoid circuits 21RL1 and RL2 sad their switching transistors 19TR4 and TR5. These would also explain the Pause not working. There are adjustments for arm position and balance in the service manual to solve your alignment and tracking issue.
Reply to Mark-sf On 1, 2, No! 3. Randomly 4. I’m using DIN, that’s what my my Beomaster 4400 has 5. What is R112/212? Kindest regards Mats
Mats, For the sound to come from both your speakers but not be controlled by your volume control is highly unusual and could only occur if the act of playing a record was injecting/disturbing the power amp section of your 4400 directly. I would ask that you try playing a few records with the volume full down and then trying again with the DIN cable unplugged and report your results.
As to R112/212 there are adjustable resisters (trimmers) that are accessed via a screwdriver through the bottom labeled Phono L & R.
While I have not heard of this issue, there are some questions that can narrow it down.
- Does the sound occur only on one channel?
- Does the sound vary with volume; for example, if the volume is turned way down is the sound soft?
- Does it occur at the same position on the record or randomly?
- Are you using the DIN or RCA jacks?
- Have you tried cleaning or replacing the two trimmers R112/212?
By back panel are you referring to the black grill that covers the connections? If you are it is only held by gravity. There is a stop piece attached to the underside in the middle of the grill piece that might have gotten stuck down.
If it is of Type 58xx I would replace the belt and clean the pulley. If the 54xx you also have an idler wheel to clean. You can find the proper replacement parts at Beoparts-shop.com.
Can you remove the platter and check whether the spinning is stopped by the motor spindle stopping or the belt slipping on the pulley because the platter is hung up?
Do you get the hum when you turn off FM Stereo? How about any other inputs?
Can’t say I remember seeing your problem, but would start by replacing the electrolytic cap in the solenoid circuit and cleaning the contacts under the plastic cover.
Did you tighten the turntable transport screws and remove the platter for your transport. If not its bouncing could have caused issues. The mute switch may have been damaged. Have you tried the tape deck?
