Mark-sf
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Unless you can find an MMC4 used your best bet is Sound-Smith SMMC4: https://sound-smith.com/cartridges/bo/smmc4 at $200.
I would agree with Martin but initially focus on tracking force if the diamond is still intact based upon your transporting without locking the screws.
Assuming you have tried it with multiple tapes, I would contact the seller as its obviously not in “superb condition”.
Since you are able to play using the < key, the issue is in the << electronic switch. I have found TR12 to be bad though rarely its been TR11. Also I have found TR8 to be bad on the muting board; however, in that case it tries to start and shuts off immediately.
Unfortunately, there is no industry standard for 12” record weight. They can range from 80-200g. I have never had a problem finding a suspension height that will work with all without bottoming or scrapping. In the end it’s critical that the platter also remain level.
The service manual provides clearance specifics so I would adjust to that with your 180g records.
I would still suspect the muting contacts. They should be cleaned and adjusted as per the service manual available at https://beomanuals.com/manuals/Beogram/Beogram%204000/Beogram_4000-Service_Manual.pdf.
Glad to see you are making progress. Are you able to start the turntable using the < key to move the arm inward? Does it stay or want to go back and shut off?
There are some major issues there that can only be explained by one or more errors in your parts replacement. Pressing 33 should ONLY cause the platter to rotate and not move the arm. It is a “clean record” function. ON should cause the collector of TR12 to latch high (17v). If pressing 33 is causing that then I would carefully check your diode orientations as you may have one in backwards or a shorted one. The slow return could also be your pulley alignment, lubrication or servo belt. If it is running at the same speed as “>” then once again there may be a diode/trans issue. This is when TR13 should latch high. Finally, don’t forget to check D9/10 and TR8 on the muting board as they perform the same functions.
To do a fair comparison I would still connect the 3500 directly to the 28s.
You likely have a shorted transistor in the On portion of the electronic sw. Check TR13 if I remember correctly. There is also a companion on the muting board for the remote.
First, which RIAA preamp are you using? I would definitely try a direct connection to the line in of your BL28’s bypassing the Moment.
Yes that is what I meant. I do see that Martin has an 8002 Cap kit at https://www.beoparts-shop.com/product/capacitor-kit-beogram-6006-8000-8002/. I have gotten parts quickly from him in the US.
You can’t get a “set”. You need to get a cap kit that includes all the values you need. These kits are available on Amazon, DigiKey, Mouser, etc. Only do the electrolytics (the cylindrical ones) first as they are the most likely culprits. Don’t forget the 47mF on the CPU board.
I doubt its the motor as its on the right as is the transformer. My suggestion would be to open the unit per the manual at https://beo.zone/media/files/Bang-Olufsen-Beogram_CD-5500-Service-Manual.pdf and identify the specific component generating heat.
No I did not check this because there is audio on the speaker pin. I would expect that an issue with the muting relay would prevent audio from passing to the speaker port. As far as I can see it is much earlier in the signal processing? When I trace the audio there is a signal on the output pin of the speaker port. This signal dissapears when I attach a load (speaker) to the port. I can’t see any damage on the port, there are no shorts on the pins. Voltage of 4.5v on the pin for the dataline seems correct.
By your earlier statement the Rt Spkr Jack (P91) works so there is no other likely failure than the relay. Anything eariler shares the audio path with P91. Datalink is not involved in the audio path.
I’m not sure what that circuit board’s function is as it’s markings and wiring could indicate that it is on the power amp outputs. You definitely have a defective left channel if it is reading 24v. That is also the channel associated with the R101 that you replaced. Fix the left channel first and you may find that the right channel no longer makes noise.
The transport screws are not used to adjust the leveling and do not come out so they are not likely stripped. The screws to level are under the platter. Take a look at the service manual at https://beomanuals.com/manuals/Beogram/Beogram%205500/Beogram_5500-Service_Manual-version2.pdf for instructions.
