[Mark-sf]

The section hcraig244 posted is correct.

[Mark-sf]

Check the link in my first reply to you for the relay.

[Mark-sf]

As long as the cartridge body (coils) is fine you can simply replace the stylus. The SP-9 was the elliptical version of your SP-7 and is available on the web such as https://www.lpgear.com/product/BOSSP09.html.

 

[Mark-sf]

The ring is just an indicator. You rotate the weight which is the cylinder behind.

[Mark-sf]

That appears to be Figure 142 and part 257022 Arm, Speed in the manual.

[Mark-sf]

You need one which is “NO” for Normally Open and is DPST with the correct pin-out.

[Mark-sf]

If they spliced the cable, then you can connect the ground wire to the braided shield of the DIN cable. As to replacement cartridges, your SP-6 has a conical stylus. An SP-12 would be better; however, I do not know why you’d have an issue with the tracking weight of an SP-10. Do you have a stylus gauge? What range are you able to set?

[Mark-sf]

Looks like a nice find! If you take the bottom off you will find where the RCA cables were attached as well as the terminal that is grounded to the chassis where you can simply solder a stranded single wire for your ground. As for belts, check out https://www.beoparts-shop.com.

 

[Mark-sf]

It most definitely can blow as those contacts conduct when you plug it in.

[Mark-sf]

Before attempting to disassemble the transformer, I would measure the primary and secondary windings with an ohmmeter. This will let you know whether it has opened. If there is resistance on both sides then you can simply hook up the primary to a raw power cord and measure the secondary voltages. If they are fine I would look deeper into the power supply.

[Mark-sf]

I would check whether there is a short instead of a 4ohm measurement. You would need a multimeter.

[Mark-sf]

B&O made the switch of sides in all of their turntables  in the mid 1980’s. They still perform the same record detection function. They became wider to display the speed while the cartridge carrier became narrower to support the smaller cartridges. The older service manuals for the 400x series provide the most detail on the tracking system.

[Mark-sf]

By muting the unit I meant going into standby. The relay does not switch all the power off.

[Mark-sf]

First you need to confirm that your standby voltages are fine. TP9 should read 6.5v DC. You should also have 5V DC at pin 5 of the P11 connector. If those are fine, then you likely have a fault in the power amp section that is muting the unit. There is no need to replace the relay as what you have observed is its normal operation.

Finding a fault in the power amp circuit is more difficult since the +/-30v supplies share the same board and there is no easy way to disconnect the power from one channel without pulling the output transistors. Since you are able to get it on for a time, I would try looking for a DC voltage on each channel w/o speakers connected while the relay is engaged and figure out which one is tripping the fault circuit as a start. This all assumes the 6.5 and 5v supplies are fine.

[Mark-sf]

The fact that the relay does activate even for a short time does not mean it’s broken but that it is losing its 6.5 volts. This will take some technical skill to fix and the service manual is online so it does not require a B&O service tech. How comfortable are you with using a multimeter and desoldering/soldering parts on a PC board?

[Mark-sf]

What is broken about the relay? It’s a simple DPST relay that is activated by 6v and most like rated at 1A for contacts. You might check whether https://www.beoparts-shop.com/product/relay-for-beomaster-5000-5500-6500-7000/ will work if it truly is bad.

[Mark-sf]

Ninni, virtually all speakers that provide for two separate pairs of binding posts also include internal crossovers and jumpers and to bridge the two inputs to use a single pair of wires. True bi-amplified speakers without internal or included amps are predominantly a DIY offering.

[Mark-sf]

I would not connect your speakers that way. Simply run one set of speaker wires and use the jumpers on your speaker terminals. You cannot bi-amp with a single amplifier. What you are proposing is ‘bi-wiring” and it’s not likely to benefit given the speaker switches and DIN connections.

[Mark-sf]

You won’t be able to detect movement from midrange drivers. You should hear them by placing your earn close in front and using pink noise.

[Mark-sf]

Martin is referring to capacitors, not relays which I believe are all 5000 mF and are C4, C17 and C18.

 

 

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