I have just had my ~1989 MMC4 re-worked / re-furbishedCan you provide more details about this? Probably the most significant info is how was your cartridge was tested it before was returned. All of the measurements of you cartridge appear to be correct. Are you sure that it is not something simple like not fully seating the cable between the turntable and the receiver? Is the cartridge deflecting the right amount when you place it on the record? Have you measured the tracking force? You may also want to look for other problem sources like cold solder joints and cracked traces. Login to view image Above is a picture of a cracked trace that was causing an bad connection. The crack was at the edge of the solder flux and was impossible to see until I removed the flux and cleaned the area with a scratch pen. Something like this could result in the symptoms that you are describing. Glitch
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Beogram 5500 LH channel not working
18 replies
"Martin, I agree but the diagram is still wrong as a single pin cannot have 1480 and .2 ohms. It would be 1480 and 740 ohms."
When muted all pins are connected. That's where the 0,2-0,3 Ohms come in.
When unmuted, the L- and R- are still connected (signal ground), so when measuring between L+ and R+ you are measuring the two coils in series.
Their common center connection to ground doesn't matter, seeing as you are not measuring with respect to ground.
OP: Any access to another Beogram to test the suspect cartridge with?
Where are you based?
Martin
When muted all pins are connected. That's where the 0,2-0,3 Ohms come in.
When unmuted, the L- and R- are still connected (signal ground), so when measuring between L+ and R+ you are measuring the two coils in series.
Their common center connection to ground doesn't matter, seeing as you are not measuring with respect to ground.
OP: Any access to another Beogram to test the suspect cartridge with?
Where are you based?
Martin
Many thanks for the replies. I'll try to answer them in turn...
- The cartridge was re-furbished by a well known UK B&O specialist independent, who seem to be well regarded. Not sure if it is fair to identify him just now, but his diagnosis was "It is suitable for a rebuild / Coils good / Diamond heavily worn not suitable for suspension only / Suspension failed", and so I went for a "Nude Elliptical Diamond, Aluminium cantilever".
- The problem _could_ be a poor connection between the turntable and the amplifier, but why would it _always_ push sound through the LH channel at needle drop & needle rise only?
- The cartridge looks to deflect fine when it lands; the tracking force on the slider was cross checked with a stylus balance scale.
- Sadly I don't have access to another Beogram.
- I am based in Sussex / UK.
- I can’t find a suitable external phono pre-amp to use with the Beogram and a Sonos ZP120 amplifier, but plugging the deck into the Sonos and raising the volume a _lot_ (due to no phono pre-amp), both channels seem to be at the same volume.
- If this last bit means that there is something wrong with the Beogram phono lead and/or the Beomaster 5500’s phono input, then what to test next? It does seem strange that the briefest of unmuting only happens at needle drop and needle raise though.
- I am awaiting receipt of an opto-reader for my MCP before I can try connecting the Beogram back up to the Beomaster - I will try the phono RCA inputs next - as the volume is too loud and I can't at the moment reduce it (the MCCP will only raise the volume, not lower it !!!)
You could try setting the tracking force very low (0.2-0.3g) and see what happens.
The needle may not track correctly, and it may jump around a bit, but it would also
merely be to test if sound is produced from both channels.
Another test could be to take off the cartridge and put it aside, start the Beogram (play)
without it and while it is "playing", insert a small strand of copper wire into
the cartridge socket, one hole at a time, listening for a healthy buzz from the amp/speakers.
The L+ and R+ socket pins respectively, should give that if the deck, leads, amplifier and speakers are fine.
Martin
The needle may not track correctly, and it may jump around a bit, but it would also
merely be to test if sound is produced from both channels.
Another test could be to take off the cartridge and put it aside, start the Beogram (play)
without it and while it is "playing", insert a small strand of copper wire into
the cartridge socket, one hole at a time, listening for a healthy buzz from the amp/speakers.
The L+ and R+ socket pins respectively, should give that if the deck, leads, amplifier and speakers are fine.
Martin
The fact that you got both channels working albeit at a low level into the Sonos points to the Beomaster phono inputs. You stated you have the RCA DIN adapter. I would try that as it allows you to switch channels to see if the bad channel follows. If it does not then it’s a Beomaster problem.
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