Cart installation leaves one channel dead

Hey, trying to crowdsource a solution here. My son has my old Dual 505-2 turntable. I bought him an Ortofon Red cart for his birthday and we installed it last week. Trouble is, now only one channel is working. Both channels were working before so we must have done something wrong. Everything seems to be hooked up properly and we can’t figure out where in the chain the problem is. Any ideas for troubleshooting or fixing?

 

Double check that you didn’t damage a tonearm wire during the installation.

 

Does this model use the 'sled' to mount the cart to? If so, try cleaning the contacts on the sled and inside the headshell, and then make sure the sled is locking into position correctly. If you don't have some sort of chemical contact cleaner to use (isopropyl alcohol on a q-tip should work), a pass or two with an emory cloth or a very fine grit sandpaper will usually do the trick.

 

No sled on this model, no.

 

Will do.

 

Each channel has a live, positive, 'hot' pin, and an earth, or 'ground' pin. Two leads.

You've connected four wires, one pair as above for L, one for R.

You need to do process of elimination.

The most likely cause is damage or misplacement of one channel on the cartridge.

First act would be to swap the left leads to the right pins on the cartridge, and the right leads to the left pins.

Does the problem change sides?





Supplementary, if that doesn't solve;

I assume the TT is connected to the amp with twin RCA/phono leads? Or something else?

Are these leads 'captive' to the TT, leaving only one end with plugs on, or are there sockets on the TT for a twin-ended lead to plug into?

 

unfortunately a very common issue.
unmount the cartridge and check each tonearm wire for continuity from headshell lead to cable terminal jack.
if good, check the cartridge as linked:
https://service.shure.com/s/article/testing-a-phono-cartridge-body?language=en_US

if good, the issue could be phono cables, amplification or speakers but not likely.
good luck!

 

Ditto, and make sure they're tight.

 

Not the first Ortofon that has had the pins in the cartridge damaged by installation or re-installation, although here it could have been bad out of the box.

Very important not to twist while pushing on the connectors. This can twist the pins loose and break the internal wires. Also important to not push on wires that have the connector too tight (spread open the connector until it takes very little force to install), or removal can then also damage the cartridge.

You can measure the impedance between of each channel with a multimeter. Set the multimeter to the lowest manual impedance range so the voltage used by the meter for testing is low.

 

Easy one.
Use a multimeter
Disconnect cartridge wires.
Check right channel.
With phono leads disconnected

Put meter between red wire on headshell
And red centre pin.
Confirm ok
Check green and phono outer connector
Confirm.
Now left chann
Check white wire and centre pin on left lead.
Confirm.
Finally check.blue and left outer.connector.
If all is well then either cartridge is faulty
Or phono stage.
Now say the right channel is producing
Sound only.
Then try both left snd right channels
From turntable into right phono input
Now if both leads plugged alternately
Into right channels provide sound then Phono stage is possibly faulty
Asduming left channel is ok on cd

 

Ding!

jeff

 

Multimeter
Before disconnecting cartridge leads

Start at the cable to the TT
meter pin to sleeve for each channel
Should see 1300 Ohm
If not, disconnect the cable that fails

Measure at the TT jack, if good, bad cable
If bad unplug the other cable
CAREFULLY without disconnecting the cartridge pins:
Measure the L + and -, then the R by lightly touching the pins.
Each ~ 1300 Ohm
If not, bad connection or cartridge.