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Technics SL-1300 very quiet left channel

Vehshya

Vehshya

New Member
Good evening everyone,

I recently picked-up a used Technics SL-1300. After cleaning it up a bit and fixing some speed issues, the thing was running smoothly. Until after about a week of listening the left channel went pop-crack-crunch and was completely gone. After some jiggling and reconnecting of cables, the left channel stayed off. But the missing channel will follow the cable (aka not a speaker or amp issue).

After reading some information on this forums, I opted to resolder on some new RCA cables. While this did not resolve fix the left channel, the audio does sound better on the right (less ground hum). I also replaced the headshell thinking that it would also be an easy thing to troubleshoot. This also didn't bring back the left channel.

But after some more troubleshooting, I noticed that there is indeed sound coming out of the left channel, but its extremely quiet. If I blast the audio and balance it towards the left channel, you can faintly here sound.

Any suggestions? (please dont say rewire the tone arm, it looks like a pia)

Thanks in advance for whatever help you can provide
 
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Do you have a digital multimeter?

If so, remove the headshell, disconnect the headshell wires from the cartridge, set meter to 10K ohms, and connect leads to the white and blue pins of the cartridge. What is the resistance reading? Now connect leads to red and green pins. What is the resistance reading?

They should be fairly close to one another, and both >500 ohms. If not, your cartridge is probably damaged. What is make/model of cartridge.

If no problem there, use meter to check continuity from the headshell wires to the far end of the RCA cables. White to left channel tip, blue to left channel shield/ring, red to right channel tip, green to right channel shield/ring.
 
spark1 said:
Do you have a digital multimeter?

If so, remove the headshell, disconnect the headshell wires from the cartridge, set meter to 10K ohms, and connect leads to the white and blue pins of the cartridge. What is the resistance reading? Now connect leads to red and green pins. What is the resistance reading?

They should be fairly close to one another, and both >500 ohms. If not, your cartridge is probably damaged. What is make/model of cartridge.

If no problem there, use meter to check continuity from the headshell wires to the far end of the RCA cables. White to left channel tip, blue to left channel shield/ring, red to right channel tip, green to right channel shield/ring.
Click to expand...

Thank you for the response!

I dont have a multimeter, but I can pick one up or borrow one to test that. I should probably have one anyway.

Not seeing the model of the cartridge, just a blue color, japan and ADC written on it. I might be missing something though.
 
You could also try removing the head shell and cleaning the contacts in the end of the tone arm.
Using a pencil with an eraser on the end, clean the four contacts until they are shiny.
Do the same on the four pins on the end of the head shell.

Mr Relish
 
Certainly, a place I'd start @MonkeyRelish. The most common problem with electrical stuff is actually mechanical in nature. I believe the contacts between the headshell and arm are the problem, or the cartridge wires going to the headshell. They might not even be wired correctly.

Red = right +
Green = right -
White = left +
Blue = left -
 
I'm watching this here. My SL-1300 just dropped the LH channel as well. The tone arm wiring is good visually as well as the contacts. The cartridge is pretty new and have had no issues with it. Audio-Technica AT-VM95SH/H. It is the turntable for sure. I changed from the Fisher KM-60/KX-200 over to the Luxman TP-114/M-117 set up and it remained LH. Checked using headphones as well. Same thing; it remained LH channel.
My multimeter is out for calibration check but should have it back this week.
 
In my case, the white contact is the top left contact in the tone arm (viewing as looking into the tone arm where the cartridge lives). It shows open on my meter. I scaled it way down but still shows open. The RCA is good. All others ring good with values of 0.001 or so.

I do have the service manual for this turntable but not too sure where to look and continue t-shooting.
 
Malcolm MacK said:
In my case, the white contact is the top left contact in the tone arm (viewing as looking into the tone arm where the cartridge lives). It shows open on my meter. I scaled it way down but still shows open. The RCA is good. All others ring good with values of 0.001 or so.

I do have the service manual for this turntable but not too sure where to look and continue t-shooting.
Click to expand...

How were your meter leads connected?
 
Hi Spark 1,
I used alligators first then pin to check it wasn't the alligators.

As it turns out it was the left RCA output lead from the turntable itself. When I couldn't get continuity from the soldered connection inside the table to the RCA center pin, I took that RCA apart and found the broken center connection. Will make quick work of that and since I'm in the neighborhood I'll also upgrade the ground lead to 20 gauge.
 
I was trying to ask at what points your meter was connected, not what type of probe/clip you were using.

You said the "white contact" showed open. I was trying to figure out what the other meter lead was connected to. In other words, what were the end points of your continuity test?

In any case, you've found the problem...a common one. So, now irrelevant.

I wonder if the original poster ever found his problem?
 
Sorry for the confusion Spark 1,
To clarify, one pin style probe was on the actual tone arm contact where the cartridge connects and the other was the center pin on the RCA. That should be a straight shot and 0.001 ohm or so reading.
 
I noticed a hum yesterday. Like a 60Hz kind of hum. Turns out my setup was too close to other electrical things like the Beverage Air beer fridge. To prove, I put a fresh keg of Double Fuzzy Yellow Ducks by New England Brewing Co. on tap, enjoyed a few pints and moved the Technics SL-1300 across the room to the Kenwood KR-9400 and DBX 3BX set up. It is perfectly quiet now. Listening to the latest by Hum. Inlet on Earth Analog Records EAR-005.:beerchug::music:
 
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