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Miracord 50H II - Very faint signal

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bimmerlucas

New Member
I recently picked up a miracord 50h II and I've been trying to get it in working condition. Currently I am dealing with an issue of a very faint signal. I can hear audio coming from both channels however it is very quiet and there is a humming that is much louder. I've already tried cleaning the headshell contacts, both on the tonearm and on the sled. I've also tried cleaning the muting arms as well as replacing the RCA cables. The ground wire is hooked up so that is not the issue. Any insight would be greatly appreciated.
 
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bimmerlucas said:
The ground wire is hooked up so that is not the issue.
Click to expand...
I have a 50H, and it didn't ship with a separate ground wire. Is that something that got added with the 50H2... or did a previous owner maybe add it trying to fix a problem?

If the 50H2 didn't ship with a ground like the 50H, that might be part of the issue? The advice I saw for the 50H was to not add a seperate ground because the table was already grounded through the audio channels, and adding one might cause a ground loop.
 
bimmerlucas said:
I recently picked up a miracord 50h II and I've been trying to get it in working condition. Currently I am dealing with an issue of a very faint signal.
Click to expand...
@bimmerlucas, what receiver/amplifier do you have the turntable connected to? Some modern amplifiers do not accept phono inputs, only pre-amp outputs.
 
Are you sure that you don't have a problem with the Sansui 771 phono input? Can you try the turntable on another amplifier, or does the phono input work with another turntable?
 
With a DMM, check the resistance from the headshell leads to the phono plug. It should be close to 0 ohms.
I think this was the wiring.
1743568546876.png
From the 50H manual.
1743568656905.png
 
dankik said:
With a DMM, check the resistance from the headshell leads to the phono plug. It should be close to 0 ohms.
I think this was the wiring.
View attachment 3470675
From the 50H manual.
View attachment 3470677
Click to expand...
When I touch the left channel pin in the tonearm I get no feedback but when I touch the right channel pin I get feedback, and in testing it’s my right channel that doesn’t work. Is that indicative of any particular issue
 
What cartridge to you have? Let's first check the wiring from the cart to the headshell.
RED = Right Ch
BLUE = Left Ch
GREEN = Right Gnd
YELLOW = Right Gnd
 
dankik said:
What cartridge to you have? Let's first check the wiring from the cart to the headshell.
Click to expand...
It’s an ADC 230XE. I already verified it’s working on another TT and double checked the wiring to make sure it was correct for the Miracord.
 

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Your wiring looks different than what I found on the internet? One of these is wrong.
If the one on the right is correct, then you L channel (blue wire) is connected to Gnd.
But, that doesn't explain why you don't get hum when you touch the tone arm?
1743569827948.png
I found a cart with your signal markings. I added colored circles to show wire colors.
Yours is wired wrong, the one on the right is correct.
The way to read the label is:
S = Signal​
G = Ground​
L = Left​
R = Right​
The two pins on the right side of the photo below are the signal pins "S".​
The two pins on the left side of the photo are the ground pins "G".​
Compare those to the markings on the cart shell...
R = Red​
L = Blue​
O =Green/Yellow respectively​
1743570564864.png
Fix that first, then try to listen again and we can chase the next problem.
 
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dankik said:
Your wiring looks different than what I found on the internet? One of these is wrong.
If the one on the right is correct, then you L channel (blue wire) is connected to Gnd.
But, that doesn't explain why you don't get hum when you touch the tone arm?
View attachment 3470689
Click to expand...
I’ve rectified this but the issue of a dead right channel still remains irregardless of the cartridge wiring. As I mentioned before I get feedback touching the right channel but not the left channel, this is with the wires coming out of the tonearm.
 
bimmerlucas said:
the issue of a dead right channel still remains regardless of the cartridge wiring.
Click to expand...
You will need at least a cheap multimeter to test the continuity from the tone arm wiring to the RCA plugs. You can buy one on Amazon or Harbor Freight for <$10. Spend more for better quality, whatever you can afford. We need to check for a short of the Left (blue) wire to ground on the turntable arm or chassis.
 
dankik said:
You will need at least a cheap multimeter to test the continuity from the tone arm wiring to the RCA plugs. You can buy one on Amazon or Harbor Freight for <$10. Spend more for better quality, whatever you can afford. We need to check for a short of the Left (blue) wire to ground on the turntable arm or chassis.
Click to expand...
I guess that’s what I’m doing tomorrow. I’ll report back once I can test
 
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