Greetings. Writing in regards to my Dual 1218, which I have really grown a liking to over the years. Not Duals best turn table, but I really do love it's sound. Anyways, it has a scratchy, dirty contact sound when the arm is being returned to resting position. Same sound you get when you turn a knob with a dirty pot. There is some kind of dirty connection somewhere... I just don't know where. I have already cleaned the speed select, start stop, & 7"-12" switches several times. Possibly unrelated, but it also makes a slight thud/pop when the arm clicks down after being returned, which is also when the motor stops. I pacify both of these issues by simply muting my amplifier with its remote from across my room, but it would be nice for it to have a smoother return. Thank you in advance for any suggestions. I have re capped speakers & amplifiers and also have experience in re building drivers, but I have virtually zero experiance working on turn tables, so if you provide advice on what to do, please be as descriptive as possible. Thanks all!
Dual 1218 tone arm troubleshoot
- Thread starter DanielR27
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Penn42
Well-Known Member
There’s a safety capacitor at the power switch that needs replaced, under a black plastic cover where the motor/power cable terminates at, that will solve the pop.
The scratching sound during tonearm motion shouldn’t be audible because Dual’s have a “mute switch” to prevent errant signals during mechanical operation. The contacts on your mute switch are probably very dirty and gummed up with old grease from the main cam.
Scratching during tonearm movement could also indicate issues with tonearm grounding. Check all the contacts under the headshell. Silver polish is great for both the headshell contacts and mute switch cleaning.
The scratching sound during tonearm motion shouldn’t be audible because Dual’s have a “mute switch” to prevent errant signals during mechanical operation. The contacts on your mute switch are probably very dirty and gummed up with old grease from the main cam.
Scratching during tonearm movement could also indicate issues with tonearm grounding. Check all the contacts under the headshell. Silver polish is great for both the headshell contacts and mute switch cleaning.
Alright, I'll figure out the best place to start, but ultimately address everything that you mentioned. Arm definitely has to have some sort of grounding issue. I'll get learned on where the mute switch is & order some silver polish for the headshell contacts. Did some clicking around on safety capacitor replacement... is there a specific cap that you would recommend from a specific vendor? Thank you, thank you
NoTransistors
Dual Turntables Super-Restorer
Polishing the P.C. board strips is a mandatory step, but is not going to solve arm grounding issues unless the board is slid ouf its slot to clean the center silver strip hidden under the copper ground strap.
That's kind of the thing is that the board slides out all the time. I swap shells to play 78's frequently need to push the board back up in between swaps. I don't really know how to fasten the contact board back into the arm, but I refuse to glue it in. Something about that feels very wrong. I will clean it in its entirety.
Penn42
Well-Known Member
The copper ground strap @NoTransistors mentions should apply some amount of pressure as it sandwiches the P.C. board to the back of the headshell. I don't think it's necessarily responsible for holding the board in place, but there should be enough pressure that it won't slide out of it's own even if the board fits in its slots loosely. If the ground strap is broken off this would definitely be the cause of the grounding issues.
Nothing is broken, luckily. All things considered, it is a very well functioning unit. I'll replace safety cap and polish P.C. board tomorrow
If you have noise when the mute switch is activated, you might have some corrosion where it makes contact.
The mute switch on Duals grounds the signal wires to the ground wires when activated so there should be no sound at all. Corrosion there would mean its not grounding, which won’t allow it to kill any signal while the tone arm is moving.
The mute switch will just look like a couple metal leafs underneath the table where the tone arms wire go through it. The big center plastic cam gear is what activates it.
Capacitor is usually a shutdown “thump” when it goes bad. It dampens the spike when the power switch turns off.
At least thats how my 1229q and my 1249 work. I’ve had the cap go bad on the 1249 and got the “thump”, but I’ve never had noise when the mute switch activates…
Edit: guess I’ve just said whats already been said…lol!
The mute switch on Duals grounds the signal wires to the ground wires when activated so there should be no sound at all. Corrosion there would mean its not grounding, which won’t allow it to kill any signal while the tone arm is moving.
The mute switch will just look like a couple metal leafs underneath the table where the tone arms wire go through it. The big center plastic cam gear is what activates it.
Capacitor is usually a shutdown “thump” when it goes bad. It dampens the spike when the power switch turns off.
At least thats how my 1229q and my 1249 work. I’ve had the cap go bad on the 1249 and got the “thump”, but I’ve never had noise when the mute switch activates…
Edit: guess I’ve just said whats already been said…lol!
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