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Dual 1218 idler wheel noise

Posted: 06 Feb 2018 19:47
by Eabbru
The idler wheel had a flat spot that made a very noticable thumping sound during quiet passages of a record. I remove the wheel and turned the diameter down a bit using my drill press and emery cloth. The thumping is gone, but I can hear a slight rumble sound. I believe I am hearing the platter as it travels past the idler. Is this normal or is there more that I can do to reduce the rumble?

Re: Dual 1218 idler wheel noise

Posted: 07 Feb 2018 18:37
by DSJR
Make sure the idler surface is truly smooth and without 'knobbles.' Failing that, replacement are out there and if it has to be a used one, organdonorparts may be able to help you. Do please note, the face on Dual idlers appears to be slightly curved or radiused and not truly flat as Garrard idlers are for instance...

Re: Dual 1218 idler wheel noise

Posted: 08 Feb 2018 11:08
by Hugues TR4
Hi,
If you really want to get rid of the maximum possible of the rumble, some people are rebuilding the old idler wheels to their original smoothness (new rubber ring).
Voice of Music.com are doing this for a reasonable price (they need the old part when you place the order).
http://thevoiceofmusic.com/catalog/phon ... urrets.asp

Hope this helps.

Cheers,

Hugh.

Re: Dual 1218 idler wheel noise

Posted: 13 May 2019 13:27
by Eabbru
Update:
I took your advice and purchased a rebuilt idler wheel from The Voice of Music. It did reduce the thumping sound, but it is still very audible. Any suggestions where to go from here?

Re: Dual 1218 idler wheel noise

Posted: 13 May 2019 14:06
by Alec124c41
Have you lubricated all the bearings: motor, spindle, and idler wheel?
Did you clean the inside of the rim?

Cheers,
Alec

Re: Dual 1218 idler wheel noise

Posted: 13 May 2019 14:20
by Eabbru
It's been over a year since I lubricated everything. What do you use to clean the inside rim?

Re: Dual 1218 idler wheel noise

Posted: 13 May 2019 14:27
by DSJR
Alec is quite correct here. These decks ALL need servicing now and dry motor bearings don't help smooth quiet running either - look on the Dualcan site for pics and tips on motor cleaning etc...

There's a Russian chap doing interesting re-manufactured 1219/1229 idlers and I believe he offered to make a smaller wheel version for the 10" platter models if he was sent an original. There's a chap in Germany who can re-tyre Dual idlers too and he quoted me around E35 plus carriage (I can never find the spare dosh, so haven't yet used his services) -

https://schall-und-crema.webnode.com/dual-ersatzteile/

He does pimpels too, but I haven't tried them.

Re: Dual 1218 idler wheel noise

Posted: 13 May 2019 19:41
by Alec124c41
I use isopropyl alcohol and parer towel to clean things.
Any irregularity on the inside of the rim will affect the sound.

Cheers,
Alec

Re: Dual 1218 idler wheel noise

Posted: 13 May 2019 20:12
by mrow2
Interesting report back re: the new-rebuilt idler from Voice of Music. I thought new, softer rubber would resolve this. There had been a service in the States which does this for any number of different machines including these, feedback had been good. Be aware 1218 would have a little more rumble than the larger 1219 in that particular lineup/production period, but there are hardly ever any complaints.

Inside platter drum surface (as Alec mentions) can be cleaned, and a rather fine paper helps to smooth and restore it; just gentle (I'm thinking a slightly diagonal pattern to the platter itself, evenly and smoothly, very fine paper, then the isopropyl and paper towel) movements all the way around, no fingerprints whatsoever after it's done. But if a new idler is noisy, then that says to me that the rubber is not quite soft enough, like a car tire which is good for 100k -- might be a little bit firm-riding.. Checking with another vendor might be the thing to do.

Also as Alec and DSJR mention, general servicing (motor bearings and platter bearing) would eliminate that aspect of the
excess rumble.

I'm searching idler rebuild services. Where are they when I want to find them? I remember this one was well thought-of:http://www.west-techservices.com/p7.htm

Another: http://terrysrubberrollers.com/

http://turntable-tuneup.com/idler-wheel-rebuilding/

In the limited time I have to search for more services before end-of-edit, I could not find the latest discussion on various services includint the Russian fellow.

Re: Dual 1218 idler wheel noise

Posted: 13 May 2019 20:34
by DSJR
Hmm. My 1214 with 4 pole motor and 1216 cast platter is currently the quietest of all my Duals save the 701! I've yet to transplant the 'new' idler from this to my 1019 although this latter was quietened a lot with the 1214 cast-off wheel.

One thing to check. The motor wiring on these decks MUST be looped and totally free, not touching anything anywhere, but this is to minimise the high bass 'background drone' these motors can put into the stylus in quiet passages of music. The idler is the main culprit (10** harder compound wheels especially) and Dual did soften and 'thin down' the tyres in later models. If the noises are low pitched rumblings and grumblings though, I'd suspect a fault or contamination of the thrust race on the main bearing as well as possible contamination of the inner drive surface on the platter. Whirring style noises through the stylus could be the main cam not properly disengaging in 'play' mode.

Re: Dual 1218 idler wheel noise

Posted: 14 May 2019 17:51
by Eabbru
Thanks everyone for your responses. I cleaned the inner rim and the idler wheel and the noise is now at a more acceptable level. I had descibed the sound as a thumping noise, but actually is sounds more like a whirling noise. So DSJR's comment about the cam not properly disengaging interests me. I had replaced the cam at one time and I'm wondering if I did something wrong or it needs adjusting. How do I check for this?

Re: Dual 1218 idler wheel noise

Posted: 15 May 2019 19:10
by mrow2
I have one other thought unless it's already above and I didn't see it: In cases like this be sure the idler wheel is flat horizontal when driving the platter and not a "toe-in" sort of situation which happens surprisingly often. Be very careful with the cast idler bracket but it seems to be able to tolerate a slight, firm "alignment" effort. You sort of need to eyeball the straightness of it with the platter off and only adjust if it seems bent down a bit. If others have had the platter off, the idler can be caught by the rim edge as platter is being lowered by someone who doesn't know the issues. It can be gradually bent in this manner. Retracting the idler with the speed shift will prevent this. Remove all fingerprints on idler and drum prior to reassembly.

Re: Dual 1218 idler wheel noise

Posted: 15 May 2019 20:52
by Eabbru
The idler bracket appears to be fine, but there seems to be too much play between the bracket shaft and idler hole. I can rock the idler back and forth. With the platter off and the motor on I can see the idler wobble up and down against the drive.

Re: Dual 1218 idler wheel noise

Posted: 15 May 2019 21:35
by BoblK
Should not be that much play at all. Sounds like either the shaft or the idler bushing is worn out. I'd bet on the softer material, the bushing ..

Re: Dual 1218 idler wheel noise

Posted: 16 May 2019 11:59
by DSJR
Re the cam. I believe later models used the muting 'fingers' to park the cam in the 'rest' position, although I gather that some decks (earlier ones?) have assistance using the main lever 'stud' which is encouraged to a park position as well.