Dual 1229Q bad channel

[Montycat]

This is becoming a P.I.T.A. :thumbsdn:

Mechanically I've got this 1229Q working pretty well. The motor is a touch noisy and could use a disassembly and lube but that's for another day. The usual old lube issues around the idler arm and speed control switch and missing steuerpimpel have all been addressed. The auto functions work well as well as the Single/Multi function.

However, I still get just one channel consistently. The Stanton 681EEE on it is good, reading about 1500 ohms on each side. There is continuity from the cartridge to the ends of the sled contacts (the style with the folded over types, not the spring loaded pins). I've cleaned the tarnish off the contacts with a salt water & aluminum foil bath, and pencil eraser on the tonearm end of things. I manipulated the sled contacts in various ways to see if I could make them make better contact. I've used a different sled (with the springy pins) and cartridge.

There is continuity from the tonearm contacts back to the mute switch block on all 4 leads. I've cleaned the mute switch contacts and made sure they are only closed (tested with meter) when the arm is moving as they should be. I cleaned the RCA jacks with Deoxit on a Q-Tip. I used 3 different RCA cables. I reflowed the solder joints at the mute switch and the RCA board. I cut the wire ground bridge between the 2 channels at the mute switch, and later re-soldered it.

Now if you are still with me, here it gets somewhat interesting. I initially had it plugged into my NAD phono pre-amp. A few times when I pulled and re-inserted the RCA cord at the pre-amp end the other channel came through. It usually only worked for a few seconds to a few minutes and then it would go dead again. The end of the RCA at the turntable was not touched or affected by pulling on the pre-amp end. Ok, maybe the pre-amp is the problem. Switching sides though did not indicate the pre was the issue. Then I bypassed the NAD altogether and went straight to the Yamaha receiver Phono in. Same issue; one channel stays dead.

The "bad" channel (red/green) does produce a pop when the mute switch engages and disengages during the tonearm cycle. Also, when I touch the cartridge leads on that side I get a significant hum. On the "good" white/blue side I don't get the muting switch pop and I get no noise when I touch it.

It might be some kind of ground loop, or maybe a bad tonearm wire but it's frustrating whatever it is.

 

[gip111]

With the cartridge mounted and when it goes dead, do you get continuity from cartridge to end of RCA plug?

 

[dshoaf]

Monty, what do you measure when you go from the center pin to ground on the bad channel?

Given all the things you've eliminated so far, I'd be looking for a pinch wire, likely around the pivot point at the tonearm or in the lead dressing out to the RCA jacks under the TT.

Cheers,

David

 

[tnsilver]

If you take out the sub headshell (TK-14) and look where it's 4 springy pins are suppose to connect, you'll notice a thin copper tab that ground the tonearm to the right channels ground (green). Sometimes this thin copper tab bends and shorts other tracks on that micro pcb. Make sure it's dead centred and doesn't short.

 

[jancumps]

If you hear a pop in a channel when the mute switch engages, you should also take a look at that input channel in your pre-amp.
The cartridge and mute switch are too low power to generate a pop.

 

[Montycat]

I did a bit more testing before work and tonight I'll do some systematic metering. I did get a meter reading from the + side of the bad channel to the other side, but will go through all of the permutations later.

The little pcb in the arm seems ok. I also looked for signs of crimping in the wires but nothing sticks out.

The pop is pretty quiet, not like a big thump. It happens whether I have the RCAs reversed or not and when using the internal or external preamp.

 

[Montycat]

More testing & fiddling but still no resolution.

I think the Right side ground (green wire) is the problem though and probably in the arm. But I measured resistance at the output end of the RCA cables and got some expected results and some not as easy to interpret.

This is with the cartridge/sled mounted. From + to - on the red RCA I get 1267Ω and on the white side 1272Ω, both about the same as at the cartridge so that seems fine.

- Red(green h/s wire) to + White = 1271Ω
- Red to - White(blue wire) = 3Ω
+ Red to - White = 1267Ω

Without the sled in place I get an open circuit from + to + and a closed (2Ω) circuit on the negative side. That seems right.

I pushed the little PCB out of the tonearm and out of the plastic holder. The wires there appear intact but I could not get a reading on the green wire from the PCB back to the muting switch, and I think I did on the others. I'm not sure though as it was bloody awkward to use the pin tips on my meter. I might have to find the set I have somewhere with the mini-grippers.

 

[Montycat]

Well, I talked to the owner of the 1229Q today and gave him the news of the extra hassle this has been. I might mess with it a touch more first but I think I'm going to rewire the arm and bypass the sled contacts altogether and just go straight to the cartridge pins. I'll have to look for some old mouse wire or something.

 

[gip111]

Well, I talked to the owner of the 1229Q today and gave him the news of the extra hassle this has been. I might mess with it a touch more first but I think I'm going to rewire the arm and bypass the sled contacts altogether and just go straight to the cartridge pins. I'll have to look for some old mouse wire or something.

The contacts from the sled to the headshell/arm are a problem with my 1219 as well, I have cleaned and tweaked with the contacts with no results, it's a great turntable but I think this is a weak point especially as they age.
I'm interested to know how you make out bypassing the contacts.

 

[gip111]

https://www.youtube.com/watch?v=6czZ0NoYbvc

 

[91r100gs]

Same here. Mine has been very iffy lately, losing the left channel again. Maybe the higher summer humidity has something to do with the problem

 

[Montycat]

Well, I finished the beast today and it works great.

Dual new wiring by Buhduh, on Flickr

New headshell leads by Buhduh, on Flickr

The short form is that I removed the PCB in the arm, rewired with Litz and a new ground wire, modified the sled to remove the leads and terminals. It works great now.

The long version is that it was frustrating on a couple of fronts, wires snagging in the arm, ground wire breaking and so on. I don't recommend it for the faint of heart or unsteady of hand.

turntable work table by Buhduh, on Flickr

New wires underneath by Buhduh, on Flickr

Litz wires by Buhduh, on Flickr

Dual pcb 2 by Buhduh, on Flickr

 

[Montycat]

So? I didn't need the original corrosion prone sled and the owner agreed. He has no interest in cartridge swapping. The exposed wire was pulled back into arm and is of no consequence, but also allows for easy installation. The ground wire is similar gauge to the original wires, of which there were 5 remember.

Also everything I did could be reversed. Nothing was broken or tossed out.

 

[Montycat]

You are right about the excess underneath. I will shorten that and route inside the antiskate post. That was an oversight.

I actually was in a bit of rush near the end as I had a ferry to catch. Seriously, I'm on one now.

 

[stereofisher]

Nice work!

Took on a 1229 as a project. Everything was going well til I hooked it up. One channel dead. It was in a very damp area for a long time. Was thinking about your handy work today while working. Saw you did wire thru the switch. Have not looked at the switch yet. How does the cover come off? Will get back down to it this weekend. I like working on Dual's but a little uneasy about wiring the arm

Eric

 

[Montycat]

Yes wiring the arm is not that easy and by no means a "shortcut". I didn't want to do it and spent hours trying not to but the break in the circuit appeared to be internal to the arm so it came down to that. I've worked on a couple of dozen Dual tts and this was the most challenging wiring-wise yet.

In other words, I doubt you will have to re-wire the arm. The usual likely culprits are the contacts of the sled to the arm, or the fine little leads in the sled itself. I've had those fail even though they looked fine.

 

[tnsilver]

Took on a 1229 as a project... How does the cover come off? Will get back down to it this weekend. I like working on Dual's but a little uneasy about wiring the arm

If you're mind is set to it anyway, try dragging in the new wiring from the head shell by attaching it to the old wiring and pulling on that gently from the other side, bit by bit. Do not disassemble the tonearm. Seriously - don't!

If you disassemble the tonearm, chances are you will lose the ball bearings and not be able to put it back together in the correct manner or adjust it properly and that is the easy part. Ask any of the pros who do that for a living. You may want to reconsider it anyway. The 1229 is one of the most complicated turntables ever built. It's a cascading pain in the neck to service and there is practically not a single washer on the entire mechanism that does not affect something else.

The service manual is an evil nightmare and you will need way more than a weekend. No offence buddy, but if you can''t figure out how to take off the springy brass plate cover of the connections depot (just push on the top and tilt out) - you're behind already and this is not something you'll want to futz around with on your own. Not this one. Not the 1229. Bad, bad choice!

For any first timer DIY'er who wants to service a 1229, my advise is clear your entire winter, get a cabin in the Swiss Alps and bring a book, lots of booze and a shotgun. There are very good chances you'll exhaust all of these resources.

 

[Montycat]

What Tnsilver says has a lot of merit. I don't think it's QUITE as bad as he says (shotgun? really?), but yes you certainly don't want to take the tonearm apart.

I have tons of patience and persistence and usually get these tables to work well. There are a number of good service documents and the owner of this one actually ordered the closest thing to a real steuerpimpel and the proper Alvania grease from an eBay vendor. The fellow sends a very thorough document along with it. I found it odd though that the file makes no reference to one of the most common trouble areas I have seen in a lot of Dual idlers.

That area is the last pivot on the idler arm as indicated in this picture from the 1229 but it is similar on the others. This gets stiff with old lube and will frequently cause the idler to not make contact with the motor capstan and platter with enough pressure to turn the platter. It comes off relatively easily if you remove the clip (idler comes off first of course), then either pull, or use heat to soften the old grease if it won't move. Clean inside thoroughly and use a light grease or moderately heavy oil. The Dual service manuals make no mention of this spot in their lubrication section either.

Other common trouble areas are of course the steuerpimpel (clutch pin) and the speed selector control.


Dual 1229Q idler arm by Buhduh, on Flickr

Anyway, I shortened and re-routed the Litz wires and ground as promised. They look kind of like this now.

Dual 1229Q litz wiring 2 by Buhduh, on Flickr

Dual 1229Q litz wiring by Buhduh, on Flickr

 

[stereofisher]

Th.anks for getting back to me...

If you're mind is set to it anyway, try dragging in the new wiring from the head shell by attaching it to the old wiring and pulling on that gently from the other side, bit by bit. Do not disassemble the tonearm. Seriously - don't!

If you disassemble the tonearm, chances are you will lose the ball bearings and not be able to put it back together in the correct manner or adjust it properly and that is the easy part. Ask any of the pros who do that for a living. You may want to reconsider it anyway. The 1229 is one of the most complicated turntables ever built. It's a cascading pain in the neck to service and there is practically not a single washer on the entire mechanism that does not affect something else.

The service manual is an evil nightmare and you will need way more than a weekend. No offence buddy, but if you can''t figure out how to take off the springy brass plate cover of the connections depot (just push on the top and tilt out) - you're behind already and this is not something you'll want to futz around with on your own. Not this one. Not the 1229. Bad, bad choice!

For any first timer DIY'er who wants to service a 1229, my advise is clear your entire winter, get a cabin in the Swiss Alps and bring a book, lots of booze and a shotgun. There are very good chances you'll exhaust all of these resources.

Been working on Dual's since high school. Have avoided the tonearms though. That is why I posted. It's raining in southern NY today. Happy 4th of July to all! It kept me out of the yard. Yeh, the cover did pop off easily. Traced the broken wire to right channel hot. It will have to wait till after vacation. I think I will try it then. Not a rush with working 1219,1229,1010S, and a 1009! Plus a 1015 that had a broken wire in the headshell. Other than that it's ready to go. Not sure what to do with it:scratch2:. It is my favorite Dual though along with the 1219! Where to you get the wires for yours. They look really good. Again thanks for getting back.

Eric

 

[mhjmhjones]

This is becoming a P.I.T.A. :thumbsdn:

Mechanically I've got this 1229Q working pretty well. The motor is a touch noisy and could use a disassembly and lube but that's for another day. The usual old lube issues around the idler arm and speed control switch and missing steuerpimpel have all been addressed. The auto functions work well as well as the Single/Multi function.

However, I still get just one channel consistently. The Stanton 681EEE on it is good, reading about 1500 ohms on each side. There is continuity from the cartridge to the ends of the sled contacts (the style with the folded over types, not the spring loaded pins). I've cleaned the tarnish off the contacts with a salt water & aluminum foil bath, and pencil eraser on the tonearm end of things. I manipulated the sled contacts in various ways to see if I could make them make better contact. I've used a different sled (with the springy pins) and cartridge.

There is continuity from the tonearm contacts back to the mute switch block on all 4 leads. I've cleaned the mute switch contacts and made sure they are only closed (tested with meter) when the arm is moving as they should be. I cleaned the RCA jacks with Deoxit on a Q-Tip. I used 3 different RCA cables. I reflowed the solder joints at the mute switch and the RCA board. I cut the wire ground bridge between the 2 channels at the mute switch, and later re-soldered it.

Now if you are still with me, here it gets somewhat interesting. I initially had it plugged into my NAD phono pre-amp. A few times when I pulled and re-inserted the RCA cord at the pre-amp end the other channel came through. It usually only worked for a few seconds to a few minutes and then it would go dead again. The end of the RCA at the turntable was not touched or affected by pulling on the pre-amp end. Ok, maybe the pre-amp is the problem. Switching sides though did not indicate the pre was the issue. Then I bypassed the NAD altogether and went straight to the Yamaha receiver Phono in. Same issue; one channel stays dead.

The "bad" channel (red/green) does produce a pop when the mute switch engages and disengages during the tonearm cycle. Also, when I touch the cartridge leads on that side I get a significant hum. On the "good" white/blue side I don't get the muting switch pop and I get no noise when I touch it.

It might be some kind of ground loop, or maybe a bad tonearm wire but it's frustrating whatever it is.

I'm having this same problem. 1229 was working fine until I switched out the cartridge sled Saturday night. I have a cartridge that I strapped for mono - I put that one in and I forget if I was only getting sound from one channel or neither. Put the original stereo sled back in and I was only getting sound from one channel. I'm about to read through this whole thread, but figured I'd give it a bump up to get people interested.