Dual CS 505-1 headshell removal and replacement

[Usky]

Earlier this summer, I picked up this Dual CS 505-1 at a thrift shop for $5. I quickly verified it had power and it even turned at 33.1 RPM using an Android app, so I figured it was worth picking up if nothing but to learn about it and see if I could get it working. I've salvaged other TTs in the past simply by acquiring missing belts or stylus (or both).

I had also read that this arm came with a custom 1/2" headshell adapter that might be a challenge to find. Short of waiting for another cheap Dual to turn up, I've seen that I can order the adapter off of eBay if necessary.

This past weekend, I finally sat down and looked at the TT more closely. The problem I've encountered seemed to be that the headshell screw (which I think is a tiny allan key? styled screw?) is crooked and has snapped off. I was thinking I could loosen the tiny flat slotted screw (green arrow in pic) and exchange the entire headshell, but I'm having the darndest time removing it in place. I'm thinking I might have to remove the entire tonearm to get at it.

Has anyone here ever worked on the Dual CS 505-1 specifically that recommend a way forward as to what to do and what to NOT do?

 

[Beobloke]

The tiny little screw on top is a locking screw for the cartridge; you unscrew this, then pivot the finger lift backwards, and the cartridge (or the 1/2” adaptor platform) can then be removed. I don’t know about the underside screw and if it will remove the headshell.

As an aside, I bought one of the 1/2” adaptors from eBay and it worked well, although some models do need a small amount of plastic to be filed down for it to fit properly - the CS505-1 is one of these.

 

[Montycat]

The tiny top facing screw does not have to be there. The lift arm does lock the cartridge or adapter in place; the screw then locks the lift arm from pivoting. If the screw can't be removed but the arm still pivots the full range you might be ok. That screw is a slotted head. Are you sure it's even in there?

The screw on the underside can be taken out if you absolutely need to but you will have to deal with the wires inside and an awkward nut of sorts inside the arm tube. Leave it alone if you can.

 

[Usky]

The tiny little screw on top is a locking screw for the cartridge; you unscrew this, then pivot the finger lift backwards, and the cartridge (or the 1/2” adaptor platform) can then be removed. I don’t know about the underside screw and if it will remove the headshell.

As an aside, I bought one of the 1/2” adaptors from eBay and it worked well, although some models do need a small amount of plastic to be filed down for it to fit properly - the CS505-1 is one of these.

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Apologies for taking so long to reply. I ended up needing to leave for a few days and only got back last night (2019-07-26). I also wanted to somehow capture a decent enough picture to post before replying. I really appreciate the clarification regarding the lift arm that pivots (mine still does) and well as the info about the need to file down some of the plastic should I go the eBay route. Lastly, leaving that screw and the arm as a whole alone would be my preference!

 

[Usky]

The tiny top facing screw does not have to be there. The lift arm does lock the cartridge or adapter in place; the screw then locks the lift arm from pivoting. If the screw can't be removed but the arm still pivots the full range you might be ok. That screw is a slotted head. Are you sure it's even in there?

The screw on the underside can be taken out if you absolutely need to but you will have to deal with the wires inside and an awkward nut of sorts inside the arm tube. Leave it alone if you can.

I appreciate the collective feedback from both yourself as well as Beobloke.

My eyes aren't working as well as they used to and even with my magnifying glass, it was hard to tell that it was slotted...but indeed it was. It's amazing what reassurance does for confidence.

I'm going to include another pic that better shows what I was dealing with as far as the screw looking crooked. The fact that you mention that "the tiny top facing screw does not have to be there" might now be a saving grace.

While I was gently pushing up on the screw from the underside while turning it counter-clockwise with a jewelers flat head, the screw actually just gave way and poked through. I suspect the reason it was donated is that is sustained some landing blow that caused the screw to go crooked, and then maybe the headshell hole was compromised. The arm still appears to pivot the range with or without the screw.

Can I assume that the screw was intended to fit into the underside C / wrench / horseshoe shaped portion of the arm that swivels...so as to lock it into place?

 

[Montycat]

Actually the screw threads into the top of the cartridge or the 1/2" adapter if using that. By its position though it also prevents the lift arm from pivoting. So, it holds the cartridge on in 2 ways. Without it the cartridge will still stay on, usually.

However, very frequently 1 or both of the small tabs or hooks on the ULM cartridges get broken by lack of care when installing. If this happens the arm will barely grab and the screw becomes imperative. I've rebuilt one of those tabs with epoxy but it's fiddly and not a certain fix.

 

[Usky]

Actually the screw threads into the top of the cartridge or the 1/2" adapter if using that. By its position though it also prevents the lift arm from pivoting. So, it holds the cartridge on in 2 ways. Without it the cartridge will still stay on, usually.

However, very frequently 1 or both of the small tabs or hooks on the ULM cartridges get broken by lack of care when installing. If this happens the arm will barely grab and the screw becomes imperative. I've rebuilt one of those tabs with epoxy but it's fiddly and not a certain fix.

More good info. Thank you. I'll see what I can do. This is one of three turntable projects that I'm working on (as time allows, parts become available, etc).

In any case I was able to remove the screw. With any luck, I can use it as intended once I obtain a suitable ULM cartridge or the 1/2" adapter. Ideally I can find another 505-1 that I can salvage for parts. I see one online but it's not in my province/state. If it was, I think I would but it for the cartridge / adapter and part out the rest. There's a guy with a shop in my town where he is always buying up old audio amps, decks, TT's etc ans so I need to put feelers out to before I do any online ordering. 2Bcontinued.

 

[Montycat]

Since you mention province I am guessing you are in Canada. Where, more precisely? I might be able to help more if you happen to be local.

 

[Usky]

Up until recently, I used to live close to downtown, but I now reside in the outskirts of Montreal.

 

[Montycat]

Up until recently, I used to live close to downtown, but I now reside in the outskirts of Montreal.

Well, not that close. I lived in St. Henri at one time but that was a long time ago.

 

[Usky]

Earlier this year, I found a guy with a small shop in Mile-X. He has vintage amplifiers, tape decks and turntables stacked to the rafters practically. I went in there to match up a missing Selector knob for a Sansui G-5000 I picked up from a church basement / thrift sale and was successful. He had 4 bins of random knobs! The main problem is that there was minimal space within which to look and sort. In any case, I was going to mention this latest project to him and see if he has any spare parts around.

I see that someone from Kitchener is selling a non-functioning TT like mine. It's crossed my mind to make an offer just for the cart, but without seeing it in person, I'm very hesitant. My main TT at the moment is a basic Rega RP1. As I mentioned, I picked up this Dual for $5, so I can take it apart and learn about it...and if I screw something up, I didn't break the bank.

I'm also slowly making my way through an Electronics for Dummies book (for lack of a better book) and watching some online tutorials. I'm aspiring to learn enough to be able to troubleshoot electronics well enough to do some basic parts replacement and soldering. Most of my projects thus far have been some cleaning pots and some basic resoldering. I recently picked up these little Pyramid Gold Series 4080 monitors (also for $5...seems to be the price they put on most of the old stuff at this one place I frequent. There aren't much to write home about but sound decent enough for cheapies. One of the two was a bit flaky, such that I would give it a bit of a slight tap, and it would stay on. I think maybe that the solder that was still there had cracked. Ever since I resoldered it it seems legit fixed. I can shake the monitor and it stays connected. This is probably very basic to some folks here, but for a newbie to cheap reclamation projects, this pleased me...and it gives me some cheap monitors to through on that latest vintage amp I want to test

 

[bobaloniny]

Actually the screw threads into the top of the cartridge or the 1/2" adapter if using that. By its position though it also prevents the lift arm from pivoting. So, it holds the cartridge on in 2 ways. Without it the cartridge will still stay on, usually.

However, very frequently 1 or both of the small tabs or hooks on the ULM cartridges get broken by lack of care when installing. If this happens the arm will barely grab and the screw becomes imperative. I've rebuilt one of those tabs with epoxy but it's fiddly and not a certain fix.

I just got a 505 with a broken tab (but at least still present) on the ULM carrier. First I super super glued it back in place, then used a torch tip cleaner to bore a hole through the top of the tab and right down through, I then coated a piece of wire with glue that fit well (22 gauge iirc) and smacked it down through the hole. Now it seems to be fine, nothing went crunch when I engaged the lever, everyones making contact and can be taken out and put back in with the same results. Now all I need is a stylus..

 

[Usky]

In the spirit of completion, I had wanted to circle back to this post. Back in October, I visited a downtown shop I occasionally frequent that has stacks of used audio gear and he happened to have 2 or 3 other Dual 505 models on hand. Along with the owner, I was able to fit an Ortofon Dual TKS-52E (model TKS52E) cartridge direct to the headshell without any need of the adapter. I'm in business and now have a backup setup which I use exclusively for testing out my used vinyl finds!