Orfoton OMB cartridge problem

[Martin Bush]

Hi all

I have been lucky enough to have been given a Project turntable, but it needs repairs.

One of which is to the cartridge. It is an Orfoton OMB with a 5E stylus. The cartridge, if you look from the end, sort of looks like the Starship Enterprise (look one up on Google and you will see what I mean). The problem I have is that part of the plastic triangular mounting part is broken, meaning I can't mount it on the headshell/ tonearm.

A new cartridge appears to be costly (as far as my pockets are concerned).

Is there an easy solution? Is there a way to repair this (I don't have the missing piece of the mounting part) or is there a cheap generic cartridge or other affordable solution?

The other thing I need to do is replace the tonearm wires. I didn't make this a thread on its own as I hope this is a simple procedure, but if anyone can recommend a good place to source these I would be grateful. I think what's happened is something had been dropped on the tonearm breaking the mounting and a couple of the wires.

Martin

[Edward Huggins]

A photograph would help - I mean model of Project is it? Ther are very many types....
It's very difficult to "break wires", but you can order a replacement harness from Project or re-solder if you are experienced with precision soldering.
As to a replacement cartridge (if really neede) we can advise you when when know more.

[Martin Bush]

Hopefully these pictures show the damage to the cartridge. It's as focused as I can get on my phone.

The triangular plate on top should be symmetrical and in fact, now I've looked again, both sides are damaged to some extent. I do have the metal weight.





As for the model I think it is a Debut 2 or Project 2. I say "maybe" as it is at home and I am at work so I can't check. I will update on that soon.

[Beobloke]

Sadly I think your cartridge mounting plate is beyond salvation unless you fancy getting creative with some glue and random bits of plastic!

Frankly a direct from China Audio Technica AT3600 from eBay would be a lot easier. It’s a surprisingly capable cartridge and will set you back around £9.

[Norman Raeburn]

Hi Martin, I have an Ortofon OM cartridge with no stylus which you are welcome to foc if it's any use. Please let me know. Norman

[gramofiend]

You may or may not be aware that the ortofon range beginning OM 5 up to 40 all have the same body and generator system. There is currently one at least on ebay without a stylus for reasonable money. They are, in my opinion, very good playing vehicles for all types of record and with the right stylus, 78's. As a general purpose cartridge they are still used in the Concord variant by dj's for scratching, a practice i do not like subjecting a stylus to. The sound is tunefull and clean and my stylus maker does a very good range of different shapes for 78 grooves!

If you do want a reasonably priced 47K moving magnet cart without going into the stratospheric prices of the Shure M44, this is the one. I would suggest that since the Project turntable was supplied with an ortofon it is one of those syergystic marraiges of tonal balance. Remember that the ortofon OM range were the last cartridges in general use at the BBC when they still used black vinyl. Indeed they still have a few players in use and I have been lucky to buy a few at auction. All had Ortofon transducers and not the earlier shure SC35, which in my opinion, had the performance with LP of that of a brick with a nail. As I remember that one did have a redeeming grace in that it played 78's quite well with the right stylus and a bit of extra weight!!
As always, have fun trying something new!

Mike

[Martin Bush]

Thanks all for your help.

I now have a solution thanks to Norman hopefully. I've also learnt a bit in the process. I'm a user of turntables rather than a tweaker or any sort of expert so I was thinking that it would have to be that specific model to fit without further modification.


I will report back on the specific model as I know I will need to replace the tonearm wires.

[Mark_RR]

Given the force required to rip a cartridge off the headshell (which is what i assume has happened), I would check the tonearm bearings carefully for damage. The Project will have a precision tonearm and the bearings will be quite delicate. They won't take kindly to the force required to pull a cartridge off by shearing the mounting lugs.

First of all feel if there is any slop or stickiness in the bearings when moving the arm. If you can feel something amiss, the bearings are probably ruined.

Assuming nothing obvious is wrong, balance the arm so it floats horizontally (Blu-tak a coin to the headshell if necessary to account for the missing cartridge). Set the anti-skate (bias) to zero. A small up or down tap on the headshell should result in the arm moving smoothly away and then back to its original horizontal position. A small difference in starting and final position probably isn't too important as long as the motion is smooth.

Finally, the arm should also swing horizontally without any sticking. Move the arm towards the spindle and let it rest, floating. Add the smallest amount of anti-skate and this should pull the arm smoothly and immediately back to the arm rest. Any tendency for the arm to stick on its journey and it is likely to mistrack or start skipping when playing a record with the low tracking force required for a decent magnetic cartridge.

[Martin Bush]

OK, so contrary to what I said earlier, it's a Project Debut 3. It was kindly given to me and has been carefully packed away for a couple of weeks so I just accepted what I was told. I dont know how the cartridge was removed from the arm - I can see no evidence of impact or distortion anywhere.

I wonder if an attempt was made to take it off to fix a wire and screws were over tightened or some other incorrect attempt made at taking it off was made.

I can detect no issues with the bearings at present. If I do find theres a problem that would be worth fixing I think wouldn't it? I mean economically speaking.

If that's the case then any advice on tone arm wires would be much appreciated. I'd want made up connections if possible. I can solder but I expect I'd make a hash of working on wires as fine as this.

[Ted Kendall]

It's quite possible somebody got cranking fever and broke the lugs that way - tightening cartridge bolts to absurd torques was first advocated in the 70s and was as daft then as it is now. If so, the arm may well have escaped serious damage - suck it and see, I would, before you worry about bearing damage.

[Martin Bush]

Thanks Ted. You know how it is when someone gifts something to you- you dont ask too many questions. I suspected I'd be able to do the repairs i suspected - they are about my level

As well as direction to a suitable tonearm wire kit, I've noticed I also need a new anti-skate weight as this is missing. By this I mean the type that's a small weight on what looks like thin fishing line. Theres various on ebay so I am presuming they are a standard item.

[Ted Kendall]

Couldn't agree more - people sometimes abandon kit for reasons which have little to do with the severity of any fault - I knew a guy once who chucked a working SP10 in the bin, largely because it wasn't belt drive!

Pre-terminated arm wires could be a problem - the trick is to put the tags on before you put the wires into the arm. You might do best to replace all the existing wires, using the remaining originals to pull in the new ones. Make sure you leave enough loop at the arm pivots so that movement isn't inhibited.

Bias weights do vary between about three and seven grammes - as it is the correcting force that matters, a small error in the weight can be compensated by altering the thread position. Alternatively, see if Pro-Ject will play ball...

[arjoll]

The 5E is a pretty entry-level cartridge; I see that they're NZD109 new, but if the stylus on your 5E is in good condition you could always get the OM5S - it comes with a spherical stylus but should take your 5E.

A cheap AT would be worth trying as well, they're probably no worse than the 5E. Dad's got an OMP10 in his 80s turntable and I was never impressed. I think the 2M Red in my Project 1xpression Carbon sounds nicer.

[Martin Bush]

Thanks both.

Is tonearm wire pretty universal? Theres various generic kits on ebay for instance for around £10.

I've done a small amount of work on thisntype of wire on a Bush player I have, but that was just resoldering inside and carefully cleaning contacts on the cartridge end. My aim there was not to ****** it up... and I didn't.

[PJL]

I just fixed a Beogram and that just uses scarily thin enamel copper wire. Resistance will not be a problem but all 4 wires are run next to each other so I am less convinced about capacitive coupling.

[BRASSBITS]

Originally Posted by Martin Bush

Thanks both.

Is tonearm wire pretty universal? Theres various generic kits on ebay for instance for around £10.

I've done a small amount of work on thisntype of wire on a Bush player I have, but that was just resoldering inside and carefully cleaning contacts on the cartridge end. My aim there was not to ****** it up... and I didn't.

take a look inside they could be enough surplus wire to pull through the arm

[Mark_RR]

I would check the arm bearings before investing any time and money in the other fixes. If the bearings are damaged then the arm is useless and will need to be changed. The tests I described are simple and free and will take about 10 minutes. You won’t be able to do my final test without the bias weight, but you can check for stiction in the horizontal plane by very lightly tapping the floating arm left and right and observing it moves smoothly. Any jerkiness means the bearings are bad. The bearings might be adjustable to loosen or tighten them, but that isn’t always possible.

[ajgriff]

Originally Posted by Mark_RR

You won’t be able to do my final test without the bias weight .......

Just hang a washer or a small piece of Blue Tack (instead of the bias weight) by a length of cotton for the check described by Mark earlier. No point in going to a lot of trouble and expense if the bearings are damaged.

Alan

[Martin Bush]

Thanks. I'm not very familiar with using anti-skate weights.

My two decks/ players don't have weights and the only time I've used one is on an old Sharp music centre my dad had.

I've had a quick check of the arm and it does seem to be OK - I will repeat the test though to be sure.

My guess as to how the damage occurred is that perhaps something was dropped or hit the stylus from above when it was in the arm rest rather than hitting the headshell or arm itself.

[bikerhifinut]

Hi Martin, They are a good if basic and simple deck, which from your point of view is a good thing.
The Supplied Ortofon OM5E is a very good cartridge and I would say only bettered by an upgrade to the Ortofon 2M Red which may be out of your pocket.
You say you have a solution to the cartridge so that's great news, I assume its a replacement body, I'd get the tip looked at if its of unknown history, if its from a forum member we can safely assume it will be a good un, styli last far longer than some would have you believe especially if kept clean. IPA is your friend here, the tips on the cheaper cartridges don't suffer from issues with alcohol solvents unlike expensive nude and bonded tips that are stuck on a cantilever rather than a press fit into the cantilever.
Can you show or describe the internal wiring issue? usually, but not always, you find the "pigtail" leads that plug on the cartridge pins are soldered on to the even thinner internal armwiring which needs to be very fine so as not to interfere with the bearings as they pass through at the pivot. If that's the case and its just a matter of getting a bit longer piece of wire to effect connection of the cartridge then I'd just solder a new piece of wire on the ends with a tag on the end. Theres a lot to be said for the designs that use short pigtails with a tag at each end with the internal wires soldered on to pins in the end of the arm wand/headshell.
I've just checked out my sisters debutIII that I have sotored while she moves house and the arm wires are very fine which suggests they are a continuous length from arm base to cartridge. This is ok if you can tease (GENTLY!) out enough to solder a set of pigtails on the ends. use a bit of heatshrink tube when the connection is soldered which will also strengthen the joint.
I weighed the antiskate weight, they are a bit of a decoration anyway but on the stylus force gauge the weight was 3.45 grams so a 3.5 gram weight is about right, antiskate is a bit of an empirical thing anyway. So theres a number of ways to get 3.5 grams, I think I'd use a length of solder and either scrunch it up or for a neater fix melt it into a pot with the end of a sewing needle in the middle to make an eyelet for the thread, a bit of cotton from the wifes sewing kit will be fine.
You may have other ways to make a weight, the material isn't important but it needs to be a relatively massy substance.
I've dropped you a PM as I may have a few odd bits that will help you with the wiring.

Andy.