Needle microscope

Hello,

I would check the state of the needles of my cartridges visually.
I guess, I would need a microscope.

Could you recommend one?
What magnification would be required?

Best regards

 

Google "fremer usb microscope" and sort through all his articles.

You can spend $7.50.

A $7.49 Illuminated Microscope Can Get You a Decent View!

or

$250.00

How to Use a USB Digital Microscope to set 92 Degree Stylus Rake Angle (SRA)

https://www.amazon.com/Dino-Lite-Microscope-measurement-function-software/dp/B000P43IQY

I can't recommend one, though. Good luck!

 

I believe the general recommendation for being able to ascertain wear to the facets of the stylus is 200x magnification. Less than that and you can maybe see dirt or debris but not real wear.

 

$11, lets you see small stuff for cheap: https://www.amazon.com/Carson-60X-75X-MicroMax-Microscope-MM-200/dp/B000P8AUMU and seems to be similar OEM to the Radio Shack microscope no longer available. Enough to satisfy most curiosity about a stylus, you can see dirt buildup, mount condition, identify a missing tip...

You have two main types of optical microscope, a backlit is common for science, where you prepare the sample between two slides, and a metallurgical microscope with direct illumination allows you to view opaque objects.

However, the way stylus wear is viewed is with 90 degree incidental light. The stylus tip points directly into the lens, and the illumination from the side reflects off the 45 degree contact point, letting one see the dimension of the flattened contact patch. This way you get a dark field, and the contact point acts as a mirror reflecting the illumination.

This requires quality optics, and you still need a reference stylus of that shape to know what to expect; this type of microscope was recommended as a sales tool by cartridge companies, with as much accuracy as the oil change guy trying to sell you a transmission flush by showing you the dirty dipstick.

This thread has imagery from an electron microscope of a lightly used needle, you can't even identify where the needle has been used at resolution far beyond optical (contact areas would be the sides):

 

Have a nice Leica at home I bought used and had serviced. Not cheap. But comes in handy for a metric ton of stuff.

 

I've got one of those Carson $12 microscopes coming tomorrow. Just going to use it to diagnose dirt on the stylus I can't get off (I've had a bit of a spiderweb problem the last couple of weeks and I think that's making dust "stick" a little more than usual), use it to align on my Mint Tractor, and possibly investigate groove damage on LPs in case I think I can clean the evil out of a disc when I cannot

 

I don't think it is really practical to use optical microscopes to actually examine a stylus for wear. By the time such wear is significant enough that one can clearly see it by visual examination, the wear would have long been obvious from audible signs of mis-tracking. In the past, I've taken cartridges to specialty shops that had really expensive microscope setups and they have not detected wear that I though was obvious from the sound (yes, it could have been the suspension going bad). Even really good scopes have a limited depth of field that means that only a small part of the stylus is sharply in focus; this makes it hard to determine the overall shape of the stylus tip. The only kind of scope that gives a really clear view with sufficient depth of field is an electron microscope.

I would stick with other means of checking the stylus, such as simply playing demanding records; if it sounds okay, then play on.

 

I got the pocket microscope in today and it requires you to basically set whatever your viewing on a surface and, at most the object can only be about 1/8" away from the lens. I don't find this practical to even find the stylus, let alone examine it. Kinda disappointed, really.

 

On the 60x-100x Radio Shack one, it's often useful to remove the guard and just hold the microscope and object in your hand. It has a short focal length, so you won't see the needle tip and cantilever shank in focus at the same time, and part of 60x means you are looking at a very small area, like the size of a comma in a book, so getting "lost" is easy. I use one of these to check the quality of soldering or read markings on tiny surface mount chips.

 

I was thining about taking off the guard. I'll give that a shot and see if it's any better.

 

Hello,

thank you for the input!

I am not sure, whether I can detect stylus wear through a microscope. But, I am also curios how the stylii I own look like.
I have replacement stylii in my storage for all carts I own. So, will be able to compare new stylii to used ones.

I think, most comfortable are USB microscopes on a solid stand. So, I could place the needle in proper position, and also could cast light from 90° onto it (with separate light source).
However, maybe I am not that curious to spend $200 for such an USB microscope. Maybe, still.

If I could find a usefull USB microscope for less, with a sensible stand, I would go for that.

Best regards