[dBel84]

Thought I would post pics for anyone who wants to try

Part 1 = opening the drivers and seeing what needs to be done.

Got both in bits

taking a closer peek at the caustic eariebejeebies

next step is to restore continuity - this is not going to be pretty with this much corrosion

..dB

 

[smeggy]

dunk in vinegar for a week

 

[wualta]

Ideally, we want to reduce the "rust" back to metal, the same function that a photographic developer solution performs, but this wouldn't restore the integrity of the v.c. traces.

I'd really love to know what in blazes is causing the corrosion in the first place. I assume it's always on the side facing the wearer, but...

 

[Kabeer]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif Ideally, we want to reduce the "rust" back to metal, the same function that a photographic developer solution performs, but this wouldn't restore the integrity of the v.c. traces. I'd really love to know what in blazes is causing the corrosion in the first place. I assume it's always on the side facing the wearer, but...

Don I think it's time for a shave

Yeah it's on the wearer side, if yamaha made it so the plastic was on the wearer side then the problem would be fixed.
Also strangely the corrosion is always on the more OUTER holes rather than the more exposed inner ones.

I would have said maybe gunk trapped under the pads. But then one of my yh1k were nearly NOS (even smelt new) and were stored in original box for decades in an attic. The attic can't have been musty or the headphones wouldn't have smelt so fresh. But when you removed them the drivers smelt musty!

 

[wualta]

That is curious. The corrosion is even enough to make me think outgassing (no jokes, now), but from what? Earpads? foam stuffing? rock wool? About the only thing we've seen break down on the YH-1000 is the earpad pleather, which is odd, since Yam didn't have that problem with their other Orthos. So I'll suspect the pleather. What breakdown product of [I assume] PVC smells musty in low concentrations and is nasty enough to attack copper? HCl (but by itself it doesn't smell musty)? a plasticizer? Argh.

Has Don B. been careless with his shavings?

 

[dBel84]

The pleather would make good sense except for the fact that of of Kabeers pair was near intact and the driver was still crud. Doesn't negate this theory though as the pleather disintegrated soon after , suggesting it had already passed gas. ( which that unshaved headphone wearing canine does frequently )

Drivers in image restored - NOT PRETTY, had to near paint the stuff on this one but impedance matches at 60R , so lets hope that it still sounds good.

Notice the dull coating on the lower image of the closeup = HP1000 seems to have this film on it which makes it a little stiffer than the YH1000 that I have had in my hands in the past.

on to other things......


made some mini xlr adapters for the woodied wharfies - now need to recable the headphones with the cable i made and we're in business. I have male mini xlr terminated headphone cable, TRS - female mini xlr adapter cable and female mini xlr to speaker plugs.

- i am not sure I would recommend these plugs generally for cables - very small to work with, cable diameter is really limited . Good solid feel once done but a PIA to make. I will probably stop here as I would need to recable all my orthos and this has little appeal.

..dB

 

[iQEM]

Quote:

Originally Posted by dBel84 /img/forum/go_quote.gif Thought I would post pics for anyone who wants to try Part 1 = opening the drivers and seeing what needs to be done. Got both in bits taking a closer peek at the caustic eariebejeebies next step is to restore continuity - this is not going to be pretty with this much corrosion ..dB

wow, very informative don...

 

[BoilermakerFan]

Quote:

Originally Posted by wualta /img/forum/go_quote.gif a plasticizer? Argh.

plasticizer migration gets my vote. Once it migrates and reacts or off gasses, it's probably producing a formaldihyde that is reacting with the copper.

 

[Kabeer]

Hmm this plastic theory miighht hold weight, except, the underside of the YH-1k pads usually tend to hold up pretty well, in fact on the NOS pair I was talking about, the underside PVC was quite hard to remove, one side was still like new and quite thick n rubbery, It took a lot to get it off (so it hadnt dissolved).
But i guess its the only reasonable theory so far.

As for the HP-1000 interesting on the impedance difference, some of that difference might be attributed to the shorted paths now, but I guess its possible that the 85ohm stock quoted figure is now more likely.

 

[Sambones]

Apparently I'm missing a conversation that happened earlier, but does this happen to other orthos? Like my Fostex T20v2's?

 

[dBel84]

thus far it is only the YH/HP1000 ..dB

 

[ujamerstand]

I'm having a hard time looking for sufficiently wide doubled sided adhesive locally, I'll be needing it to refurbish an incoming HP-1. I'd hate to use spray on adhesive to glue new pads on. What do you guys use when you are fixing the pads?

 

[dBel84]

cut strips of narrower double sided tape..dB

 

[ujamerstand]

That'd work I guess... I guess the adhesive doesn't have to be in contact with all of the back area of the pad.

 

[Kabeer]

Quote:

Originally Posted by ujamerstand /img/forum/go_quote.gif That'd work I guess... I guess the adhesive doesn't have to be in contact with all of the back area of the pad.

You just need to make sure there are no breaks in the sticky tape ring, as you want to create a good seal with the HP1, so no way of air to escape.