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Sennheiser G3 radio mic repair

Hi, just wondered if anyone has successfully been inside a Sennheiser ew100 G3 radio mic.

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I've repaired quite a few G2 and G1 mics, these are relatively easy to dismantle, and replace the SMD on/off tactile switch that usually gets broken.

The G3 is different in that it has 2 x tiny T4 Torx bolts either side of the sharkfin aerial you need to undo, to release the electronics. Someone had previously had a go at these and partially rounded the heads, and I found them extraordinarily difficult to remove. I got one off, but I stupidly further damaged the other one, which will now require drilling out as the Torx is now a rounded hole.

I phoned Sennheiser and spoke to a Service Tech. Apparently these Torx bolts are glued in - he said so as to avoid cross threading them, which I didn't quite understand, or perhaps misinterpreted. You need to heat them up first, he said.

He further said that the on/off switch was not replaceable anyway, you need to replace a whole section instead. (This mic does not turn on)

I don't know why Sennheiser have decided to make these so difficult to repair. (But I can guess)

Now wise after the event, next time I get one in I will buy a proper T4 screwdriver.

I wasn't sure what size these screws actually are, just smaller than the proper T5 screwdriver I have, so I bought a cheap set of ebay mobile phone Torx drivers to find out. These are jeweller type things, and too thin and soft to get enough torque on these incredibly stiff bolts. I shouldn't have attempted the removal of damaged bolts with this unsuitable crappy tool, but was impatient. Doh!

I will also have to suss out a way of heating the bolts to soften the glue - all around is plastic, so I though perhaps inserting the Torx screwdriver into the head and heating the screwdriver blade?

Gareth.

Reply to
Gareth Magennis
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Gareth Magennis Inscribed thus:

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Use a soldering iron !

--
Best Regards: 
                        Baron.
Reply to
Baron

Use a soldering iron !

-- Best Regards: Baron.

Hmm, you are probably right.

I'm still in paranoid mode, trying not to damage tiny delicate things that don't belong to me. The bolts appear to screw into threaded inserts, and I fear if I applied too much heat, I'd strip the inserts from the mic, rather than free the bolt from the inserts.

I'm not usually a conspiracy theorist, but am slightly leaning towards the distinct possibility that Sennheiser do not want third parties repairing their microphones.

Gareth.

Reply to
Gareth Magennis

I couldn't tell from the website photo, but if the screws are not recessed, you could cut a slot across the head of the screw with a Dremel (sp?) and remove it with a straight slot screwdriver.

Ray

Reply to
Ray Carlsen

I couldn't tell from the website photo, but if the screws are not recessed, you could cut a slot across the head of the screw with a Dremel (sp?) and remove it with a straight slot screwdriver.

Ray

They are recessed, but I had noted this may be a possibility if you had a really really small disk cutter. Sennheiser drill them out.

Gareth.

Reply to
Gareth Magennis

too

But it only takes one person to crack it and divulge to wwwland and their competitive advantage is lost - strange old world

Is there in enough facetting left in the TORX holes to grind down an Allen key to near enough match to get enough purchase. Preceeded by heating with a soldering iron a timed number of seconds, gradually getting more adventurous with the seconds on repeated attempts, after cooling off periods

Drilling out is likely to heat up anyway in a less controllable way. If you do drill out use a left hand drill bit (if unavailable from an engineering supplier then regrind a normal one with the other set/rake) and left hand action drill

Reply to
N_Cook

Make sure you store any left hand drill bits clearly marked as LEFT HAND

Reply to
N_Cook

Yep, left hand drill bit was the plan.

Cheers,

Gareth.

Reply to
Gareth Magennis

engineering

hand

The final assault is the Dremmel and small .5mm disc to cut a slot. I reatain these worn down discs precisely for this purpose. Undoubtably you cut into the surrounding material but keep the orientations the same also balanced and neat cut either side it does not necessarily look too out of place. If it does look bad then cut a strip of craft-shop metalised film around the mic and it can look totally in keeping.

Reply to
N_Cook

N_Cook Inscribed thus:

Too true !

Heating for a timed period is the way I would go. Ten to fifteen seconds would be a good period. Though if thats what their own techs do I wouldn't worry too much. On the other hand their own techs will have access to spares should they damage anything.

Oww ! Trying to regrind a drill that small is going to be a major pain in the butt... !

--
Best Regards: 
                        Baron.
Reply to
Baron

No great precision required as long as used in conjuction with a left hand drive . Its not so much for drilling out the screw but just biting into the metal enough at some point to grab the metal and then along with the localised heating produced, the screw magically undoes itself.

Reply to
N_Cook

N_Cook Inscribed thus:

I remember many many years ago the foreman giving me a drill, telling me it needed sharpening and instructing me to drill some holes in a piece of plate...

Some time passed before it dawned on me... a left hand drill ! (insert your own cuss words here)

PS. 50 years later, I still have that 6mm drill to remind me !

--
Best Regards: 
                        Baron.
Reply to
Baron

Gareth Magennis kom med denne ide:

Have you considered a bolt remover? I don't know if they come in such small sizes.

Or you could superglue the screw to the screwdriver, just don't superglue the screw to the body of the mic, so use a tiny drop.

Leif

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Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske  
beslutning at undlade det.
Reply to
Leif Neland

phone

torque on

unsuitable

glue -

screwdriver

Easy-outs are made of high carbon steel and that sort of diameter , would break off leaving a lump that would stop you drilling out the original. Superglue seems to be highly capilliary/surface active and will easily migrate from where it is intended, even if its shear strength was high enough for this use. This week a CD player where the platter had moved on spindle motor shaft. I would not use superglue to stop it moving as its almost guaranteed to migrate down through the platter , down the shaft , into the motor bearing

Reply to
N_Cook

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