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Simply opening an 160's case: impossible

One of the bolts is under the centre of the transformer, bottom right in the photo. Looking at the amplifier boards the other two bolts are directly below the centre of each black heat sink at the top of each board, between the two silver power transistors.

WD40 is a good tip and you should only have to drill the bolts out if the heads are badly damaged. If you decide to drill you need a bit which is the same size as the thread of the bolt, from memory the transformer bolt is M6 and the other two are M4. Drill at low speed and the head should detach from the thread of the bolt. Turn the case upside down and there should be sufficient clearance between the remains of the bolts and the sleeve to allow you to slide the sled out. Use a pair of grips to firmly hold the remains of each bolt in order to remove them. It is very, very unlikely that the drilling will damage any of the internal components.
 
I snapped an allen key trying to shift the hex bolt holding my CD3.5's transformer.

A cordless impact driver had it out instantly. Bit expensive though if you dont have one already.

Stu
 
A drift is a flat ended punch , it will channel energy from your hammer head over all of the allen head so as not to distort it.



The bolts used are 12.9 hardness so diifficult to drill or chisel round, and the countersink head causes them to lock like a car wheel nut because of the friction and multiple circumferences.

The idea of hitting it is to tighten it some more on impact by slightly squashing the soft alloy case ,that then creates less pressure on the back side of the bolt head so it will undo
 
Am I right in assuming you have trashed the heads on the Allen bolts, and this is the problem? If not I'd just squirt some WD40 or similar in there, leave it over night to soak in, then have a real hard go with a perfectly clean and fresh Allen key of exactly the right size.

No, unfortunately not Tony, the heads are in perfect shape so far..... and we put some WD40 already . . . only, we dried right away....but now, since the shop where the unit is now will open on Monday, the stuff will be all the time to work, if ever . . . So on Monday morning, we'll have another trial. Thank you very much!!😊
 
A pair of mole grips on a hex screwdriver bit held sideways. So the mole grips act as a lever. Put pressure downwards and use the mole grips as a lever to turn. A lot easier than a normal screwdriver.

Well Venton, here the Allen keys are L shaped, and quite small. We put one in there we'll firmly, and tried to force using a grip.....we tried very hard....no way. We even hit the grip with an hammer . . . . Monday, after soaking two days in WD40, let's hope . . . Thanks a lot!!!
 
WD40 works for me - it's a spray-on penetrating oil that will get into the threads of the bolt and hopefully allow you to loosen it.

Yes yes SJ we did it already . . .lets see if on Monday it will have some effects . . . May be . .
Thanks anyhow
 
One of the bolts is under the centre of the transformer, bottom right in the photo. Looking at the amplifier boards the other two bolts are directly below the centre of each black heat sink at the top of each board, between the two silver power transistors.

WD40 is a good tip and you should only have to drill the bolts out if the heads are badly damaged. If you decide to drill you need a bit which is the same size as the thread of the bolt, from memory the transformer bolt is M6 and the other two are M4. Drill at low speed and the head should detach from the thread of the bolt. Turn the case upside down and there should be sufficient clearance between the remains of the bolts and the sleeve to allow you to slide the sled out. Use a pair of grips to firmly hold the remains of each bolt in order to remove them. It is very, very unlikely that the drilling will damage any of the internal components.
OK misterc6, loud and clear! As I said, WD40 will hopefully have some effect on Monday, we put it on here yesterday afternoon . . . And the shop where I left the unit will reopen on Monday... from memory, all the 3 dam bolts look same size . . . But I may be wrong. I'll take in good consideration your adviser on how to act with a drill, if needed. It is confortable to know that it is unlikely do damage anything with a drill.....we'll pay anyhow a maximum of attention. Thank you very much!!!! I'll let you know how it goes.
 
I snapped an allen key trying to shift the hex bolt holding my CD3.5's transformer.

A cordless impact driver had it out instantly. Bit expensive though if you dont have one already.

Stu

Well mega lord...I'm glad you made it.... but, as I said, we tried holding an Allen key with a grip, and hitting the grip with ah hammer.....and the dam thing couldn't care the less...... but thank you anyway!! I'll let you know how it goes.
 
A drift is a flat ended punch , it will channel energy from your hammer head over all of the allen head so as not to distort it.
The bolts used are 12.9 hardness so diifficult to drill or chisel round, and the countersink head causes them to lock like a car wheel nut because of the friction and multiple circumferences.
The idea of hitting it is to tighten it some more on impact by slightly squashing the soft alloy case ,that then creates less pressure on the back side of the bolt head so it will undo

Ok hp1, it is all clear now, thanks for the kind explanation. I've very well understood the logic behind you're advise, this is important as it makes me able to act properly since I know why I'm doing this . . . The operation you suggest will be the last one before the drill....even if, as you say, 12,9 hardness seems quite difficult to penetrate . . . Let's hope we'll succeed with other means...... thanks you very much for now, I'll let you know how it goes Monday!!
 
Just by the way.....once open, there will be the issue of how to act to service the unit . . .I've found here al least 3 topics where the issue has been treated estensively, but I will open a new tread to try to confirm, and make clear all the details....let's put the issue aside for now. Have a very nice we you all, fellas :) this forum is always a nice place where to be..... quite the opposite to the official Naim forum, I hate to say . . .what a shame
 
+1. It's one of the most handy tools to shift stubborn bolts and screws.

I understand. I don't have one, but then repair shop where I left the unit has it for shure. To give it a trial does not cost anything, anyway. But let me be humbly skeptical . . . .the tool can't possibly apply more strength then an Allen key held by a grip, hit by an hammer . . . .but thanks anyway!! I'll let you know how it goes
 
By Monday the WD-40 may have all dried out. Try a few drops of "Svitol" (sold everywhere in Italy) then wait an hour or so. And get the Svitol out of the hexagonal socket screws with a piece of rag and some alcohol, so it does not encourage the hexagonal wrench to slip. Then the shops impact driver. Buona Fortuna!
 
Wd-40 is Ok stuff in pinch, but it's only really a water displacer marketed well, it's better used on a rag for cleaning stuff and not much else.

If you can get something like plusgas it is much much better and has shifted some proper rusted in bolts for me that have been in real weather.
 
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An impact driver makes many hits in a short space of time. It also turns at the same time.

Were you aplying force to turn at the same time as hitting ?

Stu
 
Use a drift and give the heads a sharp hit square on , this will loosen the thread fractionally

That sounds the best, or an impact screwdriver. Here.

There are two smaller allen bolts and a large one. I remember these being very stiff and difficult to remove the first time. I used an impact screwdriver that I used on old motorbikes, hit and twist :)
 
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An impact driver makes many hits in a short space of time. It also turns at the same time.

Were you aplying force to turn at the same time as hitting ?

Stu

Ok Stu now I see what is it....here we have that kind of tool.....but, as far as I know, it is only and exclusively used as a drill, and to drill concrete, Briks, tiles, and the like. We turn a bolt on the drill, and it starts hamming......to use it as a screw driver it should have a force control, limiting strength in order to avoid spoiling the head. I have such a hamming drill, but without the brake setting. Excuse me for the approximate technical terminology.....
Andrea (I know a Stu on the hificabin...is that you?)
 
That sounds the best, or an impact screwdriver. Here.

There are two smaller allen bolts and a large one. I remember these being very stiff and difficult to remove the first time. I used an impact screwdriver that I used on old motorbikes, hit and twist :)

Ok chilly. I've seen the link, unfortunately the seller does not send out of his country. But of course similar ones are largely available around here. A bit more expensive may be.....anyway my repair shop guy soul have some....but I can get me one too.
The is very much for being so supportive......I'll get over this bolts or else..... :)
 
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There is probably some galvanic corrosion in the threads which has tightened them up on top of the person who over tightened it last time it was opened.

A drop of diesel is a good or better than all your dw40 , plus gas ,etc only problem is the smell.
 


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