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Simply opening an 160's case: impossible

M

malandros

pfm Member
Yes fellas, this is where I'm stuck . . . believe it or not, I aint' able to open up the ol' pal . . . took away the 4 feet, and, on the bottom side, putting the amp down side up, I was able too unscrew the alone screw in the middle. But no way of loosening any of the others two . . . .you know there are, beside the feet, 3 screws in the middle of the cabinet, down there. One sits alone, while the other two sit aligned, not too far apart from each other.
Well the last two beasts, are just about unbeatable . . .I've tried everything . . no way.
I don't dare to use a drill on the screws, and even less a flame, as I don't know where those screws are sitting in . . . any suggestion, advise, or even pitiful talk, will be very welcome, thanks. Beside, any pics showing exactly where those 2 screws are going inside, where they are fastened to, will help in making up our mind about how to proceed. Hope to hear from some helpful soul soon . . . . it is a 6186 serial n. making it a late 1982 model, the first year of production
 
Hi Malandros do you have any pics of the screws that you cannot remove please then I maybe able to offer some advice.
regards
 
I thought one just had to take off the four feet, and gently slide the whole inner tray forward and out, making sure not to crack the front panel.
 
I'm assuming he means the first version which had flat panels screwed together rather than the thick extruded sleeve. I thought you just unscrewed the top on those, but I've never had one.
 
Well Chaggy78, I just left the machine to a service near by . . . we tried together to open it up. I'll be able to get pics on Monday morning , as the guy is closed on we.... I'll post them here, thanks for now
 
John_73 said:
I thought one just had to take off the four feet, and gently slide the whole inner tray forward and out, making sure not to crack the front panel.
Click to expand...
in fact, it seems does not work this way . . . taken out the 4 feet, the dam thing is as steady as before . . .
 
Tony L said:
I'm assuming he means the first version which had flat panels screwed together rather than the thick extruded sleeve. I thought you just unscrewed the top on those, but I've never had one.
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Well Tony, it is a CB however . . the look is exactly the same as an 135 or 250 . . . I can tell, I have both. . . . so I'm puzzled by "flat panels screwed together rather than the thick extruded sleeve" as I can't tell the difference .... unless by that you're referring to the inside, the part that moves out of cabinet . . . then, it means my model has a panel sliding along the inside of cabinet, and screwed to it, while in modern models, the job of holding the inside to the cabinet is left to the 4 feet, hence, the inside part has at the 4 corners harder, thicker bases, to welcome the screws and hold them tight. Sorry for being a bit unclear, but . . . did I get you?
 
John_73 said:
Have any mods been done to it?
Some photos will help :)
Click to expand...
Well John, as I said, no idea of the inside, since I'm just unable to open it so far . . . I'll post some pics of the outside, asap, that is on Monday when the guy who has it will reopen his shop
thanks for now anyway
 
I had similar problems with a 250 some years ago - Allen bolts IIRC - I got some advice from Les W but I can't remember now what he said! I never did open it up before I sold it.
 
Use a drift and give the heads a sharp hit square on , this will loosen the thread fractionally
 
hp1 said:
Use a drift and give the heads a sharp hit square on , this will loosen the thread fractionally
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hp1, I'm not sure of your meaning....language is also a problem . . . You say to use a sharp tool, (a drift, right?) to point at the center of screw heads, vertically, and, with an hammer, hit sharply, so to possibly loosen the thread of the screw . . . . did I get it?
 
The serial number indicates that this is a CB (Chrome Bumper) model.

The base will have four feet and three countersunk Allen key headed bolts on the underside. Two of these bolts are in the centre of the two power amplifier heat sinks which are also secured to the inner sled by a further two bolts each. The third bolt is for the mains transformer which has a further bolt fixing it to the sled.

You have to remove the four feet and the three bolts to enable the sled to slide out of the sleeve. If the bolts are stubborn, tap the Allen key into them with a hammer, wrap a piece of cloth around the Allen key and give its shaft a sharp tap with the hammer in an anti-clockwise direction to break the seal. Take care not to damage the front panel when sliding the heavy sled out of the sleeve. If the heads of the Allen bolts are damaged you will have to drill them out.

This photo will give you some idea of where the internal components are relative to the three bolts:

TotzsU8VkAQUcY9YjH4RrTSfLh-0wfTdO-AJhMO0EtuzoY_dJ7_mR0Gn6a9NEpv_I--w8vpSRfV9TQ=w2560-h1440-no


P.S. The NAP160 was introduced in 1971 with the bolt down case, the CB case was introduced in 1980 and the model was discontinued in 1986.
 
misterc6 said:
The serial number indicates that this is a CB (Chrome Bumper) model.

The base will have four feet and three countersunk Allen key headed bolts on the underside. Two of these bolts are in the centre of the two power amplifier heat sinks which are also secured to the inner sled by a further two bolts each. The third bolt is for the mains transformer which has a further bolt fixing it to the sled.

You have to remove the four feet and the three bolts to enable the sled to slide out of the sleeve. If the bolts are stubborn, tap the Allen key into them with a hammer, wrap a piece of cloth around the Allen key and give its shaft a sharp tap with the hammer in an anti-clockwise direction to break the seal. Take care not to damage the front panel when sliding the heavy sled out of the sleeve. If the heads of the Allen bolts are damaged you will have to drill them out.

This photo will give you some idea of where the internal components are relative to the three bolts:

TotzsU8VkAQUcY9YjH4RrTSfLh-0wfTdO-AJhMO0EtuzoY_dJ7_mR0Gn6a9NEpv_I--w8vpSRfV9TQ=w2560-h1440-no


P.S. The NAP160 was introduced in 1971 with the bolt down case, the CB case was introduced in 1980 and the model was discontinued in 1986.
Click to expand...
Now, that was indeed a full clear explanation if I've ever seen one. Well, thanks misterc6!!!! I've omitted to mention, we did try already with an hammer .... and several times. No way!!! My technician over there said he could try with a drill, but this will
Spoil both the screw and the hole of the screw. The bolt can be easily replaced, but what if the drill is going to damage something inside? I still don't get where the
internal components are with respect to the 3 bolts.... I mean I don't see any bolt's hole in there, and any way we're looking from the wrong side I believe.... am I wrong mister c6? This is a bit confusing
 
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.
 
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.
 
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.
 
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