Step by step surgery

[fas42]

Today was a good exercise in diagnosing the two rigs at the friend's house, down the road - overall, they were both performing to a very good standard at various times; one of the best listening sessions I've had there.

 

One setup uses media players exclusively as source and DAC, and it was working well enough to make it obvious that the auxiliary battery pack, which normally was used to make sure that player's internal battery maintained good voltage levels, was actually degrading the SQ. Why? One would have do a whole series of experiments to nail the precise cause - again, simplicity wins, by virtue of reducing the number of boxes involved.

 

The main house rig, using a tweaked Quad CDP, was initially not quite there; and this turned out to be a mains cable, which he had bought new, to replace the DIY, braided one - he likes to keep experimenting, and on initial installation prior to my visit felt there was a gain. However, we did some swapping, and it was clear that this in fact was a backwards step - why? Possibly because his DIY cord was better constructed, or there was an issue with how the cord had been routed; which was hard to reverse.

 

The final dollop of cream - an idea of his - was assigning the Quad to DAC duties only, and using a basic DVD player to spin the the disks, and communicate via optical. The sound was hard to fault, and made it easy to listen anywhere.

 

One particularly niggling problem remains - the media player rig has a contact integrity weakness, easily audible, in the cable between player and amplifier, but it's going to be quite tricky to create a hardwired solution; everything is so delicate in that area of the device, and he doesn't want a setup which made it easy to accidentally damage the parts - something he's going to think about some more ...

[marce]

Yet we can transmit far more delicate signals down cables and connectors...

[fas42]

It's all about signal to noise ratios - an 'unfortunate' aspect of human hearing is that we can discern 'oddness' even when buried deep in noise; it is frequently mentioned how remarkable hearing is in extracting what we do want to hear in electrical mush; which means that provided there is some pattern to it that we will be aware, or can be senstive to, unwanted anomalies at very low levels.

 

What gets damaged in the listening is what christopher3393 mentions in another thread -  "The word "beauty" came to mind often, so I started thinking and reading about it more, and noticing it more, particularly when listening to music." Yesterday, the rigs at my friend's were projecting the "beauty" of what was captured with an ease and a sense of 'truthfullness' at the peak moments; you had no desire that it "should be better!" - but, this integrity was still capable being lost far too easily; an irritating quality would start to intrude, the sense of ease evaporated.

 

And this is because the systems were not sufficiently 'rugged'; at least one or two areas were borderline good enough, and would slip out of optimum status enough to be clearly audible as "something not quite right". Of course, once one is aware of this, it is the nature of us humans to feel the tiny splinter as a major hurt - and we're motivated to do something about it.

[fas42]

An album we played which I have never come across berfore, which was ruthless in its ability to show rig status was this,

 

 

This was either excrutiatingly unpleasant, or worked quite well, depending upon everything - the value of certain recordings to highlight system tune issues is enormous.

[fas42]

Awwright! ... time for some real step by step surgery now! On my laptop, that is ...

 

It's an old beast, a good solid HP with a particularly nice audio setup built in - very long in the teeth now, the graphics driver always had an issue, now and again locking the m/c up - but wasn't a real problem. Well, it's got savage now - it's pretty clear that the graphics chip is close to completely losing its marbles: the laptop screen stopped working properly ages ago - but I rescued it by adding an external monitor, via VGA; but now even that has gone bad - the Radeon chip driver software goes nuts trying to make the circuitry behave; this is edge of your seat stuff! Luckily, by shining a torch on the almost invisible display on the main screen, I can enable VGA mode working on the external screen - and get by.

 

This morning, it was even worse - still hasn't booted up cleanly. So, obvious thing is to transfer working to the very solid, old Dell unit lying around - but, this has a terrible audio subsystem! Think, transistor radio with almost dead batteries ...

 

Would like to rescue the HP, if possible - because of the good sound it does. Lift the lid on it, and generally poke around, see if anything can be done. So will have to spend time playing around, and trying various things - I'm a person who hates throwing things out because of a silly problem, that's easily resolved. And check out best options for another laptop, if the Dell is too annoying to use.

 

Oh, dear!

 

 

It never rains but it pours Addendum: the ADSL link has gone bad again, from yesterday. Have to play footsies with taking the phone off the hook, to prod the rusty local exchange into plodding on, before it gets booted by the NBN coming ... soooon!!

 

[sandyk]

3 minutes ago, fas42 said:

it's pretty clear that the graphics chip is close to completely losing its marbles:

 

 Does the Graphics chip have a Heatsink ? Perhaps dried out heatsink grease if it does ?

[fas42]

All possible - I haven't taken it apart yet ... the problem is there from cold, if anything it improves the more you use it.

[sandyk]

9 minutes ago, fas42 said:

All possible - I haven't taken it apart yet ... the problem is there from cold, if anything it improves the more you use it.

 

Check the larger filter capacitors to see if they have leakage or domed tops. Some may need replacing if the laptop is quite old, due to excessive heat. This happened to an older monitor of mine.

[fas42]

Yes, I was thinking before, capacitors needing replacement; definitely will be scrutinised carefully - anyway, softly, softly, I don't want to muck up the hard drive in it - will organise that first.

 

But now, time for lunch!

 

And thanks for your thoughts, Alex, 👍

[sandyk]

32 minutes ago, fas42 said:

It never rains but it pours Addendum: the ADSL link has gone bad again, from yesterday. Have to play footsies with taking the phone off the hook, to prod the rusty local exchange into plodding on, before it gets booted by the NBN coming ... soooon!!

 Presumably it will use FTN, and a leakage fault on a main pair or riser pair will still cause you problems.

 Did it go bad after any recent heavy rain ?

[fas42]

There was recent rain, but relatively light. If it were the cause, I would judge that it had soak into the weak point over some time.

[fas42]

For your pleasure , Alex ... turns out this laptop is a mongrel, has to be completely dismantled, screws everywhere, to get to the good bits - http://www.insidemylaptop.com/disassemble-hp-compaq-6730s-6735s-notebook-remove-cooling-fan/ .

 

I have the 6830s, which is mechanically the same, and I'm partway through the maze - my previous, budget Dell was so much more accessible; which it needed, to do periodic defluffing.

[fas42]

OK, x thousand screws later - will I get them right putting it back together?  - the beast is exposed. And looks good apart from usual slight dust; absolutely nothing obvious. Bare minimum of smoothing caps, and they are a long way from the graphics action, can't see that as being relevant, otherwise other circuitry would be playing up too.

 

Possibly the thermal resistance is too great between the graphics chip and heat pipe, because the goo between has dried up - I'll lift the latter and check .. but I trawled the net a bit more, and it looks like graphics going bad is a common problem - people talk about oven cooking to reball the chip - sounds good, eh? - on the basis that the soldering underneath the chip has gone sour, and that frying the whole board makes it reflow. But more careful analysis posts say the real issue is that the constant thermal swings inside the chip has distorted internal tracks to the point that micro-fractures occur - and that cooking the chip 'resets' those tiny breaks. And that far more gentle heat treatment from a heat gun, hair dryer is a better method.

 

So, I'm going to give this a go. Try not to overdo the heat, and see what gives me; if nothing, then amp up the heat ... a step at a time ... .

[sandyk]

On ‎6‎/‎28‎/‎2019 at 12:40 PM, fas42 said:

This morning, it was even worse - still hasn't booted up cleanly.

 Again, this is a possible indication of a problem in the PSU area.

 I would replace (if possible) the main filter caps with other low ESR types of a similar capacitance before attempting to do anything in the graphics area which may end up in a trip to the local disposal area.

Prolonged exposure to high temperatures may result in a marked loss of filter capacitance WITHOUT any obvious signs..

[fas42]

Except, it's only the graphics area that's playing up - hard to boot is only because it's tricky to trigger off what's happening on the screen; once I get VGA mode happening, on the external monitor, it's as steady as a rock.

 

This is the motherboard, with the heat sink/pipe assembly removed,

 

 

Note that there are only three smoothing caps there, and their location - the graphics chip is the one top left of the HP Compaq label, circled by tiny SMD caps, like a clock face.

 

I'll do the easy steps first; apparently people have cooked motherboards in ovens at ridiculous temperatures, and the circuit survived; and it restored graphics functionality, at least for a short time.

[sandyk]

20 minutes ago, fas42 said:

I'll do the easy steps first; apparently people have cooked motherboards in ovens at ridiculous temperatures, and the circuit survived; and it restored graphics functionality, at least for a short time.

 

 Tread VERY gently or you will have no functionality at all.

There is also a good chance that new filter caps will prolong the life of the Laptop if nothing else.

[fas42]

To start, it will be just an extension of what people do as part of normal troubleshooting - applying heat, or cold, to determine if that affects behaviour.

 

Ultimately, I need to move to a new m/c ... amount of RAM, gotchas in whether latest versions of software can run, all add up - there's a point when its only use is as a when all else fails machine.

 

I'm typing this on a desktop that must be close to 20 years old; XP, 1G of RAM - ahh, memories ... .

[jabbr]

10 minutes ago, fas42 said:

I'm typing this on a desktop that must be close to 20 years old; XP, 1G of RAM - ahh, memories ... .

You don’t need a computer — get an iPad! Seriously you are wasting energy and the yearly energy costs outweigh the cost to upgrade. Get one of the new machines with a probe that you can stick in your ear and it will type what you are thinking  

[fas42]

Well, how about that! Finally got around to trying the heat bath treatment on the HP - and signs look good!

 

I had oodles of flimsy bits of the machine lying around, and a while ago I tried plugging all the key electrical bits together, precariously balanced on bits of paper, etc. And it started fine - so I hadn't caused a problem dismantling it - but the external monitor was still showing chaotic behaviour, as expected.

 

Removed the heat pipe; a remarkably thick layer of thermal goo mated the chips and heatsinks - which is not a good thing; the thinner the layer that gets the job done the better - could this have been causing the graphics chip to suffer excessive temperature swings while working, increasing the stress on internal tracks?

 

Finally happy with the fill-in Dell laptop to continue with in the meantime - and in the mood to go the next step. The most sensible suggestion I came across while researching was to heat the graphics chip to 120C for 5 minutes - so, created a tube to funnel hot air from a hair dryer onto a small area, about the size of the chip, and monitored the temperature with a thermal probe on the multimeter; the nozzle of the tube a couple of inches above the chip kept the temperature in the right zone ... and cooked the graphics chip for the required time.

 

Thinned out the thermal goo in a best attempt to get better contact between heatpipe and chips, and reattached. Organised the bits so a working m/c was possible, and fired it up. Yes!! It booted and went to external monitor; I was able to switch between Radeon chip and VGA, and the display looks good!

 

OK, now to put it all together again, confirming that all screws are used, - and see how it flies ...

[fas42]

Reassembled, less the 1,000 screws in the base, to see how it behaves for a bit, before adding all the covers, etc. This post has been entered using that HP - I'll give it a day or so of solid use to make sure it holds together, before tightening it all up.

[sandyk]

23 minutes ago, fas42 said:

Reassembled, less the 1,000 screws in the base, to see how it behaves for a bit, before adding all the covers, etc. This post has been entered using that HP - I'll give it a day or so of solid use to make sure it holds together, before tightening it all up.

 

 Frank 

You need to add all the covers temporarily, perhaps with sticky tape even, to ensure that there are no heat related problems before screwing it all up. Don't forget too, that the present cold weather may hide problems, so you will need to do this with perhaps the room warmed up .
You don't want to have to go through this tedious process again at a later date.

Alex

[fas42]

41 minutes ago, sandyk said:

 

 Frank 

You need to add all the covers temporarily, perhaps with sticky tape even, to ensure that there are no heat related problems before screwing it all up. Don't forget too, that the present cold weather may hide problems, so you will need to do this with perhaps the room warmed up .
You don't want to have to go through this tedious process again at a later date.

Alex

 

Thanks for those thoughts, Alex ... the biggest heat related problem is that the stupid heat exchangers used in these computers gunk up with fluff in no time at all; and the fan speed goes beserk, trying to blow air through! Previous laptop had to be degunked a couple of times; the plus was that it was fairly easy to get access to the area - this HP has to be completely dismantled to get to the same spot; clever bit o' design, that ... . Luckily, blasting with air, and  blowing hard into the outlet with your breath, gets most of the crap out of the way, spreads itself throughout the insides, .

 

The story is that the graphics chip can go bad again if graphics activity is overdone - so, cut down on those computer games !! ... actually, YouTube clips, etc, are about the closest I get to working the laptop hard in that way - just have to pace myself, .

 

[fas42]

Okay, the HP is behaving itself, so in go all the screws - amazing, no hardware left over!! Most fun was hearing a rattle inside the beast - and then realising I was a screw short ... how the hell did that one bit of metal manage to deposit itself itself where it shouldn't, I'm still scratching my head on that one. Lots of shaking and tipping over and over resulted in the miscreant popping out of the battery slot ...

 

Enough differences between the web guide I linked to earlier, and my m/c to cause me to retrace my steps on occasion - the other fun bit was that there were 3 different lengths of the main thread size, meaning shifting screws around a bit until they all grabbed.

[rando]

What did you use for thermal paste on CPU & GPU? Or did you judge the surfaces mated closely enough to go bare metal on metal?

 

Factory made computers always receive a fat inaccurately placed glob that dries into a mess.  The real key to thermal performance is how clean you get the chips and heatsinks.  Even microscopic amounts of the old paste form an effective barrier to heat transfer.

[fas42]

The thermal paste that was there was still in good shape! Still as squashable as if it had come straight out of a tube - one type, grey, on the CPU, two other blue pads which were still as putty-like as one could want. So I scrapped up the CPU goo, and created a small ball in the centre to squash down; the blue paste I thinned out to get a much closer mating of chip and heatsink, no problems smearing it to get full coverage - prior to this I had cleaned off the graphics chip top to a polished finish, before applying the heat blast. Then aligned the heat pipe on top, and pressed down as hard as I dared, to get minimum separation.

 

Yes, could have been super fussy with doing the thermal paste thing - but the m/c is running fine, even after bouts of high CPU usage - the hot weather in 6 months time will tell me if I could do better. As mentioned, keeping the heat exchanger relatively dust free is the best strategy to stop overheating, I've found.