Test Equipment: Oscillocopes

[MileHigh]

In my "tear apart tinkerer" life there were a few times where I got in over my head an I was unable to put back together what I tore apart.  When it comes to intermittent problems, those can be a real serious pain to troubleshoot and fix and sometimes it can take weeks.  And that's with a bench full of equipment at your disposal.  I am not saying this problem is truly intermittent but it has some traits like that.  If it is truly thermal, then finding the bad component with a heat gun and freeze spray is doable, if you really know what you are doing.  Brian may not have even known that heat guns and freeze spray existed for this purpose.  Then you throw in the dangers of high voltage, and how ideally you would have a second scope to fix the first scope, etc.

Perhaps Brian will get lucky and cleaning the contacts will do the trick!

[Brian516]

Well, I am going to repeat my cautionary note again.  I get the impression that Brian has no electronics experience at all and finding bad components and changing them inside an oscilloscope is not a trivial matter even if you have the service manual.

As an example:  Brian, if you switched off the power to the scope but left it plugged into the wall socket, did you know that if you touched a component with a regular soldering iron things could "blow up?"  If you didn't know that then that shows you should be careful.

Here is a way of looking at it:  From what I can see from your clips the problem is annoying but tolerable.  The scope is still working and showing you waveforms.  The suggestion is to just use it like that for now.  In six months if you truly are interested in this stuff and are learning the whole time, then perhaps try to fix it.  However, there is a chance that in six months you will have moved on and dropped the whole thing.  Then fixing the scope becomes a moot point because you will not be using it.

MileHigh

Yes, I know very well the proper way to use and work on electronics.  I'm not a complete moron.   I can solder perfectly well, know how to desolder.
I'm not trying to be rude here, but I'm not some average dummy.   I may not know anything about oscilloscopes, and I may be a beginner in learning about how more complex circuits function, but I've known how to solder and how to fix things for a long time now.   
A little background on me:  When I was a little kid, my favorite thing to do was take things apart, learn how they work, and then put them back together.  I never cared about action figures or pointless stuff like that.  I started doing construction at 13 and excelled at it, started fixing cars at 15, and excelled at that.
I've wired up multiple houses, mapped out the circuits in houses built in the early 1900's that had knob and tube wiring, rewired houses, fixed circuits, etc.
It was only recently that I got back into smaller electronics though.   I'm a little older now and don't learn as quick as I used to, and it's not as easy for me to figure things out like I used to, but I still can. 
So what I am saying here is I'm not your average numbnuts and I don't like to be treated as such.

[Brian516]

Milehigh,

Sorry for lashing out at you.   I shouldn't have.    I just really hate being spoken to like I'm a dimwit, and that's how I felt after reading your comment about knowing to have devices unplugged before doing any work inside of them.  I know it's probably a bit too early into my electronics learning experience to be worrying about learning how to use a scope and everything, but I love "toys" (especially electronic equipment that give me a better idea of how something is functioning....), and this one was too cheap to pass up.   If I had to spend a few hundred to get one, you bet I would have waited until I really needed one.
Even so, I appreciate the help with all this and for you guys putting up with me not knowing more than just the very basics of electronics...

The major thing that I need to start doing is taking the time to read the manual, and even the manuals for other things I have like my Fluke DMM and other DMM's. I'm sure there are functions on them that I am missing out on, plus I need to learn how to calibrate them myself.   I guess it's just that manly instinct to just " figure things out as I go " that I need to get over, especially when it comes to this type of equipment.  I would have easily figured out that having it on the X-Y setting was my issue before if I would have bothered to open the manual to the 'Obtaining Basic Displays' section.


Anyway.... back on track...

My internet was down earlier for a while I guess due to the heavy snow and crazy wind, so I decided I would pull it open again and inspect, again, this time focusing on the dipped caps....

I found one on the vertical preamp that has a hairline crack in it, and one on the IC board in the Power supply +5V rail.
The one on the +5V rail is number C1559.  It's split apart by one of the leads. It looks to have been caused by heat, from the component itself though since there are no heat marks around it, the fan works, and everything else in the area is in great shape.

The one on the vertical preamp board only has a hairline crack on the top of it. I thought it was just the paint but i ran my fingernail over it and there is definitely a crack.
It is part number C161 on board A3.  It is also part of a +5V section of the board, interestingly enough.  both caps go to ground.

Could this possibly be part of a bigger issue, since they are both on +5V? 

http://i1081.photobucket.com/albums/j347/Brian_Bloom/CAM00162_zpszrmhxqju.jpg
(also notice the axial cap to the right of the bad tantalum cap - it's outer plastic is peeling off.  Appears to just be cosmetic, unless you think it happened because it's going bad.)
Brian

[MileHigh]

Brian:

All is well and fine.  The soldering iron issue happened with someone well known around here about a year ago and he is a guy that also loves to take stuff apart.  My language may not always be the most politically correct but I was not trying to prejudge you.  You seem to be making progress so I hope that you fix it and then you are off to the races.  Just be careful of the high voltage.  TK is the expert there and might have some sound advice for you about that.

MileHigh

[Brian516]

Brian:

All is well and fine.  The soldering iron issue happened with someone well known around here about a year ago and he is a guy that also loves to take stuff apart.  My language may not always be the most politically correct but I was not trying to prejudge you.  You seem to be making progress so I hope that you fix it and then you are off to the races.  Just be careful of the high voltage.  TK is the expert there and might have some sound advice for you about that.

MileHigh

That's unfortunate that someone didn't know not to stick an induction stick into a hot electronic device....  I wonder how big of a "poof" or "POP" it made.   Nowadays I don't take stuff apart that I intend to keep in one piece unless it's broken. 
The internet and text messages aren't the greatest modes of comm since there is the full lack of tone and emotion, so a lot of times things don't come out the way one intends them to.  That happens a lot to me especially it seems.   Sometimes when I go back and re-read something a bit later I realize that It reads completely different from the way I intended it to.
Fortunately, going into this I knew enough about electricity to have some respect for it. Especially high voltage. Especially DC HV, since at least AC will throw you away from it, instead of getting stuck to it.  I at least know how to read schematics and understand when caps will need to be discharged before handling.

I posted a pic in the above post of the bad +5V PSU cap.  The other one isn't worth bothering to take a pic of, since you wont be able to see the crack in it anyway.... maybe if I rubbed it with some powdered pencil graphite it would be noticeable enough to capture in a pic....

Brian