Test Equipment Anonymous (TEA) group therapy thread

[Robert763]

My desoldering arsenal😜
-Gun type desoldering iron (or three😔)
-Quickchip low temp solder
-Fresh 'sealed' solder wick with a good soldering iron
- desoldering hollow pins - various diameters
- two soldering irons both with broad inserts
- soldering tweezers

I have always worked on the principle that a soldering iron that can really transfer the heat quickly will get the job done with less total energy transfer to the part. I almost always add more solder to start with - typically I use my favourite - with a bit of silver - I think it wets better.

My best effort ever was to remove a soldered in and dying-battery-NVRAM out of a HP 3458A and didn't stuff it up - was able to read the calibration data and write it to a new chip🤞, I don't think I breathed for about half an hour 😂

Few pro rules are that always biggest practical tip and always new stuff first when removing.

If surroundings are not a problem it's quite surprising how easily quite small things can be done with that legendary sledge hammer style thing.
https://ie.rs-online.com/web/p/soldering-irons/7719524
I did IC stuff without a fuss, tip corners were somewhat sharper though.
There ergonomy is much more important and heat exchange is from joined area anyway.

Breathing is a funny thing.
I've learned that I'm not breathing in many situations, that's actually pretty annoying sometimes.
One is when something small and steady movement is needed, it's also unpremeditated so no stored breath and so must be aborted many times and store some.

Big bits are better for removal. My go-to in the Metcal PS900 is a 5mm Chisel (I'd go for 6mm or 1/4" if they did one). This will cover 3 pads / pins on a 0.1" pich device and has the cross-section to transfer lots of heat. I can happly use the corner of it to solder a 1mm pitch row if I want to.

[Ice-Tea]

To be clear: I sold this item, buyer wants a refund and these are his pictures. It was a new box, 3cm styrofoam on the bottom, instapak front and rear and all the voids filled with bubblewrap.

As Vince also mentions: I just can't seem to match the dent with the damage to the box. Even though the buyer clearly has other comparable machines for which this one might serve as a spare parts mule, I'm not inclined to think there's faul play involved. It's much more likely the parcel monkeys are  more capable of destroying stuff than one can imagine.

[factory]

The larger & heavier items of TE are more often damaged, in my experience as a buyer, I don't know if they drop the boxes, due to the weight, or they fall of automated sorting machines. 
The pictures do look like one you sold in August, wonder if the cracked front handle broke off too, hope you got it insured, or you can get it returned, so you can recover some of the loss in parts.

Hoping my HP 132A survives now, it's only 18kg, but a large as a 141T SA, currently making it's way across the Atlantic with GSP. 

David

[AVGresponding]

How... how even?? Seriously?



Double wall cardboard box. 3cm styrofoam on the bottom. Instapak pouches front and back. Voids filled with bubble wrap. I don't understand how this came to pass unless they launced it a pole or something. Styrofoam looks pretty much intact.

I'd guess dropped down a flight of stairs, the first impacts small but launching it into an arc to land diagonally on the front of a stair tread from a height of at least a couple of metres.

[factory]

Ooh, it has the Counter/Timer/Trigger and GPIB option too.

Bugger, just realised the GPIB option board that was in the spares, with my four 24xx scopes, only fits the later ones with the newest A5 CPU board, it looks to fit where the readout board goes in all my (older) scopes. Worse still I bought the CRT socket cover with attached GPIB cable from Qservice some time ago. 

David

[m k]

It's much more likely the parcel monkeys are  more capable of destroying stuff than one can imagine.

My 2nd guess is that it's squeezed from corners and sharp dent is there because the screw distracted the force.
It would also mean that the box has been displaced in the truck.

[m k]

I can happily use the corner of it to solder a 1mm pitch row if I want to.

Maybe here is a good moment for a sort of a caricature situation I once had.
Tools were few finger loops of tin and a Portasol and repair job was an asphalt station.

[BU508A]

Seller is asking 150US-$ plus shipping for it. I offered him 120$ and he came back with 140$ which I've accepted.

I've bought them here:
https://www.ebay.com/itm/144429008467
18 out of 20 are currently available.

I want to use one as an input capacitor for a DIY low noise amplifier (0.1 - 10Hz) but I need to measure first their leakage currents. I hope, it is in the sub-nA area.

That's very low frequency... what are you gonna use this amplifier for ? Detect seismic activity in your building to trigger an alarm and wake you up at night so you get a head start and can exit the building before it collapses, and save your life ? Then the local media will be amazed :" look, there is ONE guy who survived, it's a miracle "... .Then BU replying at the mic : "No, it's everything but a miracle, it's engineering and expensive tantalum caps ! : 

This is the reason, why I've ordered them:
https://www.eevblog.com/forum/metrology/diy-low-frenquency-noise-meter/msg938456/#msg938456

Please see also the AN124 from Jim Williams about the same topic.
I've attached it below.

[Vince]

Well looks like Ice Tea jinxed it for me ! 

Just received my rack mount 7603 Tek scope... size limitations imposed by the shipping company meant guy had to chose between protecting the front panel, or the rear...
At the front, some empty space, filled with an extra plug-in in bubble wrap. I am glad to report that the front of the scope is 100% intact, that was the most important for me, as a damaged front depending what needs fixing, is either lots of expense and time locating and buying spare parts.... or simply a write-off.

So overall I am "glad" it's only the rear that got damaged. The two air filter housings protrude and protected the scope, acting as crash/crumple zones so to speak... they are simply bolted on it looks like, and are just folded sheet aluminium, so should be possible to remove them and straighten them to an acceptable degree.  Hell when I retrained into aviation I spent nearly a year at the bench hand crafting custom sheet aluminium parts and riveting them... mostly meant to work in airframe maintenance... but never worked in that, as I was hired from day one to work in quality inspection instead. Well looks like I have now an excuse to make use of my skills, see I am worth anything at all !

The air filter housing took most of the hit but not 100% of it. As you can see there a little bit of damage in the upper left corner area, where the fuse holder is. Somehow the fuse holder is intact, but the BNC connector next to it (first from the top), is damaged, as well as being at an angle relative to the others. Socket must have taken a hit from the left it looks like, then the BNC socket transferred the load to the rear panel of the scope, and caved it in. So ned to remove that socket, straighten the panel and fit a new socket.

OK so overall still very happy with my purchase, and as you can see he gave me an extra / fourth plugin... a vertical amp yeah ! So I won't have to buy one. I can now removed the extra time base plugin that was in the first bay and replace it with this vertical plugin instead, and restore the scope to a more normal configuration ! 

He also supplied a home made CD which contains the PDF manuals for the two plugins and mainframe. The latter being dated November 1977 which is precisely my month and year of birth, which I guess is destiny and means the version of the manual will actual be the one that matches my actual scope.... since you said there many versions and finding the correct one can be a challenge...

So... looks like I traded some metal work to fix the rear, for an extra plugin..  I guess it's a win as it would have cost me quite a bit (paid only 50 for the scope) to buy and ship another plugin.

So, I have now two identical vertical plugins : 7A18 dual channel, and two identical time-base plugins : 7B53A dual time base, cool 

Having two of everything will of course help a lot when trying to trouble-shoot problems... I get a reference point, as well as part I can swap to help establish a diagnosis.
So quite happy overall....


OK that's all for now !

Now I will start playing with it... first I need to find the post of whoever suggested to do a resistance check on all power rails, and where from to do that, I forgot.

Then.... TURN IT ON !!!! 

[Ice-Tea]

It's much more likely the parcel monkeys are  more capable of destroying stuff than one can imagine.

My 2nd guess is that it's squeezed from corners and sharp dent is there because the screw distracted the force.
It would also mean that the box has been displaced in the truck.

Oh! I think I can see that. Like the box and styrofoam would have flexed but not sheered and the metal case being less lucky being far less flexible. Yeah, that would make sense.

[factory]

Vince, that packing is terrible, guess the guy had 30 years experience of packing thing so they get trashed. 


They should have packed that loose plug-in in a separate box, to avoid destroying all the controls on the three installed in the scope. 

David

[Vince]

Yes !

As I said ealier, I only believe what I see, and am used sadly to having poor packing from people who brag about how nicely they will pack it... and excellent packing from people who didn't even say anything about their packing...
So I am not too surprised.

But when you buy on-line, it's always luck of th draxw when it comes to packing quality, so you just have to accept it, factor the risk into your purchase decision, or stop buying anything...

As I get older I tend to see the glass half full rather than half empty, somehow. Not sure why...
So in this case I am glad the delicate front panel survived and I only the sheet metal work at the back suffered, which is much less problematic in comparison (to me at least).

[AVGresponding]

Vince, that packing is terrible, guess the guy had 30 years experience of packing thing so they get trashed. 


They should have packed that loose plug-in in a separate box, to avoid destroying all the controls on the three installed in the scope. 

David

It would almost have been better to have no packing at all. At least then the courier can see how fragile it is.

[Vince]

You have to pack it in this case, they don't take lose items...

As for hoping they would see how fragile it is.... that would imply tehy know what a scope is, which tehy don't obviously. All the wold see is a lump of metal that looks sturdy, and think the opposite : "looks beefy to me, no worries ! " !
They would probably smash the CRT and every knob.

If it's fragile you are supposed to write it in big letters all over the box... but we all know what happens to items marked "Fragile"... it's counter productive.... 

[Vince]

OK I just finished resistance checking all power rails.

Manual (the one I have at least) doesn't say where to measure... they close up pic of the board / connector they show, doesn't say what board it is. An annotation on the pic reads "Readout board remove" ... but that's about it. So I checked the readout board first, no joy, no match at all. Eventually found that the Z-axis amplifier board fit perfectly.... they could have just that, couldn't they have....

Before I found that board, my first idea was to at least get to the voltage regulator board. It's mounted at the read and comes out from the back of the scope. First remove the bent/damaged cover which... well it's not an air filter housing in the endthen, just vents for the many T03 transistors mounted right behind it on a heat sink.


Anyway, here are the results :

-50V  = 40.4k
+130V = 21.3k
+50V  = 6.64k
+15V  = 1.9k
+5V   = 11.64k
-15V  = 1.5k

The lowest rails are the +/- 15V ones, at one or two kilo-ohms, which is good I guess, far from a short at least...

So I guess I can power it up now, can I ? can I ?!!! 

.. but not now... need to go to the junk yard dispose of the packing/box, then quick stop at the supermarket for some food... then this evening I will start playing with it and power it up.... will the magic smoke escape ? Will we have a trace ? A signal even ? Hmmm..... the suspense is unbearable ! 

Oops, forgot to mention I am very pleased to see that the insides of the scopes are... mint ! 
It's like new. Just as new as it is dirty outside. So this scope is not a rust and mold bucket, excellent point going for it !
Makes it worth cleaning it and fixing whatever migh be wrong with it.

See you in a bit for the verdict then !!! 

[DC1MC]

Just in case some kind soul knows (the MCU forum is completly mute)

I'm looking for a datasheet of this animal INFINEON TriCore 12209896, or equivalent to a non automotive part from the series, make my b-day happy, as I've failed miserably with the tri-lug triax connector

Cheers,
DC1MC

[Vince]

INFINEON's website lists a shit load of Tricore chips, didn't find it in there ? Are you sure the part number you gave is actually the art number ?! Looks weird for a part nulber, and none of the Tricore chips listed on their site has  P/N formatted like this....

At least they give you a 250 page datasheet to tell you all about the tricore ...core, how to program it etc...

OK I will go and hide in the corner 

[Vince]

Tek 7603 scope

Well well well........ uhhh........ erm.... uhhhh.....   

Checked the fuse on the voltage regulation board before shoving it back into the scope's butt. Fuse was good.
Then checked the main fuse in the fuse holder at the back.... there is a fuse, and it's good.

Plugged the scope into the dim bulb tester, for extra security you never know, can't hurt.
Made sure the scope's power button was pulled-in / in the OFF position.

Then I flick the switch on the bulb tester to then juice to the scope..... instantly the music stops, computer powers off, fuck me.... the scope tripped the RCD ! 

It was so cool checking the resistnace of all the power rails... that I forgot the very basics... buzz the power plug to check for shorts 

So I just did that. Buzzed live and neutral, no short, as expected (or else the fuses would have blown, or my circuit breaker would have).
So then I check earth pin relative to the live and neutral. DMM beeped intermittently when I buzz one of the two pins.... 

So yeah, needs some more work and investigation before I can power it up..

I guess a Y cap then ? Are there RIFA caps in these scopes ?! 
I will check the schematics and pull some more part off of that scope to get to the bottom of the problem.... stay tuned...

[factory]

Did you have a look for damaged/crushed/trapped wiring? the mains cable goes in near to the impact damage.

Also thinking back to the Tek 453 I repaired, the mains cable on that had rubber cores and those were all perished.



David

[Vince]

Yes you are right, it was due to the mangled metal work at the back.

I figured that once I checked the schematics and saw that there was zero RIFA  / Y cap in this thing...

However it was also due to poor freaking poor / dangerous design from Tek if I may say so ?! 

Look at that... live and neutral fom the power cord are black, and white..

The black one as you can see goes to the fuse holder, which is very well insulated no worries.

However the white wire, look at that ! It goes to a metal lug where it is soldered to the wire going inside the scope to the power supply. Lug is held in place by a screw, onto a plastic post.
... look how close to the metal work the lug is !!! 
Well I mean, due to the damaged/bent metal work, it's touching it of course, causing the RCD to trip, but... at this particular location the metal work is only slightly bent. Even if it weren't bent, the lug would still be stupidly close to the metal work, like  a 1/16" or something not that much more ! 

So as a quick fix, I unscrewed the lug, and shoved it inside a long piece of large heat shrink tubing. Put the screw back onto the plastic post so it's there in case I ever want to put the lug in place once I get to to straighten the metal work.

so, no short anymore, I can power up the scope now ! NO !!!!

As I was moving the scope around, I noticed a screw (I guess !) rattling inside the scope = NOT GOOD !!!

Scoep is bloody heavy so it's not easy to shake... tried my bst but I could not get the screw or whatever it is, to exit the scope. That, plus the fact that I think I located the sound to a particular area..... I think it's likely trapped inside the CRT shield !!! 

Boy unfortunately I don't see much choice right now, that pulling the CRT out to get access to the area ! Recipe for disaster ! 

[Vince]

Making progress !!

Before resorting to the risky business of pulling the CRT out, I tried one thing : part of the left side of the  scope is accessible via a removable access panel that's there to give access to a board that's there.
Removed that panel, shined some light in there, and immediately found the rattling screw, got lucky !!! 


So, I could then power up the scope at last ! And I immediately got traces on the screen ! 

Not familiar with 7000 scopes so I played with all the knobs and eventually managed to display a sine wave on all 4 channels yeah ! 
Readout works as well 

So it's functional, but not working right at all though... look at the video clip I just made for you ! 



1) At the bottom of the screen near the center, there is a sloped straight line.... appears to be part of the readout (reacts to the readout brightness control).
2) The first trace at the top just can't trigger, it's moving all the time, and the shape f the signal is no correct at the very start, there is a sharp bend to it somehow
3) Last / fourth trace at the bottom spans only a small part of the screen, on the left, and the span varies from zero to XX % of the width, all the time. It comes and goes, as you can see in the video.
4) Not seen in the video, but the signals are only visible on a particular sweep speed. For most sweep speeds, I get nothing at all on the screen ..... 
I could try the other TB plugin though, see if that is the problem or not.

BUT.... I am not worried at all by any of this, at least not at this point because.... I already found a major issue that sure could cause all sorts of weird problems !

Checked all voltage rails.  The reference rail, -50V, is spot on at -50.0V. All 5 analog rails are spot on and very low ripple (2 or 3 mV AVG on the DMM, good enough for now at least).
BUT.... the digital +5V rail is kaput ! DMM said 4.1Vdc and 1.4Vac !! 
So I scopes it, see below. As you can see, I do get a nice stable 5V but.... every half cycle / 10ms, I can a huge voltage drop that goes almost all the way to the ground ! Surely the TTL chips in the scope can't like that....

So first thing now is to investigate and fix this 5V rail, then resume testing.

The fan is indeed loud and sounds horrible, just like in the video ! At first I thought maybe the damaged metal work in this area is hitting the fan blades, like always happens in my Tek 500 series hollow state scopes but... no, not so here. 100% of the noise is due to the fan an nothing else. Sounds like the bearing is shot. will need a new fan, will look into that.

But that will be for tomorrow... 00H30 here, tired and time to got to bed. 

[TERRA Operative]

That 5v rail probably has a busted rectifier diode.

[srb1954]

That 5v rail probably has a busted rectifier diode.

The ripple is at 100Hz so both diodes are rectifying OK.

It is more likely that the main filter capacitor has a severely depleted capacitance. Temporarily tack another 10,000uF cap across the main filter cap to see if that improves the situation.

[Brumby]

Congratulations Vince!

The rear panel damage is unfortunate but, as you said, much better than having any on the front panel.  From what I can see, if you were able to remove that panel you might have a reasonable chance of straightening it out.

A couple of strokes of luck in having your RCD tripped and finding that loose screw, avoiding more severe unhappinesss ... and to get actual traces on the screen is a big step in the right direction.

Looks like you have a high chance of success here - and I'm wishing you every step in it's rehabilitation has maximum result with minimum problems.


Well, I did say "wish" ... it is a Tek after all.

[med6753]

Vince, based upon the scope trace of the +5V supply it seems pretty obvious that it's filter capacitor related. If indeed that's the case I would recommend you re-cap the entire PSU, not just the defective one in the +5V supply. I'm assuming that the PSU design is similar to that found in the bench 7603 so it will have the same upright cans as shown below which can be a bastard to get removed from the board. Installing the replacements can be accomplished very neatly by using these adapters available from Ebay:

https://www.ebay.com/itm/272799971348

If for some reason they don't ship internationally contact me via PM and I'll make arrangements to get them to you.