Test Equipment Anonymous (TEA) group therapy thread

[Ice-Tea]

Yes it's my CMS33.

I saw those. Couldn't quite make out the value in them. Got a TL;DR? 

[AVGresponding]

The problem is that I don't have fine cutting tools like a Dremel or the like, to cut the cnnector open. So... the repair might have to wait until I can afford a Dremel.

If you're determined to remove the insulator/spacer cap, you can use a hacksaw blade; it gives you more fine control than a Dremel anyway, though obviously requires more effort.

Use a fine pitch blade, 32TPI or more, wrap 1/2 to 2/3 of the blade in multiple layers of tape, and you have yourself an improvised padsaw.



EDIT: Have the teeth facing backwards, so it's cut on pull, rather than the usual cut on push.

[med6753]

Vince, the leads coming out the base of the CRT are soldered to the base pins. Even if the glue holding the base to the glass comes loose the socket won't come off.

The white rods internal aren't plastic. They are ceramic and are spacers and support for the gun assembly.

If the piece rattling around inside doesn't fall to the screen when the CRT is placed straight up as shown chances are it's something within the gun assembly itself and unfortunately most likely metal.

[tggzzz]

Thanks for your comments. Yes Sphere might be a source... when I am rich. At least it's a ray (pun !  ) of hope !

I wish I spoke a foreign language sufficiently well to be able to make (deliberate) puns.

Now I can look at the neck to see the guts of it inside. I am not competent so don't know what to look for, but from a newbie perspective, at the least I can say that the mechanicals inside so to speak, don't look anywhere near as thin / fragile / delicate as I imagined, and there are even like white rod that act as spacers and support for the various pieces. I honestly don't see how that could get bent during shipping, or at all 

I think there might be hope : I can hear something rattling in the CRT... but I can't see it INside the glass... it sounds more like it's inside the black plastic connector on the neck, that holds all the pins/terminals.
I see that the glue that holds it to the glass of the neck, is hard, dried and broke free. It's not holding to the glass anymore. So the connector can wiggle a bit, though it doesnt fell like it's going to come oiff anytime soon. The wires inside must be quite thick and holding it well in place.

Here's a picture of a scope tube that was doing a good impression of a torch because the grid had become disconnected. No idea how that weld had broke without the tube being destroyed.



I went and picked up a replacement from a chap that had a shed full of glowing HP/Tek equipment, and during discussions he offered me  flaky Tek485 - which I bought. And we know where that lead.

So, I guess the rattling noise inside must be pieces of the glue that are wondering about. So maybe the arcing sound are happening not inside the CRT, but inside the socket ??

One thing to look for is an "odd" metallic patch on the glass. If that's a "getter" designed to absorb gas in the tube, then its appearance can indicate whether the tube's seal has broken.

I eventually found a good, if geeky, use for the CRT.

[mnementh]

I'm probably developing crapacitors m'self. It's not a [hp] but a Tek. TDS 520.  Some horror repair threads on here, but also a tip on enabling FFT. That'd be yum.

Mmmmhmmm... same here. When the signal caps go bad, it makes you sound like that old lady who shouts at squirrels... or the old man who can't remember any president since the Gipper.

But when the ones on the power rails go... man. Everything becomes a uphill battle... even getting downstairs for your morning cuppa.   

mnem
More power tooya, buddy.

[Robert763]

Yes it's my CMS33.

I saw those. Couldn't quite make out the value in them. Got a TL;DR? 

Think of a modernised HP 8920B or Marconi 2955 with added spectrum analyser. And in the case of the CMS33 aircraft VOR / ILS navigation system testing.
Basically a portable 400kHz to 1GHz combination test set with:
RF signal generator
RF power meter ( uW to 100W)
Spectrum Analyser
Modulation meter
Receiver
AF scope
AF generator  x 2
AF power / voltmeter
Selective calling tone generation
In-line power and VSWR

see https://www.testequipmenthq.com/datasheets/Rohde-Schwarz-CMS33-Datasheet.pdf

Good news with mine is the loose N type was just that two loose M3 csk screws on the mounting plate.
The black line on the display went away on it's own
And it passes all internal tests.

[Specmaster]

   And sorry; I take for granted that anybody can lay hands on these, as they're a standard hardware store item over here from the Hillman drawers in a variety of sizes and depths. Also SOP for car audio installers; certain kits of speakers even come with them standard. 

As a matter of fact, those abominations apparently  are so common in the US that you lot feel a need to replace something nice:



...with them. "ACK! THPPTT!" as Bill the Cat would say.

Simply inappropriate for use with speakers in a sheetmetal door. The door metal is too thin; they'll distort it as you tighten up the screws, disrupting the seal of the speaker against the panel. They're great for what they're meant for: Holding gear in a equipment rack. Not so much for speakers.

Honestly, clipnuts are a bodge for this reason too... but the thin flat metal they're made of means they are the least likely to affect proper seating of the speaker, especially if you have a foam gasket from the original speaker, as most do nowadays.

Sometimes you just don't have any better choice. They're what you can do to get the job done in a reasonable timeframe at reasonable cost to the customer. 

mnem
 

Quite right, those ears would destroy the speaker seal.

The speaker is all fixed in place and is working a treat, there is a distinct drop in the bass output of that speaker compared to others, but hey, its bass and its a hell of a lot better than having no bass coming from that door let me tell you all 

I used 4.8 x 12 mm rivets with the rivet gun for a cordless drill, did the job with ease  So now I can just keep my eyes open for the correct speaker to appear on eBay that comes from another Superb L&K, but that I doubt will any time soon as I posted yesterday, there are almost like hens teeth or even rocking horse poo, that car is seriously rare. 

[Vince]

@Tggzzz : that's some intense nerdery, what a decoration !

Your wife supporting that must be a gem....

OK a broken weld inside... that's more difficulty to spot ! Pun again, spot weld ! 
Oh dear, what's wrong with me today ! 

@AVG : Hack saw blade indeed works a treat, job done, 5 minutes tops ! Because I am a tough guy (not!) I didn't even wrap it with tape.  So I can now see inside the socket...

@Papa Smurf : ... now that I am inside, I can see the pins are NOT soldered, the terminals are crimped ! Hmmm..... what if some are dodgy...
So I wiggled a bit the socket, what's left of it I mean, while looking very closely are each wire, where they enter the terminal. This way I could 100% positively say that pin #14 is not crimped properly : I can see the wire coming in and out of the terminal as I wiggle the socket !!! So at least one intermittent connection there. Pin #14 is one of the two heater filaments.

Then I grabbed the DMM and checked continuity of all the other pins, and think I found another one with an intermittent connection : pin #11. This is one of the two horizontal deflection plate.

So.... some hope maybe. Maybe I can try to put some solder inside these two terminal, hoping that would weld the wire inside it ? But that's assuming the wire is not coated in corrosion, or the solder won't make a good contact either 

Have to go, neighbour just knocked on the door, saying I can borrow his truck and trailer... need to go get some gravel for the front yard... see you later then.

[TERRA Operative]

Well, my finger hit the buy button before I even could think what was happening... Roughly US$150 all up..

I see TM500, I buy TM500......... 

[mnementh]

What do you have that's a more capable scope, and why do you think it is?

Nothing as of yet, hence why I did contemplate buying it, that plus the Megazoom thing that I was curious to experience as you were raving about it. But, as I have said, using this scope is not the way I plan on acquiring the logic decoding capabilities. I would not mind having serial decoding and stuff on a scope, but not on this particular scope. I would be interested in having them in a fancy expensive modern scope like the R&S our German friend just acquired, for example, but even then, it still would not be in, replacement of a proper standalone logic analyzer. It would only be as a complement.

Mmmmokayyy... here's the thing. These were the scopes that in their day, were some of the best you could get at doing one very important thing: observing a analog signal and the digital datastream associated with it at the same time, and triggering on either. This is a very common troubleshooting scenario you'll find yourself in when working with anything digital.

This single functionality is not something a standalone LA does as well, and as you've said, you don't have any more capable scope ATM. So for 50 bux, even if you have to skip lunches for a day or three, you could have had one of these groundbreaking scopes, and not an early one, but one of the mature, evolved designs... at a time when it would literally be one of the most, if not the most capable all-around scope on your bench. There's no way you could lose money on this thing.

I'll admit I've overlooked a great deal that was right next to something I had a raging nerd-boner for and didn't realize it until it was too late. More than once.  Every last one of us has done it, and nobody in here would think less of you for it; we'd all offer you our condolences and wish you better luck next time. 

From here, it looks like that's exactly what happened, and all the grumbling about appearances and such is just "sour grapes" type excuses to yourself for overlooking it; I remember you vehemently swearing on several occasions that you care about functionality first and appearance second. Well I can tell you this is a very functional scope, a real all-around workhorse, and you really did miss out.

If it'd been me (and honestly, I can see me possibly not even realizing what that scope was until I saw it in the pictures afterwards), I'd be calling myself aout loud repeatedly, in here, for at least a week. 

I have an earlier version of the Megazoom MSO and it is the last 'scope I would get rid of. Not the fastest, not a full function logic analyser but so capable and Sooo easy to drive. The UI is second to none if you are used to analog 'scopes. I Had the later model at my last work and  also access to a later LeCroy with touch screen and all the bells and whistles. Yes, sometimes I NEEDED to use the LeCroy because of it's bandwidth etc but as a "daily driver" no way. The HP's "mixed" signal" bit is very important to me. If you work with ADCs DACs, PWM etc it is so useful to trigger the analog off the digital (or vice-versa), zoom in see exactly what is going on.
To do that with a LA you need to couple the LA to the scope trigger. Assuming of course the LA has a trigger output. And you have to set up two instrumants and correlate the timing.  Yes the rubber button styling is a bit naff, but this really was the sweetspot of general purpose CRT based 'scopes.
Unless you are doing high speed digital work why would you need a higher speed than 60/100MHz? for RF you would be starting to look at spectrum and network analysers.

1000x this.

And one thing we often forget, because it's hard not to look at the screen and think "Oh, just another CRO..."

It's not a CRO. It's a 100% digital scope that uses a CRT because at the time it was made, similar resolution (~1100lines @60Hz!!!) LCDs were prohibitively expensive, looked dim, had horrible greyscale bit depth (lots of greyscale is necessary for their implementation of slew rate-dependent trace intensity, mimicking the behavior of top-tier CROs), and had ridiculously slow refresh rates.

A CRT was actually the best possible display for all the information these scopes needed to be able to deliver to the user.

mnem
 

[mnementh]

"The two things that really drew me to vinyl
were the expense and the inconvenience."

          BWAHAHAHAHA!

Thanks for the belly laugh; I really needed it after doing limb-to-limb combat with a mess of brush and small trees around our backyard shed, and receiving several minor lacerations for my trouble.

All before my morning cuppa.  But now the painters should be able to get in there and spray the shed to match the house. 

mnem
   Fortunately, MaKobalt SawzAll is like The Hulk in these situations; it always wins. 

[mnementh]

Enthusiasm for TE, you ask?
Have a look at this:

To be assaulted with that annoying delivery first thing in the morning makes me want to punch him unconscious. 

Then why do you subscribe to his channel...? 

Reminds me of the old trick-cyclist joke about causality:

One rhinoceros to another: "Well, if it makes you cross-eyed, why do you keep staring at it...?"

mnem
*unrepentant*

[mnementh]

Vince, all kidding aside. What is the HV on that CRT? I'm assuming about 2kV, right? And it's a 5 inch round tube?

If yes to both questions you may be able to adapt a CRT out of an old Heath or EICO scope. The Heath's used a type 5PU1. Not sure about the EICO's. That 5PU1 has the deflection plate access at the base just like that hp and the HV requirements are 2kV.

Hey... this made me think of something...

What if the arcing isn't just a fault in the CRT, but caused by either HV or a bias voltage being ridiculously too high? Is it possible that the arcing could be made to go away if this was the case and all voltages were brought back in spec?

I know there's a high likelihood of carbon tracks from the arcing rendering that moot... but maybe...? 

mnem
"Hope is the thing with feathers that perches in the soul..." ~Dickenson

[mnementh]

@Tggzzz : that's some intense nerdery, what a decoration !    Your wife supporting that must be a gem....
OK a broken weld inside... that's more difficulty to spot ! Pun again, spot weld !  Oh dear, what's wrong with me today ! 

@AVG : Hack saw blade indeed works a treat, job done, 5 minutes tops ! Because I am a tough guy (not!) I didn't even wrap it with tape.  So I can now see inside the socket...

@Papa Smurf : ... now that I am inside, I can see the pins are NOT soldered, the terminals are crimped ! Hmmm..... what if some are dodgy...
So I wiggled a bit the socket, what's left of it I mean, while looking very closely are each wire, where they enter the terminal. This way I could 100% positively say that pin #14 is not crimped properly : I can see the wire coming in and out of the terminal as I wiggle the socket !!! So at least one intermittent connection there. Pin #14 is one of the two heater filaments.

Then I grabbed the DMM and checked continuity of all the other pins, and think I found another one with an intermittent connection : pin #11. This is one of the two horizontal deflection plate.

So.... some hope maybe. Maybe I can try to put some solder inside these two terminal, hoping that would weld the wire inside it ? But that's assuming the wire is not coated in corrosion, or the solder won't make a good contact either 

Have to go, neighbour just knocked on the door, saying I can borrow his truck and trailer... need to go get some gravel for the front yard... see you later then.

Damn the scroll...   Okay...

First, the glue around the CRT was probably not accidental, or g'rilla abuse. It was most likely where they glued the protective felt ring to the tube. It would be designed to carry the tube against the body of the CRT shield, nice & cozy against the usual thumps & bumps of shipment & installation into the rack.

Second... I didn't catch up in time to suggest this... I would have recommended you try assembling the whole mess without the CRT shield in place, so you could determine exactly where the arcing is coming from...

BEFORE you do something drastic like hacking the octal base apart. *cringe*   

I still recommend you do this before proceeding any further... even if you have to make a temporary support for the CRT out of cut-up bits of cardboard or somesuch.

mnem
Good hunting!

[AVGresponding]

@Papa Smurf : ... now that I am inside, I can see the pins are NOT soldered, the terminals are crimped ! Hmmm..... what if some are dodgy...
So I wiggled a bit the socket, what's left of it I mean, while looking very closely are each wire, where they enter the terminal. This way I could 100% positively say that pin #14 is not crimped properly : I can see the wire coming in and out of the terminal as I wiggle the socket !!! So at least one intermittent connection there. Pin #14 is one of the two heater filaments.

Then I grabbed the DMM and checked continuity of all the other pins, and think I found another one with an intermittent connection : pin #11. This is one of the two horizontal deflection plate.

So.... some hope maybe. Maybe I can try to put some solder inside these two terminal, hoping that would weld the wire inside it ? But that's assuming the wire is not coated in corrosion, or the solder won't make a good contact either 

Have to go, neighbour just knocked on the door, saying I can borrow his truck and trailer... need to go get some gravel for the front yard... see you later then.

I would have recommended you try assembling the whole mess without the CRT shield in place, so you could determine exactly where the arcing is coming from...

BEFORE you do something drastic like hacking the octal base apart. *cringe*   

I still recommend you do this before proceeding any further... even if you have to make a temporary support for the CRT out of cut-up bits of cardboard or somesuch.



mnem
Good hunting!

First, it's not an octal base; there are not 8 pins. Second, you're not going to find bad crimps any other way. It should be possible to 3dp a new base out of ABS, though whether there is an existing model on thingiverse or on here is another matter.

[Saskia]

just wondering, would it be possible to laser weld some broken stuff inside a CRT ?

[tggzzz]

just wondering, would it be possible to laser weld some broken stuff inside a CRT ?

Not in my case: the gap was too wide and they weren't in contact anymore.

[factory]

@Tggzzz : that's some intense nerdery, what a decoration !

Your wife supporting that must be a gem....

OK a broken weld inside... that's more difficulty to spot ! Pun again, spot weld ! 
Oh dear, what's wrong with me today ! 

@AVG : Hack saw blade indeed works a treat, job done, 5 minutes tops ! Because I am a tough guy (not!) I didn't even wrap it with tape.  So I can now see inside the socket...

@Papa Smurf : ... now that I am inside, I can see the pins are NOT soldered, the terminals are crimped ! Hmmm..... what if some are dodgy...
So I wiggled a bit the socket, what's left of it I mean, while looking very closely are each wire, where they enter the terminal. This way I could 100% positively say that pin #14 is not crimped properly : I can see the wire coming in and out of the terminal as I wiggle the socket !!! So at least one intermittent connection there. Pin #14 is one of the two heater filaments.

Then I grabbed the DMM and checked continuity of all the other pins, and think I found another one with an intermittent connection : pin #11. This is one of the two horizontal deflection plate.

So.... some hope maybe. Maybe I can try to put some solder inside these two terminal, hoping that would weld the wire inside it ? But that's assuming the wire is not coated in corrosion, or the solder won't make a good contact either 

Have to go, neighbour just knocked on the door, saying I can borrow his truck and trailer... need to go get some gravel for the front yard... see you later then.

That looks a right mess now, the base should have the wires soldered to the ends of the hollow tubes, exactly the same as ancient US TV picture bulbs, Shango066 has transferred the CRT bases from dead tube to replaced broken ones and yes bad solder connections are sometimes found, you want to avoid soldering anywhere near the glass seal unless you want it to crack. 

If you need a replacement base, I do have a dead 175A CRT (vacuum gone & heater O/C) somewhere.

David

[cyclin_al]

Who was it that wanted a 5245L counter?
One on ePay.de at the moment, the asking price is almost back to what they were before TSP video and no ancient oval connector to worry about. 

https://www.ebay.de/itm/275290271369

David

Was MEEEEEE !!!!

Hmmm... 125 Euros BIN.. reasonable indeed... But too much for me right now 

Especially since it comes with zero plugins.

Later for sure... there will be more for sale.

For now, I have its French counterpart my Ferisol counter, I am happy with it, loving it 

Darn, you were supposed to protect the Canadian French wallet on this one ... am very slightly (SWMBO has other priorities) temped, even with the shipping and extra fees.

[mnementh]

I would have recommended you try assembling the whole mess without the CRT shield in place, so you could determine exactly where the arcing is coming from...

BEFORE you do something drastic like hacking the octal base apart. *cringe*   

I still recommend you do this before proceeding any further... even if you have to make a temporary support for the CRT out of cut-up bits of cardboard or somesuch.   - mnem   Good hunting!

First, it's not an octal base; there are not 8 pins. Second, you're not going to find bad crimps any other way. It should be possible to 3dp a new base out of ABS, though whether there is an existing model on thingiverse or on here is another matter.

Oy... you're right. Also   

I said BEFORE doing something drastic like cutting the $&%! NOT-octal base apart... NOT instead of.

As in, make sure there isn't arcing INSIDE the CRT before you do anything destructive.

We still don't KNOW that we have bad crimps. He could just be having a bad day with poor contact with the meter probes on crusty wires and pins. I can't count the number of times that has happened to me... to every single one of us. 

At this point... mocking it up temporarily in situ definitely should show you if you have arcing inside that pin, under any circumstances.

As for printing a replacement... while I would gladly help a fellow TEA out with that... I just don't see Vince liking the idea of printed bits on his prehistoric iron there. 

If he does manage to fix the thing as he has it there, a safer and much more VINCE fix might be (Kapton tape around the neck to seal off the exposed wires EDIT: Looking again, with the arc-barriers (term?) between the pins, not really feasible. shit.) to epoxy or CA the pieces back in place (where the arc-barriers between the pins will still match up) and cover with a bit of heat-shrink or a layer of Kapton tape if there's clearance with that clamp on the neck.

Let's see what he comes up with. At this point, it certainly seems he has little to lose no matter what path he takes.

mnem
 

[Robert763]

A bit more detail on the CMS33 repair.
The top and bottom covers slide off after you remove the two rear foot moldings. To get to the N type socket fixing to the front sub panel you have to remove the fascia panel / keyboard panel. Apart from the four obvious screws in the corners there are five tiny, <2.5mm, countersunk screws. Four are painted grey and are not hard to spot. The fifth is under the main control knob. You also have to remove the concentric contrast / volume knobs. The panel is connected by a flexible PCB  so don't pull on it
The N socket is held by two countersunk screws.
I can't easily locate the HDD but not going to pull stuff further apart at this stage.

[Cerebus]

   And sorry; I take for granted that anybody can lay hands on these, as they're a standard hardware store item over here from the Hillman drawers in a variety of sizes and depths. Also SOP for car audio installers; certain kits of speakers even come with them standard. 

As a matter of fact, those abominations apparently  are so common in the US that you lot feel a need to replace something nice:



...with them. "ACK! THPPTT!" as Bill the Cat would say.

A caged nut, while a million times better, isn't really a particularly satisfactory solution either, too loose, rattley, needs a punched square hole and so on. There is, of course, a device designed to take a proper machine screw rather than some unter-fastener like a self tapping screw and it's called a rivnut:



I really can't understand why someone sane would eschew one of those for one of these POSes with all the sharp edges, corrosion traps etc.:

[mansaxel]

A caged nut, while a million times better, isn't really a particularly satisfactory solution either, too loose, rattley, needs a punched square hole and so on. There is, of course, a device designed to take a proper machine screw rather than some unter-fastener like a self tapping screw and it's called a rivnut:

Oh, indeed. The cagenut only excels where a sloppy fit is required. The rivnut is a much better proposition in many instances.

Just to clarify;  I never intended for the cagenut to be used by Spec in the door; pop rivets are indeed the more proper choice. My reaction to the Dragon-suggestion of the clipnut was aimed at the sad, pathetic practice of Wire-Nut-Land to use clipnuts where cagenuts are appropriate, i.e. in equipment racks. It's just, but barely so, above the practice of threading the rack strips themselves.

Tool fetischism mode:  So, what rivnut kit should I get?

[factory]

....snip....

Can one find a CRT for this scope these days ? Or one that would fit and be electrically compatible at least ? How expensive are they, if at all available ?
I rescued the scope because it's cute and was free.... I can't justify nor afford to put lots of money for a new CRT... that would need to get shipped of course so might be damaged as well when getting to me 

It's 00H36, I am about to go to bed... and I am very sad, I won't be making sweet dreams..... 

EDIT : the parts list in the manual says the CRT is " P31 PHOSPHOR INTERNAL GRATICULE " , part number 5083-0353

EDIT #2 : just google the P/N. It found one on Ebay USA, sold for .... 570 dollars ! for 450kHz CRT !!! 
Scope is a write off 

https://www.ebay.com/itm/274969806314

That hasn't sold, the listing states seller ended it early i.e. not sold, probably got fed up seeing them not selling, which is hardly surprizing given their stupid prices for untested CRTs.
I don't believe them stating "new in mil box" either, as the phantom tape bomberᵀᴹ has put black tape round the CRT base and is missing the cap to protect the pins. 
The seller name "BangyBang" rings alarm bells to avoid, don't want any of their CRTs going bang on arrival, maybe they should try selling something more fitting to their name, like November 5th/New-years eve rockets. 

As you have the CRT out, try comparing the sizes/pin function to the 5AQP* CRT, these were used in the older 120A, 122A and 130A, they could be similar, but don't have the internal graticule.
https://www.surplussales.com//pdf/CRT/tuc-5aqp1a.pdf
For reference the 5083-0353 P31 CRT was used in both the 120B & 130C.

The three screws on the outside of the tube shield are for the trace rotation coil, this is not present in the earlier scopes without internal graticule.


This is the dead bulb from the first scope I ever bought, a 175A.

Took me ages to find something else to fit, eventually found the special high writing rate CRT for it, in used condition, in the box and with the protective cap present, some phosphor burns but can't complain too much as I've never seen another.
I have since bought a spare standard CRT for it as well.




David

[Specmaster]

<snip>
A caged nut, while a million times better, isn't really a particularly satisfactory solution either, too loose, rattley, needs a punched square hole and so on. There is, of course, a device designed to take a proper machine screw rather than some unter-fastener like a self tapping screw and it's called a rivnut:



I really can't understand why someone sane would eschew one of those for one of these POSes with all the sharp edges, corrosion traps etc.:

I did think long and hard about using a rivet nut, in fact I had them and the tool for installing them in my Amazon basket ready to order, but then I decided that the foam gasket would not be able to provide a proper seal between the door skin and the speaker frame because the speaker is 2nd hand and the gasket has already had many years of compression applied to it. So I went with the standard rivets, the same system was used when the car was built, so the gasket just has to sit on the flat door skin and job done. Nobody else can detect the difference in the bass levels between the front speakers, so I think I can live with it, sounds great once again.