Test Equipment Anonymous (TEA) group therapy thread

[Cerebus]

2. Avoids the risk of losing/misplacing a component.  A board is harder to lose.

You've clearly never been in my "box room of doom". 

[Cerebus]

Is it proper TEA if you make it yourself?

Depends what you mean by "proper".

For me, I would ask: Is it Equipment used for Testing (in any sense)?

Your answer to that would be my answer to your question.

It's theft, isn't it? All Proper TEA is theft 

Back of the bike sheds laddie! NOW!

[Cerebus]

that's ok until you get half way home and realise you've got velcro ties stuck all over your ass.

If your arse is hairy enough for Velcro to stick to it the cable ties are not your problem. 

[Saskia]

cough. lung bug. fever rising. called in sick at the job already.eff.

[tautech]

SA input protection.


Thanks for your replies people.

So in short, it sucks to be a SA....

Not so much really if you observe some pretty basic cautions.

~5 years back I'd never used one or knew much about them when I brought our demo SSA3032X and sweated mighty hard about blowing RF inputs and although I also got Siglent's Utility kit with it that included a 10dB DC block after a while I rarely ever used it.
I did a # of simple projects with it then later realized one of Siglent's SA/VNA models would be a better fit for my personal needs so got a SVA1015X that I moved on as 2nd hand when SVA1032X were released and that is what I use for most everything RF today.
My first SSA3032X got boxed up and spent a year or so sitting until the right customer came along but sadly Charlie seems not to have done much recently with it.
https://www.youtube.com/c/CharlieMorrisZL2CTM/videos

While you can certainly bust the inputs on these and there have been a couple on the blog lately only bad mistakes or forgetting safety steps will damage any of these as they have 50V rated inputs.
With their 51dB* of available internal attenuation and left on Auto they pretty much look after themselves and give audio and visual warnings should you be nearing any possible damage limits.

A couple of chaps here have these and the most popular is SSA3021X Plus converted to SVA1032X that gets you to 3GHz which is enough for most of us.

(*read datasheet for input limits)

[tggzzz]

After reading recent posts in this thread, I feel like I should just sell my spectrum analyzer. I'm too scared to ever use it now. 

it's sort of like having a scope with input termination options.  you had better think twice before you select 50 ohms.

have never blown one up myself, but have seen lots of attenuators toasted by others.

be a nervous nelly........check everything twice or keep external protection hooked up all the time (or until you are convinced you are not about to do something stupid) and you will be fine.

edit  one of the nice things about my hp54601 and hp54622 is that they don't have 50 ohm inputs.  you have to really really work at killing one of them.  that is one reason they are my daily drivers and the hp54502 and 54504 only get turned on when 400 Mhz of bandwidth is actually required.

Tek 485s have both a 1Mohm//15pF attenuator and a 50ohm attenuator, with a relay to select which is in use. It also has a voltage sense which automatically switches to 1Mohm if the power would damage the 50ohm attenuator.

If only all scopes paid such attention to practical details.

[Specmaster]

cough. lung bug. fever rising. called in sick at the job already.eff.

Oh dear, let's hope It's nothing too bad and passes quickly, take care of yourself.

[nixiefreqq]

After reading recent posts in this thread, I feel like I should just sell my spectrum analyzer. I'm too scared to ever use it now. 

it's sort of like having a scope with input termination options.  you had better think twice before you select 50 ohms.

have never blown one up myself, but have seen lots of attenuators toasted by others.

be a nervous nelly........check everything twice or keep external protection hooked up all the time (or until you are convinced you are not about to do something stupid) and you will be fine.

edit  one of the nice things about my hp54601 and hp54622 is that they don't have 50 ohm inputs.  you have to really really work at killing one of them.  that is one reason they are my daily drivers and the hp54502 and 54504 only get turned on when 400 Mhz of bandwidth is actually required.

Tek 485s have both a 1Mohm//15pF attenuator and a 50ohm attenuator, with a relay to select which is in use. It also has a voltage sense which automatically switches to 1Mohm if the power would damage the 50ohm attenuator.

If only all scopes paid such attention to practical details.

now that IS a nice feature.  was not aware of it.  makes me almost want to go in search of a 485.

THANKS FOR NOTHIN'

[tggzzz]

now that IS a nice feature.  was not aware of it.  makes me almost want to go in search of a 485.

THANKS FOR NOTHIN'

That's what we are here for. A good 485 is a joy to use, triggering up to >1GHz.

Another almost unique function is the calibrator output with a risetime of <1ns.

The over-voltage protection is well documented too; see the screendump below. The partial schematic shows the input stage; red dot is the relay, green dot the 1Mohm attenuator, blue dot the 50ohm attenuator.

[Cubdriver]

2. Avoids the risk of losing/misplacing a component.  A board is harder to lose.

You've clearly never been in my "box room of doom". 

\

Nor my house.  I misplaced my Lucent rubidium oscillator for a while...   

-Pat

[Vince]

You definitely have rich people's problems !

[Vince]

SORTING TIME

OK so some more stuff to sort... this time OPTO stuff.... I like opto stuff, it's just cool.

[...]

1h20AM, I have just finished Googling and sorting all my photo couplers 

52 total.  3 of them were scrapped as I can't read what's on them. Then 2 of them I can read perfectly but Google can't find me anything. See pic below, if you know what they are, I am all ears.

So that left me with 47 I could actually research.

I thought it would be boring but it was not at all... because there was much more diversity in these things than I had imagined was possible.

Other than a couple Fairchild and one NEC, 90% of the stuff is split evenly between only two manufacturers : Sharp and Toshiba.

Great variety as I said...


- Some have photo transistor
- Some have photo darlington
- Some have a photodarlington with a built-in reverse protection diode between Collector and Emitter.
- Some have a photo diode associated with a regular transistor
- Some give you access to the base of the transistor, so you can drive it yourself should you want to for.... I don't know what reason.
- Some have Faraday shield between the emitter and detector.
- Some can be driven with AC signals : inside there are TWO LEDs, wired in // in reverse polarity.

The one thing they have in common though, is just how slow they are, and how highly unpredictable their speed is. rise and fall times, turn on and turn off... vary so immensely from the factory, and are also affected so greatly by how much voltage and current you use for the output transistor...
some datasheet don't even mention the "storage time", even though it's super important as it ruins every hope you had at fast switching, if you only looked at the rise and fall times...
Some DO show the storage time in the timing diagram BUT... in the tables of parameters it does NOT tell you how much it is ! SO basically the thing is useless, as this parameter is what makes or breaks you max speed... since it appears to be usually much slower than the rise and fall times.

It was cool looking at all that diversity... I felt like a biology student flipping a rock on the beach and looking closely with his microscope to marvel at just how much life there can be under there, and taking notes to write a report for his professor...that would be TEA jury for me.

Now that gives me an idea for yet another little experiment. I have dozen of the TLP559  and PC817, two different manufacturers then.

I could measure the timing characteristic of all of them, using obviously the same operating conditions stated in the datasheet, and makes statistics to see how real life correlates to the numbers we see i the datasheet. Are they realistic.. too optimistic... or too pessimistic.
I gather that the LED in photocouplers can "wear out" over the years, so I anticipate that I might eventually get results in average a bit worse than when they were new.

If you want to do that experiment, press #1. If you don't want it, press #1 as well, because I will do it regardless ! 

[Anthocyanina]

Perhaps this is the sort of question to be asked here, or perhaps it would just lead to people saying "yes! go for it"  I don't need more oscilloscope probes at the moment, but someone posted locally about some oscilloscope probes, tektronix p2220, new selling each for 10$, mixed with other brands of probes, each probe for the same price, unbranded, uni-t, the tek ones. It sounds like a really good deal, it could also be a scam of some sort, but i got pictures of the probes and wonder if anyone would go to the trouble of getting the pictures, and of the random ones too, just to scam so little money. It's 4 tek ones, are those ones worth it? should i risk losing 40 for something i don't need that may be good, or may not be anything at all? the cables are bent a bit tight, so maybe the seller doesn't know about probes, which may also be why they're selling all for the same price?  am i getting to close to the TEA way? 

[Vince]

You forgot to post the pic !!! 

Yes it's TEA stuff, you are definitely at the right place...

BEWARE : the P2220 probe is designed to work only on a very limited range of Tek scopes !

See Tek's website there :

https://www.tek.com/en/datasheet/passive-voltage-probe-1x-10x

Meant for use only with the following Tek scopes :

The P2220 probe is compatible with TDS200, TDS1000, TDS1000B, TDS2000, TDS2000B, and TPS2000 Series oscilloscopes.

How do I know ? Well I was in your very position a year ago and nearly made the same mistake you were about to make... like you I asked on here and people saved my wallet ! 

So since you said you don't even need more probes.... I guess it's best to keep your money and not buy them !
Instead, spend your 40 bucks on some piece of TE, an old DMM, some test leads, pliers, screw drivers, new tips for your soldering iron....

[Specmaster]

In the saga of replacing car speakers it was my turn yesterday. Original speaker had broken its foam surround, and thus unbound, proceeded to jump its voice coil, former and all out of the magnet gap.

Replacement was surprisingly hard to locate. Turns out it is the most basic speaker kit sold as original fit, with a dual-cone broadband driver. The LF-only ones are easier to find; or at least were back when I swapped on my older cars, who had higher-spec drivers. However, local auction site supplied a used pair for about 41€, which is very good.



Fitting is pretty easy; the driver is mounted in the door with 4 pop rivets, which drill out. A quick-disconnect is supplied, so electrical connection is child's play. 4 new pop rivets and you're done.

The harness has a parallel (MetraHit checked, hence.) connection to a tweeter. Which appeared blown as I tested my work. Closer inspection revealed that no, there was no tweeter at all. What sits in the hole is a dummy.



The left one is an actual tweeter; the right one is a dummy.  They do make a good job of hiding the fact; the quick-connect is present and works, albeit sans electrical connection. I quickly dug tweeters out of the doors of my parts cars, and made a significant upgrade to the system.

What the... hell model of car have you got, then? I thought Volvo was supposed to be a premium brand, and they can't even fit tweeters to all doors and channels  Mine even has mid range and tweeters, woofer at the bottom, mid range in the middle and tweeters right at the top by the door latch. Only 4 pop rivets hold your woofer, did you get any distortion / vibration of the speaker chassis on deep bass as a result of tahat that or are your speakers slightly smaller than most, mine had 6 rivets to secure it to the door skin. I should think you certainly notice the extra top end now?

[med6753]

now that IS a nice feature.  was not aware of it.  makes me almost want to go in search of a 485.

THANKS FOR NOTHIN'

That's what we are here for. A good 485 is a joy to use, triggering up to >1GHz.

Another almost unique function is the calibrator output with a risetime of <1ns.

The over-voltage protection is well documented too; see the screendump below. The partial schematic shows the input stage; red dot is the relay, green dot the 1Mohm attenuator, blue dot the 50ohm attenuator.

And I can testify that the over voltage protection of the 50 ohm input does work. The Type 105 Square Wave Generator upon power up for a second goes high them settles to the set output voltage. That high was enough to trip the input over to the 1MEG input and set the red warning light. Cycle power on the 485 to reset.

[Brumby]

2. Avoids the risk of losing/misplacing a component.  A board is harder to lose.

You've clearly never been in my "box room of doom". 

Nor my house.  I misplaced my Lucent rubidium oscillator for a while...   

Note my use of the comparative: "er".

I did this as I am well aware that each of us will have our own degree of disorganisation - but that, within each of our own little realms, a (bigger) board could be more easily located than a smaller component.

But, I should concede that such a concept is based on a rather simplistic logic ... a logic that may be ill-fitting to the subject.  (Scurries away wondering where the box is I was looking for last week........... )

[mnementh]

cough. lung bug. fever rising. called in sick at the job already.eff.

Take care of yerself Valkyrie. Lots of decongestant and antihistamines. I also like Lemon Ricolas for symptomatic relief. 

mnem
and of course, bedrest. Why are you up reading this...?

[med6753]

2. Avoids the risk of losing/misplacing a component.  A board is harder to lose.

You've clearly never been in my "box room of doom". 

Nor my house.  I misplaced my Lucent rubidium oscillator for a while...   

Note my use of the comparative: "er".

I did this as I am well aware that each of us will have our own degree of disorganisation - but that, within each of our own little realms, a (bigger) board could be more easily located than a smaller component.

But, I should concede that such a concept is based on a rather simplistic logic ... a logic that may be ill-fitting to the subject.  (Scurries away wondering where the box is I was looking for last week........... )

Several months ago I took the time and effort to better organize the TE closet plus organize and label the totes of parts in the garage. I like to think I can now quickly find what I might need but I'm sure I'm probably kidding myself. 

Edit.....although last week when I needed a rectifier bridge for the 475A it was quickly located in a 465 parts unit. Murphy sez wait till next time.   

[Kosmic]

You forgot to post the pic !!! 

Yes it's TEA stuff, you are definitely at the right place...

BEWARE : the P2220 probe is designed to work only on a very limited range of Tek scopes !

See Tek's website there :

https://www.tek.com/en/datasheet/passive-voltage-probe-1x-10x

Meant for use only with the following Tek scopes :

The P2220 probe is compatible with TDS200, TDS1000, TDS1000B, TDS2000, TDS2000B, and TPS2000 Series oscilloscopes.

How do I know ? Well I was in your very position a year ago and nearly made the same mistake you were about to make... like you I asked on here and people saved my wallet ! 

So since you said you don't even need more probes.... I guess it's best to keep your money and not buy them !
Instead, spend your 40 bucks on some piece of TE, an old DMM, some test leads, pliers, screw drivers, new tips for your soldering iron....

Other than the fact that the compensation range is rather limited, they look like standard 1x - 10x passive probe 

[mnementh]

...I pulled one of my 3478A's back off the shelf to finish the backlight mod I was working on. Just gotta work out a way to hold the LCD panel assembly in without fouling the chassis. I had originally planned to flip the OEM bracket around to make things fit with some standoffs, but it hits the chassis, so I might have to fabricate a plate from some aluminium. Once that's sorted, it's just a matter of getting a 7809 vreg to run the LED's and it should be good to button back up and test. Fingers crossed there's no other faults in the unit (as my luck would have it....).

I like how even the backlighting appears from this pic... what approach did you take? LED(s) & diffuser at each end of the LCD?

mnem
 

[Saskia]

cough. lung bug. fever rising. called in sick at the job already.eff.

Take care of yerself Valkyrie. Lots of decongestant and antihistamines. I also like Lemon Ricolas for symptomatic relief. 

mnem
and of course, bedrest. Why are you up reading this...?

just woke up, 39 C fever and dry cough . I guess it's everybody's fav bug even tho the test was negative yesterday. probably picked it up during physiotherapy..
I"m letting in fresh air before I continue sleeping ...

[Brumby]

Valkyrie ... do take care!

Several months ago I took the time and effort to better organize the TE closet plus organize and label the totes of parts in the garage. I like to think I can now quickly find what I might need but I'm sure I'm probably kidding myself. 

Edit.....although last week when I needed a rectifier bridge for the 475A it was quickly located in a 465 parts unit. Murphy sez wait till next time. 

I hear you.

[mnementh]

cough. lung bug. fever rising. called in sick at the job already.eff.

Take care of yerself Valkyrie. Lots of decongestant and antihistamines. I also like Lemon Ricolas for symptomatic relief. 

mnem
and of course, bedrest. Why are you up reading this...?

just woke up, 39 C fever and dry cough . I guess it's everybody's fav bug even tho the test was negative yesterday. probably picked it up during physiotherapy..
I"m letting in fresh air before I continue sleeping ...

Uggghhh... best wishes, m'dear. Hope your hubby is up to pampering you as you need and deserve right now. If you can choke it down, maybe a little rice and/or cottage cheese to give your body the energy it needs for this fight.

mnem
*worried sigh*

[mnementh]

You forgot to post the pic !!!     Yes it's TEA stuff, you are definitely at the right place...

BEWARE : the P2220 probe is designed to work only on a very limited range of Tek scopes !

See Tek's website there :   https://www.tek.com/en/datasheet/passive-voltage-probe-1x-10x

Meant for use only with the following Tek scopes :

The P2220 probe is compatible with TDS200, TDS1000, TDS1000B, TDS2000, TDS2000B, and TPS2000 Series oscilloscopes.

How do I know ? Well I was in your very position a year ago and nearly made the same mistake you were about to make... like you I asked on here and people saved my wallet ! 

So since you said you don't even need more probes.... I guess it's best to keep your money and not buy them !   Instead, spend your 40 bucks on some piece of TE, an old DMM, some test leads, pliers, screw drivers, new tips for your soldering iron....

Other than the fact that the compensation range is rather limited, they look like standard 1x - 10x passive probe 

Yeah, same here... as long as it's a genuine Tek P2220 or P2221 probe, not the Chinesium ones sold under the same or similar-sounding name. Either  should work well with your 2465 or your 54645A up to their rated spec... and I'd def trust them to perform at higher than rated spec before I'd trust Chinesium cheapies to perform at their rated spec. 

What may not work is the automatic ratio selector, which I think these have. But for that price, who cares as long as they're geniune Tek?

mnem