Test Equipment Anonymous (TEA) group therapy thread

[Vince]

Opening the box reveals this: A spanking brand new piece of TE in its original box.

Wow !! 

Looks like your new job is better paid than the old one ! 

I normally don't care for modern digital scopes, I mean anything from this millenium, but the modern R&S ones I actually like enough to want one, had I the money I mean !

Will be watching used prices in the coming years I guess...

[vk6zgo]

...but they asked me to stay "until they could find a replacement".

That was your opportunity.  It would seem you gave an answer which should have been better considered.

When I finally quit, they tried to pretend  I was retiring!
At the HR "pre-departure" interview, I was asked why I was leaving, & had a lot of reasons, mainly to do with them being morons, but decided to "bite my tongue", as I knew it would rebound on the wrong people.

Instead, I said,
"They are very reluctant to change."

The HR person replied,
"Funny!----- You're the fifth person to say that!"

[BU508A]

RTM2004? Very nice!  With all options?

[mnementh]

Yes I was wondering about that, but didn't post about it, one thing at a time I thought ! 
For now the purpose was to debug the thing.

But now that it's clear the Mica caps were the problem, yes I can now try to find a good replacement.
Problem is... I though Mica caps don't exist anymore these days ?! 

I don't know enough about the specs of mica o know what modern / readily available cap technology would be a good replacement.

A modern C0G/NP0 dielectric ceramic cap would also be a suitable substitute for mica in a circuit like this. These have adequate performance to match or exceed the mica caps in terms of tolerance, low loss and temperature stability.

SMD versions of C0G/NP0 caps are readily available from the usual suppliers but finding a supplier with a good range of leaded C0G/NP0 parts may be more difficult.

Thanks, will keep that in mind...

Given the highly agitated state of the angry pixies involved in this circuit, I'd definitely double-check the derating curve on those.

mnem

Yep, 500V rated SMD caps are not particularly small 1206 IIRC to get that sort of V rating.

Well, no... I was thinking VCC (variance in capacitance applied to circuit vs DC bias), not thermal derating. But a little Google-Fu answered my question; COG(NPO) are a Class I cap, so no appreciable VCC curve.

I was thinking back to my work with people designing high-speed/high-current multirotor ESCs, where VCC derating was a nightmare. When you're trying to make it profitable at ~$20 a copy, you really don't have a lot of choice about using cheap MMLCCs. 

For those playing along at home, some relevant resources:

https://ec.kemet.com/blog/mlcc-dielectric-differences/

mnem
 

[capt bullshot]

RTB2004, 300MHz, all options.

Vince: My new job isn't paid much different than the old one. In fact, I've got less money now because I've changed from 40h to 35h per week. Wouldn't want that back, anyway.

This acquisition is based just on the two questions:
- Do I want it?
- Can I afford it?

[mnementh]

Opening the box reveals this: A spanking brand new piece of TE in its original box...   

Shiny! Seems like there was some precision measurement involved even before purchase, to make sure it fits the shelf 

Ditto!!! On BOTH points!     Congrats, Cap'n! 

mnem
*wondering how deep Cap will slide down this new rabbit-hole...*

[mnementh]

RTB2004, 300MHz, all options.

Vince: My new job isn't paid much different than the old one. In fact, I've got less money now because I've changed from 40h to 35h per week. Wouldn't want that back, anyway.

This acquisition is based just on the two questions:   - Do I want it?   - Can I afford it?

Whufff... that model varies greatly dependent upon the options. from ~$2K to over $4K.

Something like this bundle...?

https://www.tequipment.net/Rohde-&-Schwarz/RTB2K-COM4/Mixed-Signal-Oscilloscopes-(MSO)/

mnem
*still  *

[capt bullshot]

like this bundle...?

https://www.tequipment.net/Rohde-&-Schwarz/RTB2K-COM4/Mixed-Signal-Oscilloscopes-(MSO)/

Yes, exactly. The RTB2K-COM4.

[mnementh]

Now I wanna mug you for that scope... 

mnem
you can take that as a compliment. 

[Zucca]

Now snowing, and I have to go out. Bah!

(Only "Bah!" because it's enough snow to be a nuisance, and not enough to be fun.)

Don't drive your BMW in snow, unless you are prepared to laugh or cry a lot.
(press on DSC button and DTC (Dynamic Traction Control) active helps to not get stuck, long press on DSC button it is not suggested... on public roads)

In our internal trainings they tough us "Remember, there is no restore button after a crash".

[mnementh]

mnem
*toddles off to design something in Frustion360*

[Specmaster]

Yeah long live Mouser, many of them there, 8,500 !    Lucky you US bastards !

Here on Farnell MUCH less choice, only 174 references, and 90% of them aren't really available : not in their European stock / warehouses, US only, they charge 18 Euros to get them here ! 

Luckily out of the handful that can be bought locally, they happen to have the two values I need, 56pF and 250pF, yeah ! Exact same voltage rating as well, 500V, cool.

They are precision caps at that : 1% for one, 5% for the other, vs 10% for the old one. Should do it 

Bloody expensive at 5 Euros a pop ! Glad I only need 3 of them. So 15 Euros + 10 Euros shipping, 25 Euros for 3 tiny caps, wow.... 

Oh come on, you are joking, there must loads of suppliers in France who can supply these, you just have to use the search engines better.

Why would I be making this up ?! Just look for yourself on their site if you don't believe 

No need to use their search engine or parametric search, at the risk of missing on stuff indeed, no... their cap section is neatly organized and they have a sub-section devoted solely to Mica caps 

You completely misunderstood my point, which was originally you thought they were no longer available. There simply has to be many online suppliers in France that sell these as they are very common especially on RF equipment from simple domestic radios right the way through to very specialist gear. So I was merely saying that using google wisely is your best friend, and means that sometimes you have to be inventive with your searching parameters, try using terms like "electronic component suppliers" etc instead of just searching for the actual part required as a generic search term. That way, you will build up a library of part suppliers that you should be able to source your requirements from, unless it is really obsolete.

[AVGresponding]

Pretty simple stuff but when things go right and using test gear that guarantees confidence, its such a huge relief...





 

Holio-fuck, how many pixies? I hope that was a cell-equalisation charge

[mnementh]

15.5 volts is completely normal for a fast-charge/boost charge condition with a charger. Some high-current alternators will boost to 14.2-14.8V for a few seconds right after a long crank/hard start. 

mnem
*tzzzzzt*

[TERRA Operative]

Anyone into Halo? Watching the new series?

Besides a big glaring obvious thing they did (that I don't thing they should have done) that was specifically never done in the game, it was entertaining enough to keep me rabidly interested.


Oh, also this. Latest TEA thing on the bench and under construction. A Retro Chip Tester Pro, will be great for testing TTL stuff from all the old gear I always end up restoring.

[BU508A]

RTB2004, 300MHz, all options.

Welcome to the RTB2004 club. 

Same here RTB-2K-COM4 but with 100MHz.
Now I need to find a good offer for an upgrade to 300MHz ...   

[AVGresponding]

15.5 volts is completely normal for a fast-charge/boost charge condition with a charger. Some high-current alternators will boost to 14.2-14.8V for a few seconds right after a long crank/hard start. 

mnem
*tzzzzzt*

It is but you don't want to do it often, and I'd hesitate to do it as part of a recovery-from-flat charge. 14.4V is a standard voltage for old-skool alternators.

[Specmaster]

15.5 volts is completely normal for a fast-charge/boost charge condition with a charger. Some high-current alternators will boost to 14.2-14.8V for a few seconds right after a long crank/hard start. 

mnem
*tzzzzzt*

It is but you don't want to do it often, and I'd hesitate to do it as part of a recovery-from-flat charge. 14.4V is a standard voltage for old-skool alternators.

The alternator on my car will go upto 14.8V if required, but normally sits around the 14.4V level but a battery left charging at 15.5v will cook and boil away the electrolyte and that is real nasty. The fumes and smell of the gas makes your eyes steam and your throat feel like its on fire. I remember having to go out late one night and recover a double-decker Bristol FLF that refused to restart its engine when the time came for its return trip on its bus route. When I got to the terminus with the replacement bus, the passengers and crew were standing around outside, despite it raining. The batteries were located under the stairs in the conductors' stowage area and when I walked inside to check the batteries for bad connections, I found out why 

I then had to phone up for the breakdown truck to come out and tow the bus back for new batteries and alternator/regulator change.

[med6753]

Here you go Brumby. This one's for you. More 7000 series plug-in goodness.  Military 7603N on bench 1 for some power up time replacing a 465B/DM44 and 475A. I gotta pull the center plug-in and clean the attenuator deck. It's very noisy.

The military 7603N has no fan and a linear PSU and gets damn hot in the back. Later versions of the 7603 did have a fan. Adding a fan would involve cutting the covers because they are louvered rather than a screen like the 7904. Not gotta happen.



Ain't I a stinker? Can't help myself. 

3 bays....  100MHz, I believe?  Hmmmm.   Beggars can't be choosers, I suppose.

How much for $hipping?

For some reason the military 7603N is only spec'ed to 65MHz. Why? Don't know. Other than some mechanical bits like different type covers and slightly different front panel it's identical to civilian 7603N. I would have to examine the vertical circuits carefully to determine if there really is a difference electrically. 

[med6753]

15.5 volts is completely normal for a fast-charge/boost charge condition with a charger. Some high-current alternators will boost to 14.2-14.8V for a few seconds right after a long crank/hard start. 

mnem
*tzzzzzt*

It is but you don't want to do it often, and I'd hesitate to do it as part of a recovery-from-flat charge. 14.4V is a standard voltage for old-skool alternators.

The alternator on my car will go upto 14.8V if required, but normally sits around the 14.4V level but a battery left charging at 15.5v will cook and boil away the electrolyte and that is real nasty. The fumes and smell of the gas makes your eyes steam and your throat feel like its on fire. I remember having to go out late one night and recover a double-decker Bristol FLF that refused to restart its engine when the time came for its return trip on its bus route. When I got to the terminus with the replacement bus, the passengers and crew were standing around outside, despite it raining. The batteries were located under the stairs in the conductors' stowage area and when I walked inside to check the batteries for bad connections, I found out why 

I then had to phone up for the breakdown truck to come out and tow the bus back for new batteries and alternator/regulator change.

Classic British double decker bus on a classic British roundabout. How quaint. 

[ch_scr]

W2AEW has a new video "The ULTIMATE Electrical Engineers Toolkit: Analog Designer's Edition"
with a few nifty gadgets most of us could do with:

Viewer discretion is advised

[Robert763]

15.5 volts is completely normal for a fast-charge/boost charge condition with a charger. Some high-current alternators will boost to 14.2-14.8V for a few seconds right after a long crank/hard start. 

mnem
*tzzzzzt*

It is but you don't want to do it often, and I'd hesitate to do it as part of a recovery-from-flat charge. 14.4V is a standard voltage for old-skool alternators.

The alternator on my car will go upto 14.8V if required, but normally sits around the 14.4V level but a battery left charging at 15.5v will cook and boil away the electrolyte and that is real nasty. The fumes and smell of the gas makes your eyes steam and your throat feel like its on fire. I remember having to go out late one night and recover a double-decker Bristol FLF that refused to restart its engine when the time came for its return trip on its bus route. When I got to the terminus with the replacement bus, the passengers and crew were standing around outside, despite it raining. The batteries were located under the stairs in the conductors' stowage area and when I walked inside to check the batteries for bad connections, I found out why 

I then had to phone up for the breakdown truck to come out and tow the bus back for new batteries and alternator/regulator change.

As a teenager I won an engineering competion and one of the prizes was a series of visits to Chloride facilities (including in the USA) this included a facility where industrial lead acid batteries were having their plates "formed". Health and safety was a bit less formal in the late seventies. Just a few minutes in there was enough to clear your sinuses and everything else.

[Robert763]

Here you go Brumby. This one's for you. More 7000 series plug-in goodness.  Military 7603N on bench 1 for some power up time replacing a 465B/DM44 and 475A. I gotta pull the center plug-in and clean the attenuator deck. It's very noisy.

The military 7603N has no fan and a linear PSU and gets damn hot in the back. Later versions of the 7603 did have a fan. Adding a fan would involve cutting the covers because they are louvered rather than a screen like the 7904. Not gotta happen.



Ain't I a stinker? Can't help myself. 

3 bays....  100MHz, I believe?  Hmmmm.   Beggars can't be choosers, I suppose.

How much for $hipping?

For some reason the military 7603N is only spec'ed to 65MHz. Why? Don't know. Other than some mechanical bits like different type covers and slightly different front panel it's identical to civilian 7603N. I would have to examine the vertical circuits carefully to determine if there really is a difference electrically.

Is the CRT the same part number? Military means ruggedized and the a rugged CRT may not have the same performance as the standard one.

[med6753]

Here you go Brumby. This one's for you. More 7000 series plug-in goodness.  Military 7603N on bench 1 for some power up time replacing a 465B/DM44 and 475A. I gotta pull the center plug-in and clean the attenuator deck. It's very noisy.

The military 7603N has no fan and a linear PSU and gets damn hot in the back. Later versions of the 7603 did have a fan. Adding a fan would involve cutting the covers because they are louvered rather than a screen like the 7904. Not gotta happen.



Ain't I a stinker? Can't help myself. 

3 bays....  100MHz, I believe?  Hmmmm.   Beggars can't be choosers, I suppose.

How much for $hipping?

For some reason the military 7603N is only spec'ed to 65MHz. Why? Don't know. Other than some mechanical bits like different type covers and slightly different front panel it's identical to civilian 7603N. I would have to examine the vertical circuits carefully to determine if there really is a difference electrically.

Is the CRT the same part number? Military means ruggedized and the a rugged CRT may not have the same performance as the standard one.

Good point. I'll have to check. I have a copy of the manual.

[med6753]

W2AEW has a new video "The ULTIMATE Electrical Engineers Toolkit: Analog Designer's Edition"
with a few nifty gadgets most of us could do with:

Viewer discretion is advised

I was wondering when he was finally going to pull out the bullshit...oops...I mean management repellent. He did not disappoint.