Test Equipment Anonymous (TEA) group therapy thread

[mnementh]

Sure, but with two you can run them slower to reduce the noise further without lowering the volume of air thru-put.  McBryce.

You can tell BD isn't active on here at the moment, he'd be moaning about noisy fans 

This'd shut him up. 200mm x 30mm, 25dBA @ 850RPM Max.   

Picked it up at The Thrift the other day cuz green tags were 50% off, so 6 dollah.

mnem
and of course because 200mm Big Mandingo fan. 

[mnementh]

took some pictures earlier in the week at a stand of trees about 1/2 mile from the house. the majestic bald eagle.  subsist mostly on dead fish washed up on shore, roadkill, and garbage dumps.

"For my own part I wish the Bald Eagle had not been chosen as the Representative of our Country. He is a Bird of bad moral Character. He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk; and when that diligent Bird has at length taken a Fish, and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him."

Benjamin Franklin

Nice pics nonetheless.

Remember too, that Franklin lobbied for the Turkey as our national bird since it is at least native to North America. Which bird (at least the domesticated variant) has supposedly been observed to stand out in thunderstorms with its mouth open en masse until it drowns. 

Mayhaps we should... it certainly would make the national bird representative of the "average American" consumer, wouldn't it...?

mnem

[Robert763]

Best all-round car Ive ever owned was a Audi S4 Avant, the B5 2.7 biturbo V6.
Never failed. Could take it to any venue from a funeral / job interview to a car meet without issue. Could get a huge load of TE in the back. Only downside was fuel consumption and later on maintenence costs.
I would not buy any 21'st century Audi.

[mnementh]

Started lay out for cooling fan install on 7904. Template installed for drilling of the mounting holes. The fan will mount in that open space in the back above the PSU down in the lower right. The fan will draw the air in from the bottom vents and exhaust it out the side. The individual who initially did this also installed a fan on the opposite side by the vertical output board. He must have used a very slim fan. The fans I have won't clear the board and the cover. So I'll just run for now with one fan. It will probably be sufficient anyway especially since this scope never had a cooling fan.

More as I complete the install.   

Hold off drilling holes, if you haven't already buddy. This is actually a good job for 3DP. Before you roll your eyes    at me to death... let me explain.

These fans typically do not work well bolted right up to a grille like this; they aren't meant to push against the static pressure this generates. A spacer... even a thin one of 10-13mm depth... makes a world of difference in how well they work, and also helps them work quieter.

In your case, it would serve twofold purpose... a bespoke adapter would help make it work better, and it would allow one to make it such that the mounting of the fan to the case uses the existing grille holes, such that you don't have to drill at all.



Give me some measurements; exact center-center on the hole spacing on that grille... and I'll see what I can whip out for you. I already have a template for 120mm fan mounting.

Alternately; you CAN easily make that fan mount using the existing grille holes; just rotate it a bit (yes, from the inside it'll look all crooked, but from the outside you'll barely be able to tell) such that two diagonal holes in the fan line up with the top row and bottom row of holes in the grille. I've done this gazillions of times on temp installs for testing purposes (and for rando projects where time was more important than looks), and it works out well.

As the holes in the grill are smaller than the 4mm (nominal for self-tapping screws) mounting holes in a 120mm fan, you'll need to use screws and nuts that will fit through the holes in the grille; I'm reasonably sure you have something that will work.

mnem
 

[Cerebus]

I was saving up for a used BMW i3...
But I can take a bike for the time being 

My 2018 i3S goes back to the leasing company on Friday.   We are going down to one car, which puts me on a bicycle or bus several times a week.


The i3S is one of the best cars I've ever had.   Only car I've had with zero faults. Everything worked on delivery and everything still works.



If you get a used i3, be sure to get a 2017 or newer.     2017 was the first year with the 94Ah (~34kWh) traction battery.  2018 was the first year with LCI (facelift) which looks about the same but has many improvements.     Stay far away from 2013's and 14's. 

In my opinion the S is the one to get but the stiffer ride is not for everyone.  Also the rear tyre size is unique to the i3s.   

The i3 is one of the very few production cars with a carbon fibre body.  All of the others are exotic sports cars.

I'm in the process of hunting for a replacement car, the old one (1997 reg) 22 years of highly reliable service to me has  reached that point after  where things are inevitably starting to go wrong. My engineering spidey senses are telling me that every fault fixed now will soon be replaced by a new fault.

Having been pleasantly surprised that some electric and hybrid vehicles have reached the 2nd hand market at sane prices I was looking through electric and hybrid cars on one of the used car websites sorted only by proximity to me, just looking to get a feel for what was available and at what price with no regard to make, model, or any other criteria. While scrolling through I was pointing out pictures to SWMBO. An i3 hove into view - "Ah! Ugh! NO! WTF is THAT!" came out of SWMBO. I tend to agree with her that it has a face that only a mother could love.

I'm toying with the idea of going later to take a look at a 2016 BMW 330e plug-in hybrid up the road from me. A 4 door saloon, rather pedestrian by my tastes which tend towards 2 doors and an open top, but the performance is surprisingly acceptable (0-60 in a fraction over 6 seconds) and by dint of the peculiar way that all the UK bodies have set the standards counts as a low emissions vehicle which qualifies for £0 annual road tax, no congestion charge and dodges any other emissions based pricing that is increasingly being applied to things (e.g. residents parking permits where I am).

[med6753]

Started lay out for cooling fan install on 7904. Template installed for drilling of the mounting holes. The fan will mount in that open space in the back above the PSU down in the lower right. The fan will draw the air in from the bottom vents and exhaust it out the side. The individual who initially did this also installed a fan on the opposite side by the vertical output board. He must have used a very slim fan. The fans I have won't clear the board and the cover. So I'll just run for now with one fan. It will probably be sufficient anyway especially since this scope never had a cooling fan.

More as I complete the install.   

Hold off drilling holes, if you haven't already buddy. This is actually a good job for 3DP. Before you roll your eyes    at me to death... let me explain.

These fans typically do not work well bolted right up to a grille like this; they aren't meant to push against the static pressure this generates. A spacer... even a thin one of 10-13mm depth... makes a world of difference in how well they work, and also helps them work quieter.

In your case, it would serve twofold purpose... a bespoke adapter would help make it work better, and it would allow one to make it such that the mounting of the fan to the case uses the existing grille holes, such that you don't have to drill at all.



Give me some measurements; exact center-center on the hole spacing on that grille... and I'll see what I can whip out for you. I already have a template for 120mm fan mounting.

Alternately; you CAN easily make that fan mount using the existing grille holes; just rotate it a bit (yes, from the inside it'll look all crooked, but from the outside you'll barely be able to tell) such that two diagonal holes in the fan line up with the top row and bottom row of holes in the grille. I've done this gazillions of times on temp installs for testing purposes (and for rando projects where time was more important than looks), and it works out well.

As the holes in the grill are smaller than the 4mm (nominal for self-tapping screws) mounting holes in a 120mm fan, you'll need to use screws and nuts that will fit through the holes in the grille; I'm reasonably sure you have something that will work.

mnem
 

Thanks for the offer but too late. Holes already drilled and fan mounted.

[Brumby]

Med and fans .... no quarter given, just results.


Can't say I'm surprised in the least.

[Specmaster]

Don't ya just love the Amazon tracking system, I just tracked my Dupont kit delivery and discovered that the driver is in the next street and is currently just 6 stops away from me. So looking forward to making my extension leads so that I can work easier on the SC110 scope.

Only problem is, that I have to go bloody shopping now as I shall be out tomorrow at RAF Mildenhall 

[mnementh]

Thanks for the offer but too late. Holes already drilled and fan mounted.

Sorry aboot the bad timing buddy... I was a wee bit preoccupied with making myself halway presentable for my Doctor's appointment to be poked and prodded and clucked at because it's been so long since my last colonoscopy.

One good thing came of all that aggravation... doctor's scale sez I weigh 330lb/150kg. This is approx 40lbs/18kg down from my worst "going stir-crazy in the middle of lockdown" weight, and 25lb/11kg down from when I started doing Keto again after the move. Lots of yo-yo-ing because of moving twice in 4 months, but still the trend is downward.

We'll see what the blood work sez aboot my cholesterol, blood sugar and WTF-ever else they test for. 

mnem
*toddles off to do something... else.*

[mnementh]

Med and fans .... no quarter given, just results.   Can't say I'm surprised in the least.

Oh, please... just don't go there. 

mnem
*not a fan*

[med6753]

Yep, just results.  Bench testing before tying into the scope's +15V supply. The +15V through a 7812 regulator which drives the fan. Basic hand testing is demonstrating that the fan is pushing air quite well. Gonna let it run for a while to make sure the 7812 doesn't get too warm without a heatsink. I doubt it will.

Edit, the fan is also very quiet.

[Cerebus]

The rear hatch is all glass.  It will break if you look at it the wrong way.   I've been very careful.  I've read that the glass on the 2013's and '14s would sometimes shatter spontaneously. 

So let me get that right.



The whole of that rear hatch, right down to the colour change above the shut line over the bumper/body is glass? The whole panel that includes the light clusters and badge?

That would totally un-nerve me. The thought that a sufficiently energetic stone thrown up by another vehicle could shatter the whole rear hatch is not something that I'd like to be driving around with in my head. Toughened glass is strong, very strong, much stronger than a lot of people realise, but it's still vulnerable to sharp, hard impacts. Let's hope that the kind of vandals who slash tyres for kicks don't figure out how much damage they could do to an i3 with a sprung automatic tungsten carbide centre punch.

[SeanB]

They just need a broken spark plug, the ceramic is plenty strong and sharp enough to break the glass. Walking around with one here will get you arrested under possession of burglary tools, unless you also are actually a mechanic.

[mnementh]

Yep, just results.  Bench testing before tying into the scope's +15V supply. The +15V through a 7812 regulator which drives the fan. Basic hand testing is demonstrating that the fan is pushing air quite well. Gonna let it run for a while to make sure the 7812 doesn't get too warm without a heatsink. I doubt it will.

Edit, the fan is also very quiet.

Ummm.... yeah... but I thought you wanted it to pull air out of the case? The way you have it here, it's pulling air into the case. You can tell just by looking at the curvature of the blades which way it's supposed to go, even if you didn't know that the supports/cable are almost always on the back of the fan.

mnem
notice I didn't say booty-fab even once.  oh fuck... 

[Ice-Tea]

Just wondering where you fellas would go if you needed a 30dB N-N attenuator (++GHz)? Ordered two from a UK shop a while ago but they never arrived...

EDIT: ... and gal. Sorry Saskia.

[Saskia]

took some pictures earlier in the week at a stand of trees about 1/2 mile from the house.

the majestic bald eagle. 

subsist mostly on dead fish washed up on shore, roadkill, and garbage dumps.


"For my own part I wish the Bald Eagle had not been chosen as the Representative of our Country. He is a Bird of bad moral Character. He does not get his Living honestly. You may have seen him perched on some dead Tree near the River, where, too lazy to fish for himself, he watches the Labour of the Fishing Hawk; and when that diligent Bird has at length taken a Fish, and is bearing it to his Nest for the Support of his Mate and young Ones, the Bald Eagle pursues him and takes it from him."

Benjamin Franklin

exactly like our government does with us with what little money we earn. They even tax what we get out of our state pension plan ...

[med6753]

Yep, just results.  Bench testing before tying into the scope's +15V supply. The +15V through a 7812 regulator which drives the fan. Basic hand testing is demonstrating that the fan is pushing air quite well. Gonna let it run for a while to make sure the 7812 doesn't get too warm without a heatsink. I doubt it will.

Edit, the fan is also very quiet.

Ummm.... yeah... but I thought you wanted it to pull air out of the case? The way you have it here, it's pulling air into the case. You can tell just by looking at the curvature of the blades which way it's supposed to go, even if you didn't know that the supports/cable are almost always on the back of the fan.

mnem
notice I didn't say booty-fab even once.  oh fuck... 

When I took that picture and I looked at the install I went "you asshole, that fan is mounted backwards".  I decided to leave it and post anyway and see if anyone would notice. This picture is the CORRECT mounting.



Since you DID notice you get a cookie. 

[Brumby]

Ummm.... yeah... but I thought you wanted it to pull air out of the case? The way you have it here, it's pulling air into the case. You can tell just by looking at the curvature of the blades which way it's supposed to go, even if you didn't know that the supports/cable are almost always on the back of the fan.

Oh, please... just don't go there. 


(OK.... Maybe unoriginal, but entirely appropriate.  )


Yes, I know I'm late to the party - but, hey, keeping up with this thread is a challenge sometimes.

[mnementh]

Just wondering where you fellas would go if you needed a 30dB N-N attenuator (++GHz)? Ordered two from a UK shop a while ago but they never arrived...

EDIT: ... and gal. Sorry Saskia.

Valkyrie is one-a-da-guyzz. I think she'd be mildly miffed at being considered otherwise just cuz of gender...

That sed... My fleaBay search for this is usually : inmet, aeroflex, weinschel, mini-circuits, 18ghz

This usually returns at least a dozen hits of the value I want, while kicking out most of the dross. If I don't get something I like, I'll then try each of those brands individually with 18Ghz, but that often returns a lot of cables, connectors, etc. I personally like INMET/AeroFlex, as testing back in the day with my IRC VTX Power Meter indicated flattest slope and uniformity from one atten to the next based on testing with same VTX/Antenna in the 5.8GHz band.

The mini-circuits 18GHz attens were close in performance but IIRC the datasheet derated wattage above 6Ghz due to SWR, but their 6Ghz attens (which came with the IRC meter) were just horrible that close to their upper limit.

Hope that helps,

mnem
 

[mnementh]

Ummm.... yeah... but I thought you wanted it to pull air out of the case? The way you have it here, it's pulling air into the case. You can tell just by looking at the curvature of the blades which way it's supposed to go, even if you didn't know that the supports/cable are almost always on the back of the fan.

Oh, please... just don't go there.     (OK.... Maybe unoriginal, but entirely appropriate.  )


Yes, I know I'm late to the party - but, hey, keeping up with this thread is a challenge sometimes.

Sorry... I can't hear you over the sound of how awesome this cookie is...   

mnem
Don't you dare delete my cookies!

[TERRA Operative]

I hate Texas Instruments DIP IC sockets.

[mnementh]

https://i.imgur.com/iHoiqJA.mp4

Pffffft... I just tripped over this while looking for my old account on imgur.   

mnem

[Andrew_Debbie]

So let me get that right.

The whole of that rear hatch, right down to the colour change above the shut line over the bumper/body is glass? The whole panel that includes the light clusters and badge? 

Yes.  It is all glass.  BMW do not sell just the glass.   Replacing the glass is perhaps too hard to get right or not possible.  They designed the i3 to be as light as possible.  The body is not like other cars I've seen.    To fix shattered glass, you have to buy the entire tailgate assembly and an install kit.

I made sure my insurance has good glass cover. 

[dl6lr]

[..]

As the battery is old, I recharged it. Trying to do so with my power supply (bloody HAMEG, now Rohde&Schwarz, manual explicitly states battery charging is possible) the PSU went *POOF* Had to use the old style charger from the garage.
[..]
The PSU has blown the pass transistor and vaporized the shunt resistors. Have to order...

Oh, sorry to hear that! What's the exact type/model number, please - just so I can avoid these in the future?

Good luck for your repair.

THDplusN_notsobad

Sure. It is a HM 7042-2 Triple Power Supply. Despite the blown pass transistor, which could be due to a cheap TIP33C from ISCsemi, it has some design flaws (later for more). I got it cheap (€10,-) in defective state, it took me some time due to no available schematics. When I got it the second channel (0-32V, 2A) was displaying silly amps and no output. Problems I found in the device were:
- pre-owner removed the transformer windings from the channel
- pass transistor was blown
- shunt resistors vaporized

Then I got output and the ammeter showed proper results, but it produced nasty spikes on switching the output on/off. I finally found a SMD resistor that is across the DPDT-relay contacts was blown too, this lifts the regulation feedback from the output during switching (break-b4-make) so the regulation will drive the pass transistor like crazy trying to maintain the output voltage during switching.

During burn in tests I loaded it with 2A at 1V and the pass transistor was blown again. I replaced and noted to myself that this is not a foolproof lab power supply. Testing current step response with dynamic loading in CC mode showed some voltage spikes  on the output. Did not investigate further (confirmed by another owner of that PSU, at first I thought this was one more fault).

Design flaws that AFAIK still exists in later models (HM7042-5 is different and may behave well):

- channel 2 pass transistor is a TIP33C that will operate out of SOA on maximum load as the voltage after the caps is about 60V unloadad, 50V loaded, so the single TIP33C will (try to) dissipate up to 100W
- dodgy current regulation with very slow response, produces significant overvoltage spikes on step response
- manual states switch mode pre-regulation, but this is only implemented for the first channel (yes, that is quite a surprise that both channels are different)

[salvagedcircuitry]

I was saving up for a used BMW i3...
But I can take a bike for the time being 

My 2018 i3S goes back to the leasing company on Friday.   We are going down to one car, which puts me on a bicycle or bus several times a week.

The i3S is one of the best cars I've ever had.   Only car I've had with zero faults. Everything worked on delivery and everything still works.

If you get a used i3, be sure to get a 2017 or newer.     2017 was the first year with the 94Ah (~34kWh) traction battery.  2018 was the first year with LCI (facelift) which looks about the same but has many improvements.     Stay far away from 2013's and 14's. 

In my opinion the S is the one to get but the stiffer ride is not for everyone.  Also the rear tyre size is unique to the i3s.   

The i3 is one of the very few production cars with a carbon fibre body.  All of the others are exotic sports cars.

Very cool! I was looking for a 2016+ but they have literally doubled in value from this time last year, making the i3 completely unaffordable at the moment.
I read about the plastic brackets used on the motor mounts in 2014-2015 and that properly freaked me out from a mechanical standpoint. Then again, most of the vehicle is carbon fiber reinforced plastic, which is pretty neat feat in itself. The 2016+ versions all have aluminum mounts.
The two things that trouble me about the i3:
-The incredibly stupid tire implementation
-The gatekeeper approach to every part on the vehicle

The tire situation has largely been resolved. This guy has a great solution:
https://old.reddit.com/r/BMWi3/comments/oqzo3y/i3s_aftermarket_wheel_upgrade/
He basically uses mini cooper tires on different rims with spacers. I'm 100% for this.

However, the part repair aspect is pretty dodgy. For example, if the heat pump on the vehicle fails, there is no 3rd party heat pump available. Even if you buy a new heatpump unit from bmw, you cannot just simply install it. You have to register the part to the car. You have to either bring it to the dealership and have them initiate the canbus handshake from the car to the part or use a obsII port dongle and hope the software has the ability to initiate the handshake. Some sites mention that bmw uses 5 different canbus networks in the vehicle and they use some kind of proprietary signature verification that sits on top of canbus, so even if you had fancy test equipment, you would have to reverse engineer what kind of nonsense bmw added to the standard canbus platform.

Another interesting aspect of the bmw i3 is that if the vehicle is in an accident where the airbags deploy, the entire battery pack is rendered isolated. The internal relay contactor inside the battery pack is disengaged and requires pack disassembly to replace that contactor. There is of course a software solution to re-engage the contactor, but it is only available to dealerships and I dont believe it is something you can just request. I have not read about any 3rd party utility that re-engages the battery contactor.
It is an interesting vehicle it is just so darn locked down.