Test Equipment Anonymous (TEA) group therapy thread

[Robert763]

Q: What goes; "Pieces of seven, pieces of seven"?

A: A parroty error

(I'm bored)

[mnementh]

*groooooooan*

mnem
*soggy ol' boot outbound*

[mnementh]

On the topic of TEA, here is the best I can do so far this year:     

 

Typical.

mnem
Actual delivery: 2nd Tuesday next week.

[tggzzz]

Long story short: Some of my requirements were poorly met by HP equipment, the Sales Engineer -without hesitation- admitted so and recommended some competitors models to look at for those requirements. Some of my requirements were no problem, and the Sales Engineer fixed up a deal for me to purchase an ex-demo logic analyser (forget the exact model now) complete with 80286 and 80386 emulator modules. Something like a £10k value deal sorted out and agreed in an hour because the Sales Engineer's attitude gave me the confidence to believe his assessment that the LA would meet my needs - it did - and the confidence that I'd be treated decently if there were any problems.

That sounds like absolutely standard HP practice before Princess Fiorina arrived.

When setting up a new HP site, the employees were constantly bombarded with "Bill and Dave" stories indicating the corporate culture that Hewlett and Packard wanted. Your anecdote could be one of those stories.

My first professional contact with HP[1] involved them digging us out of a hole when a plotter failed just before an exhibition. It influenced me when I joined HP in 1987.

[1] other than a very professional jon interview as an undergraduate; In only turned down the job offer because of a mere 17 days annual holiday

[AVGresponding]

What part numbers were the 5W and 10W of the same size? I've never seen that.
The Ohmite 805 is 5W and similar to the 10W Welwyn WH5 but the WH5 is actually 1.1mm longer in the body than the 805 despite having the same mounting centres.

The Welwyn WH5's seem to be the outliers in size; the other 10 watters are TE CGS HSA5's, Arcol HS10, and some RS branded ones that I can't seem to find now.

Even so, they are only a millimetre or so longer than the other 10W jobbies, which are the same size as the 5W Ohmite 805F's and Yageo AHA500's.

Another interesting observation I made was two of the 25W had a (relatively) unusual 2 ohm value that was spot on with the Fluke 87V despite being 10% tolerance rated, so I warmed up the LCR819, and measured them at 1.9957 and 1.9952 ohms. That's somewhat better than 10%...

[Robert763]

Other difference may be the thermal resistance (internal dimensions and filler paste properties) of different makes.
The 2 ohms ones, being non preferred values, were probably a short production run with more care taken. Additionally there are no 5% or 2% versions to cherry pick from the production batch.
I've heard of an exercise where a batch of 1k 10% carbon composition resistors were given to students to measure the values and plot the result. The theory is the values plot a normal distribution. In practice there wee two edges of the bell curve with a 5% gap in the middle. All the ones close to 1k had been selected out and sold as higher precsion parts. Not so likely with modern componens though.

[AVGresponding]

I think I might shove some power through them and see how much they heat up, say a watt or so. That ought to be enough for a comparison.

The date code on those Arcol 2 ohm resistors is 91-21.
The range of dates is quite wide, from early 80s to late 20-teens.

[Cubdriver]

Other difference may be the thermal resistance (internal dimensions and filler paste properties) of different makes.
The 2 ohms ones, being non preferred values, were probably a short production run with more care taken. Additionally there are no 5% or 2% versions to cherry pick from the production batch.
I've heard of an exercise where a batch of 1k 10% carbon composition resistors were given to students to measure the values and plot the result. The theory is the values plot a normal distribution. In practice there wee two edges of the bell curve with a 5% gap in the middle. All the ones close to 1k had been selected out and sold as higher precsion parts. Not so likely with modern componens though.

I've heard that, too - 20% parts could mostly be expected to fall in the -20~-10% and +10~+20% ranges, the ten percenters would be -10~-5 and +5~+10, and the 5s would be +/-5%.  Makes perfect sense from a production standpoint when binning parts.

-Pat

[Specmaster]

@Cerebus just got a phone call from someone who wanted to buy a PC. I told him that I am selling off my surplus PC test/eval equipment and that my stuff has been slightly used. Then I asked him what he wanted it for to assess if the stuff I had was suitable and sufficient for his requirements.

He said that part was a completely new experience for him.

90% of customers have an XY problem. They ring up saying "I want to buy X" when what they should say is "I am trying to do Y" or at least  "I am trying to do Y and your X looks like it's suitable". It never hurts to break the script and ask them what they intend to use "X" for. To be fair, so many front line sales staff are so crappy nowadays due to lack of training that the customers can be forgiven for having trained themselves to skip that step.

!000% this all day long. I was always under the impression that for the first few minutes the salesmen should be fairly quiet and let the customer reveal what he is looking for and then the salesperson can add extra bits to the discussion and try to sell a solution to the customers needs, rather than what you want to sell to them. A happy customer will come back again and again if they feel that the salesperson listened to them and tried to resolve the issues, but a person who feels pressurised will vote with their feet and tell their friends to do the same.

[Specmaster]

don't wait too long, if more of that breaks, the membrane will suffer.

There is also a high risk of the voice coil moving off-centre and fouling magnets and then possibly damaging the coil itself.

[AVGresponding]

This keeps getting relisted cheaper, I imagine it's of limited use without the leads/pods though:

https://www.ebay.co.uk/itm/Dolch-Logic-Instruments-PALAS-40C50-Logic-Analyzer/373427965467


£35 shipping probably isn't helping either.

[Specmaster]

This keeps getting relisted cheaper, I imagine it's of limited use without the leads/pods though:

https://www.ebay.co.uk/itm/Dolch-Logic-Instruments-PALAS-40C50-Logic-Analyzer/373427965467


£35 shipping probably isn't helping either.

Yep, you are correct, there is also a TTi Logic Analyzer that someone keeps listing but without and leads and I suspect that leads would be costly if you can find any.

[Specmaster]

@med6753
The Pioneer I'm guessing is itself pretty old now? I'm pretty sure that the more modern AV receivers / amps are intelligent enough to understand what type of signal it is processing, especially that has a built-in THX decoder processor so that if you are playing a CD or listening to radio then it switches into the normal 2 channel stereo mode on the front speakers only. Give a DVD film signal and will switch itself into video mode rather than surround sound which is what you get with older systems and the real budget ones. These decent systems tend to fall into one of 2 camps, either 5.1 or 7.1 systems, that relates (5.1) front left & right, rear left & right, subwoofer and centre speaker for locating above or below the TV screen and way you get the full sound stage imagery. The 7.1 systems are the same but with a mid-position left and right speakers so that you position your seats, right in the middle, so you can then totally immerse yourself in the sound stage, and it would then sound just as it would if you were there in real life, in the action.

I don't know for sure, but I get the impression that what you want from your current setup is for the CD and radio to come only from the front speakers, but DVD sound from all 5, and to get there from the Pioneer is a lot of fiddling with the controls each time, is that correct?

[mnementh]

No, I think all med wants it to do is play music effing loud enuf to occasionally annoy the neighbors. I was the one who raised the point aboot a DTS/THX decoder, and then the whole gang sortof jumped on the bandwagon.

sorry, med. 

mnem
 

[tggzzz]

This keeps getting relisted cheaper, I imagine it's of limited use without the leads/pods though:

https://www.ebay.co.uk/itm/Dolch-Logic-Instruments-PALAS-40C50-Logic-Analyzer/373427965467


£35 shipping probably isn't helping either.

32 channel, 25MHz => i wouldn't bother with it.

You can probably make leads, but halfway decent grabbers will cost >£1.50 each

[med6753]

No, I think all med wants it to do is play music effing loud enuf to occasionally annoy the neighbors. I was the one who raised the point aboot a DTS/THX decoder, and then the whole gang sortof jumped on the bandwagon.

sorry, med. 

mnem
 

Nailed it.  No 5.1. No 7.1. Just 2 channel LOUD. 

[AVGresponding]

32 channel, 25MHz => i wouldn't bother with it.

You can probably make leads, but halfway decent grabbers will cost >£1.50 each

Haha I wouldn't touch it with a ten foot pole, I was just being nosy. If it needs pods like the TTi LA's do, you'll need more than some ribbon cable and a few grabbers.

I have a TTi TA320S and the pods are pretty much unobtainium at reasonable prices.

[BU508A]

Q: What goes; "Pieces of seven, pieces of seven"?

A: A parroty error

(I'm bored)

*whisper*

Pst!

Could this please somebody explain it to a stupid and confused German TEA fellow?
I'm asking for a friend ...

 

[Specmaster]

No, I think all med wants it to do is play music effing loud enuf to occasionally annoy the neighbors. I was the one who raised the point aboot a DTS/THX decoder, and then the whole gang sortof jumped on the bandwagon.

sorry, med. 

mnem
 

Nailed it.  No 5.1. No 7.1. Just 2 channel LOUD. 

In that case then, why bother with the right-hand side of the drawing? If the Sansui is not loud enough, grab an amp/receiver that has the power you need, upgrade the speakers if they can't handle the power, job done. Most amps will accept 2 CD inputs; CD1, CD2, Tuner, AV or AUX, Tape1, Tape2 and even today Phono, give you 2 sets of speakers A/B switched between A or B and A+B so if you wanted the other set of speakers in another room for example, thats easy to do. That should give you everything that you require with less space and fewer complications and less chance of a hum loop being introduced.

Or is there something else that I'm missing here?

[AVGresponding]

Ok some rough and dirty results on the 5W vs 10W in-the-same-size-aluminium-metal-clad-resistor.

Sheesh! Superhyphenationhopemycalibrationsnotatrocious!

T_a=~22^oC
t_end=180s
P=0.5W

Ohmite 805F series, 5W 250 ohm. Tt_end=34.8^oC

Welwyn WH5 series, 10W 33 ohm. Tt_end=32.6^oC

Arcol HS10 series, 10W 0.22 ohm. Tt_end=32.5^oC

Now, it should be noted that (a) the timing is +/- to the tune of a few, no more than 5, seconds, and (b) more importantly, due to the voltage drop in the power leads I had to adjust the voltage on the fly. This was of course slower to compensate the higher the current, so the 10W package results are likely skewed low.

It does look like there's a marginal difference between the 5W and 10W, I remain unconvinced that it amounts to a 5W difference in P_D though.

[Specmaster]

Q: What goes; "Pieces of seven, pieces of seven"?

A: A parroty error

(I'm bored)

*whisper*

Pst!

Could this please somebody explain it to a stupid and confused German TEA fellow?
I'm asking for a friend ...

 

A likely story 

[AVGresponding]

Q: What goes; "Pieces of seven, pieces of seven"?

A: A parroty error

(I'm bored)

*whisper*

Pst!

Could this please somebody explain it to a stupid and confused German TEA fellow?
I'm asking for a friend ...

 

"Pieces of eight" is the traditional cry of Captain Flint, the shoulder parrot of Long John Silver.

If there are only 7 pieces, presumably the parity bit has been dropped...


EDIT: From the book Treasure Island

[SilverSolder]

Q: What goes; "Pieces of seven, pieces of seven"?

A: A parroty error

(I'm bored)

*whisper*

Pst!

Could this please somebody explain it to a stupid and confused German TEA fellow?
I'm asking for a friend ...

 

To work it out, you need to know:

Pieces of eight -  https://en.wikipedia.org/wiki/Spanish_dollar

Parroting - (present participle) repeat mechanically.  "encouraging students to parrot back information" 
synonyms: repeat mindlessly · repeat · repeat mechanically · echo · say again

[AVGresponding]

This remains the best shoulder parrot ever:

[Cerebus]

Q: What goes; "Pieces of seven, pieces of seven"?

A: A parroty error

(I'm bored)

*whisper*

Pst!

Could this please somebody explain it to a stupid and confused German TEA fellow?
I'm asking for a friend ...

 

"Pieces of eight" is the traditional cry of Captain Flint, the shoulder parrot of Long John Silver.

If there are only 7 pieces, presumably the parity bit has been dropped...


EDIT: From the book Treasure Island

And for a 'meta' version of that, we have Reacher Gilt in Pratchett's Ankh-Morpork whose parrot constantly screeches "12 1/2 percent".