Test Equipment Anonymous (TEA) group therapy thread

[xrunner]

New transistors arrived for the preselector repair project. Very promising but not yet installed ...

[PA0PBZ]

New transistors arrived for the preselector repair project. Very promising but not yet installed ...

Oh come on! 

[mnementh]

In Other News..

In Other News...
Looking like the resistance measurement issues with my 3478A are in fact F/R jack switch-related. Cleaning seemed to help; went from fluctuating between .6 ohms and .3 ohms shorted (using banana patch cords, not clips; these measure 0.09-0.1 ohm and 0.045-0.46 ohm on my Fluke 189 and DE-5000 respectively) down to fluctuating 0.22xx - 0.19xx ohms. After reviewing the schizzmatics, I discovered I could bypass 1/2 of the switch by swapping a couple leads at J107; that dropped shorted resistance to 0.116x - 0.1170 ohms.

Part of me is saying, as I know I'm likely going to really want the rear jacks about twice in my lifetime, that I should just bypass the switch completely and solder the front ports into service; it'll be more accurate and reliable anyways... meanwhile, the purist in me keeps trying to strangle that part.  We'll see who wins after dinner. 

mnem
"There's no rest for the wicked, but the virtuous have no pillows."

That switch was my first and only suspect for the cause and also the only part of the meter that is likely to be dormant for long periods. As such it would allow crud to be building up undected  until someone activated the switch and allowed crud to migrate courtesy of the contact wiper which has some under its wiper. I'd give it another of contact cleaner and give it some beans while operating the switch remove that crud, also I'd try some pure alcohol on it, nothing to lose. [emoji38]

I've tried spraying contact cleaner in it three times; gently lifting up the top cover so I can spray inside. Last time I undid the metal stakes and removed the spring & ratchet so I could lift that end to spray inside. I'm considering to remove and immerse in alcohol while working back/forth as a last ditch effort before attempting to disassemble; it's almost as much work as disassembling though.

mnem
*Kindof buzzing on 4 hours sleep and 3 cups of coffee*

So, today the "Purist" in me won; I completely disassembled the F/R switch and gave it a proper enema, scrubbing its guts with a brush and alcohol and deluging it to flush out WTFE was causing the intermittent contact.

In all honesty, I couldn't see ANYTHING; everything looked like gorgeous, shiny gold-plate on both the wipers and the contacts inside... but when I put it all back together, it went from fluctuating wildly on the last 3 digits to stable with fluctuation only in the last digit, and Front/Rear jacks within a few ticks on the last decimal of each other.

The proof of the pudding certainly is, as they say, in the eating. 

I intend to do a write-up on this with more pics when I have some more "me time"; for now, here's some pics which I hope will be mostly self-explanatory.

For those who're wondering, the scrub-brush I use here is called a disposable "mascara wand"; I use these and .22 cal rifle cleaning brushes to freshen up banana jacks on meter as well.

You can buy these ~30/$5 at Wally World, or ~100/$3 on AliEx, Banggood, etc.

USE A NEW ONE! Don't try to snurch one from the wife and clean it... you CANNOT Get it clean enough.   



[EDIT 12/3/2018]

While sorting through pictures on my camera card from my 3478A resurrection project to archive the raw pics, I found this. I didn't see it while I was actually WORKING on the flaky F/R switch, but look what showed up in a couple of the shots left on the cutting room floor... this pic was taken immediately after removing the switch core from the body. Just goes to show you... sometimes what you find isn't as important as following through with the procedure anyways. A thorough, careful cleaning fixed this switch even though I missed the culprit while I was in there.

[/EDIT]

mnem
*Time to get the kids*

[bd139]

Congratulations - you got a winner there 

[mnementh]

Or, you can go the lazy man's way and get a Jameco kit.  https://www.jameco.com/z/ANGCLKV1-Wicked-Device-Angular-Clock-Kit_2207831.html

Yeah, Alan's version is pretty much made of awesome... while the Jameco one feels cheesy from 1000 miles away looking at it through a computer screen.

I think that Alan's dealio is definitely one of those "you get more than you pay for" things. 

mnem
If you're gonna do it, do it right.

[Housedad]

My latest TEA came in ..   My HP 5385A counter. 

Test Equipment Depot sure knows how to pack equipment.

First is a really heavy duty box, (a Keysight box, no less)  Followed by a layer of dense foam on top and then the unit was in a mylar antistatic bag and then put in foam end blocks.  Really nice.   Came with a scanned manual on CD and a new power cord.  They weren't kidding in the Ebay listing as excellent  condition.  Wowser.  One tiny scratch on the front plate.  Everything else is pristine.

[xrunner]

Good deal that will serve you very well for a long time.

[mnementh]

Congratulations - you got a winner there 

Yeah, gotta go through it now and check everything again. 

And need to read the destructions a little more than just skimming over, so I don't make stupid mistakes like running the F/R switch bass-ackwards again... 

mnem
*p00t!*

[Neomys Sapiens]

@mnem: nice work on that switch!

But, notwithstanding his three laws, Asimov is a bit shallow when compared to the last century universal genius, who also happend to have written SF: Stanislav Lem.
While he wrote outstanding works of fiction, of which Solaris is probably the best known, but FIASKO is the best IMHO, his non-fiction works are even less known. SUMMA TECHNOLOGIAE is exactly what its name says, and it is the book to which I turn in the most difficult times of being an engineer, not for reference or directly usable information, but in the hope that this outstanding depth and clarity of mind will inspire me.

[xrunner]

New transistors arrived for the preselector repair project. Very promising but not yet installed ...

Oh come on! 

OK just replaced the MRF901 it and did some tweaking - it works again. 

It's got about 6 dB of gain now. The specs call for -6 dB of rejection @ +/- 300 kHz and -40 dB @ +/-1 MHz. Looks pretty good. I want to replace one N connector due to a worn out center pin, but it looks like it's going to be OK for use.

[mnementh]

@mnem: nice work on that switch!

But, notwithstanding his three laws, Asimov is a bit shallow when compared to the last century universal genius, who also happend to have written SF: Stanislav Lem.
While he wrote outstanding works of fiction, of which Solaris is probably the best known, but FIASKO is the best IMHO, his non-fiction works are even less known. SUMMA TECHNOLOGIAE is exactly what its name says, and it is the book to which I turn in the most difficult times of being an engineer, not for reference or directly usable information, but in the hope that this outstanding depth and clarity of mind will inspire me.

I read them ALL.  . I first read Lem in Amazing Stories or Analog when I was like 12; I had a dangerous pulp habit well into my 30s. There isn't a golden age author I haven't read most everything they wrote, and then the second age too; even Piers Anthony until he started writing for his small children. Have a soft spot for Heinlein, del Rey and Sturgeon, and later for Brin & May, and of course Niven. Haven't read much since I met my wife though... Read most of the Temeraire series, restarted the Uplift Saga twice but got beaten into submission by parenthood.

C'est la vie!

mnem
"If you prick me, do I not... leak?"

[bitseeker]

Or, you can go the lazy man's way and get a Jameco kit.  https://www.jameco.com/z/ANGCLKV1-Wicked-Device-Angular-Clock-Kit_2207831.html

Yeah, Alan's version is pretty much made of awesome... while the Jameco one feels cheesy from 1000 miles away looking through a computer screen.

I think that Alan's dealio is definitely one of those "you get more than you pay for" things. 

It'd be neat to make a compact version with vertical analog meters.

Hold on... it's already been done. That saved me some time. LOL!

[Berni]

As we're speaking of oscilloscopes:

I fetched my repaired DSPX3034A today and put it on my bench having activated the easter egg screen saver as my nearly first step for a nicer photo.   

Ok, this is what I have now:
It's a DSOX3034A with the original four 500MHz probes and all accessories (as far I can tell) and the power cord.
The Keysight marked folder holds the calibration certificate.   


Ok, this is what I paid for my "new" scope (I think I won't beat that again):
500,-€ price
4,99€ domestic shipping to me
32,40€ express shipping to Keysight

Over all I paid less than 540,-€ for this now freshly manufacturer calibrated 350MHz/4Gs/s 4 Channel former Agilent scope.
I'm relieved and happy that I didn't end up with four Agilent 500MHz probes (which isn't too bad..) and a bricked Agilent DSOX3034A. 
BTW -It was rebadged to Keysight along with the repair avoiding booting up an Agilent Scope with a Keysight splash screen..   

I'm really excited -so many buttons and functions!      

I'll play around with it now...       

Nice score there!

On my MSO6000 I'm running a version that's one release behind latest just so that my boot screen keeps saying Agilent rather than Keysight.

[Specmaster]

Congratulations - you got a winner there 

Yeah, gotta go through it now and check everything again. 

And need to read the destructions a little more than just skimming over, so I don't make stupid mistakes like running the F/R switch bass-ackwards again... 

mnem
*p00t!*

Yep, I agree with bd, its cleaned up real nice as well. Maybe you couldn't find any problem because it was a snagged spring maybe on the contact and got released when you dismantled it? Either way, it's a great score and maybe you ought to have this (jammy git) award considering the price you paid for it. 

How in blue blazes do you insert an image in text here, I have tried the insert image iscon and feck all happens, I expect the fault lies with this fat lump sitting at the fecking keyboard as usual 

[mnementh]

Wife wakes me up at 5AM... "Honey, there's no hot water..."

"Okay... I'll go look..." and drag my ass out of bed with meter and screwdriver; in my underclothes and with about 4 watts of consciousness, I unscrew the side cover and determine that there is power to the top half but not the bottom. Pop the thermal reset and a few seconds later hear the faint rattle of water heating; check and there's power going to the bottom element too, though evidence of a half-melted wire at the thermostat.

"Fuckit... it's making hot water. I can explore further when I wake up." I think to myself.

Start the washing machine; hot water steaming up in the tub already.

"Fuggin' a-diddy..." I say out loud to no-one in particular. Turn off the washer and go tell my wife. at this point ten, maybe twelve minutes have passed since she rousted me out of bed.

"Hey baby... It's making hot water now. You should be able to go shower."

"Oh, I don't have time for that now. I washed up in the sink, I'm gonna go redneck style today."

 

"So, you had to wake me up from a delicious dream at the butt-crack of dawn exactly why?"

"Because." she answers, and kisses me on the nose, then starts dressing the kids for school.

Strangely, I'm completely satisfied with this. 


mnem
But the rest of the world can fuck off and die in a ditch.

[Specmaster]

Who is this Dawn that you up the butt crack of and do you think that maybe your wife might be aware of her and hence the reason for your early morning awakening? 

[bd139]

I am Bernard Black until about 10AM. If the shower is cold it stays cold until 10AM

[med6753]

"Hello landlord, there's no hot water"

"OK, I'll fix it"

After many, many years of home ownership and having to fix all that shit myself......

Strangely, I'm completely satisfied with this   

[med6753]

I am Bernard Black until about 10AM. If the shower is cold it stays cold until 10AM

Had to look him up. Rude, obnoxious, and Irish....my kind of people. 

[mnementh]

I am Bernard Black until about 10AM. If the shower is cold it stays cold until 10AM

Oh sweet cheese & crackers. I just did a Gurrgle...

https://youtu.be/JwF_LnTqLUM

   I fuggin' 'ate you; it hurts. 

mnem
*snip*

[mnementh]

Who is this Dawn that you up the butt crack of and do you think that maybe your wife might be aware of her and hence the reason for your early morning awakening? 

You did note the bit about the "delicious dream", right?   

mnem
Yes, Dawn is an actual chocolate moose. Stay the eff out of my head; it's dangerous in here.

[Specmaster]

You did note the bit about the "delicious dream", right?   

mnem
Yes, Dawn is an actual chocolate moose. Stay the eff out of my head; it's dangerous in here.

I left that bit out for comedic value, besides I'm Bernard Black don't you know? 

[mnementh]

Well, just be glad you came back when I was nibbling on the ears, instead of earlier when I was at the other end, doing... other things. 

mnem
Warning: I seem to have lost my mind. If you find it just back away and dial 911.

Whatever you do, DON'T HANDLE IT. It is deranged and extremely dirty.

[mnementh]

In Other News...

Water heater problem appears to have been little more than a loose screw. Elements measure 10.8 Ω, ∞ against the tank, so should be healthy. Contact on t-stat and screw itself cleaned up nicely with minimal effort and a brass brush; no burnt metal. Cut the melty wires back to good core and restripped; tightened all screws and will come back in a couple weeks with IR gun to follow up.

*Puts post-it on monitor*

mnem
Now I can get back to my regularly scheduled misery...

[Specmaster]

In Other News...

Water heater problem appears to have been little more than a loose screw. Elements measure 10.8 Ω, ∞ against the tank, so should be healthy. Contact on t-stat and screw itself cleaned up nicely with minimal effort and a brass brush; no burnt metal. Cut the melty wires back to good core and restripped; tightened all screws and will come back in a couple weeks with IR gun to follow up.

*Puts post-it on monitor*

mnem
Now I can get back to my regularly scheduled misery...

And back to Dawn.........

The reason why that struck a cord with me is that a few years back I was attending a residential sales training course in a hotel near Birmingham (UK) and at breakfast one morning we were having breakfast (what else) and the waitresses name was Dawn and as the lecturer was explaining his jogging habits, he was telling the group of attendees that he "liked to be at the crack of dawn" for his daily jog. Unbeknown to him was that at that precise moment was standing just behind him when he said that and she screamed out and dropped the plates full of "full english" breakfasts she was carrying, all over him and ran off to the hotel manager and lodged a complaint against him.

We never used that sales lecturer or that hotel ever again.... I wonder why.