Author Topic: Test Equipment Anonymous (TEA) group therapy thread  (Read 1935464 times)

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Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10525 on: May 11, 2018, 09:09:42 am »
Aliexpress added to shit list. Just threw three hours down the shitter. This is TEA related as I found the old frequency counter I built years ago and am making a new front end for it as the old one had random impedance. Also need to stuff it in a new case.

So I’m using a 1mH axial inductor as part of a Pi filter to stop digital spikes getting into the front end.

Powered it up. Nothing. Hmm.

Poked around with DMM. No 5v supply to RF section. Hmm.

Eventually traced this to the inductor being open circuit. Must have damaged it via soldering.

Stuffed another one in. Same outcome. Fucks sake. Must need heat sinking.

Stuffed another one in with heatsink clips on the legs. Nope still dead.

Get DMM out and test it. Open circuit!

Get pack out and test a few unused ones. Open circuit!  Fucks sake.

Cracked one open with a pair of pliers and what did I find?

NO FUCKING WIRE in them.  :palm:

Well done China!
Can't believe that you never checked them before soldering them in, even a cheapo crappy LCR meter would tell you if they were O/C or anywhere near the right value. I always thought that didn't trust the Chinese so you checked thing before installing them, well I bet you won't make that mistake again  :-DD
Who let Murphy in?
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10526 on: May 11, 2018, 12:13:17 pm »
Indeed. Learned that one didn't I. Passives usually just work so I'm a bit miffed.

Ordered some from RS but they're not turning up until Monday now.
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10527 on: May 11, 2018, 12:18:35 pm »
Wack a claim in for them even though they don't cost a lot it's the principle that's wrong and needs stamping on. The odd rogue trader gives China a bad press it doesn't deserve in reality.
Indeed. Learned that one didn't I. Passives usually just work so I'm a bit miffed.

Ordered some from RS but they're not turning up until Monday now.

From mobile device so predictive text might have struck again [emoji83]

Who let Murphy in?
 

Online Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10528 on: May 11, 2018, 02:56:34 pm »
Good god I thought I was alone!  :)

Really interesting reading this thread and trying to convince myself that I'm perfectly normal.

Nevertheless, I must admit that having TEA is a lot of fun! (This statement has not been endorsed by my wife)



 

Offline Brumby

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10529 on: May 11, 2018, 03:01:19 pm »
Good god I thought I was alone!  :)

Really interesting reading this thread and trying to convince myself that I'm perfectly normal.

Nevertheless, I must admit that having TEA is a lot of fun! (This statement has not been endorsed by my wife)

Keep reading and the convincing will just happen.  (This is the therapy on offer here.)

If you haven't already, check out the glossary on page 1.  I'm sure you will feel quite familiar with more of those terms than you may have anticipated.  It is a good sign.  Trust me  ;)
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10530 on: May 11, 2018, 03:19:50 pm »
Good god I thought I was alone!  :)

Really interesting reading this thread and trying to convince myself that I'm perfectly normal.

Nevertheless, I must admit that having TEA is a lot of fun! (This statement has not been endorsed by my wife)

Keep reading and the convincing will just happen.  (This is the therapy on offer here.)

Think of this thread as being an echo chamber, with all that implies.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Online Kosmic

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10531 on: May 11, 2018, 03:45:28 pm »
If you haven't already, check out the glossary on page 1.  I'm sure you will feel quite familiar with more of those terms than you may have anticipated.  It is a good sign.  Trust me  ;)

Yes I did. That's how I realized I actually suffer from TEA. I exhibit a lot of symptoms described there :)
 

Offline Specmaster

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10532 on: May 11, 2018, 04:15:08 pm »
Indeed. Learned that one didn't I. Passives usually just work so I'm a bit miffed.

Ordered some from RS but they're not turning up until Monday now.
While on the subject of RS,  :wtf: are they doing in the customer services / accounts section? My meter was booked out as "Dispatched" on Wednesday so I thought it'd be here by now. Just spoke to customer services who checked with the lab and discovered that it has been done and is now doing a soak test before issuing a serial number for the certificate so it wont be dispatched till Monday now  :palm: Well I suppose it was a Bank Holiday week after all.

On a plus note and related to the thread overall, I received my Kelvin leads for it today and I only ordered them 2 weeks ago from China so they can get their fingers out at times with their postal system  :-+
Who let Murphy in?
 

Online BillB

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10533 on: May 11, 2018, 04:16:48 pm »
If you haven't already, check out the glossary on page 1.  I'm sure you will feel quite familiar with more of those terms than you may have anticipated.  It is a good sign.  Trust me  ;)

Yes I did. That's how I realized I actually suffer from TEA. I exhibit a lot of symptoms described there :)

I think I'm going to petition the APA to get TEA and some of those associated conditions added to the DSM-6.  Maybe I can collect a disability check for this affliction?
 

Offline nixiefreqq

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10534 on: May 11, 2018, 04:18:13 pm »
Good god I thought I was alone!  :)

Really interesting reading this thread and trying to convince myself that I'm perfectly normal.

Nevertheless, I must admit that having TEA is a lot of fun! (This statement has not been endorsed by my wife)

my initial understanding of this sites mission statement could not have been more wrong.

thought it was to help us fight our weakness.

so I tried to encourage others to hold the line and resist like chamberlain and the 20th maine at little round top (its a gettysburg thing).

but there is no such thing as a tea sufferer who will not fold up and collapse like a two dollar cardboard suitcase.

guess if you can't keep 'em sober you can at least offer aspirin in the morning.

gotta' run...….need to search for a 5255a heterodyne converter.  we have a lot of unconverted heterodyne building up down in the basement. 








 
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Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10535 on: May 11, 2018, 08:33:41 pm »
That is quite a pile of gear.

So how much of it works or is that your equipment repair queue. If you have enough old gear the repair queue can get longer without even buying anything.

I would hazard a guess that about a third of it is functional to some degree; possibly more.  A lot I haven't plugged in yet because I haven't yet looked it over to make sure there are no major weak spots where the magic smoke might get out.  And yes, I have an ugly repair queue.  Somehow that doesn't prevent me from adding to it when something piques my interest.  Some are strays from the museum I volunteer at; stuff that doesn't sell at swap meets and might otherwise hit the dumpster often follows me home, and things that look like they may only bring a few bucks at the swap meets I often preemptively buy, giving them more than we think they'd sell for - the two ancient HP generators on the hearth joined the fold that way.

Now to find the spare time (so called because I seem to have so little of it!) to dig into this stuff!

-Pat

*Wipes a tear from his eye*

That's... *sniff* just beautiful, man. *snif* You are an inspiration to us all!  :-+


mnem
I'm all verklempt...
 

Offline tautech

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10536 on: May 11, 2018, 09:13:12 pm »
On a plus note and related to the thread overall, I received my Kelvin leads for it today and I only ordered them 2 weeks ago from China so they can get their fingers out at times with their postal system  :-+
When the stars align I've had stuff in as little as 4 days.  :)

But mostly postage delays are related to their and our holidays, for example things grind to a halt in late Jan as everyone knows they go on a 2 week break in early Feb for their New Year. Then straight after, all the stuff that's been ordered online while they're on hols then snarls up the system for a few more weeks. Takes till early March before things come right again.
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Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10537 on: May 11, 2018, 10:07:10 pm »
Mnementh, you owe me a beer. Remember that Tek 2465 for sale local to me? Well...it's now mine. As promised I waited almost 2 weeks and decided this past Wednesday to toss them an offer. They wanted $75 USD for “non-working”. I offered $50 USD. They counter offered $60 USD. I accepted the offer. Picked it up today. But the best part follows....

When I got it home I discovered why it wouldn't power up. The screw on cap for the fuse holder as well as the fuse were missing. I don't have a spare so I took it off my 2465 DMS. Installed it and stood back and hit power on. The scope came up with all self tests pass! The pix shows it currently on the cart going thru a burn-in. The only anomaly I've noticed so far is that the sweep cal is a little off. Other than that it looks real good.

I'm going to let it cook for a while then give it a good cleaning. I'll have to order a fuse holder as I don't have that type in my spare parts bin. Does anyone have a spare knob for the Readout Intensity that they would be willing to give up? Right now I am happier than a pig in shit. A fully functional 2465 for $60 USD. Can't beat that!    :-+ :-+ :-+
An old gray beard with an attitude.
 
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Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10538 on: May 11, 2018, 10:18:29 pm »
That’s a good win!  :-DD
 
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Offline GerryBags

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10539 on: May 11, 2018, 10:44:00 pm »
Great score! No knob, I'm afraid. I had to order one from Greece, of all places. I have just finished the psu on my 2467B.... after also doing the SMD caps on the control board. I've checked and double checked, but I'm still a little  :scared: to power up. I know who fixed it, you see?

So.... how far back did you stand?

P.s.: I'm a fan of Tek's idea of having the actual power switch at the back and a long connecting rod to the front panel, you start off as far away as they could design you to be.  :-DD
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10540 on: May 11, 2018, 11:06:23 pm »
Great score! No knob, I'm afraid. I had to order one from Greece, of all places. I have just finished the psu on my 2467B.... after also doing the SMD caps on the control board. I've checked and double checked, but I'm still a little  :scared: to power up. I know who fixed it, you see?

So.... how far back did you stand?

P.s.: I'm a fan of Tek's idea of having the actual power switch at the back and a long connecting rod to the front panel, you start off as far away as they could design you to be.  :-DD

I did the re-cap on the PSU on the 2465 DMS and it took me 2 days. What a PITA. But I didn't screw anything up and it powered up. This 2465 I'm going to wait. In fact there's a good chance that perhaps it's been done in the past. It has a cal sticker dated 2001. When I open it up I'm going to look and also check the voltages at J119.

I stood back far enough that I could quickly shut it down if something went boom. The 465 pulled that stunt on me when a tant exploded and scared the crap out of me.

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Offline GerryBags

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10541 on: May 11, 2018, 11:51:40 pm »
It works! No errors either. Once it warmed up and was fed a signal it just got sharper and no smoke! It's not a fan of a free-running sweep, though. So far, it seems like it will be well worth saving all the calibration data from the NVRAM asap, as it looks pretty accurate. I am stupid, though, I didn't even think to check the battery on the chip that is in there while I had the board off. I have a pic but my internet is being particularly bastardy tonight...



 

Online GreyWoolfe

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10542 on: May 12, 2018, 01:22:11 am »
From med6753--Right now I am happier than a pig in shit. A fully functional 2465 for $60 USD. Can't beat that!

I thought I did good at getting mine for $159.  What a deal!
That which doesn't kill you still requires a co-pay.
 

Offline Brumby

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10543 on: May 12, 2018, 02:58:23 am »
Right now I am happier than a pig in shit. A fully functional 2465 for $60 USD. Can't beat that!    :-+ :-+ :-+

If I wasn't happy for your win, I could really hate you right now.

Congratulations.   :-+
 

Offline mnementh

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10544 on: May 12, 2018, 03:28:21 am »
Mnementh, you owe me a beer. Remember that Tek 2465 for sale local to me? Well...it's now mine. As promised I waited almost 2 weeks and decided this past Wednesday to toss them an offer. They wanted $75 USD for “non-working”. I offered $50 USD. They counter offered $60 USD. I accepted the offer. Picked it up today. But the best part follows....

When I got it home I discovered why it wouldn't power up. The screw on cap for the fuse holder as well as the fuse were missing. I don't have a spare so I took it off my 2465 DMS. Installed it and stood back and hit power on. The scope came up with all self tests pass! The pix shows it currently on the cart going thru a burn-in. The only anomaly I've noticed so far is that the sweep cal is a little off. Other than that it looks real good.

I'm going to let it cook for a while then give it a good cleaning. I'll have to order a fuse holder as I don't have that type in my spare parts bin. Does anyone have a spare knob for the Readout Intensity that they would be willing to give up? Right now I am happier than a pig in shit. A fully functional 2465 for $60 USD. Can't beat that!    :-+ :-+ :-+




The fact those particular parts are "missing" suggests to me they were robbed off this one to fix another "better" 24xx scope; you want to go over it with a fine tooth comb as they are a pretty complex beast and it may be an intermittent fault, or maybe one of the channels is hinky. Under any circumstances, getting it back to life so quickly is certainly promising; I don't want to jinx ya, just warning you to double and triple-check yours.  :clap:  :-/O  :-+

When you take the DC-DC converter out to inspect the caps, you'll have to remove the squirrelcage fan. It can be a total assache as hey use a shaft adapter that works like the collet-type RC airplane prop adapter above, only it's half aluminum (the threaded rod/nut you can see) and half made of plastic that is old and brittle and just looking for an excuse to break. Do NOT attempt to loosen it by turning the aluminum threaded shank with a screwdriver! This is about guaranteed to break the adapter. I got one off successfully by removing the nut completely then warming the middle of the squirrelcage and threaded aluminum shank with my heat-shrink gun, then gripping the body of the squirrelcage in and pressing the threaded shank in to release the collet; that only worked on one of 3 that I have. An air rework station set to around 600 degrees F with an 8mm nozzle should work similarly and give you a chance.

You'll want to clean and oil the fan motor; on both of mine I used light synthetic oil with PTFE (Current bottle is called "Sonic Super Oil" bought off fleaBay) made for oiling  rollerblade/skateboard bearings. This is a Hall-effect controlled brushless motor, and the bearings are inside. Once you have the DC-DC converter out, prop it up on end with the motor shaft up. Saturate the exposed shaft with light oil as described above (NOT WD-40 or 3-in-1; these are penetrating oils and will destroy the bronze bearings), work the shaft back & forth and spin a few times by hand, then let it sit overnight propped upright to allow the oil to seep into the rear bearing area that you can't reach from the outside. Wipe the excess oil off when you get up in the morning and spin the shaft, it should be noticeably smoother and easier to turn; you may even be able to distinctly feel the rotor "stepping" as you turn it. This is normal.

Also, check all the DC rails that noise/ripple is within spec; these 'scopes are pretty fault-tolerant, so just because it passes POST doesn't mean the internal power isn't noisy as hell. My 2230 is a prime example... it has crazy noise on the 5V rail but it still works and has a nice trace, and it gets through everything on the POST except the LAST test - the high-speed acquisition RAM write test - before it throws a code.

Here's links to a pdf parts list, a pdf dissertation on rebuilding the Tek 24xx DC-DC converter, a page that helped me with links to a lot of other useful info on repairing the 2465, and here is KO4BB's archive of service manuals and resources for the 2465B/2467B. Please don't forget to give back a little via the button; hosting those documents isn't free and you can skip Starbucks or McD's for a day. :-+

Also inspect the electrolytic caps on the A5 board while you're checking the NVRAM battery; they're known for leaking and damaging traces.


Right now I am happier than a pig in shit. A fully functional 2465 for $60 USD. Can't beat that!    :-+ :-+ :-+

If I wasn't happy for your win, I could really hate you right now.

Congratulations.   :-+




Well, you can hate me then, I guess; it's already my fault.  :-DD  To add insult to injury, guess what I have on my bench waiting to go in a little box along with some other random junque?


That is, if med6753 confirms they are the ones he needs.   :popcorn:



In other news... When Windoze ATTACKS!!!

I kindof fell off the internet for a few days after the Windoze Spring Update forced me to allow it to install itself, then immediately proceeded to blow up my PC. How do you troubleshoot when it suddenly refuses to accept any input from ethernet, mouse or keyboard the instant control is handed off from BIOS? I couldn't even get it to boot in safe mode: tried a dozen mice/keyboards, even a couple PS/2 ones I keep for when I have to deep-dive embedded Windows XP on Point Of Sale & Info Kiosks. I've been working from my old win7 laptop and my phone since Monday.

After pulling my hair out for several days and numerous attempts, I finally successfully recovered from a restore point just before the attack. Now I can get back to work and play as per my normal state of abnormal.  :-DD


Cheers,

mnem
It's hard work, but hey... I have a lot of Karma to burn off.   };=)~~~~<
« Last Edit: May 12, 2018, 03:46:50 am by mnementh »
 

Offline Brumby

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10545 on: May 12, 2018, 05:41:30 am »
Well, you can hate me then, I guess; it's already my fault.  :-DD  To add insult to injury, guess what I have on my bench waiting to go in a little box along with some other random junque?

Nah - you're good.  It's far more satisfying to see something restored to its proper state.
 

Offline bd139

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10546 on: May 12, 2018, 05:47:21 am »
P.s.: I'm a fan of Tek's idea of having the actual power switch at the back and a long connecting rod to the front panel, you start off as far away as they could design you to be.  :-DD

This is all fun and games until the plastic goes brittle!  Pop. Bugger! Try frigging or finding a replacement one.

Older tek stuff that used glass fibre rods were much better.
 

Offline GerryBags

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10547 on: May 12, 2018, 06:00:52 am »
Now you mention it, it is a puzzle how you would go about rigging up a replacement. I needn't have been so worried, anyway, it now works a treat now it's had plenty of warm up. I'm going to do a thorough functional check tonight and see if I can copy out the cal data from the screen. It's a nice feeling finally having a working 2467B.... while it lasts! I'm touching veneer-clad chipboard, does that count as wood?
 

Offline tggzzz

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10548 on: May 12, 2018, 07:05:11 am »
These 24x5 repair notes are sufficiently useful that we would benefit from them being on some 24x5 repair thread, not merely buried in theses 10,000+ posts!

Thanks.

Here's links to a pdf parts list, a pdf dissertation on rebuilding the Tek 24xx DC-DC converter, a page that helped me with links to a lot of other useful info on repairing the 2465, and here is KO4BB's archive of service manuals and resources for the 2465B/2467B. Please don't forget to give back a little via the button; hosting those documents isn't free and you can skip Starbucks or McD's for a day. :-+
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Offline med6753

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Re: Test Equipment Anonymous (TEA) group therapy thread
« Reply #10549 on: May 12, 2018, 12:01:36 pm »
mnem, those 2 parts are exactly what I need.   :-+ You still have my snail mail address, right? Isn't great when a fellow TEA'er can help each other with their addiction?  :-DD Hopefully I can return the favor one day.  :-/O

To address your concerns....I have a 2465 DMS and I am VERY familiar with the squirrel cage fan and that colet assembly. I was able to get mine apart without breaking it with lubricant and careful prying. That was 2 years ago when I completely re-capped both supply boards. The fan motor in that scope is a little noisy upon initial power up but quickly quiets down after a few minutes. That Siemens fan motor is unobtanium and stupid complex to rebuild. So as long as it works I'm leaving it alone. The fan in this new 2465 is quiet...so far.

I've had this new 2465 on for several hours and I've also gone thru several power cycles. Absolutely NO issues except for the mentioned sweep cal being slightly off. I would think if there was an intermittent issue I'd see it by now. Later today I'm pulling the covers and give it a good visual check and measure the supply voltages at J119 on the main board. If they are OK I'm NOT pulling the power supply boards.

The A5 board: This is a 2465. The A5 is pin thru hole board with almost NO tants or other caps. Very much unlike the 2465A and 2465B which have the SMT A5 board. Also, the cal data is in an EAROM which doesn't require a backup battery. So no worries here but I understand that those EAROM chips supposedly have a finite read/write cycle and then start crapping out. The EAROM chip in the Buffer (Option) board in my 2465 DMS does take intermittent checksum errors so there seems to be some truth in that rumor.

I'll post some pix later today when I pull it apart.     
An old gray beard with an attitude.
 


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