Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

Google for "PP3 explode"

I've never known a 9V battery to do that or leak, so perhaps the key is to settle for zinc carbon batteries and replace then more regularly and that means as well that you get more stable pile type of construction.

But surely aren't Lipo batteries just as dangerous as well?

[Mr. Scram]

You can open a case from this link : https://resolutioncenter.ebay.com

Thanks, that wasn't as obvious as you'd hope. Let's see what happens.

[Brumby]

A bit late to the disk drive party - but I've been pondering the question of will I share this...

Back in the 80's I was working for a company as an analyst/programmer after having spent 2 years as an operator on an IBM 370 system using 3340 disks.  These disks always reminded me of the USS Enterprise.


They had the feature of integrated heads, so that each disk pack had its own set of heads.  This avoided the problem of a head crash on one disk being propagated onto other disks and other drives by operators who were no diligent.  The head assembly was protected by a plastic roller shutter which was drawn out of the way as the disk was loaded onto the drive.  A large peg and locking mechanism engaged the head assembly.  This peg was the actuator for a very grunty linear actuator that resided in the drive unit.  A large electric motor engaged with a plate at the bottom which connected through to the spindle.  The motor turned the platters and the linear actuator performed the seek motion of the heads.

Within the plastic casing, there was a metal frame upon which was mounted the spindle bearings and spindle as well as the heads and the tracks they would run back and forth over.  This frame was supported by three rubber mounts - that were under tension.  Yes, the entire platter and head assembly were hanging by these three rubber mounts.

Over time, we had a failure of one of these mounts and the platter and head assembly no longer sat level - and so the drive could not load it.  Being the creative guy that I was, I was able to work out a way to support the platter assembly from below while the drive loaded the disk.  Once loaded, the mechanics of the motor and head driving units kept the disk held well enough to be used.  The only thing that was done was an immediate copy off that disk - and then it was retired.

As my interests in all things electrical (I can't begin to tell you how many things people brought in for me to fix - from car cassette/radios to kitchen mixers) I was able to procure one of these and I went about the teardown exercise.

That was many years ago and I still remember some of the fun I had.  The stuff the outer casing was made of was incredible.  A full swing blow with a 21oz ball pein hammer just bounced off.  There were platters, there were spacers and there were a lot of exceptionally well engineered heads - but after all was said and done over the years, there is almost no trace of this unit left.

Except for these:



These are the ball bearings that the heads ran on back and forth along the tracks.

[bitseeker]

Google for "PP3 explode"

I've never known a 9V battery to do that or leak, so perhaps the key is to settle for zinc carbon batteries and replace then more regularly and that means as well that you get more stable pile type of construction.

I've had a few 9V alkaline batteries leak. Definitely not as many as alkaline cylindrical ones. The worst 9V failure I've had was one that pushed the bottom of the battery out almost a centimeter. Fortunately, the device it was in had a long battery compartment or it'd have gotten mighty stuck (or broken the enclosure).

[bitseeker]

A bit late to the disk drive party - but I've been pondering the question of will I share this...

Back in the 80's I was working for a company as an analyst/programmer after having spent 2 years as an operator on an IBM 370 system using 3340 disks.  These disks always reminded me of the USS Enterprise.

Cool. It looks like a Federation starship.

[mnementh]

@Mnem, sorry bd139, I did get there first, I was testing it while you were posting I guess.

The warning comes up at 6.4V but it carries on, reading correctly right up til the battery gets to 5.62V at which point it beeps at you and displays blanks to a error message.

Personally I'm pleased that it uses a 9V battery as these are less prone to leakage than single cells but if getting caught without a battery miles from anywhere is why you like Lipo batteries, you can get rechargeable 9V batteries that should provide pretty good battery life seeing as the current draw is around 6.5mA.

The leads are 1KV 10A rated and are silicon, tips are gold plated, I certainly wouldn't lose any sleep over the colour being red as opposed to yellow, I have meters here that are black, yellow, brown and now red, truth is that when you're using them, you totally ignore the colour, the only thing that you focus on is the display and the accuracy and colour has zero influence over those.

These meters are most certainly worth a shot, I have plenty of Flukes that I'm putting on Ebay soon and with the return on them, I'll think I'll be buying another 867 and maybe the PC interface and software, I very much doubt that I'll regret it.

Hmmm... I remember reading some testing on other meters that showed they started to have accuracy problems below 6V... but that's promising. I should be able to use a regular 600mAH 8.4/7.2V Nominal LiPo with it, which should last forever, even if I cheat and add a LED on a switch.

Very tempting, as my excursion to the local pawn shops yielded only a 179 for $220. And a HP DV6-2150US laptop supposedly dead (it's restoring to factory even now) for $15, and they threw in a T95N-MINI MX+ TV Box as well.

I think I'm gonna toddle off to ded now... my retail therapy just yielded even more crap I need to work on.

mnem
ZZZzzzZZZzzz...

[Specmaster]

@Mnem, sorry bd139, I did get there first, I was testing it while you were posting I guess.

The warning comes up at 6.4V but it carries on, reading correctly right up til the battery gets to 5.62V at which point it beeps at you and displays blanks to a error message.

Personally I'm pleased that it uses a 9V battery as these are less prone to leakage than single cells but if getting caught without a battery miles from anywhere is why you like Lipo batteries, you can get rechargeable 9V batteries that should provide pretty good battery life seeing as the current draw is around 6.5mA.

The leads are 1KV 10A rated and are silicon, tips are gold plated, I certainly wouldn't lose any sleep over the colour being red as opposed to yellow, I have meters here that are black, yellow, brown and now red, truth is that when you're using them, you totally ignore the colour, the only thing that you focus on is the display and the accuracy and colour has zero influence over those.

These meters are most certainly worth a shot, I have plenty of Flukes that I'm putting on Ebay soon and with the return on them, I'll think I'll be buying another 867 and maybe the PC interface and software, I very much doubt that I'll regret it.

Hmmm... I remember reading some testing on other meters that showed they started to have accuracy problems below 6V... but that's promising. I should be able to use a regular 600mAH 8.4/7.2V Nominal LiPo with it, which should last forever, even if I cheat and add a LED on a switch.

Very tempting, as my excursion to the local pawn shops yielded only a 179 for $220. And a HP DV6-2150US laptop supposedly dead (it's restoring to factory even now) for $15, and they threw in a T95N-MINI MX+ TV Box as well.

I think I'm gonna toddle off to ded now... my retail therapy just yielded even more crap I need to work on.

mnem
ZZZzzzZZZzzz...

Really think that you'd like a 867 once you had a play with it. Not sure what they sell for in the states, but ours cost almost £80 less than Amazon are selling them for and the supplier also offers calibration services. So for the cost of 2 from Amazon I can get 3 and a   PC kit all delivered the next working day.
It already has become my goto meter and I have around 11 Fluke handheld meters that are now on my disposal list. The continuity function is a real joy to use, it is blisteringly fast and never misses.

It is Joe Smiths and also Martin Lortons goto meters now and if you goto Joe's YT channel you will see that he constantly uses his as a reference point in his many meter tests and that alone speaks volumes to me.

Like the T12 it really is good but unlike the T12, it can and does take on many makers costing double or more times its price and wipes the floor with them.

So this is me now asking you, if you take the plunge, to do what you asked me to do with T12, play it forwards.

It is also sold in green and rebadged as I think a Greenwood, more details in one of Martins videos.

[bitseeker]

Greenlee rebadges Brymen in the US, but they don't do it for all Brymen models. The Greenlee DM-860A is the Brymen BM869s. They don't do the BM867. The next one down is the Greenlee DM-830A, which I think is the Brymen BM829s.

It does appear that Greenlee made space in their model numbers for some more rebranding, though.

[Specmaster]

Greenlee rebadges Brymen in the US, but they don't do it for all Brymen models. The Greenlee DM-860A is the Brymen BM869s. They don't do the BM867. The next one down is the Greenlee DM-830A, which I think is the Brymen BM829s.

It does appear that Greenlee made space in their model numbers for some more rebranding, though.

Yep it was Greenlee and the 869 which is the 867 temperature x 2 and VFD added on.

[med6753]

Google for "PP3 explode"

I've never known a 9V battery to do that or leak, so perhaps the key is to settle for zinc carbon batteries and replace then more regularly and that means as well that you get more stable pile type of construction.

But surely aren't Lipo batteries just as dangerous as well?

I had a Fluke 77 destroyed by a leaking (not exploding) 9 V battery.

[med6753]

Well my replacement BNC's are in the U.S. Not sure where though, it doesn't specify. I am assuming JFK but it could be Boston or somewhere else. I doubt I'll have them delivered by tomorrow. Still have to clear Customs then USPS will pick it up.

[bd139]

Google for "PP3 explode"

I've never known a 9V battery to do that or leak, so perhaps the key is to settle for zinc carbon batteries and replace then more regularly and that means as well that you get more stable pile type of construction.

But surely aren't Lipo batteries just as dangerous as well?

I had a Fluke 77 destroyed by a leaking (not exploding) 9 V battery.

That nearly happened to mine. I got it just in time though.

[tggzzz]

Our country is too small to have more than one time zone so we just have DST to make us feel better

Usually, but not always. Have a look at, IIRC, 1968-1971, which included the Unix epoch instant.

[tggzzz]

Nah, NZT but we have DST over the summer months.

You lot even get summer wrong, whereas usually we don't get summer.

[Cerebus]

...  The stuff the outer casing was made of was incredible.  A full swing blow with a 21oz ball pein hammer just bounced off.  ...

Polycarbonate, intended as a containment mechanism if the disk decided to go totally Tonto at a few thousand RPM. Those spindles are basically flywheels and, depending on the drive model, weigh a few kilos to several hundred kilos. That, spinning at a few thousand RPM, has not insignificant energy bound up in its motion. It used to be a standard practice for bored technicians and programmers to pull out the specs for proper man sized disk drives, calculate the kinetic energy of the spindle at full working speed and work out how much of the building it would demolish on its way out if it ever broke free of its bearings.

I was once in the computer room at Queen Mary College when they had total mains power failure. A loud computer room suddenly became somewhere you could hear a pin drop. Once our ears got used to the silence we realised there was still a slight noise coming from somewhere. They had a big fixed head disk in the centre of the room, a crazy huge thing about four to five feet tall with several 30" platers (or thereabouts) in one cabinet and a separate cabinet for the electronics. Because the power had gone completely this had failed to brake and so the spindle was still running just on momentum and continued to do so for several hours until power was restored — when someone had the job of deciding whether it was safe to re-apply power to, and restart, the fixed head disk while it was still spinning.

[tautech]

Nah, NZT but we have DST over the summer months.

You lot even get summer wrong, whereas usually we don't get summer.

But you're getting a good roasting this year I believe.

I don't mind DST even though I was bought up and still live on the land. I do like the longer summer evenings and the increased social interaction they can provide.
A few years back when we went to Perth to have Xmas with our son, the full sun at 4.15 in the morning was hard to get to grips with as they don't have DST.

As for getting summer wrong, maybe as we never have snow at Christmas. Anyways, you can stick snow as far as I'm concerned, it's only good in drinks providing it's not yellow ! 

[med6753]

I was once in the computer room at Queen Mary College when they had total mains power failure. A loud computer room suddenly became somewhere you could hear a pin drop.

And you can hear a mouse fart at 50 paces too. Had that happen during a hurricane in IBM mainframe test with dozens of P6 and P7 systems undergoing test. Fan noise to absolute silence in a nanosecond. And dark too...until the emergency lights kicked on. Took you a second to realize what happen. Was really weird.

[tggzzz]

...  The stuff the outer casing was made of was incredible.  A full swing blow with a 21oz ball pein hammer just bounced off.  ...

Polycarbonate, intended as a containment mechanism if the disk decided to go totally Tonto at a few thousand RPM. Those spindles are basically flywheels and, depending on the drive model, weigh a few kilos to several hundred kilos. That, spinning at a few thousand RPM, has not insignificant energy bound up in its motion. It used to be a standard practice for bored technicians and programmers to pull out the specs for proper man sized disk drives, calculate the kinetic energy of the spindle at full working speed and work out how much of the building it would demolish on its way out if it ever broke free of its bearings.

Indeed, but it is piffle compared to the rotational energy in a power station steam turbine.

I remember that, as I kid, I had a book on modern transport in which there was a bus that spun up a flywheel when breaking, and used the energy when pulling away. I presume that going round a corner wasn't too difficult, since by then the flywheel ought to have slowed down.

[Cerebus]

I remember that, as I kid, I had a book on modern transport in which there was a bus that spun up a flywheel when breaking, and used the energy when pulling away. I presume that going round a corner wasn't too difficult, since by then the flywheel ought to have slowed down.

"Ladies and Gentlemen, this is your driver.

I'm going to have to turn the bus in a minute, when the conductor sounds the bell three times would you all please move to the left side of the bus. It would be especially helpful if all the passengers on the top deck lean out of the left hand windows as well. Thank you for you cooperation."

[bd139]

I suspect it was more "we better go round this corner slowly or the flywheel is going to tear the bus in half" 

As for noise, modern DCs are bloody noisy. I wear ear protection in our cage.

[med6753]

More progress on the Tek 465, both good news and bad news.

Good news: Fixed the no trace issue on Channel 2. Dirty transistor sockets. Deoxit is the greatest thing since sliced bread. 

Bad news: Found the attenuator issue with Channel 2. The X10 attenuator is shorted. Verified that by swapping it with Channel 1. Bd...I know you mentioned having shorted attenuators. Before I start searching where did you get replacements?

I'm pretty sure this is the last issue with this 465 other than replacing the input BNC's.

[bd139]

Looking good.

I got mine off eBay or out of my mule scope. Sphere sell them: http://sphere.bc.ca/test/tek-parts/tekpots.html (half way down)

[med6753]

Looking good.

I got mine off eBay or out of my mule scope. Sphere sell them: http://sphere.bc.ca/test/tek-parts/tekpots.html (half way down)

Yep, I see them. Thanks. Gonna check other sources too.

[med6753]

Sitting on it's side on the bench. Channel 2 trace restored. Making sure it stays on. It does have a shorted X10 attenuator. Channel 1 looks real good.



The offending attenuator. Will order a replacement.



Just a scandalous pron shot of the lower board.    Enjoy! 

[bd139]

All these photos are making me miss my 465 now

BTW you can pop the lids off on the attenuator modules. They are thin film printed resistors. Might be able to identify why it died. I’ve seen some that had burns and bubbled ones. The latter mostly worked if you gave them a poke.