Test Equipment Anonymous (TEA) group therapy thread

[Squarewave]

On Fluke ruggedness, I’ve seen a lot of totalled Fluke 25’s at hamfests radio rallies. YMMV on assigning responsibility there 

I've got loads of Fluke 25s, love them.

[bd139]

On Fluke ruggedness, I’ve seen a lot of totalled Fluke 25’s at hamfests radio rallies. YMMV on assigning responsibility there 

I've got loads of Fluke 25s, love them.

I have one. And it was destroyed when I got it, electrically speaking. Someone had blown the HRC fuse and decided to bypass that and then did whatever stupid thing they did again immediately and actually melted the rotary switch  . Thanks to Specmaster though it got some new guts

[tautech]

More local CL finds.

https://newjersey.craigslist.org/ele/d/sparta-tektronix-mhz-oscilloscope/7510713135.html

That 2235 looks to be in good shape and reasonable price. About 1.5 hours away. Very tempting. BD.....does the 2235 have the trouble prone switcher PSU? Also, if I need a vintage transistor I know where to go. 

https://newyork.craigslist.org/que/ele/d/ridgewood-oscilloscope/7519309169.html

My first scope. Actually, was my Father's. When I left home to strike out on my own my younger brother got it. The seller is delusional with that $100 USD price. Not interested.

I wouldn’t touch another damn 2235 again. I was a nervous wreck after blowing MOSFETs on the preregulstor on that asshat.

https://www.eevblog.com/forum/testgear/tektronix-2235-repair-thread/

After reading your shit show with that 2235 it's definitely giving me 2nd thoughts. I'll mull it over during the weekend. Hopefully someone buys it by then or it just might be road trip and a glutton for punishment.   

You might find some guidance on proper handling of the prereg in this thread Med:
https://www.eevblog.com/forum/repair/tektronix-2215-scope-repair/

Member Per Hansson gives Vince and the rest of us an education in Miller capacitance effects on MOSFET gates.

[dl6lr]

I’m aiming higher. This has been used in broadcast measuring van. And it came with manual with all the instructions one may ever need.
Hope it will re-activate and even elevate my DXing 
If not, I can still use it for 10MHz frequency reference GPS antenna, 4G router antenna, weather station, … 

Been there, done that. Be carefull they can kill. One nearly got me.

Thanks for the warning. Lightning? Collapsed? Accidental retracting?

I'd imagine that a genuine risk with those is driving off after failing to retract it. Add almost any overhead structure, but especially HV power lines to "fire for effect".

A crane on a barge plus overhead high tension lines works very well as Hydro One found out this afternoon.

[tggzzz]

On Fluke ruggedness, I’ve seen a lot of totalled Fluke 25’s at hamfests radio rallies. YMMV on assigning responsibility there 

I've got loads of Fluke 25s, love them.

I have one. And it was destroyed when I got it, electrically speaking. Someone had blown the HRC fuse and decided to bypass that and then did whatever stupid thing they did again immediately and actually melted the rotary switch  . Thanks to Specmaster though it got some new guts

Not sure which territory that falls into

• you can make something foolproof but not damnfoolproof
• you can't make something foolproof because fools are so damn ingenious

On second thoughts, since no ingenuity was involved, it has to be the former.

[Cerebus]

On Fluke ruggedness, I’ve seen a lot of totalled Fluke 25’s at hamfests. YMMV on assigning responsibility there 

Totalled electrically, or totalled mechanically? The former is possible for any of us on a bad day, the latter would require such a level of creative incompetence that I don't think I want to risk being within 300m of someone capable of doing so.

[BU508A]

Re AVO weird battery requirement - on my to do list:

Mikeselectricalstuff coin battery mod

Ah, a nylock so they don't become loose by themselves...

They do this, but it is not cheap.

https://www.ebay.de/itm/265531737706

[Specmaster]

On Fluke ruggedness, I’ve seen a lot of totalled Fluke 25’s at hamfests radio rallies. YMMV on assigning responsibility there 

I've got loads of Fluke 25s, love them.

I still have parts of 25's if ever they are required, I think I might even have a working one somewhere but where??? I swapped mine over for the better option, 27, with the extra functions and the Fluke yellow cases and complete with the extra tough carrying cases.

[tautech]

Re AVO weird battery requirement - on my to do list:

Mikeselectricalstuff coin battery mod

Ah, a nylock so they don't become loose by themselves...

They do this, but it is not cheap.

https://www.ebay.de/itm/265531737706

LR44 inside sleeving from the $2 shop is the simplest fastest fix for the now nearly unobtainium 15V cell.

[BU508A]

LR44 inside sleeving from the $2 shop is the simplest fastest fix for the now nearly unobtainium 15V cell.

V74PX / 10LR54 - 15V
Diameter: 16mm
Height: 35mm

LR44 - 1.5V
Diameter: 11.5mm
Height: 5.4mm

LR54 - 1.5V
Diameter: 11.6mm
Height: 3.05mm

LR41 - 1.5V
Diameter: 7.9mm
Height: 3.6mm

I think, the LR54 will fit better than the LR44 which is 2mm too high.

[Specmaster]

I'll take objection on this one. Fluke distributor visited the school where I was getting my first degree; that was part of the demonstration. Their professional sparky series of meters are designed to withstand a fall from the top of at least a 12-foot ladder.

Cheers,

mnem
 

Yep, good luck doing that with an AVO, but then only a blithering idiot would dream taking an AVO up a ladder.

Then what the fuck good are they?

mnem
a portable meter that doesn't port...?

I guess I must be a "blithering idiot", along with thousands of others, then .

Back in the day, there were no "steenkin' DMMs", so if a meter had to be used at height, you used whatever you had-----AVO, Simpson, University Graham, Metrix, or whatever, all of which were big & heavy.

Skill & care allowed people to do this---we weren't "cowboys", just had to work with what we had.
One big advantage to AVOs was the rugged leather handle on the top which allowed it to be tied off to any convenient point, like the top rung of the ladder.

Remember, those were the days when the "portability" of 7000 series Tektronix Oscilloscopes was lauded in their sales material.

The first type of portable DMM to receive approval by my then employer was the Beckman 310.
These rugged meters gave good service, the Fluke bench DMMs (too long ago to remember the model numbers), not so much.
One model of Fluke used to "play up" regularly, but was easily fixable, the next model was a total turd, ----the common saying was "it's a 'fluke' if it works!"

They never went for the early portable Flukes with the side buttons, which was probably a good idea--a later employer had one at the transmitter site with several buttons missing.

I bet it was the much more rugged later design which the Fluke guy chucked across the room!

There was plenty of smaller, just as capable meters specifically designed for portability such as the excellent TMK500 or the AVO minor for instance, the AVO model your referring to was designed as a lab type instrument.

[vk6zgo]

There was plenty of smaller, just as capable meters specifically designed for portability such as the excellent TMK500 or the AVO minor for instance, the AVO model your referring to was designed as a lab type instrument.

The TMK was a bit fragile, & the "Minor" was, as I commented earlier, regarded as a bit of a "toy".
In practice, AVO 8s were used extensively in the field.

[Specmaster]

There was plenty of smaller, just as capable meters specifically designed for portability such as the excellent TMK500 or the AVO minor for instance, the AVO model your referring to was designed as a lab type instrument.

The TMK was a bit fragile, & the "Minor" was, as I commented earlier, regarded as a bit of a "toy".
In practice, AVO 8s were used extensively in the field.

You say the 500 is a bit fragile, I suppose that is because it has a taut band suspension for the meter movement. I have 2 of these, 1 I purchased as an apprentice 60 odd years ago and that one was chucked in the back of a van and driven thousands of miles, survived 5 house moves. The other, purchased recently off eBay as spares or repair, and it too survived the couriers known mistreatment of packages and only required some repairs to the switch and is as good as new. So these little meters actually are far tougher than you'd give them credit for in reality.

[McBryce]

I bet you're older than me, by quite some margin, but I love Avometers 

Yep, if you drop them, they're donald ducked, though the movements can survive, the casing will be shattered.

I don't love them, and have a couple of carcasses I will unload for a pittance.

Long ago I was working with GPO[1] Martlesham Heath and they told me of a "competition" between Avo 8 salesmen and  a DMM salesman. Everything was evenly matched until the DMM salesman picked up his offering, threw it across the room, and suggested repeating the competition.

[1] no, it wasn't BT for a few years

I suppose there's always lots of ridiculous comparisons to make, that being one of them. No instrument is meant to be thrown. I guess that's where the DMM salesman lost his argument - it was all evenly matched, until he lost his temper.

Edited: for quote bracket thing was missing.

I'll take objection to on this one. Fluke distributor visited the school where I was getting my first degree; that was part of the demonstration. Their professional sparky series of meters are designed to withstand a fall from the top of at least a 12-foot ladder.

Cheers,

mnem
 

Yep, good luck doing that with an AVO, but then only a blithering idiot would dream taking an AVO up a ladder.

Yep, don't think that the full size AVOs were ever meant for anything other than bench/lab work of sorts. They made much smaller ones for out and about.

Nah! the little "Multi Minors" were pretty much a toy, something an EE might keep in his desk drawer.
The big AVOs went everywhere!

I have a working Avo Minor in my collection. I've only ever used it to confirm its function. It's otherwise just for decoration (without lamp added). They are only 100mm x 75mm and pretty much useless for any serious measurements.

McBryce.

[Squarewave]

I have a working Avo Minor in my collection. I've only ever used it to confirm its function. It's otherwise just for decoration (without lamp added). They are only 100mm x 75mm and pretty much useless for any serious measurements.

McBryce.

Back in the day, meters like this were great for indication, where serious accuracy wasn't needed, such as, is that supply on or isolated, rather than how accurate is that last volt? Granted, these days we can have excellent reliability in a small more rugged instrument. Technology has come a long way over the years.

[Specmaster]

I bet you're older than me, by quite some margin, but I love Avometers 

Yep, if you drop them, they're donald ducked, though the movements can survive, the casing will be shattered.

I don't love them, and have a couple of carcasses I will unload for a pittance.

Long ago I was working with GPO[1] Martlesham Heath and they told me of a "competition" between Avo 8 salesmen and  a DMM salesman. Everything was evenly matched until the DMM salesman picked up his offering, threw it across the room, and suggested repeating the competition.

[1] no, it wasn't BT for a few years

I suppose there's always lots of ridiculous comparisons to make, that being one of them. No instrument is meant to be thrown. I guess that's where the DMM salesman lost his argument - it was all evenly matched, until he lost his temper.

Edited: for quote bracket thing was missing.

I'll take objection to on this one. Fluke distributor visited the school where I was getting my first degree; that was part of the demonstration. Their professional sparky series of meters are designed to withstand a fall from the top of at least a 12-foot ladder.

Cheers,

mnem
 

Yep, good luck doing that with an AVO, but then only a blithering idiot would dream taking an AVO up a ladder.

Yep, don't think that the full size AVOs were ever meant for anything other than bench/lab work of sorts. They made much smaller ones for out and about.

Nah! the little "Multi Minors" were pretty much a toy, something an EE might keep in his desk drawer.
The big AVOs went everywhere!

I have a working Avo Minor in my collection. I've only ever used it to confirm its function. It's otherwise just for decoration (without lamp added). They are only 100mm x 75mm and pretty much useless for any serious measurements.

McBryce.

Yeah, the multi minor is by far the best option for portability and back in the day designed for use in the field. Of course, back then nobody had the kind of protection that for safety that we have today.

[McBryce]

I have a working Avo Minor in my collection. I've only ever used it to confirm its function. It's otherwise just for decoration (without lamp added). They are only 100mm x 75mm and pretty much useless for any serious measurements.

McBryce.

Back in the day, meters like this were great for indication, where serious accuracy wasn't needed, such as, is that supply on or isolated, rather than how accurate is that last volt? Granted, these days we can have excellent reliability in a small more rugged instrument. Technology has come a long way over the years.

My favourite "pointless antique mini meter" is the Pifco All in One. They are just a work of art. They are tiny (65mm diameter) and look like a mini alarm clock / pocket watch. I have 3 working models. The legs are also probe connection points, but would you connect this to the mains while holding it?? 

McBryce.

[dl6lr]

-hp- 4952A update:

The disk drive seems to be borked. It will not format a disk, but grind of the coating... Plus the insert/eject does not work very well.
So I removed the drive to inspect and clean it.  Cleaning did not help very much.
Unnecessary to say this is an old DD drive from Sony, model MP-F52W-30. The only 34pin connector carries supply voltages on normally grounded lines. It uses !DISKCHNG (2) and !CHNGRESET (1)  and !INUSE (1) signals from/to the drive and a strange combination of !DRVSEL (10) and a single !MOTON (16) signal pins.
So I will start researching how to modify a ususal 3.5" drive to make it "compatible". Splitting the ribbon cable to separate the supply voltages should be the easiest part. I suspect one can just ignore the !INUSE output to the drive, as it only controls the LED. Disk change is available on some older TEAC on solder pads, maybe you can ignore the CHNGRESET too or handle it with some external logic.

This will take some time, first to grab a drive from the box and test it, then to figure out how to modify it.

Some more photos from the inside, someone already had the fun of Rifa. And the arrangement of the three TO220 is a little suspicious. Processor board with NiCd cell and FDC controller and mainboard with CRT control:

[BU508A]

-hp- 4952A update:

The disk drive seems to be borked. It will not format a disk, but grind of the coating... Plus the insert/eject does not work very well.
So I removed the drive to inspect and clean it.  Cleaning did not help very much.
Unnecessary to say this is an old DD drive from Sony, model MP-F52W-30. The only 34pin connector carries supply voltages on normally grounded lines. It uses !DISKCHNG (2) and !CHNGRESET (1)  and !INUSE (1) signals from/to the drive and a strange combination of !DRVSEL (10) and a single !MOTON (16) signal pins.
So I will start researching how to modify a ususal 3.5" drive to make it "compatible". Splitting the ribbon cable to separate the supply voltages should be the easiest part. I suspect one can just ignore the !INUSE output to the drive, as it only controls the LED. Disk change is available on some older TEAC on solder pads, maybe you can ignore the CHNGRESET too or handle it with some external logic.

This will take some time, first to grab a drive from the box and test it, then to figure out how to modify it.

Some more photos from the inside, someone already had the fun of Rifa. And the arrangement of the three TO220 is a little suspicious. Processor board with NiCd cell and FDC controller and mainboard with CRT control:

Maybe this could be helpful:
https://www.rudiswiki.de/wiki9/HxCFloppyDiskEmulator

[dl6lr]

Maybe this could be helpful:
https://www.rudiswiki.de/wiki9/HxCFloppyDiskEmulator

Yes, I know this page. I would like to have the real floppy drive be functional first but the 300rpm vs. 600rpm could be a real problem. Normally I use FlashFloppy on those Gotek emus but will cosider the HxC software.

[Robert763]

Re AVO weird battery requirement - on my to do list:

Mikeselectricalstuff coin battery mod

Ah, a nylock so they don't become loose by themselves...

They do this, but it is not cheap.

https://www.ebay.de/itm/265531737706

LR44 inside sleeving from the $2 shop is the simplest fastest fix for the now nearly unobtainium 15V cell.

The official Ever Ready BLR121 is a stick of 10 LR54s in a plastic case. The LR54 is quite thin I don't think 10 LR44 would fit in a single stack. I had this slightly kanky one in a NOS bag. Fluke says 7.4 V

Edit: BU508 got it right independently. The BLR121 does have two contact buttons that are 2.1 mm high adding 4.2 mm to the total stack giving 24.7 mm.

[Cerebus]

My favourite "pointless antique mini meter" is the Pifco All in One. They are just a work of art. They are tiny (65mm diameter) and look like a mini alarm clock / pocket watch.

I always think that they look like a model of a naval mine, with all those 'spikes' sticking out.

[Per Hansson]

Some mentalist paid almost working unit money for something that looks like it has some potentially serious front end damage:  https://www.ebay.co.uk/p/1923238610?iid=185523787974

Did you follow the AD to the actual unit? Reason I ask is that eBay is being "helpful" and shows another unit with your link.
Better described in the attached picture:

[mnementh]

SWMBO needed my BFEC (big fucking extension cord) for a auxiliary function at her school today.

I am but half a tinkerdwagon now... 

mnem
I suppose I could fire up the generator...

[AVGresponding]

Some mentalist paid almost working unit money for something that looks like it has some potentially serious front end damage:  https://www.ebay.co.uk/p/1923238610?iid=185523787974

Did you follow the AD to the actual unit? Reason I ask is that eBay is being "helpful" and shows another unit with your link.
Better described in the attached picture:

Yes, I am aware. The one that sold for £233 was in my watch list, but I did not bother to link it in the thread until after it was sold, for the reason that I thought it had potentially serious damage which the magnitude of the bidding did not take into account. I'll point out that I acquired my working* K2000 for a mere £20 or so more than this.

*It had two very minor error codes which I reasoned were quite likely to be a no-cost fix, and was proved correct.