Author Topic: List your test equipment "scores" here!  (Read 775081 times)

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Offline bitseeker

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Re: List your test equipment "scores" here!
« Reply #975 on: November 05, 2016, 01:41:20 am »
The brush to use on files is called a card brush

Aha! I've seen those. Didn't know what they were for or called.
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Offline CJay

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Re: List your test equipment "scores" here!
« Reply #976 on: November 05, 2016, 11:55:57 am »
The brush to use on files is called a card brush

Definitely, from what I remember using a brass brush on a file is a pretty good way to wreck it and if my metalwork (shop?) teacher caught us using anything other than the card brush we would be given a stern lecture about how not to destroy his files. (filing aluminium without using a lubricant was also a fairly dangerous thing to risk getting caught doing)
 

Offline TerraHertz

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Re: List your test equipment "scores" here!
« Reply #977 on: November 05, 2016, 05:37:23 pm »
The brush to use on files is called a card brush

Definitely, from what I remember using a brass brush on a file is a pretty good way to wreck it and if my metalwork (shop?) teacher caught us using anything other than the card brush we would be given a stern lecture about how not to destroy his files. (filing aluminium without using a lubricant was also a fairly dangerous thing to risk getting caught doing)

I'm amazed at the things people say & believe sometimes.
Please explain how soft, fine brass wire tips are going to damage the high-carbon steel of a file? Considering that the file can cut into solid brass all day and not get blunt.
As opposed to the hardened spring steel of any kind of steel wire brush. You _can_ use a steel wire brush, if you're careful to only run parallel to the file grooves. Which you do if you're trying to remove stuck swarf. Go the other way and you might as well file hardened steel (ie throw the file away, because you just ruined it.)
The card brush is useful because the bristles are both short and mounted in a flexible base sheet that allows them to tilt. So it's a way to apply a stiff but limited force to stuck swarf. But I don't bother with them - just one more rarely used special tool I can do without.

Personally to clean files I never use anything but soft brass wire brushes, and kerosene as a releasing/penetrating lubricant (because it's cheaper than WD40.) If some metal has stubbornly stuck, then run the tip of a scriber along the file grooves that need cleaning.

Removing surface rust is a different problem to stuck swarf, since it's all over all surfaces. Needed some scrubbing across the grooves too, so definitely only with a brush much softer than the steel.

Actually it was surprising. I don't know what wear-state the files were in before they were left to rust in a tub of rainwater for a while. But after scrubbing the rust off (and high-carbon steel seems to rust less than other steels) the files were all very sharp, like near new. Maybe a little rusting is similar to the acid-etch sharpening method?

And though I've never tried acid-etch (keep meaning too), I don't know why some people can't see how it would work. The solution doesn't preferentially eat corners, it takes off _surface_. So, think of a triangular point, but with the point slightly rounded. Now remove a little of all surfaces. Yes, it reduces the radius of the rounded bit, and can re-create a sharp point.

Btw, I had some more contact with the people who tossed that Tektronix digital video gen. And did score some other assorted bits and pieces, more on that later. But the answer to the mystery is that the owner was a hoarder, the Tek was something he bought at an auction, and no he didn't have the rest of an editing suite to go with it. Which was a great relief in a way, since the first person I spoke to with good English mentioned they'd already sent piles of stuff to recycling, and I was getting pretty depressed wondering if some really nice things had been scrapped. Still wish I'd seen the house though. Always satisfying to see a _worse_ hoarder's pile than my own.
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Offline CJay

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Re: List your test equipment "scores" here!
« Reply #978 on: November 07, 2016, 11:50:32 am »
The brush to use on files is called a card brush

Definitely, from what I remember using a brass brush on a file is a pretty good way to wreck it and if my metalwork (shop?) teacher caught us using anything other than the card brush we would be given a stern lecture about how not to destroy his files. (filing aluminium without using a lubricant was also a fairly dangerous thing to risk getting caught doing)

I'm amazed at the things people say & believe sometimes.
Please explain how soft, fine brass wire tips are going to damage the high-carbon steel of a file? Considering that the file can cut into solid brass all day and not get blunt.
As opposed to the hardened spring steel of any kind of steel wire brush. You _can_ use a steel wire brush, if you're careful to only run parallel to the file grooves. Which you do if you're trying to remove stuck swarf. Go the other way and you might as well file hardened steel (ie throw the file away, because you just ruined it.)
The card brush is useful because the bristles are both short and mounted in a flexible base sheet that allows them to tilt. So it's a way to apply a stiff but limited force to stuck swarf. But I don't bother with them - just one more rarely used special tool I can do without.

Personally to clean files I never use anything but soft brass wire brushes, and kerosene as a releasing/penetrating lubricant (because it's cheaper than WD40.) If some metal has stubbornly stuck, then run the tip of a scriber along the file grooves that need cleaning.


I was lead believe it's because the brass can clog the teeth on fine files rather than blunting them and that, I would assume, would also depend on the type of brass alloy used.

Your use of kerosene as a lubricant may also negate the effect entirely.

I just know that a card brush didn't require the use of lubricants to clean a file, as such it seemed sensible to use one when cleaning a file.
 

Offline JacquesBBB

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Re: List your test equipment "scores" here!
« Reply #979 on: November 07, 2016, 07:40:13 pm »
I just got a TDS220 from my favorite dumpster.

When I powered it,  the screen  was  dark, but I noticed that it  was working. obviously,  the CCFL tube was dead.
I checked the power supply that looked OK, and ordered a CCFL on aliexpress.
The best deal I found was 10 for 16 € ( in fact I received 11, so its less than 1.5 € each).

I have changed now the CCFL. Many plastic parts were very brittle, and I had to  use some Kapton tape for remounting,
but everything is now fine and in working order.

So the total cost of the repair was 1.5€.

I have already several other scopes, including a recent Rigol1054z (the only one that I had to pay for),
but I like the TDS220.
It has roughly the same form factor as the Rigol, and same bandwidth (100 Mhz). Of course, it has not
as many features, and is only 2 channels.
But it has a huge advantage :

It is totally silent !

I was really looking for such a scope. It is very enjoyable when you are in a quiet atmosphere,  not to have  the fan noise
of some modern devices.
In fact, my old fashion power supplies (coming straight from the dumpster) are linear PSU and also totally silent, contrary
to many new SMPS that usually need a fan.

I am sure that the evolution will go towards fanless devices, as it is now for many  laptops,  but  makers are probably still
thinking that a lab is a noisy atmosphere, so additional noise is not a problem, and they prefer to increase the performances,
without considering the noise level.  I am sure this will change. Meanwhile, its nice to have some of the old,
not so performant but silent stuff.
 

« Last Edit: November 07, 2016, 07:43:10 pm by JacquesBBB »
 

Online tautech

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Re: List your test equipment "scores" here!
« Reply #980 on: November 08, 2016, 05:29:01 am »
I just got a TDS220 from my favorite dumpster.

When I powered it,  the screen  was  dark, but I noticed that it  was working. obviously,  the CCFL tube was dead.
I checked the power supply that looked OK, and ordered a CCFL on aliexpress.
The best deal I found was 10 for 16 € ( in fact I received 11, so its less than 1.5 € each).

I have changed now the CCFL. Many plastic parts were very brittle, and I had to  use some Kapton tape for remounting,
but everything is now fine and in working order.

So the total cost of the repair was 1.5€.
..............
A TDS210 I was given had a dead backlight too, confirmed by the torch method.  ;)
They use a discrete push pull oscillator on the backlight inverter primary and the dipped ceramic cap for it measured pF's.  :scared:
IIRC it was supposed to be 0.047uF.
That's all that was wrong with it.  :)
« Last Edit: November 18, 2016, 10:02:01 am by tautech »
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Offline Berni

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Re: List your test equipment "scores" here!
« Reply #981 on: November 08, 2016, 07:47:57 am »
Getting a bunch of those drivers is probably a good idea given how much test equipment with LCDs uses them for backlights. Even brand new equipment made today seams to use them on larger displays.

I also think too much equipment has fans, ridiculously loud ones sometimes even. My lab tends to be pretty quiet as the PC in there is fitted with quality fans and set up for speed control so as a result the PC is so quiet i don't even hear its on unless one of the mechanical harddrives are spinning. Turning on a piece of equipment with a loud fan in there makes it seam like a jet engine just started up. I tend to replace loud fans in equipment, but that's not always possible. For example my HP 8566 gets pretty hot even with the loud hurricane creating fan blowing trough it
 

Online nctnico

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Re: List your test equipment "scores" here!
« Reply #982 on: November 18, 2016, 08:37:13 am »
Yesterday I managed to 'win' an Ebay auction for an Agilent N3305A 150V/60A 500W electronic load module listed 'for parts'.

This is supposed to go into a DC load mainframe which I already have (bought from a forum member) and it came up just in time because I have a project coming up where it will be usefull. I have been angling for one of these modules for years on Ebay and now I got one. Unfortunately it was an auction so I put in a bid a couple of hours before the end and just see where it goes. Much to my surprise the price stayed well below my bid at US$56 and only one 'sniper'. Still I can do without the excitement though.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline rx8pilot

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Re: List your test equipment "scores" here!
« Reply #983 on: November 18, 2016, 03:52:21 pm »
Yesterday I managed to 'win' an Ebay auction for an Agilent N3305A 150V/60A 500W electronic load module listed 'for parts'.

If it does not immediately work....hopefully an easy fix. I got a lot of Chroma DC modular loads in various condition. The broken parts have all been trivial - the circuits that do the heavy lifting are fairly difficult to damage. Good luck.
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Online nctnico

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Re: List your test equipment "scores" here!
« Reply #984 on: November 18, 2016, 04:29:59 pm »
Fortunately -in line with HP's spirit- the full schematics for the N3300 series mainframes and load modules are available!  :-+
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Offline PaulAm

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Re: List your test equipment "scores" here!
« Reply #985 on: November 18, 2016, 06:46:31 pm »
Recently someone was selling Fluke 27/fm meters on ebay for $15 US ea with free shipping.

Not guaranteed, no accessories and power on test only, but heck, $15?  I bought 2.  We'll see when they show up, but reports so far have been favorable.  They're worth it just for spare parts.

I'll probably regret not buying more.
 

Offline bitseeker

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Re: List your test equipment "scores" here!
« Reply #986 on: November 18, 2016, 11:58:33 pm »
Great score, nctnico. That's only $0.11/watt. ;D
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Offline retiredcaps

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Re: List your test equipment "scores" here!
« Reply #987 on: November 19, 2016, 12:04:47 am »
Recently someone was selling Fluke 27/fm meters on ebay for $15 US ea with free shipping.
Originating thread might be at

http://www.antiqueradios.com/forums/viewtopic.php?f=8&t=310451&sid=dbeba29713fb8afd3b55daad910f56c8
 

Offline wasyoungonce

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Re: List your test equipment "scores" here!
« Reply #988 on: November 20, 2016, 09:10:14 am »
Picked up an older Analogue Scope, Tektronix 2236, for $135 in Australia (Melb) this morning.  Purchased off Gumtree (like USA craigslist) so no fee's!   Found most people on fleabay (and Gumtree) wanted way too much but this was ok price.  Appears to be working A1 so far.   I'll do the PSU capacitors just to be sure!  Need to get a decent repair manual...the online A4 sized documents just don't cut it.

The guy purchased from is giving up TV/radio repairs.  Just no money in it these days and I tend to agree.   We had a good chat, nice to meet like folks.
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Offline mtdoc

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Re: List your test equipment "scores" here!
« Reply #989 on: November 20, 2016, 06:37:49 pm »
Picked up an older Analogue Scope, Tektronix 2236, for $135 in Australia (Melb) this morning.

Nice!  The first used Tek scope i bought was a 2236. I still enoy using it. The multimeter functions are not much use in the age of cheap DMMs but the counter and scope measurement functions I still find useful.
 

Offline Alex Nikitin

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Re: List your test equipment "scores" here!
« Reply #990 on: November 22, 2016, 12:46:47 pm »
The latest addition to my home lab. Measured on a freshly calibrated HP3458A shows the value of +5.5ppm from 10K, or less than +6ppm from the original measuremed value printed on the unit (which is in turn less than the uncertainty of the HP3458A measurement).

Cheers

Alex



 

Offline CJay

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Re: List your test equipment "scores" here!
« Reply #991 on: November 22, 2016, 01:37:47 pm »
Recently someone was selling Fluke 27/fm meters on ebay for $15 US ea with free shipping.
Originating thread might be at

http://www.antiqueradios.com/forums/viewtopic.php?f=8&t=310451&sid=dbeba29713fb8afd3b55daad910f56c8

Arghh, they've got some great gear for sale at great prices but shipping to the UK just makes it impossible
 

Offline macboy

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Re: List your test equipment "scores" here!
« Reply #992 on: November 22, 2016, 02:30:52 pm »
Picked up an older Analogue Scope, Tektronix 2236, for $135 in Australia (Melb) this morning.

Nice!  The first used Tek scope i bought was a 2236. I still enoy using it. The multimeter functions are not much use in the age of cheap DMMs but the counter and scope measurement functions I still find useful.
No cheap DMM will measure 2 Gohm, I can assure you of that. And most won't have a low ohm range with 0.01 ohm resolution either. The 8-digit 100 MHz counter is also useful if you don't have something better on the bench.
 

Offline mtdoc

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Re: List your test equipment "scores" here!
« Reply #993 on: November 22, 2016, 07:30:18 pm »
No cheap DMM will measure 2 Gohm, I can assure you of that. And most won't have a low ohm range with 0.01 ohm resolution either.

Good point! I guess since I don't recall having yet had the need to measure resistance at either of those extremes, I hadn't considered that!   Cool - another justification for keeping it around! (Next time my wife asks why I need so many of those things..  ;D.) 
 

Offline wasyoungonce

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Re: List your test equipment "scores" here!
« Reply #994 on: November 23, 2016, 12:36:08 am »
Good point! I guess since I don't recall having yet had the need to measure resistance at either of those extremes, I hadn't considered that!   Cool - another justification for keeping it around! (Next time my wife asks why I need so many of those things..  ;D.)

Just noticed the the CTM is registering 957Hz with the probe on 1Khz probe adj.  Don't know if it's the CTM or the probe adj...probably the latter.

edit:
Ahh ....quote from Yahoo Tek group .."The spec. for the 2236 states the "probe adjust" produces 1kHz +/- 20% @ .5V +/- 5%. My scope is producing 940 Hz @ .5V p-p."  Its normal.
« Last Edit: November 23, 2016, 12:50:14 am by wasyoungonce »
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Online tautech

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Re: List your test equipment "scores" here!
« Reply #995 on: November 23, 2016, 07:48:05 am »
Good point! I guess since I don't recall having yet had the need to measure resistance at either of those extremes, I hadn't considered that!   Cool - another justification for keeping it around! (Next time my wife asks why I need so many of those things..  ;D.)

Just noticed the the CTM is registering 957Hz with the probe on 1Khz probe adj.  Don't know if it's the CTM or the probe adj...probably the latter.

edit:
Ahh ....quote from Yahoo Tek group .."The spec. for the 2236 states the "probe adjust" produces 1kHz +/- 20% @ .5V +/- 5%. My scope is producing 940 Hz @ .5V p-p."  Its normal.
Exactly why you mustn't use the internal probe cal output to make ANY internal adjustment of a scope.
But some scopes have an internal frequency adjustment for the probe cal output and when they do it's handy to set it close to the spec'ed 1KHz even if it's only for sanity checks.  ;)
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Offline wasyoungonce

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Re: List your test equipment "scores" here!
« Reply #996 on: November 23, 2016, 08:04:58 am »
Exactly why you mustn't use the internal probe cal output to make ANY internal adjustment of a scope.
But some scopes have an internal frequency adjustment for the probe cal output and when they do it's handy to set it close to the spec'ed 1KHz even if it's only for sanity checks.  ;)

Many thanks I'll look this up I know the CTM has an adjustable TXCO...but I'd need a ref std before fiddling with that. 
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Online tautech

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Re: List your test equipment "scores" here!
« Reply #997 on: November 23, 2016, 08:20:46 am »
Exactly why you mustn't use the internal probe cal output to make ANY internal adjustment of a scope.
But some scopes have an internal frequency adjustment for the probe cal output and when they do it's handy to set it close to the spec'ed 1KHz even if it's only for sanity checks.  ;)

Many thanks I'll look this up I know the CTM has an adjustable TXCO...but I'd need a ref std before fiddling with that.
Don't get too fussy, you'll turn into a standards nut.  :scared:
In fact if you take macboy's advice the internal frequency counter will be plenty accurate enough.

Picked up an older Analogue Scope, Tektronix 2236, for $135 in Australia (Melb) this morning.

Nice!  The first used Tek scope i bought was a 2236. I still enoy using it. The multimeter functions are not much use in the age of cheap DMMs but the counter and scope measurement functions I still find useful.
No cheap DMM will measure 2 Gohm, I can assure you of that. And most won't have a low ohm range with 0.01 ohm resolution either. The 8-digit 100 MHz counter is also useful if you don't have something better on the bench.
Avid Rabid Hobbyist
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Online nctnico

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Re: List your test equipment "scores" here!
« Reply #998 on: December 02, 2016, 07:02:24 pm »
A quick update on the N3305A DC load module (150V / 60A / 500W) I bought recently. This is the photo from the actual Ebay listing:


Unfortunately the module I received was banged up pretty bad. It was well packed and the box didn't show any damage so my guess is the seller must have used an image from somewhere else for the Ebay listing. After taking the rear shield off (including the binding posts) and straightening it I tested the module. It seemed the constant current mode worked just fine but it didn't read any voltage (remote/local sensing didn't make a difference).

A quick inspection showed several resistors placed in a string hinting towards some kind of voltage divider and they where near the 'impact zone' so I measured them. It appeared some where off so for good measure I replaced all the 100k Ohm ones (4 in total). Fortunately the schematics for these modules are available and it shows these resistors are 0.1% types.

I didn't take the module apart except for removing the two capacitors on the right to allow measuring the other resistors. After the repair the voltage readout worked again and it is spot on compared to my Agilent 4.5 digit DMM. I did some further testing (full load  >:D) and it seems the module is hard limited to 560W.
« Last Edit: December 02, 2016, 07:04:31 pm by nctnico »
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Offline Falkra

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Re: List your test equipment "scores" here!
« Reply #999 on: December 03, 2016, 04:18:39 pm »
Well done, good repair. :D
Thanks for posting pictures.
 


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