Author Topic: Buying 'damaged' equip deliberately??  (Read 2090 times)

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Offline ConKbot

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Re: Buying 'damaged' equip deliberately??
« Reply #25 on: January 30, 2020, 06:52:45 pm »
I haven't heard of weights on a BGA before, but on a board without ideal coplanarity of the pads (older board with some warp, imperfect cleaning to save the PCB the stress of extensive solder wicking)I can see the logic in it. No X-ray at home to inspect for balls that didnt join to the pad correctly, so make sure they all lowered enough to bridge, with a touch of weight.
 
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Offline george.b

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Re: Buying 'damaged' equip deliberately??
« Reply #26 on: January 30, 2020, 08:54:52 pm »
Well, since the repairs seemingly lasted, there is at least some logic in it, but how to determine the proper weight, then? I, for one, have no idea how much weight the molten solder balls can withstand just by surface tension, or how much they'll deform in response to how much weight is applied, before collapsing.
 
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Offline ebastler

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Re: Buying 'damaged' equip deliberately??
« Reply #27 on: January 30, 2020, 09:33:20 pm »
How did I "obtain" the laptops??? Don't know what you 'assume', and/or need to question?...
[...]
In Adelaide, (when I moved), the Graphics Chips were removed, cleaned, re-soldered & mounted utilizing
a professional Reflow Station at an acquaintances premises. (Doing them all at the same time/day).
The 'weight' was not a bloody brick for christ sake! It was about 50 Grams, just to assist the re-seating.
[...]
And of course Antivirus/Antimalware (free).  I'm sorry, but your 'assumptions' were all wrong. And offensive.  :palm:

No offense intended, sorry, I just wanted to probe a bit. If you re-read your original post which I was referring to, you may realize that it was easy to misunderstand.

Why did you put "obtain" in quotation marks? Why did you put "reflow" in quotation marks? I was actually wondering whether you had obtained the computers via some sneaky way. And I was in fact thinking that the "reflowing" might not have involved any heat at all, but just pressure, meant as a "poor man's reflow".

I seem to recall that we have discussed your unconventional use of quotation marks before. In any language I am aware of, quotation marks do not imply emphasis. Rather, they are either used to delimit quoted text, or to denote that you are using a term ironically, or in some other way giving the term a different meaning than the literal one.

If you insist on using quotes for emphasis, you are inviting the occasional misunderstanding. I recommend using bold, underlined or italic text instead, all of which the forum software handles nicely.
 
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Offline Refrigerator

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Re: Buying 'damaged' equip deliberately??
« Reply #28 on: January 30, 2020, 10:39:32 pm »
My dad just bought a new samsung washing machine for cheap because it was damaged during shipping.
The sheet metal was bent slightly so it meant that it couldn't be sold at the store for full price, other than that if works perfectly well.
Just started a blog at http://brimmingideas.blogspot.com/ . Not much in it as of now but more is sure to come :)
 

Offline Excavatoree

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Re: Buying 'damaged' equip deliberately??
« Reply #29 on: January 30, 2020, 10:55:26 pm »
As others said, you have to be ready to accept anything.   I'd rather buy something that doesn't work from a user, and not a repairer, who will no doubt have tried the "easy stuff."  True, the person could have missed something, but usually, those are the "dog" units that are good just for parts.

I bought a Fluke 78 meter from someone who described it as not reading "OL" in the resistance mode.  That's usually a simple repair - a bad component in the input circuit.   I received the meter, and was dismayed to see that the seller had tested all of the "usual suspects."  "Well," I thought, "I guess this one is a case and some parts."

However, I did re-check everything.  "Just in case."  Sure enough, none of the components were bad.  "That's it.  I've bought a 'dog.'"  I made one more test.  I disconnected a connection at the very end of the input circuit, to the main analog IC.  "if it's still has the problem, I know it's toast."  I fully expected that.  However, it turned good.  I used my magnifier, not a nice one like Dave has, but a cheap binocular one, and found a small burnt place on the board between two traces.  I ground the carbon away, and re-connected everything.  It worked, but the voltage values were a hair off.  "I wonder if the seller tried to adjust the calibration pot?  Maybe that's all it is."  I was afraid there was another problem.

I wrote the seller to ask, and he was short with me.  "It needs a new board." he said.  I replied "yes, whatever, but did you adjust the calibration pot?"   He replied "Yes, but it didn't do anything.  It needs a new board."   I thanked him, and re-calibrated it.  It's fine.

Sorry if that was too long of a post, but it shows that you never know what you are getting into, and sometimes, it's not what it first seems.
 
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Offline george.b

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Re: Buying 'damaged' equip deliberately??
« Reply #30 on: January 31, 2020, 12:31:58 am »
I wrote the seller to ask, and he was short with me.  "It needs a new board." he said.  I replied "yes, whatever, but did you adjust the calibration pot?"   He replied "Yes, but it didn't do anything.  It needs a new board."   I thanked him, and re-calibrated it.  It's fine.

Component-level repair is a dying art. :(
Congrats on the repair :-+
 

Offline james_s

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Re: Buying 'damaged' equip deliberately??
« Reply #31 on: January 31, 2020, 03:34:06 am »
As others said, you have to be ready to accept anything.   I'd rather buy something that doesn't work from a user, and not a repairer, who will no doubt have tried the "easy stuff."  True, the person could have missed something, but usually, those are the "dog" units that are good just for parts.

Or worse, they've already used a bunch of the subassemblies to repair other units and what you end up getting is a Frankenstein's monster made of all the broken parts cobbled together. I definitely avoid defective gear from sellers that obviously repair things because I know that if it was an easy fix in most cases they would have already fixed it.
 

Offline worsthorse

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Re: Buying 'damaged' equip deliberately??
« Reply #32 on: January 31, 2020, 04:53:42 am »
i wouldn’t buy damaged consumer goods, though i often buy “for parts only” test gear but that is mostly because consumer gear is often designed (these days anyway) to be unrepairable; most (older) test gear is designed with repair and maintenance in mind.

for example, i recently bought two fluke 8840A DMMs for 20USD. One with a cracked display, the other “didn’t power up”.  found the manuals, determined that the unit w the cracked display was otherwise fine, used the second for parts, and ended up with a first rate DMM for ten percent of the going rate.

that i was able to sell the remains for a bit more than my original purchase price was a bonus.  ;D

on the other hand, i could talk about the tek 184, also “for parts only” that was pretty much a write off.

in the end, i buy busted stuff because i have fun fixing it and enjoy having gear “i made right” andgetting a bargain is a fringe benefit. 
if someone succeeds in provoking you, recognize that your mind is complicit in the provocation.
 

Offline GlennSprigg

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Re: Buying 'damaged' equip deliberately??
« Reply #33 on: February 01, 2020, 09:57:05 am »
How did I "obtain" the laptops??? Don't know what you 'assume', and/or need to question?...
I paid about $200 for those, along with other 2nd hand parts, from a small Computer Repair Shop
in Darwin, in the Northern-Territory, who was no longer 'trading', & getting rid of old stock. Hope that's OK...  :P

I'm not the one who questioned your means of obtaining them, but writing "I 'obtained'", between quotation marks, does leave margin to assume you were being ironic. Quotation marks are meant either to quote someone/something, or for ironic effect. Although I didn't question it, that did make it seem suspicious to me as well, especially accompanied by "virtually for free". $200 doesn't count as "virtually for free" to me anyway, but oh well.

Sorry. I know you didn't say that.  B.T.W... the $200 was for a bunch of other bits & pieces too, as well
as 15 laptops, working out to about $10 per laptop!  :)  So was ok, as we knew what was wrong with them.
(This topic finished  ;D ;D)
 
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Offline Chris56000

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Re: Buying 'damaged' equip deliberately??
« Reply #34 on: February 01, 2020, 10:43:59 am »
Hi!

My biggest gripe is people who remove handles, bumpers, back facias and other items to use them in stupid rotten lab racks and then throw the removed bits away and worse, use a stock photo to sell it on again!

I bought a Keithley DMM two years ago that came minus handle, bumpers and rear panel and sold it straight on again because I could see no way of obtaining the missing parts, and yes it was a "stock" photo!

I got an Enertec Oscilloscope minus the handle because the seller used a "stock" photo instead of a true one – where am I going to get one of these from now Schlumberger have stopped supporting T & M?

Chris Williams
« Last Edit: February 01, 2020, 10:49:34 am by Chris56000 »
It's an enigma that's what it is!! This thing's not fixed because it doesn't want to be fixed!!
 

Offline Rerouter

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Re: Buying 'damaged' equip deliberately??
« Reply #35 on: February 01, 2020, 10:50:59 am »
If the fault is an easy repair for me, for a lot off the asking price, I am willing to jump at some stuff

E.g. recently grabbed a 6 month old ~$2100 LSI RAID card with backup battery and all options active, for $350 because the backup battery connectors were crushed (someone tried removing the plug with pliers as best I could tell), replaced the connector for about $4 on ebay (same one used for lipo balance leads), and working well,
 

Offline Berni

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Re: Buying 'damaged' equip deliberately??
« Reply #36 on: February 01, 2020, 01:37:23 pm »
Hi!

My biggest gripe is people who remove handles, bumpers, back facias and other items to use them in stupid rotten lab racks and then throw the removed bits away and worse, use a stock photo to sell it on again!

I bought a Keithley DMM two years ago that came minus handle, bumpers and rear panel and sold it straight on again because I could see no way of obtaining the missing parts, and yes it was a "stock" photo!

I got an Enertec Oscilloscope minus the handle because the seller used a "stock" photo instead of a true one – where am I going to get one of these from now Schlumberger have stopped supporting T & M?

Chris Williams

Well when you are building a test system for a production line and you need 10 pieces of test gear in order to do a full test of the product in the required 5 seconds per product it makes a lot of sense to bolt the equipment into a rack and wire it all down the back to the test fixture.

Imagine the horror of uneducated production line workers moving the test system to a new location by carrying individual pieces of test gear and having to hook them up again afterwards. There is no way they would ever get the system running properly and they would have to wait for the engineer who designed the test system to come over and fix it for them. But if its all in one big rack all they have to do is unplug the big power cord coming out of the back, pick the whole thing up with a forklift, drop it off in the new location and plug it back into a wall socket and wait for it to boot up again. Done! Once again the screen shows up a big green "PASS" message whenever the production worker plugs in a working DUT in to it.

Eventually they throw out the whole rack once its not needed anyore and someone picks it up for resale on ebay. Nobody knows where the original bumpers and handles are (or they are sitting in a landfill for the last 20 years now). These then sell for nice low prices on ebay because the seller just hauled 20 of these multimeters back home and wants them to sell in a reasonable amount of time so he prices it lower than everyone else.

I never had problems with a ebay seller hiding the fact it has rack mounts. It ways always shown in photos for everything i bought. If whatever i bought is a really nice piece of gear and i want it to look as nice then i buy a 2nd hand set of handles for it and put them back on. Other times im glad it came included with rack mount hardware because it makes it easier to build into my own rack. For large equipment a rack is genuinely a better place for it. I don't have the desk space to permanently keep a 70cm deep spectrum analyzer on it, nor do i enjoy moving it around as its >100lb, so it lives in the rack with all the other massive boatanchors where its easy to move around, since the whole rack is on caster wheels.
 

Offline grizewald

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Re: Buying 'damaged' equip deliberately??
« Reply #37 on: February 01, 2020, 02:41:09 pm »
The worst thing about the eBay sellers who are effectively selling scrapped equipment is the way the equipment gets removed from the original site.

All they do is send in a bunch of blokes with bolt cutters who cut every single cable so that they can remove the equipment as quickly as possible. So you end up seeing power sensors with the most important part missing, you also never get the test leads with any scrapped multimeter and when you look at how much a single Fischer connector for a Solartron meter costs, it makes you want to cry.

One thing you can do to save yourself trouble when buying scrapped test kit is to look at the sellers address on Google maps. One UK seller that I have experience with is based at an industrial site and the view on Google showed that they keep all of their stock outdoors in freight containers. You can imagine what the damp and extremes of temperature will do to any sensitive equipment!

  Lord of Sealand
 

Offline unknownparticle

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Re: Buying 'damaged' equip deliberately??
« Reply #38 on: February 01, 2020, 02:56:29 pm »
I know a few ebay electronic sellers who don't have much idea of what they are selling, that is stuff like test gear etc.  So I've had a few bargains that way. Like a big Kepco rack mount PSU, 0-60V and 0-25 Amp, described as spares or repairs only, does not power up. Thing is, I know that this unit needs a programming plug to be inserted on the back panel for it to do anything, and it was missing!  It was probably wired into some external equipment and just yanked out when the PSU was decomissioned.  Got it for £20, found a plug after a few months, wired it to basic front panel controls config and it worked perfectly!
Another bargain was an ACDC Electronics electronic load type EL750, but the dual channel version! These are old school but go to 60 volts and upto 200 amps!!!  Seller described as unknown function but maybe a power supply, untested, parts only.  Got that for £10 and it was local collection!  Works perfectly!
Plenty of stuff described as 115 VAC, that I know can be set to 240 VAC, so all for cheap!
DC coupling is the devils work!!
 

Online rdl

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Re: Buying 'damaged' equip deliberately??
« Reply #39 on: February 01, 2020, 03:56:30 pm »
Seems to me that, if an eBay seller uses a "stock" photo and doesn't mention any missing parts in the description, you should have some recourse because of "Not As Described".
 

Offline james_s

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Re: Buying 'damaged' equip deliberately??
« Reply #40 on: February 01, 2020, 07:24:30 pm »
Seems to me that, if an eBay seller uses a "stock" photo and doesn't mention any missing parts in the description, you should have some recourse because of "Not As Described".

Absolutely, in almost all cases ebay will side with you and give you a full refund, you may even get to keep the item. There are few reasons to use a stock photo for used gear and missing parts definitely count as "not as described".

The missing handles/bumpers/etc thing drives me nuts too. If I were racking up a bunch of gear I'd put all those bits in a box, label it and stuff it into a space in the rack.
 
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Offline unknownparticle

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Re: Buying 'damaged' equip deliberately??
« Reply #41 on: February 01, 2020, 08:52:24 pm »
Sellers like that will describe as spares or repairs only, study the images carefully, what you see is what you get. 
DC coupling is the devils work!!
 

Offline vk6zgo

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Re: Buying 'damaged' equip deliberately??
« Reply #42 on: February 02, 2020, 02:17:43 am »
Seems to me that, if an eBay seller uses a "stock" photo and doesn't mention any missing parts in the description, you should have some recourse because of "Not As Described".

Absolutely, in almost all cases ebay will side with you and give you a full refund, you may even get to keep the item. There are few reasons to use a stock photo for used gear and missing parts definitely count as "not as described".

The missing handles/bumpers/etc thing drives me nuts too. If I were racking up a bunch of gear I'd put all those bits in a box, label it and stuff it into a space in the rack.

Out "in the Wild", when equipment is installed, often all such ancillary stuff is neatly placed in the "store", either locally, or back at the Depot.

There, they sit for years, till nobody remembers what they are.

In most cases, when the equipment is disposed of, the bits are still lurking in the store for years longer, with nobody making the connection between the two.

When the store is finally "cleaned out", all such hardware probably finds itself in a box, which either goes in the dumpster, or is sold off.
Sometimes, even semiconductors & other circuit components of a particular device follow the same path

These "orphan" parts, if still present, are often a boon to a struggling tech:-

I had a major "win" when digging through the store at one of my old jobs---- a treasure trove of  semiconductors, neon indicators, etc from a long gone piece of equipment.
These were all useable in existing equipment.

On another occasion, we were way out in a remote community, & needed a BJT.
Nothing spectacular, just a general purpose NPN with a little bit higher specs than a bc108.
Looking through the Broadcast store, there was nothing that fit the position, so we were becoming resigned to staying there  until one arrived from Perth.

The site had previously been a HF comms site, where I had been stationed for a 6 month stint, many years before, & the HF spares cupboard was still there.
Not expecting any luck, we dug through it, & "lo & behold" found a Motorola MM1711, which was in a similar package, & from memory had similar specs to the one we needed to replace (although its hFe was higher).

It worked like a charm!
(& we got to fly home!)

 


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