Author Topic: EEVblog #455 - Auction Bonanza  (Read 17198 times)

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Offline Eliminateur

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Re: EEVblog #455 - Auction Bonanza
« Reply #25 on: April 19, 2013, 11:27:16 am »
i've seen those APC ups inside and they're stunningly beautiful (sadly i couldn't poke or dissasemble them too much as they where in operation), it wmuld make an incredible teardown.

btw, you could use it to power your entire lab with exquisite pure super smooth filtered synthesized AC!, no noisy horribly distorted mains AC with common mode noise! :P
 

Offline PhilNY

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Re: EEVblog #455 - Auction Bonanza
« Reply #26 on: April 19, 2013, 02:04:37 pm »
Dave
I still admire the construction of the Gen Rad & Keithley stuff. The decade boxes are extremely well made and are only damaged when a novice puts too much current through them. I just loved getting inside those units and was marveled by the quality of components used in those lab standards.
Great find. Love the lines of those GR's & KEGs
Phil
 

Offline LaurenceW

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Re: EEVblog #455 - Auction Bonanza
« Reply #27 on: April 19, 2013, 04:21:06 pm »
Dave, those APC UPS are very nice, but the batteries are reckonned to only last for three years, five if you are VERY lucky. So there may not be a lot of life left in them, if they are the originals, and/or have been allowed to go pancake-flat.  I suspect that inverter is one of the "online" types, which rectifies incoming mains to DC then inverts it into a local, isolated AC supply again. The batteries kick in when the incoming AC dips for any reason. But you are on a locally generated  (and hopefully low noise, spike-free) supply all the time, with no direct connection to the utility mains supply.

A great haul, though.

So what does Oz do for a "standard" second, now, then? :)
If you don't measure, you don't get.
 

Offline Eliminateur

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Re: EEVblog #455 - Auction Bonanza
« Reply #28 on: April 19, 2013, 04:44:54 pm »
the "3 year" duration is pure bullshit to force you to pay for batteries and toss away perfectly usable ones, the 3 years is like the famed "3db" thingy, it's when the batteries are ~at 50% their original endurance -which if your equipment does not use a lot of power it will still mean HOURS of runtime-.
i've had those kind of APC UPS with 5yr+ batteries still running, and it's not an outlier, it's more of the norm.

BTW, that UPS is most likely a SURT2200RMXLI (hah, being an APC partner perks :P), all the APC upses with that much power are online only, this not being the exception.

You could probably sell that entire setup north of 1K dollars, the external battery pack is pretty expensive
 

Offline KJDS

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Re: EEVblog #455 - Auction Bonanza
« Reply #29 on: April 19, 2013, 04:55:40 pm »
Look up this guys, it seem to be an interesting network analyzer (not come up with screen buto for 50$ it is a good purchase) http://www.govliquidation.com/auction/view?auctionId=6158299&convertTo=USD

That's just the display unit, it still needs a frequency sweeper and some detectors and a bridge to make a scalar analyzer.

Online PaulAm

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Re: EEVblog #455 - Auction Bonanza
« Reply #30 on: April 19, 2013, 05:26:03 pm »
I  am running my network on a APC 3000 right now.  I've been running APCs for years because 1) they're great, 2) used prices on surplus units are reasonable and 3) you can dump the APC software and use open source apcupsd to monitor and control them.

The battery lifetime does get a little iffy after 4 or 5 years.  The UPS will do a power test every once in a while and if the batteries have sulfated the UPS will give you an urgent warning and you may find yourself with a shutdown system.  The 3-5 year lifetime is preventative maintenance to avoid that.  On a commercial op you need to follow that, but on a private setup you can run them until the batteries fail.

Battery failure is probably the number 1 reason they show up surplus.  If I want to spring for batteries, I can usually pick up an APC unit from my local university surplus sales for $25-50.  I picked up 2 3000 and 2 1500 units for $250 the other year with 2 year old batteries from my local craigslist (I'm US, btw).  I'm running the 3000 at 15% load which will give me 40+ minutes of backup time.

I used to go to auctions quite a bit, but they were more fun before online buyers came along.  I used to get all kinds of interesting stuff for a couple dollars.  The last few auctions I went to  you might as well have just bought retail.  You'd come out ahead after the buyer's premium and fees.

Nice haul on this one though
« Last Edit: April 19, 2013, 06:20:35 pm by PaulAm »
 

Offline M0BSW

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Re: EEVblog #455 - Auction Bonanza
« Reply #31 on: April 19, 2013, 08:05:37 pm »
 I wouldn't tear it down I'd just leave everything alone, and enjoy using it, lovely haul there  you lucky lad. :-+ :-+
no one would or will tell me how to delete this account
 

Offline wastrix

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Re: EEVblog #455 - Auction Bonanza
« Reply #32 on: April 20, 2013, 12:13:15 am »
This turned up on eBay recently: http://www.ebay.com.au/itm/Keithley-241-Regulated-High-Voltage-Power-Supply-Keithley-515A-Megohm-Bridge-/290897188795?pt=AU_B_I_Electrical_Test_Equipment&hash=item43bad2d7bb

I'm guessing it came from the same auction.

Tesla500 did a bunch of videos on a similar APC UPS:
 

Offline EEVblog

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Re: EEVblog #455 - Auction Bonanza
« Reply #33 on: April 20, 2013, 12:16:47 am »
This turned up on eBay recently: http://www.ebay.com.au/itm/Keithley-241-Regulated-High-Voltage-Power-Supply-Keithley-515A-Megohm-Bridge-/290897188795?pt=AU_B_I_Electrical_Test_Equipment&hash=item43bad2d7bb

I'm guessing it came from the same auction.

Very likely.
I should undercut him by half, then mine looks like a bargain!
 

Offline amspire

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Re: EEVblog #455 - Auction Bonanza
« Reply #34 on: April 20, 2013, 12:30:45 am »
This turned up on eBay recently: http://www.ebay.com.au/itm/Keithley-241-Regulated-High-Voltage-Power-Supply-Keithley-515A-Megohm-Bridge-/290897188795?pt=AU_B_I_Electrical_Test_Equipment&hash=item43bad2d7bb

I'm guessing it came from the same auction.
I think I have seen they have been trying to sell it for years - they just refuse to reduce the price. It might explain why Dave was able to pick up his lot so easily - the Melbourne equipment hire guys knew it was hard to sell.

I found the manual: http://bee.mif.pg.gda.pl/ciasteczkowypotwor/Keithley/515A.pdf

Hand drawn schematics! The circuit is actually pretty simple. Easy to make as long as you can get the resistors up to 1,000,000,000,000 ohms they use in the range multiplier. All it takes is 100,000 10Mohm resistors in series for the highest range.  The accuracy is from 0.012% up to 10MOhms at 10V up to 0.5% at 1015 ohms tested at 500V.

I gather the accuracy limits are partly due to the difficulty in calibrating the unit - the resistor calibration set Keithly sell can only manage 0.5% accuracy for a 10,000,000,000,000 ohm resistor. Pathetic!
« Last Edit: April 20, 2013, 12:35:38 am by amspire »
 

Offline amspire

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Re: EEVblog #455 - Auction Bonanza
« Reply #35 on: April 20, 2013, 12:53:39 am »
The resistors in the 8 decade switch don't look all that great. The best are 0.01% and the top range only has 0.5%. They could be selected resistors to make matched sets, so the actual relative match of the resistors may be better then the manufacturers accuracy.

So the 8 decade switch is to provide the range and not 8 digit resolution.
 

Offline EEVblog

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Re: EEVblog #455 - Auction Bonanza
« Reply #36 on: April 20, 2013, 12:56:00 am »
I think I have seen they have been trying to sell it for years - they just refuse to reduce the price. It might explain why Dave was able to pick up his lot so easily - the Melbourne equipment hire guys knew it was hard to sell.

Yes, that's common with these mobs, just keep relisting till you find a sucker.
I'm pretty sure they bid on the pallets of bokren gear.
Can't believe I got the counter/rebidium/psu for the price I did. They mustn't have read the description correctly, as anyone in the business should know the Agilent counter alone is worth double what I paid.
 

Offline amspire

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Re: EEVblog #455 - Auction Bonanza
« Reply #37 on: April 20, 2013, 01:15:58 am »
I can understand them missing the Rubidium standard - at first glance it looks like a bit of custom-built hardware that is probably useless. They probably don't have your radar for clues like the "SRS" indicating the Standford Research module.

Maybe they had blown the budget getting the other pallets. That other pallet you listed did include a Datron 4920M AC Calibration Standard and that might have really caught their eye. They must have their own calibration lab to check out their rental gear, and it is very rare to find a meter accurate to about 10ppm for AC.
 

Offline KJDS

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Re: EEVblog #455 - Auction Bonanza
« Reply #38 on: April 20, 2013, 08:52:04 am »

I think I have seen they have been trying to sell it for years - they just refuse to reduce the price.

There are huge amounts of stuff on ebay that could be applied to.

Offline casinada

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Re: EEVblog #455 - Auction Bonanza
« Reply #39 on: April 21, 2013, 07:26:14 am »
Dave,
You can use the UPS to power the whole lab. You have quite an investment in equipment so better use a good ups system. During summer time here in Arizona we have lots of lightning storms and is when equipment die whether is because of surges, brownouts or power outages. You got it practically for free, may as well use it :)
The beauty of the Smart line is that they convert the AC to DC and then the DC to a perfect sinusoidal AC. If I remember correctly it is isolated.
 ;D
 

Offline max-bit

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Re: EEVblog #455 - Auction Bonanza
« Reply #40 on: April 21, 2013, 08:22:14 am »
sometimes at auctions can hit different price :)
example of Poland
allegro ~ ebay
http://allegro.pl/tektronix-tds-3032b-i3124473312.html
1500 PLN ~ 430 USD
I have not bought it, but someone had luck


 

Offline ptricks

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Re: EEVblog #455 - Auction Bonanza
« Reply #41 on: April 21, 2013, 01:26:40 pm »
Good find on the UPS. I buy those sized units all the time when I see them at auction. I bought a pallet of them a couple years ago, about 20 for under $50 for the pallet. Every single one of the ones I have bought at auction have worked because they all have the same fault, bad batteries. Battery replacement cost is so high, and it has been about 2-3 years so most places just discard the unit.

Inside the UPS is a parts superstore. Mosfets , each unit of mine has about 25 of them. Relays probably about 10, omron brand, not cheap stuff. Caps about 20 , nice nichicon branded. Transformer - massive 1:1 transformer with a 20A rating, heatsinks about 4-5 nice heavy ones, torroid cores used in filtering 4-5, circuit breakers, fuses, misc components. Really great stuff for building power supplies. These units are pure sine wave so lots of uses.

For batteries you can use marine or solar  batteries and these UPS are rated for the stated wattage rate continuous  not like the low end UPS that will overheat if run for 30 minutes.

The batteries can sometimes be restored depending on how they failed. Often it is because all the water has evaporated out of the cells. Use a hydrometer to check the electrolyte , often just adding more water can bring the battery back to a useful state. 

Before anyone says "these are sealed batteries, they don't need water" they are sealed, but still vent over time. Take a sharp tool and get under the top plastic cover and snap it off, under that is 6 cell covers, little rubber caps, pull those off and check the water level. They have to vent the batteries because in an overcharge situation the battery could burst if not for the safety vent. The safety vent isn't 100% air tight so over 2-3 years the electrolyte level drops. BTW, car batteries are the same system and many car  batteries can be prolonged or restored with added water.


 

Offline Eliminateur

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Re: EEVblog #455 - Auction Bonanza
« Reply #42 on: April 21, 2013, 07:51:52 pm »
ptricks, thos batteries DONT HAVE ANY WATER, they use a gel-type solid electrolyte that's why they're "unspillable", so no adding anything possible
 

Online SeanB

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Re: EEVblog #455 - Auction Bonanza
« Reply #43 on: April 21, 2013, 08:02:16 pm »
You can add water, the gel is quite liquid, and does dry out. I have gotten a year or two on many SLA batteries that way. 10ml of water per cell is all they often need to get to a usable state. If it rattles though then it has broken internal connections. Even car batteries that are "sealed for life" have cell fillers under either a sticker or a welded down cover. remove, top up and away you go for another 2 years.
 

Offline Eliminateur

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Re: EEVblog #455 - Auction Bonanza
« Reply #44 on: April 21, 2013, 08:12:16 pm »
but opening those sealed things is messy, it's all glued and gunked
 

Offline max-bit

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Re: EEVblog #455 - Auction Bonanza
« Reply #45 on: April 22, 2013, 04:01:09 am »
Gel batteries so that you have 5-6 years to break down
At higher temperatures (above 25 C), this process accelerates
about 2 x faster for every 3 to 4 C
25 C - 5 life years
29 C ... 3 ...
etc
 

Offline amspire

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Re: EEVblog #455 - Auction Bonanza
« Reply #46 on: April 22, 2013, 06:39:53 am »
Gel batteries so that you have 5-6 years to break down
At higher temperatures (above 25 C), this process accelerates
about 2 x faster for every 3 to 4 C
25 C - 5 life years
29 C ... 3 ...
etc
The other thing is if you have a UPS with good batteries, don't leave it on a shelf for 12 months. At least once a month you have to plug the UPS in and recharge the batteries, otherwise the batteries will self-discharge to a point where they will degrade.

Basically use the UPS or sell it.
 

Offline ptricks

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Re: EEVblog #455 - Auction Bonanza
« Reply #47 on: April 22, 2013, 11:42:05 am »
ptricks, thos batteries DONT HAVE ANY WATER, they use a gel-type solid electrolyte that's why they're "unspillable", so no adding anything possible

Even if gel cell type they dry out eventually, most are not gel though and use AGM which is much more susceptible to water loss than gel. Out of the 100+UPS batteries I have encountered only 2 were gel.

I find quite a few high end brands like yausa and panasonic and it is shame these batteries are not restored because they do have quite a few years left on them. The cheaper ones like BP are not so good , most of them end up with a dead cell or heavy sulfur build up on the plates.
 

Offline Eliminateur

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Re: EEVblog #455 - Auction Bonanza
« Reply #48 on: April 22, 2013, 12:04:00 pm »
i have a ton of these batteries in the shop, i'm going to try and pop the cell lids and see what's in there....
 

Online SeanB

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Re: EEVblog #455 - Auction Bonanza
« Reply #49 on: April 22, 2013, 07:22:21 pm »
Pretty easy, generally there is a sticker on top covering a set of caps or a small plate solvent welded on in spots. A bit of gentle persuasion with a screwdriver and it pops off.
 


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