Help testing instruments and components

Discussion in 'General Electronics Chat' started by MicroMike, Sep 30, 2012.

  1. MicroMike

    Thread Starter New Member

    Sep 30, 2012
    Greetings! Being new to these forums I'm crossing my fingers I've posted in the right place.

    I'm in the process of trying to liquidate the contents of my fathers prototyping lab via ebay on behalf of my mother who needs money to to cover rising medical and living expenses. My problem is that most of the items are practically worthless unless I can guarantee they're in working order. Years back I ran a small electronics assembly company putting together Terradyne test boards and stiffener frames for a major IC design and fabrication firm, so I know my way around a few basic tools and have been able test meters, power supplies, converters, transformers, etc.

    My major problem comes with the higher ticket items. My dads 'lab' once I got there, turned out to be an electronics hoarders dream. Stacked to the ceiling with instruments and components that mystify me because, I'll admit before experts, I was nothing but a solder-by-numbers lab monkey. There are nearly a dozen Tektroniks oscilloscopes, Boonton and Wavetek sweep generators, an ENI OEM-6AM-1B RF power supply and many other high-ticket items that aren't worth the components they're made of unless I can certify they're in good working order.

    What I'm looking for is a person or people who can help me find or provide me with basic test procedures for the more complicated devices in the collection. Also, Should my tale of woe be insufficient inducement for said assistance it just so happens that I have tens of thousands of tools, instruments and components to offer in trade. :D

    Thanks in advance for any help.

  2. t06afre

    AAC Fanatic!

    May 11, 2009
    A good test for the scope is to hook the probe up to the calibration output. Then turn the knobs. And see verify that scope picture change correctly. Modern scopes also have a selftest. If this is not passed something is wrong. The waveform generators may be verified by connecting them to scope. And of course this will also test the scope. One thing you should take some care of is the scope probes. They are often made to match the scope. See if you can sort that out. So the scope probes end up on the correct scope. The probes often have small markings stamped on them. Also another note then testing be sure that the scope probes are not set to damp the signal 10 times. A bummer I often made as a beginner
  3. Kermit2

    AAC Fanatic!

    Feb 5, 2010

    I've bought stuff on ebay where the seller has expressly stated in capital letters.

    THESE ITEMS ARE SOLD AS IS. There will be no refund or exchange, and all sales are final.

    With the full understanding that I might be purchasing a non-working item, I payed for them and was happy with what I got.
  4. MicroMike

    Thread Starter New Member

    Sep 30, 2012
    t06afre: Many thanks for the tips about the scopes. I'll post further if I have any problems translating those directions into actual tests. :)

    Kermit2: Yes it is true that many of these items can be sold whether they work or not. The issue arises where pricing is concerned. Trying to get the best price for the instruments means testing and possibly calibrating. Listing the condition without possibly telling a lie is an issue because ebays 'used' condition includes sentences like
    "The item may have some signs of cosmetic wear, but is fully operational and functions as intended." and "See the seller's listing for full details and description of any imperfections." Listing it as used means to avoid butting heads with ebays buyer protection policy I must, as you say, list the item 'AS IS' and detail what if any testing it has had which can drastically affect the price. For example: my fathers main Tektroniks scope can be listed for anywhere between US$99 and US$599 depending on whether it's listed as non-working parts unit, powers on but untested, partially tested, fully tested, fully tested and calibrated and tested with professionally certified calibration. This price gap grows the more an item is worth. No one wants to buy a $5000 instrument for more than a few hundred if they have to take the risk that the most expensive components within may need replacing. Simply, the idea of dumping these instruments for parts unit or untested as is prices when I could have sold them for 5 to 20 times that price by simply consulting an expert is very unappealing when the future of my loved one may be at stake.

    I can't express how thankful I am to have found a forum in which to pose these questions without being subjected to the all too common abuse and noob bashing I've encountered in so many other places. To the moderators and members of AAC: I doff my proverbial hat.

  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    Hey Mike, first I am very sorry for your loss.

    As far as the instruments go, you may want to check out any local calibration labs in your area. For a price they will do the full check out and calibration of your scopes, and provide that nice certificate.

    The price will vary on the instrument, but they will provide you with a price quote before hand so you can see what you are buying: if a scope goes for $100 untested and $500 tested then if the calibration is less then $400 you are in the red. Offhand I would guess an analog scope would run around $200 to calibrate so you would gain $200 by doing this.

    You might try a scope or two and see how the process goes. Of course, the cal house may give you a discount when doing several units at one time.