Troubleshooting electronics resources

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When a problem develops with your XPS or AES spectrometer and you contact RBD Instruments for assistance, we frequently hear the same question – “What could be the source of the problem?”. The troubleshooting electronics tips below may help to find out.

Most problems on XPS and AES spectrometers can be broken into two broad categories – Optics problems and electronics problems. Optics (electron optics) are parts of the system that are installed on the vacuum chamber and include things like spherical capacitive analyzers, cylindrical mirror analyzers, sputter ion guns, x-ray sources, neutralizers and so on. Electronics include units such as power supplies and controllers.

Optics can generally (but not always) easily be tested by simply measuring the resistances on the electrical feedthroughs as specified in the optic’s manual. For example, a 04-303 ion gun should have contact between pins 1 and 2 (the filament) only. All other pins should be open to each other and to ground. By open, we mean that the electrical resistance is infinite. If pin 3 were shorted to ground, we would know that the objective lens inside the ion gun has a flake that is shorting it out, and the ion gun needs to be taken apart and rebuilt. But an optic component can have correct resistances and still have a problem (such as an open contact). Sometimes a short in an optic can also cause a failure in an electronic unit.

Electronic units are the source of problems with XPS and AES spectrometers more often than optics. Most of the students who use XPS and AES spectrometers in a university environment do not have enough training or experience with electronics to really dig into the electronic circuitry, but there are still a number of simple steps that can be taken that may result in a successful repair.

First of all, make sure that all power is off to any electronic unit that you work with. Measurements of voltages should always be performed by personal who have been training to work with electronic components and (often) high voltage. Potentially lethal voltages are present in these types of systems. If you are not properly trained, do not attempt to measure voltages in electronic units.

But, as long as the power is off and the unit is unplugged, you can safely visually inspect the unit and the boards inside of the unit for obvious signs of damage. For the most part, these are indicated by discoloration of the circuit boards, melted traces, melted transistors, dried up capacitors, and burnt resistors. If you find some components that are visibly damaged, then replacing them may solve the problem. Or, there may also be additional problems and the damaged components are just a symptom.

Some things to look for include:

Heat damage to a circuit board: Discoloration of the board which indicates that a component has been running very hot.

Melted components: Transistors (the plastic type) can actually melt when overheated. This is easy to spot.

Cracked capacitors: When capacitors dry out (after say 20 years or more) they can fail. See the links below for detailed instructions on how to test a capacitor. Be careful with larger value capacitors as they can hold a charge for a long time. Just to be safe, discharge capacitors before you measure them by clipping a resistor (a few hundred to a few thousand ohms is typical) across the contacts. This is not necessary for small value low voltage capacitors.

Burnt resistors: Resistors that burn up can turn to carbon and be difficult to identify without a schematic and board layout. Measure the resistance of suspect resistors with an ohmmeter. Sometimes you need to lift one end of the resistor (desolder one end of the resistor from the board) when measuring resistors in circuit as other components that may be in parallel with the resistor can affect the reading.

Shorted diodes and transistors: You can use a DVM in the diode check mode to test diodes and transistors for shorts. See the links below for detailed instructions on how to do that.

Dullness on transistor housing: If a metal housing (cover) transistor overheats often the finish on the transistor housing may be dull as a result of overheating. You can compare the finish to other similar transistors and then use a DVM in the diode check mode to test the suspected transistor. Plastic housing transistors that have melted are readily apparent.

Below I have listed some links to troubleshooting electronics resources. If you can’t fix the problem on your older Physical electronics (PHI) electronic unit yourself after following the steps in this post, we can provide you with technical support, repair services, loaners or exchange units. Contact us for more info at https://www.rbdinstruments.com/technical-support.html

 Troubleshooting Electronics resources;

Video on how to test a diode: https://www.youtube.com/watch?v=qSDRsz5-t7I

Article on how to test a diode; http://www.allaboutcircuits.com/vol_3/chpt_3/2.html

Video on how to test a transistor: https://www.youtube.com/watch?v=_3G8t-cV1d8

Article on how to test a transistor: http://www.tpub.com/neets/book7/25h.htm

Video on how to test a capacitor: https://www.youtube.com/watch?v=TFa6JfVu3B4

Article on how to measure a capacitor: http://www.wikihow.com/Measure-Capacitance

 General troubleshooting information:

http://physicsed.buffalostate.edu/pubs/StudentIndepStudy/EURP08/Links/circuit.html

 

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Super easy email blacklist

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To summarize this post here in case you don’t have the time to read the whole post, if you get a lot of spam emails then I would recommend that you DO NOT GET RACKSPACE web mail.

Our company switched to Rackspace web-mail about three years ago and although overall it has been reliable and easy to navigate, there is one aspect that is excruciatingly painful to use – adding an email address or domain to the Rackspace blacklist so that it will be blocked from that point on.   I have contacted Rackspace about this many times over the last 3 years to try and have them add a one click super easy email blacklist button (like they have for Add to Contacts) but I have never gotten a response back. When I have called and spoken with some of their reps about this issue it turns out that the reps do not even use Rackspace for their emails, they use other programs for their emails. And they acknowledge that adding email or web addresses to the Rackspace blacklist is time consuming.

The Rackspace help page states that you can add an email address or domain to the Rackspace black list in as FEW as 6 steps. Here is a link to the help page on Rackspace: http://www.rackspace.com/apps/support/portal/1507

But unless you want to write the email address or domain down on a piece of paper and the type the information in by hand, it actually takes 13 steps to add an email address or domain to the Rackspace blacklist:

  1. Open the email
  2. Click on name in email file – an email dialog box will open
  3. Copy the email address or domain
  4.  Close new email – do not save
  5.  Click on box next to your name in upper right hand corner of the Rackspace email dialog box
  6.  Select settings
  7.  Click spam settings
  8.  Click blacklist
  9.  Click add
  10.  Paste email or domain address into box
  11.  Click Add
  12.  Click Save
  13.  Then you can delete the email that you want to block

Most email programs allow you to block an email or domain by simply right clicking the email. I guess that the folks at Rackspace did not give their web-mail a lot of thought when they were in the design phase. Or maybe they use some other program for their personal and business emails. I am not a programmer myself, but I don’t think that it would be that hard to add a link to the blacklist similar to what Rackspace already has for adding a contact to the address book. I do know that I waste time every day when I add junk email addresses and domains to the Rackspace blacklist. I need to blacklist the junk emails otherwise they just keep coming back.

If you are a Rackspace user also find the process for adding an email or domain to the blacklist to be cumbersome and a time-waster, please forward this blog post to the link below. Maybe if Rackspace hears from enough users they will move this feature request up the list of priorities.

Contact Rackspace by clicking on this link and then paste this blog link or the text from this blog into the chat. The sales person will then forward the feature request to the appropriate department.