As of January 1st, 2022, RBD Instruments has discontinued support for our PCMAPII interface boards used on legacy PHI / Perkin-Elmer scanning auger electron spectrometer systems such as the model 590 and 600.
This blog post lists all of the documentation related to the PCMAPII interface board. If your PCMAPII board develops a problem and this documentation does not help, please contact RBD Instruments for other options.
The links below will open up PDF files that you can view and print.
The other day I was working on a particularly difficult electronics problem with an ion gun controller and to help figure it out, I needed to dust off my trusty Huntron Tracker. I don’t need to use it very often, but when needed, there is nothing better for troubleshooting electronics problems.
First introduced in 1979, the Huntron Tracker displays an analog signature, which is a combination of resistive, capacitive, inductive, and semi-conductive characteristics. This visual display is very helpful for comparing electronics components on a defective board. The Tracker is particularly useful for comparing components on a known defective electronics board with a known good one. The Tracker applies a tiny AC voltage to the probes so you can test components with no power applied to the board that you are testing.
You can usually find defective electronics components with a DVM (digital volt meter) by testing diodes and capacitors, then measuring resistance values. But there are times when all of the individual components check out as OK with a DVM, but you know that there must be at least one defective component because the board does not work properly. For those times, the Huntron Tracker works like a champ every time. By finding some components that read differently with the Tracker, you can get a clue and ultimately, find the problem.
The early model Huntron Trackers had a little CRT display and three power level settings. Those models are still available on EBay for about $300.00. The Tracker that I use is one of these early ones and it still works well.
Over the years Huntron Trackers have evolved and today’s models include more power settings, automated testing, and software. For more info visit Huntron at –
https://huntron.com/products/tracker28s.htm
If a new Huntron Tracker is out of your price range or you can’t find an older one, there are also inexpensive curve tracer kits available on eBay that provide Tracker functionality using an oscilloscope. To find those, go to eBay and search for Curve Tracer kit.
The pictures below show how helpful the Huntron Tracker can be when trouble shooting a difficult problem. In this case a 150V Zener diode was slightly loading down a voltage supply, but only within a narrow temperature range. The Zener diode checked out fine with a DVM but the Tracker showed a difference in a part of the circuit between the board with the problem and a known good board. Using the Tracker I was able to isolate the issue to the diode. I think that without the Tracker this problem would have been very difficult to isolate.
1-30-20 I updated this blog post to include a video on how to isolate a thermally unstable electronic component using a heat gun and cool spray.
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.
How to isolate a thermal problem: https://www.youtube.com/watch?v=8lpil4WdQLo
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
http://physicsed.buffalostate.edu/pubs/StudentIndepStudy/EURP08/Links/circuit.html
