Mcknib is right, it should test most components without having to do anything funky - One exception is JFETs, where it will tell if you if it's N-Ch or P-Ch and the pinout, but won't give you VGSoff or Idss. You'll need something like a
Peak DCA75 or the
Greatly Improved JFET Matcher II.
If you're new to these types of AVR testers, here are links to manuals & such (they are kinda tricky to find):
- TC-1 Multitester TC-V2.12k Manual - Original TC-1 manual
- MPJA Quick Guide - Another, shorter guide to the TC-1
- TransistorTester with AVR microcontroller Version 1.12k - Detailed description of how the unit works & what kinds measurements it will produce
To start off the troubleshooting, kind of a silly question: Which ZIF test sockets are you using?
When testing a transistor, you'll need to make sure the legs are inserted into three different socket numbers (one each into 1, 2, & 3). If you place the transistor legs into the "2 3 2" sockets to the far right, or the "K A A" zener diode test sockets on the bottom left, it will come up with a "No, Unknown, or Damaged Part" error.
View attachment 33191
Fortunately, you can use any set of numbered slots, and in any order, as the TC-1 will adjust the measured pinout to match. Make sure you also close the lever completely to lock in the legs before hitting the "Start" button.
Here are some other things you can check:
- Check the voltage output of your power source with a multimeter (preferably under load). You shouldn’t be powering it from less than 4.5V or more than 6V DC. If you’re using a microUSB cable, make sure whatever you’re powering it from can provide up to 500mA of current.
- Open the case. Carefully inspect the PCB & display for mechanical damage (cracks, chips, damaged/disconnected wires, etc.). Also look for solderless/cold solder joints, flux residues & general grime. These things are cheap for a reason, so look closely & take pictures of any questionable connections.
If you're still having issues, it's probably worth doing the calibration:
Calibration & Self-Test - You'll need the 3 included interconnected metal pins to perform this.
- Connect the three test leads to the inputs 1, 2 & 3 of the ZIF-socket and connect the three crocodile clips to these three pins.
- Press Start to perform a self-test, in which the device also calibrates itself. This procedure takes about 10 seconds and is accompanied on the display by a thermometer scale on which you can see the progress of the test.
- At some point, after 22% of the test procedure, the text 'Pls Isolate Probe' will appear and you need to remove the three test leads.
Going forward, here is some info I've aggregated on using the TC-1 to test Ge transistors. Some of the measured parameters are a little unclear at first glance:
Germanium Transistors:
- Hfe - Gain - hFE = parameter measured under DC conditions, hfe = parameter for AC signals.
- Vbe - Voltage b/w Base & Emitter - (mV) - 0.65-0.7V for Si, 0.15 to 0.3V for Ge.
- Ic - Collector Current used for test - (mA) - Most pedal transistors run Ic <1mA. Some (i.e. Harmonic Percolator) run below 100uA. Some testers measure HFE at 5mA or higher, which is not particularly useful to pedal builders.
- Iceo - Leakage Current at the Emitter - (mA) - Iceo = (1+ β)xIcbo where Icbo is the reverse leakage current of Base-Collector junction - Anything <100uA is good - Collector-to-Emitter current w/Base lead not connected to anything (an extreme case as in most circuits, the Base has a DC path to somewhere)
- Ices - Collector-to-Emitter current with the Base lead shorted to the Emitter - (uA) - Leakage Current in-circuit is somewhere in between Iceo & Ices.
How do the TC-1 Iceo & Ices measurements compare to R.G. Method’s leakage values? - Iceo is pretty much dead on. Close enough at least to not have to worry about it. +/-20uA is not a deal breaker.
- Measured Parameters- These are current parameters, so we use “I”. The next two letters, C & E, refer to the Collector & Emitter pins. The last letter is how the remaining pin (B = Base) is connected; “O” for open-circuit (not connected) or “S” for shorted (to the Emitter in this case).
- Iceo = Collector-Emitter Leakage current with Base not connected to anything (an open circuit)
- Ices = Collector-Emitter Leakage current with Base shorted to Emitter.
When measuring Ge transistors, you have to let them sit in the tester for a few minutes so they can cool off after being heated by your fingers. Only then will you get a stable reading, or any reading at all. Even better, always handle w/tweezers as your body temp will mess with the readings (especially Leakage)
P.S. It's worth mentioning that you need to discharge any capacitors before testing. Discharging them into the tester can damage the microcontroller or other circuitry.
