CES Model 500 - Modern Electronics Trainers I need to get more connection leads for this trainer, how can I obtain additional or replacement leads. All leads for all of our trainers can be purchased directly from us. The cost is $36.00 for a set of replacement leads. You may email your purchase order directly to the support address, support@cesindustries.com, or you may fax your request to 1-631-293-8556. The microphone was "borrowed" by a student and never returned, can I obtain a replacement? The microphone can be ordered directly from CES for a cost of $5.00. You may email your purchase order directly to the support address, support@cesindustries.com, or you may fax your request to 1-631-293-8556 The student wired an experiment incorrectly, will this damage the trainer? No! All CES trainers are designed to be "student proof ". Incorrect wiring will not harm the trainer in any way. I have an older 500 series trainer, and my +V2 power supply is no longer delivering +9V, what is wrong? Do I need to send the trainer in for repair. Trainers manufactured before 1995 use a different voltage regulator to supply the +V2 power supply. It is possible that this regulator has become defective, and needs to be replaced. If this is the case, contact technical support, and a replacement part can be shipped directly to you. It is not necessary to return the trainer for repair as the regulator can be replaced in the field. If you do not wish to replace the part yourself, you may ship the trainer back, and the repair will be made under the warranty. The activity manual makes reference to an external transformer, but I do not have one, how can I do this experiment? The external transformer that is mentioned in the manual has been incorporated directly into the trainer, and is no longer supplied as an external part. The transformer connections are located on the front panel, immediately to the left of the white solderless breadboard. The students just completed wiring the AM radio experiment, I checked all the connections, and there is no errors, yet, the radio receives no signals. What is wrong? The problem is not with the trainer, or with the students wiring. The most likely problem is weak signal. The environment in which the trainer is installed will play a major role on the reception quality of the radio experiment. You may find that is necessary to add an external antenna consisting of a 10 or more 2 foot stacking leads, which you will connect to the antenna input of the radio experiment. If you still do not receive a signal, you may have to "throw a few feet of wire out of a window" to get the signal from outside of your building. In addition, computers running in the classroom will have a degrading effect on the performance of the trainer.