What is the preferred size of holes in the PCB to be used as guides in the fixture?
The recommended size is between ø3,0 and ø6,0mm. The guide pins are manufactured to fit the actual PCB.
Is it possible to make a fixture if the PCB doesn't have any suitable holes for guide pins?
If there are no holes suitable for guide pins the edges of the PCB may be use as guides. As the edges of the PCB is usually not cut with the same tolerance as holes in the PCB you cannot expect a precision as good as when the PCB is guided by holes.
Is it possible to replace test probes?
Yes, the test probes are mounted in receptacles (sockets). So it is fairly simple to pull out the test probe and replace it with another. E.g. it could be a test probe with another type of tip.
Is it possible to place test probes on the top side of the PCB?
In some cases it is possible, but Yes, on some of the fixtures. But it is not recommended and it is only possible with a limited number of probes and it should only be used as the last possible solution.
Can high voltage on the PCB be isolated?
The usual method to eliminate the risk of electric chock is to build a shield on the retention gate. As an extra security hidden contacts may be mounted to ensure that electric power is only supplied to the PCB when the shield is in position.
Retrofit of test probes
In some cases it is required to have more test probes than originally mounted in a finished fixture. In most cases extra test probes can be retrofitted. The challenge is to align the fixture and achieve the necessary precision.
PCB locks on guide pins
If the guide pins are not straight the PCB may lock when moved. In certain cases this may be overcome by straighten one of the guide pins: Place a PCB in the fixture. Carefully note where the guide pin touches the edge of the guide hole. Use an extension stick and a hammer. Carefully knock the guide pin in the right direction. Do only amend one guide pin. Always remove the PCB before the guide pin is amended. It is important to use e.g. a wooden stick to avoid the hammer hits the test probes. This methode can have 'magic' impact to have the PCB move smooth.
Is it possible to view LED's on the "solder" side of the PCB?
Yes, in some cases is it possible to mount a mirror in the bottom of the fixture. In other cases could the solution be an USB camera.
An ATP2020 cassette with mirror for control of LED's
Can test probes connect direct on suitable connector pins?
This not recommended. But in certain cases is it possible to compensate the test probes level to fit the level of the connector pins.
An ATP2020 cassette with test probes connecting to the test pins of a connector.