This article is the second part of the “Staccato Controller” project (link Part 1: https://www.pieraisa.it/blog/001i-progetto-completo-con-pcbway-staccato-controller-guida-completa/), made with the supplier of printed circuit boards Pcbway https://www.pcbway.com/ and is focused on these three aspects:
- Analysis Microscope of quality of the printed circuit boards received
- Assembling of the first prototype
- Testing of the first prototype
Analysis of received printed circuit boards by PCBWay
As a first consideration I would like to underline the speed with which the printed circuits were produced and shipped. in 4 Days from the order I received the printed Circuits. In my opinion the typical time is 7 working days, then in some fortunate cases can be less. The quality of PCB, in my opinion being prototypes is absolutely acceptable. The following photos were performed using USB microscope and are the main points where you can assess the quality of the process, as a ways, holes, serigraphy, silkscreen, centering.
Figura 1: Silkscreen
Figura 2: Metalizations
Figura 3: Metalizations
Figura 4: Tracks
Figura 5: PCB 1.6mm
Figura 6: PCB 1.6mm
Figura 7: Drills
Figura 8: Drills
Figura 9: Pads
Figura 10: Socket Mounting
First prototype mounting
Proceed with the mounting of the Low-profile components: resistances, transistors, capacitors and at the end the potentiometer facing the external side of the board and the last connectors. The potentiometer can also be mounted apart from the board for mounting directly on the front panel of the VTTC Coil. On the screen counter-connectors related to the serigraphy IN and OUT carry the wires respectively for the supply voltage at 12v to 50hz and the connection to the cathode of the valve and the negative terminal of the MOT transformer, such as the in the figure Diagram.
Figure 14: First prototype assembly
Figure 15: Bottom side soldering
Testing of the first prototype
To verify the correct operation disconnecting the Staccato Controller by means of a connector IN the board with a 12v 50hz voltage, which is insulated from the supply voltage of the valve filament; For example, it may be withdrawn from a 230:12 lowering transformer or a VARIAC. Check that the LED L1 turns to the rhythm of the frequency set by the R13 Potentiometer. Then connect the OUT connector to the VTTC coil, keeping it still off. Tension the transformer T1 and wait for the filament of the valve to heat up. After approx. 1 minute, voltage can be supplied to the anode via the Transformer. At this point, the electrical discharges will be timed by the Staccato Controller and it will be possible to vary the repetition frequency by acting on Potentiometer.
Figure 16: Staccato Controller, Signal at 50hz RectiatOr and pulse at maximum frequency (25hz)
Precautions For connection to the Tesla coil
The Staccato Controller drives a Tesla coil that manages high voltages and high currents and therefore it is necessary to follow the following safety requirements:
- Make sure there are no flammable substances nearby. The VTTC Tesla coil develops heat and especially triggers electric arcs that can trigger flames.
- Do not touch the high-voltage parts such as valve, diode transformer and capacitors, even after the coil has worked, because the electrical charge stored in the capacitors is stored for several minutes.
- After operation, disconnect the power supply and discharge the coil capacities, placing a resistance of at least 100 ohm and 5 watts of power between the electrodes of the capacitors, making sure not to come into contact with the Resistors.
Figure 18: Staccato Controller, mounted on VTTC Tesla Coil