Solder the Harlequin, Revision F, March Solder the Harlequin - please read carefully (also the addendum!) before starting

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1 Solder the Harlequin, Revision F, March 2014 Page 1 of 8 Solder the Harlequin - please read carefully (also the addendum!) before starting You should check the kit for completeness (see addendum). If you solder your SMD parts yourself you should start with soldering U48 (AD724JR) necessarily consider the orientation in opposite to all other ICs on the PCB pin 1 of this IC is positioned right top, if you place the PCB with the speakers hole right in front and the connectors backwards! (Fig. 1). Fig. 1: the text refers to the orientation on table here shown As shown in Fig. 2 a small wire is to be soldered from the small tin-coated layer to pin 15 of U48. You can get such small wire if you fan out a flexible wire (stranded wire) of about 0.14mm² and use one single fiber of it. Fig. 2 : additional wire to be soldered at pin 15 of U48 Now you should solder all resistors but not R1, R2 and R13. Also the diodes D9, D10 and D11 can be soldered (consider polarity!). The crystals should be soldered next. Make sure, that the washers are placed on the leads of the crystals before you plug them onto the PCB.

2 Solder the Harlequin, Revision F, March 2014 Page 2 of 8 Inductor L1 is the very next (if you solder the SMD parts yourself) because to solder this part you need enough space left and right of it for the soldering iron. Fig. 3: L1 surrounded by big parts covering the solder pads Now you can solder R1,R2 und R13 the resistor arrays. Also U46 (SMD-switching regulator) should be soldered (if you do it yourself). D13 follows. Note that you have to solder at D13 the wires on both sides of the PCB because I had to drill out the holes to a bigger diameter they are then not plated-through. Fig. 4: Make sure to solder D13 on both sides of the PCB

3 Solder the Harlequin, Revision F, March 2014 Page 3 of 8 Next parts to solder are all IC sockets be aware of the orientation. The marker should be left or backwards if speakers hole is left in front of you. Fig. 5: Complete soldered PCB make sure to solder the IC sockets in the right orientation Now C25 (10 pf) must be soldered while a SMD resistor of 4.7 MOhm should be placed between its pins at the bottom layer (see fig. 6). If you solder the jacks yourself then now it is the right time to do. I recommend to glue the MIC/EAR jacks as well as the power jack using resin or superglue gel. After that all capacitors should be soldered. Note that some of the 0.1 µf capacitors have to be bent to a pin distance of 5.04 mm.

4 Solder the Harlequin, Revision F, March 2014 Page 4 of 8 I recommend not to solder D12. Instead I prefer to solder two bridges (Fig. 7). It is designed to insert D12 for protection against false polarity at the DC input cable. But as D12 is a graetz bridge there is a "voltage lost" of about 1.4 V. The ground of the Harlequin is then connected to the ground of the DC power supply via a diode so both ground levels are different. There is no problem if the power supply only supplies the Harlequin. But if you plan to supply the Harlequin and additional hardware (like TFT monitor, an interface or an audio amplifier) connected to the Harlequin from the same power supply then the DC current for the Harlequin would go through the ground connection of the edge connector. That is not good. So I myself use two bridges instead of D12 giving the DC connector the same polarity as known from the ZX Spectrum (minus in the hole and plus at the outer ring of the DC plug). Figure 7 shows the bridges Br 1 for ground and Br 2 for plus DC input (9 V 12 V). You are free to insert instead of Br 2 a fuse or/and a Fig. 7: bridges instead of D12 switch. But if you decide to supply an interface connected to the edge connector of the Harlequin I would recommend to place a fuse and switch better at the power supply to avoid a situation when the interface gets power and the Harlequin does not. Together with the pinheads for the jumpers (J12, J15 see addendum) all of the transistors should be soldered now. Be aware of the right orientation. Fig. 8 shows the right orientation of the eight small transistors 2SA1175 (or 2SA933 which have identical function). Fig. 8: orientation of transistors Q6 Q13 (address bus drivers for keyboard)

5 Solder the Harlequin, Revision F, March 2014 Page 5 of 8 Addendum All ICs but U46 and the PAL coder U48 are placed at a black foam rubber matte conductive and together with the PCB in a zipper bag. All IC sockets are plugged into the pin holes of the PCB for delivery. The SMD-ICs are soldered onto the PCB and the jacks are glued and soldered if you told me to do so. If you solder the SMD parts yourself you should start soldering U48 (AD724JR) and the small wire mentioned in the text. Following parts are included in the complete parts set:

6 Solder the Harlequin, Revision F, March 2014 Page 6 of 8 The complete parts sets are sorted into zipper bags that are marked as follows:

7 Solder the Harlequin, Revision F, March 2014 Page 7 of 8 Following parts are in the small part kits:

8 Solder the Harlequin, Revision F, March 2014 Page 8 of 8 The small parts sets are sorted into zipper bags that are marked as follows:: Important note about the jumpers Only two jumpers should be placed on the Harlequin. One of them is J12 and the second one is J15. All other pinheads for jumpers should not be soldered onto the PCB because you may not plug any jumper onto them! They are used for switching the board to NTSC. In that case there have to be cut some lines on the board because the PCB is configured to serve PAL standard. In case you like to use it for NTSC output please contact Superfo (Don Dindang) or me (Ingo Truppel) for support! Note: The ICs at the black foam rubber matte conductive are arranged at exactly the same way/orientation than needed on the PCB. That's why you can take them and plug them on their corresponding location on the PCB after soldering the IC sockets. But please make sure that I did not do any mistake check them for right position! DC power supply: The Harlequin needs an input voltage of about 7 V 24 V. Because of using a switching regulator the input current drops while increasing the input voltage. But note, that the DC input voltage is present at the edge connector without regulation (as present in the plain ZX Spectrum) to supply external interfaces. Therefore you should avoid using input voltages higher than 14 V. If you connect the Harlequin to a TV set with a SCART connector, you should supply the Harlequin with an input voltage higher than 9 V, preferably 12 V, because the DC input voltage is connected via a resistor to pin 8 of the SCART-plug (a zener diode limits the voltage to 12 V) and this way tells the TV set to see the video signal as 4:3 ratio signal. A voltage below 8 9 V instead means 16:9. Tape signal input EAR: The resistor R37 may be omitted, if you need a higher input sensitivity at the audio input (EAR = Tape In). The lower R37 the higher is the hysteresis of the audio input. That means the lower R37 the lower is the sensitivity for noise but at the same time the higher signal amplitude is needed for loading programs. If you should note that your tape recorder or any other audio source you use gives too low signal for loading try to remove R37.