Building the SD Loader KIT
1. Solder the Arduino Nano in place, USB port at Left of PCB. Have long pins out the bottom of PCB, as you can cut these down after soldering in place. No need to add the 6 pin block, as it is not used.
2. Now place the SD reader onto PCB, the curved pins should be out the top of the PCB going towards the left side. The pins should be going through the SD reader PCB and through the main PCB to the underside. Solder the SD reader in place, under the main PCB. Now carefully solder the pins on the top of main PCB to the top of the SD reader.
3. Now solder the network resistor in place, below the SD reader. This must be with the Dot on the left most pin. That is the common connection.
4. Solder all 5 push buttons along the bottom of the PCB, do these one at a time, ensuring they do not fall loose as you turn the PCB over to solder.
5. Place the Audio jack in place, holding down with blue-tack (for a closer finish remove the small plastic stumps from below the jack with snippers!). Solder in-place with all 5 connections.
6. Now solder the Yellow ceramic capacitor below the audio jack, this can go either-way around.
7. Optional extra – add a small piece of foam (not supplied) onto the PCB, behind where the OLED screen will go. Use a drop of glue, and make sure the foam is non-conductive.
8. Solder the OLED screen in place, again holding in place with Blue-tack or tape.
- You are now finished building the main PCB.
- Turn PCB over and spray Isopropyl alcohol on back and clean off any flux residue with an old toothbrush.
- Lastly, apply the sticky feat in each corner of PCB.
- Time to fill your micro SD card with either .Tap or .TZX game files.
- Place micro SD card into SD card reader, and apply a USB power supply to the Arduino Nano USB port.
- The OLED screen should come to life and allow you to scroll between files on the sd card.
- Connect the SD Loader to your Spectrum 48K with an audio cable (Stereo or Mono).
Now load some games and enjoy.
NB: Some faster micro SD cards (class 10) do not work well sometimes, so try to use slower/older sd cards where possible.
Building the 4116 & 4164 dual chip tester KIT
1. Solder the Arduino Nano in place, USB port at top of PCB. Have long pins out the bottom of PCB, as you can cut these down after soldering in place. No need to add the 6 pin block, as it`s not used.
2. Now solder the small Yellow ceramic capacitor near the Nano.
3. Now solder the L79L05 -5v regulator next to yellow ceramic capacitor, flat side facing towards the left of PCB. (Be careful NOT to mix this with the L78L12 regulator!)
4. Solder 2 of the 3 (C3,C4) 10uf Capacitors above and below the L79L05 regulator. Positive legs facing towards bottom of PCB, negative legs nearer the Top of PCB.
5. Now solder the 2 Diodes in place (D1,D2), both with the stripes towards Left of PCB.
6. Solder the 7660 chip in place, with the notch towards left of PCB.
7. Now solder the remaining Yellow ceramic capacitor and the L78L12 +12v regulator in place below the leftmost Diode. Making sure the voltage regulator has flat side towards the left of PCB.
8. Solder the last 10uf capacitor (C1) to the left of the 7660 chip.
9. Solder the small Black 22uf capacitor (C2_B) below the 10uf capacitor, to the left of the L78L12 +12v regulator.
10. Now solder the LED lights in place, with Long legs towards the right of PCB.
11. Use a piece of Blu-tak or tape to hold Barrel Jack (J1) in place at top left of PCB. Use plenty of solder and allow it to flow to make a good joint.
12. Turn the PCB over to add the SMD resistors (R1,R2,R3,R4). Add a small drop of solder on one pad only, then using tweezers, reheat the drop of solder and slide the resistor into the molten drop. Hold in place to cool, now apply solder to the other side of resistor. Repeat this for all 4 resistors. R1,R2 behind the Nano are the 2200, and R3,R4 are the 1001 towards the ZIF sockets of PCB.
13. Now solder both ZIF sockets in place, with arm towards top of PCB. NOTE: Solder the ZIF sockets in place in the OPEN state.
14. Solder the Push Buttons in place.
15. Lastly, apply the sticky feet in each corner of PCB.
You are now finished building the PCB.
• Turn PCB over and spray Isopropyl alcohol on back and clean off any flux residue with an old toothbrush.
• Plug in a 9v power supply to the Jack socket of the Finished PCB, center rail positive. (do not use an old Spectrum PSU, as they are center negative)
• Using a multimeter check the voltages for –5v, +5v, +12v.
If all voltages are near to the correct values (within a few points) and your LEDs have lit up then congratulations, your Combined 4116 & 4164 PCB is complete.
WARNING: Be very careful not to put your Dram chip into the tester sockets upside down. This can break your new tester board. Pin 1 should be at the top left of ZIF socket, towards the top of the PCB.
Place either a 4116 in the 4116 Socket, or a 4164 in the 4164 Socket, and press the relevant TEST button. The LED lights will flash for up-to 17 or 68 seconds (depending on which chip is testing).
A green/blue light means the Dram chip has passed basic tests, and can be tried in a real computer. Remember this is only a guide, and the chip may not be any good in full speed retro computer setup.
A red/yellow light means the Dram chip is questionable, and should not be risked in a classic computer setup. Run the test a few times, before you bin the chip.