| IC Tester HELP - Assembling section Assembling IC Tester upgrade This is upgrade instructions for first IC Tester device. IC Tester 2 has already this upgrade. Due some problems on few controllers, I decide to make upgrade on IC Tester device. Problems are: Small errors in powering device and need for external power supply. IC6 was misplaced, but device is working and it's consuming a loot power. If there was stable power supply (not battery) IC6: 7806 was producing voltage above 5.2 Volts and IC1 is heating. On some controllers low voltage check isn't working. Reports were that device isn't powered or it's powered all the time. R4 and R5 should be in that case manually calibrated to correct value. On some controllers reading at parallel (printer) port are very low and signal from device can't be read at computer. Reports were that there was error in setting data to device. R9 and D1 with R8 and LED3 was in that case too big holdback for computer signal. In making addon there was problem to get stronger power supply than test socket provide. For start you need to desolder some elements from IC Tester board and replace one, then you will make IC Tester upgrade - power supply and connect it with wires to IC Tester board. Step 1: Desolder next elements from IC Tester board: IC6, R8, LED3, R9, D1, D2, D3, C1, R4 and R5 Step 2: In next to R3 near IC2 and T1 you must with wire connect top and bottom copper lines. That position is shown on picture below as dark blue dot. On opposite side of board between T30 and IC5 place resistor R47 of 56 ohms and with peace of wire short connect it with IC5. This resistor R47 replaces R9, D1, R8 with LED3 and enables that all parallel ports on all controllers can get writing signal. NOTE: use this modification only in power supply with 7805, DO NOT use it if there is 7806 because it produce higher voltage and it could burn your computer! On picture new elements are shown in dark blue color. Red points A, B and C will be used later to connect power supply and IC Tester board. Picture below is silkscreen layer with position of elements on modified board:
Step 3: Now we need to get parts for power supply board. Some desoldered parts you can reuse and others you must get. Here is list of all parts for power supply board and few parts for IC Tester board:
Part No | Part Type | Amount required
IC6 | 7805 | 1
T33, T34 | BC 547 | 2
T35 | BC 558 | 1
D1, D4 | 1N4148 | 2
D2, D3 | 1N4002 | 2
LED3 | Red, 3 mm | 1
LED4, LED5 | Yellow, 3 mm | 2
R8 | 5,6 kOhm | 1
R42 | 75 kOhm | 1
R43 | 560 kOhm | 1
R44, R45 | 470 kOhm | 2
R46 | 100 Ohm | 1
R47 | 56 Ohm | 1
C1 | 330 uF/10V (microF) | 1
C2, C3 | 470 uF/25V (microF) | 2
C4, C5 | 100 nF | 2
CONN2 | 3,5 mm stereo headphone jack | 1
CONN3 | 3 pin male single lined connector | 1
Other | Piece of wire to make short connection from R47 to IC5 | 1 cm
Other | 3 wires | 12 cm
Other | 3,5 mm stereo headphone connector | 1 (2)
Other | 9V power connector | 1
D2 and D3 are 1N4002 but you may use 1N4007 or similar diode. For C1 you may use any from 220 to 470 uF (micro Farad) of 10 Volts or higher voltage, but watch for size of element. For C2 and C3 you may use vertical (standing) capacitors, but you need to place them horizontally, in the middle of page you have picture where I use both. WARNING IC6 is now 7805 not 7806. DO NOT USE 7806 ANY MORE because you can burn IC1 and your computer. Step 4: Making board, you have under download section IC Tester upgrade part where is PDF document in which are printed board layout. Print it out and make board. If you need change something in board, use PCB file with appropriate free software to modify it. On picture below is power supply schematic:
Here on top of picture is voltage regulator which produces 5V. It's assembled of D2-3, C1-5, IC6 and CONN2. For this regulator you may use for input battery, current from 6 to 12 volts and connect positive side to both ~/+ poles, to get lower current drop on diodes D2 and D3. You can remove 9V connector from parallel cable which connects IC Tester and computer and use it here on stereo headphone connector for CONN2 (see bellow on page). If you using transformer and electric network, you must use transformer with dual voltage and 0 (ground) point. Transformer may be from 2x5.5V to 2x12V, 0 (ground) point is connected to 0/- point at CONN2, and other two points each one to ~/+ point at CONN2. When you now connect transformer to electric network, if all are connected ok, both LED4 and LED5 must light up. Power supply can regulate even if only one ~ point and 0 (ground) are connected, but there will be interference from electric network. That interference is local grid frequency and performed tests on IC Tester may not be accurate, eq. when you testing some ICs with Schmitt triggers, results aren't correct and you may have a lot of errors which really don't exists. Do not use IC Tester if both LED4 and LED5 are not light up. CONN3 is additional external out for addons power supply. Points A, B and C are places which are connected with wires to IC Tester board, to ensure power supply of IC Tester device. Transistors T33-35 with R42-46 and diodes D1, D4 and LED3 are replacement for R4 and R5 to ensure that there was low power signal if voltage drop below 4.8V (+/- 0.06V depending on variation of used elements). If you using battery LED3 will light up if voltage drop below 4.8V, which is lower border for powering IC1, signal from point A will be in that case negative (GND), otherwise there would be no signal. Step 5: Soldering elements to board.
On upper picture is silkscreen layer with position of elements on power supply board. Suggested soldering guide: Solder all resistors (R8, R42 - 46) to board. Solder CONN2, you may need to adapt holes to fit on your stereo headphone jack. Note, at picture on top of CONN2 is 0/- point, in the middle is first ~/+ point and on bottom of CONN2 is second ~/+ point which have six holes. Checks first how are pins on your headphone jack oriented and then adapt holes to match it. Now solder capacitors in this order: C2, C3, C5, C1 and C4 Solder diodes from D1 to D4. Next solder three wires of 12 cm to A, B and C holes and then CONN3 Now solder IC6 and all transistors (T33 to T35) At end solder all LEDs (LED3 to LED5). You may LED4 and LED5 infracted to look on side as CONN2 (see on pictures below).
On picture above you have how looks soldered all elements. As you can see capacitors C2 as regular horizontal and C3 as radial vertical placed horizontally, on board you have holes for both types. On picture below is shown how you can infract LED4 and LED5.
Step 6: Making input power connector.
You can make one for battery or one for transformer or both. On picture above are both connectors. I'm using 3,5 mm stereo headphone connector because it's cheap and it can be easily found in stores. Connector for 9V battery is using two wires, positive and negative. On stereo headphone connector positive wire (red) is soldering together with left and right positive position on connector. Negative wire (black) is soldering at GND position on connector which is longest lamella, see picture below.
When making power connector for transformer, on dual AC output of 5.5V or higher (up to 12V) you connect one wire to left and one to right position (two short lamellas on 3,5 mm connector). 0 or ground, which is actually wire from centre of transformer output coil (or joined wires ends from dual output) is soldering to GND position - longest lamella on connector, see picture below.
Step 7: Testing power supply, connect external power source (battery or transformer) on CONN2. LED4 and LED5 must light up, if they not or only one light up you aren't connected properly power at CONN2 or there's wrong soldered wires at connector. If both LEDs are light up, measure at B (+5V) and C (GND) wires if there is 5V present (there may be variation up to 5.16V). If you didn't get current on B and C points or current exceed 5.16V, there may be problem in IC6 or diodes D2 and D3, check them out. If they working, then it must be error in capacitors or connector for CONN2, check them. When current is higher of 4.8V, LED3 (red) must not light up and on A point must not be GND. If LED3 is light up and current is higher than 4.8V, check if transistors working, otherwise try to adjust R42 and R43. Now if you can place resistor between battery and connector (or transformer out and connector) to make current drop on 4.7V. In that position LED3 must light up and on A point must be GND, if isn't check transistors if they working or try to adjust R42 and R43. After you successfully done all, now we can connect power supply board with IC Tester board. On picture below is shown how LEDs working if current is below 4.8V.
Step 8: Solder wires from points A, B and C at power supply to points A, B and C at IC Tester board, you have on picture below how it must look like.
Step 9: O.K. that's it, now go to Testing ICT device section and perform full test on upgraded IC Tester device to be sure that everything working fine.
(C) Copyright Silvio Klaic, you can write to me at sklaic@student.math.hr