Conversion of the JR-40MHz module for operation in modern transmitters Wilhelm Meier Version 0.3, 07/19/2020: HW_1.0 Translated from German to English - www.onlinedoctranslator.com contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 1.1. License. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 1.2. purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 2. A word of caution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 3. Why the renovation? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 3.1. motivation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 3.2. Result. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 4. The conversion in detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 4.1. Source material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 4.2. Interface to the transmitter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 4.3. Changes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 4.4. New housing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18th 4.5. antenna. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 4.6. First commissioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 5. Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 6. Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 6.1. soldering iron. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 6.2. Voltage regulator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 7. Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 1. Foreword | 1 1 Introduction 1.1. License This document is published under the following License released: License This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivatives 4.0 International License. To view a copy of this license, seehttp://creativecommons.org/licenses/by-nc-nd/ 4.0/ or write to Creative Commons, PO Box 1866, Mountain View, California, 94042, USA. 1.2. purpose This document describes the modification one Graupner / JR 40MHz- Transmitter module for use in modern transmission systems such as a FrSky-X9D, one Jumper T12 or one RadioMaster TX16s. Conversion of the JR 40MHz module [HW_1.0] | 1 (27) 2 | 2. A word of caution 2. A word of caution It is tempting, the old Graupner / JR 40MHz-Send module in a modern system of the type about Jumper T12 or T16 or RadioMaster TX16s to plug in. Because mechanically the old module fits into the module slot of the modern system. This is not entirely unintentional, as it turned out to beModule housing or the Module bay as de facto-Standard established in many transmission systems. Place the module bay and the module housing none Standard. Of theGraupner / JR-Module slot is amore mechanicalQuasi-standard: Transmitter systems have such slots on the back to plug in additional RF transmitter modules. Even the 5-pin connector on the back of the module fits mechanically. However, this refers to a quasi-standard not on the assignment of the plug contacts in the 5-pin connector. many - In the old In the world of 40MHz / 35MHz systems, a certain assignment has spread, but that not corresponds to the assignment for the 2.4 GHz modules. The assignments are not compatible with each other! This electrically different assignment of the plug contacts is a Operation without modification is not possible If a modern transmitter is plugged in with an old one that has not been rebuiltGraupner / JR 40MHz Transmitter module switched onso he can Channel take damage in the process! - Figure 1. Different versions of the Graupner / JR 40MHz module So one should resist this temptation. It's going ok not without the renovation. The conversion itself is simple and low-cost. Anyone who can handle a soldering iron to some extent should be able to carry out this conversion on their own. 2 (27) | Conversion of the JR 40MHz module [HW_1.0] 3. Why the renovation? | 3 Figure 2. The mechanical dimensions allow it to be plugged into a modern system (here: Jumper T12). But: caution (see text). 3. Why the renovation? 3.1. motivation The 40MHz transmission technology can actually be described as outdated today. Nowadays one expects trouble-free operation, operation without annoying channel agreements with other RC model builders in the immediate vicinity and some safety and comfort features such as telemetry. As is well known, all of this is usually not possible with 27MHz, 35MHz or 40MHz technology. The modern 2.4GHz systems have all of the above features (and many more). Nevertheless, there is at least one branch of RC model making that relies on 40MHz. And these are the model submarine builders and captains. The higher the transmission frequency, the poorer the electromagnetic waves penetrate the water. At 2.4GHz the penetration is almost zero, at 40MHz it is still so far that you can use it to control a model submarine. Of course, even lower transmission frequencies, for example in the long-wave or medium-wave range, would be more suitable. However, the legislature has not released any frequencies for controlling RC models. In addition to the other technical problems that then arise, the subject has thus become superfluous. 3.2. Result What can you achieve now through the modification of such a transmission module and the possible ones with it operationin a modern facility? Of course, the above-mentioned disadvantages remain, and the possibility of RC submarines is an added advantage. Other aspects are: advantages Conversion of the JR 40MHz module [HW_1.0] | 3 (27) 4 | 3.2. Result • A Transmitter for Everyone Models. • A Sender can with two HF modules are equipped: one 2.4GHz and one the converted 40MHz module. • The essential better programmability of modern transmitters can be applied to the 40MHz range. • Possibly bad service for old channels in the meantime. Disadvantage: • The transmission remains analogue and therefore prone to failure. • There is still a need for a channel agreement among the model builders. • The long, unwieldy antenna remains. The following pictures show how such a converted module can be plugged into a modern sneder. 4 (27) | Conversion of the JR 40MHz module [HW_1.0] 3.2. Result | 5 Figure 3. A modern transmitter (RadioMaster TX16s ) with the converted 40MHz-JR module (view: from below) Conversion of the JR 40MHz module [HW_1.0] | 5 (27) 6 | 3.2. Result Figure 4. A modern transmitter (RadioMaster TX16s ) with the converted 40MHz-JR module / view: from above) 6 (27) | Conversion of the JR 40MHz module [HW_1.0] 3.2. Result | 7th Figure 5. A 40MHz scan receiver that can still be delivered without any problems Figure 6. Another modern transmitter (Jumper T12 ) with the converted 40MHz-JR module (view: from above) Conversion of the JR 40MHz module [HW_1.0] | 7 (27) 8 | 3.2. Result Figure 7. Another modern transmitter (Jumper T12 ) with the converted 40MHz-JR module (view: from below) 8 (27) | Conversion of the JR 40MHz module [HW_1.0] 4. The conversion in detail | 9 4. The conversion in detail The conversion is described step-by-step in the following. 4.1. Source material Unfortunately, different versions of the Graupner / JR 40MHzModule under the sameOrder number appeared. The following pictures show the inside view after unscrewing the module cover of some variants known to the author. - Note the conductor tracks that are connected to the 5-pin socket connector on the upper right Walk off the edge of the picture. Figure 8. Version A of the 40MHz Transmission module Figure 9. Version B of the 40MHz Transmission module Conversion of the JR 40MHz module [HW_1.0] | 9 (27) 10 | 4.2. Interface to the transmitter Figure 10. Version C of the 40MHzTransmission module Crucial for the different versions A., B. and C. is only the assignment of the plug contacts of the 5-pin socket strip. This is always the same and therefore easy to identify. - 4.2. Interface to the transmitter A modern transmitter delivers the following signals to the looking out long pins of the module bay: 1st exit: PPM-Signal: the composite, analog signal with the servo information (8 channels). 2nd input: so-called heartbeat (depending on the transmitter and the selected function in the transmitter, the meaning may differ) 3rd output: battery voltage (after the on / off switch), unregulated 4th output: ground 5th input: telemetry data 10 (27) | Conversion of the JR 40MHz module [HW_1.0] 4.2. Interface to the transmitter | 11 Figure 11. The pin assignment in the module slot of a modern transmitter system That old Graupner / JR 40MHz-Module expects the following signals on its socket strip: 1st entrance: PPM-Signal 2nd entrance: 6V Regulated supply voltage for the crystal oscillator 3rd input: supply voltage in the area 7.2V - 12V for the HF output stage 4th input: ground 5. Output: antenna signal Conversion of the JR 40MHz module [HW_1.0] | 11 (27) 12 | 4.2. Interface to the transmitter Figure 12. The assignment for the socket strip of the Graupner / JR 40MHz Transmitter module in an old transmitter When comparing the pin assignment of the plug and socket, it is noticeable that 1. Pin2: heartbeat versus 6V-Supply voltage 2. Pin5: input telemetry data versus Antenna signal apparently do not match. From this the following can be drawn measures derive: • It has to be regulated 6V-Supply voltage can be generated, and • The antenna signal must not reach the telemetry data input, but must reach the rod antenna in some other way. 12 (27) | Conversion of the JR 40MHz module [HW_1.0] Translated from German to English - www.onlinedoctranslator.com 4.3. Changes | 13 Figure 13. Circuit diagram of the conversion: after the conversion, Pin2 and Pin5 are on the socket strip not more connected to the module 4.3. Changes First, the circuit board is removed from the housing: Figure 14. The general view of the top of the board of the old RF module Conversion of the JR 40MHz module [HW_1.0] | 13 (27) 14 | 4.3. Changes Figure 15.Detailed view of the area of the socket strip from above (Pin1: far left, Pin5: far right) From the bottom the board looks like this: Figure 16.Detailed view of the area of the socket strip on bottom (Pin1: at the very top / right, Pin5: at the very bottom / right) As shown above, the connections must Pin2 transmitter < → Pin2 module and Pin5 transmitter < → Pin5 module first interrupted and then rewired. First of all, the conductor tracks are interrupted. This is best done with a sharp utility knife. Make sure that the connections have actually been broken, for example by using aOhm meter or a Multi-meter or Continuity tester is remeasured. 14 (27) | Conversion of the JR 40MHz module [HW_1.0] 4.3. Changes | 15th Figure 17. Detailed view: severed conductor tracks from Pin2 and to Pin5 Figure 18. Further detailed view: cut conductors from Pin2 and Pin5 The next step is then the necessary Voltage regulator to generate the regulated 6V - Integrated supply voltage. This is installed in such a way that it comes from the unregulatedBattery voltage the regulated 6V generated. Basically, a very simple, integrated voltage regulator is sufficient here. The most famous family of voltage regulators are likely to be those of the so-called.78xxSeries. So there is7805 for 5V - output voltage and the 7806 for 6V-Output voltage. However, these controllers have one disadvantage: they need one between the input and output Voltage difference from approx. 2V. If you consider that with a modern transmission system that has about twoLiIon- Batteries are operated at the nominal voltage 7.4V lies, and that this is entirely on 6.4V is allowed to drop, you can tell that you are using a voltage regulator of the 7805 operates outside of its control range. Hence we need a voltage regulator, its more necessary Longitudinal voltage drop less than approx.1V is. Voltage regulators with a small longitudinal voltage drop are referred to aslow-drop-out - Controller, or in short as an acronym: LDO. Now is6V rather one unusual Voltage, and therefore the selection of LDOs is clear. One example is thisLF60CV (sa Voltage regulator). The 6V low-dropout voltage regulator LF60CV gives an overview of the data. And inThe pin Conversion of the JR 40MHz module [HW_1.0] | 15 (27) 16 | 4.3. Changes Allocation of the voltage regulator we see the pin assignment of this type. First, a point is sought where the unregulated supply voltage can be tapped on the top of the board. To do this, you simply follow the course of the conductor path on the underside of the circuit board, starting from this pin 3 of the socket strip. This is easily possible with the documented variant at a connection of a resistor: Figure 19. Wiring the input of the LF60CV with the unregulated supply voltage Then the entry point for the regulated 6V-Tension of the wanted. To do this, starting from Pin2, you follow the socket connector via the already severed Trace the course and look for a component (such as the Series inductancewhich looks almost like a resistor), which is easily accessible from the top. In the case of the documented variant, this can be found at a connection of a series inductance. Here the connection was cut on the underside of the board. Figure 20. Feeding the output of the voltage regulator to the feed point 6V at an inductance For feeding the mass to the LDO can usually be extended by an unused soldering eye with an enamelled copper wire, for example. The ground is often also at the edge of the board as a wider conductor track 16 (27) | Conversion of the JR 40MHz module [HW_1.0] 4.3. Changes | 17th located. Figure 21. Wiring of the ground of a soldering eye: here it has to be extended with a piece of enamelled copper wire With almost all integrated voltage regulators in the so-called TO-220 Housing is the metallic back of the housing with the exit or one of the three legs of the LDO conductively connected. This area may therefore not come into contact with other components of the module. It is therefore insulated with some duct tape. Figure 22. Further details. Conversion of the JR 40MHz module [HW_1.0] | 17 (27) 18 | 4.4. New housing Figure 23. Isolation of the voltage regulator housing Figure 24. Isolation of the voltage regulator housing The voltage regulator needs to be pressed flat on the other components. Otherwise the module will no longer fit into itJR-Casing. 4.4. New housing It is advisable to insert the module board including the changes into a new, somewhat different module housing. One finds onThingiverse different variants for your own 3D printing, all of which are more or less suitable because the screw mounts often interfere. In addition, an opening must be created for the quartz. 18 (27) | Conversion of the JR 40MHz module [HW_1.0]