Dual 1176LN Module Assembly
MNATS 1176LN (Rev J PCB) Clone Module Assembly
The assembly of this module is fairly straightforward provided you know what variant/options you are constucting. The PCB caters for a number of different parts and configurations so it's essential that you decide your configuration and purchase the components required for it.
Here's a scan of the PCB overlay with all the extraneous silkscreen greyed out. This makes a very useful part of the service manual in order to locate components since once they are installed, you can't see the designators. It also helps during assembly since only the required components are shown.
Here's a scan of the PCB overlay with all the extraneous silkscreen greyed out. This makes a very useful part of the service manual in order to locate components since once they are installed, you can't see the designators. It also helps during assembly since only the required components are shown.
If you are using the on-board power supply, build that section first and check the supply output rail voltages to confirm that they are correct. There's only a small handful of components associated with this section so it should be fairly easy to build and test.
Now construct the rest of the module. Start off with the resistors. It pays to double check each one prior to insertion and soldering to save headaches locating it after something doesn't work.
Add the caps, trimmers, diodes and transistors, making sure that they are inserted the correct way around and in the correct holes. C16 is not necessary as it appears to be a compensation cap for op-amps that require it. The LF351/TL071 op-amps do not require this.
Double check the FET orientation. I've marked the g/s/d terminals on the PCB overlay as a reference. The 2N5457 devices are oriented backwards (ie the flat side of the package faces the curved overlay marking). The data sheet for the 2N5457 device is on the FET page as a reference.
Add the op-amps, in sockets if preferred for easier servicing, and finally the transformer.
Now construct the rest of the module. Start off with the resistors. It pays to double check each one prior to insertion and soldering to save headaches locating it after something doesn't work.
Add the caps, trimmers, diodes and transistors, making sure that they are inserted the correct way around and in the correct holes. C16 is not necessary as it appears to be a compensation cap for op-amps that require it. The LF351/TL071 op-amps do not require this.
Double check the FET orientation. I've marked the g/s/d terminals on the PCB overlay as a reference. The 2N5457 devices are oriented backwards (ie the flat side of the package faces the curved overlay marking). The data sheet for the 2N5457 device is on the FET page as a reference.
Add the op-amps, in sockets if preferred for easier servicing, and finally the transformer.
Switch Module
This version was constructed using rotary switches, primarily for the ease of panel cutouts. Using a 6 position rotary switch for the ratio selector meant that another two compression settings, 6:1 and 10:1 could be included. Adding these settings meant that a new PCB for the rotary switch and its resistor chain was needed. In order to fit all the resistors and not foul other panel mounted components, both rotary switches (ratio and metering) were included on the one PCB, spaced apart by 1.380" (35mm).
There are two versions of the switch module, the only difference is the rotation of the switches. This allowed an alternative knob with an offset grub screw to be used and still line up with the panel markings.
The original component designators and interconnection point references have been retained. The new resistors are designated in the 90's (R90, 92, 93, 94, 95, 97, 98, 99). The PCB and circuit are available in the accompanying PDF links. The assembled PCB is shown below.
The switch module has an optional resistor marked RT on it. This resistor can be selected during testing to set the desired threshold at which compression starts.
It should be noted that the switches are mounted on the back side of the PCB and the other components and wiring attachment points are accessible on the top side of the PCB.
There are two versions of the switch module, the only difference is the rotation of the switches. This allowed an alternative knob with an offset grub screw to be used and still line up with the panel markings.
The original component designators and interconnection point references have been retained. The new resistors are designated in the 90's (R90, 92, 93, 94, 95, 97, 98, 99). The PCB and circuit are available in the accompanying PDF links. The assembled PCB is shown below.
The switch module has an optional resistor marked RT on it. This resistor can be selected during testing to set the desired threshold at which compression starts.
It should be noted that the switches are mounted on the back side of the PCB and the other components and wiring attachment points are accessible on the top side of the PCB.
