RWC

Ray West (Consultancy)

VMC - LM7 Substitute

The Sony VMC-LM7 Adaptor provides the PC7 camera with facilities for external microphone input and LANC control. It plugs into the 26way connector which is also used for the external power supply/charger. (The LM7 also has the 26way connector replicated so that you can use external power at the same time as mic/lanc.) In the UK, it costs about 50.00 when available. There are one or two minor disadvantages with the Sony adaptor, and the following notes should give you sufficient information to make your own adaptor, utilising the external power lead connector. However, if you end up melting the connector, or otherwise making it unuseable, the cost of the replacement power lead will probably be more than the VM-LM7, so don't blame me.


To make your own LM7 Adaptor (good eyesight and steady hand required, and you should be familiar with precision soldering!)

Use the charger lead connector. The 26 pin connector is held together by two small screws. There are three wires in the power lead (which in my lead were: red +ve, white -ve, and a thin blue control wire, but yours may differ) and if you wish to use the adaptor without this attached power lead and charger, get a four way plug and socket. (If you also want to use an external battery, then get an extra plug for this battery lead.)

Confirm that the white wire is connected to pins 25 & 26 , and the red is connected to pins 1 & 2, looking down on camera with lens to top lh corner, (The connector terminals are in four staggered rows, as shown below)

   
1   5       ...        21     25
  3         ...            23
    
  4         ...            24
2   6       ...        22     26 

The list of connections follow, you will be able to verify many of these, but some are for service purposes.


1,2 Volts in : 3 n/c (multi x in/out) :
4 Charger control voltage : 5 multi Sy :
6 S Status 2 : 7 Multi Sc :
8 S Status : 9 multi Vid : 
10 Rf DC out : 11 Gnd : 
12 X charge in H : 13 multi audio /R :
14 batt/ext  : 15 multi audio /L : 
16 Lanc gnd : 17 Aud Gnd :
18 Lanc sig : 19 Lanc DC : 
20, 21, 22, 23, 24 n/c : 25,26 volt gnd

14 is connected to 25/26 via pcb within charger plug

On the LM-7, the standard LANC connector is a 2.5 mm stereo jack socket, the audio is microphone input, and is a standard 3.5 mm stereo jack socket.

To connect to LANC, (using a standard 2.5mm stereo jack socket) tip to pin 18, ring to pin 19, screen to pin 16. (This will also power our LANC controllers, and the Sony RM-95.)

To connect to Microphone (using standard 3.5mm stereo jack socket), screen to pin 17, ring to pin 15, tip to pin 13

Pin 14 is shorted to pin 25 within the existing power connector. If you leave that short in situ, then you will have to use an external power source. This connection is sensed by the camera, and it assumes external power will be present. If you wish to use your adapter without external power, then carefully cut the copper trackwork on the small flexible printed circuit between pin 14 and the pin 24 & 25 trackwork. As you will probably want to use the same adaptor to conect to external power, then you will need a four way plug and socket. If you connect the socket to the adaptor, then connect pin 1 of the socket to pins 24 & 25, pin 2 of socket to pin 4 of adaptor, pin 3 of socket to pin 14 of adaptor and pin 4 of socket to pins 1 & 2 of adaptor. (A 'sort of standard' exists for 4 pin XLR connectors for external power supplies in which pin 1 is -ve, pin 4 is +ve).

For the plug, which will be connected to your Sony power supply cable, connect pin 1 to power +ve (red), connect pin 2 to control wire (thin blue), pin 4 to -ve (white), and connect pin 3 to pin 4 within this plug. If you want to use an external battery, then connect its plug in the same way, but make no connection to pin 2.

The connections are tightly spaced. It was my intention to make a small intermediate terminal board, for attaching the leads to the three sockets. Wire wrapping wire would have been soldered between the adaptor pins and the terminal board.

In the end --- I thought it was more expedient to purchase an LM7!!!

contact us to let me know how you get on.