Ok its time to post the final part of my project where i will show how i installed the optical TX link in my Mscaler and the RX side in Dave.
I start with the Mscaler side.
Since i want to longer test my circuit before i make a final PCB i decided to place my experimental PCB inside.
I start with getting power from HMS's own 5v power rail. There are actually 3 regulators inside which make from 15VDC input: 5v, 3.3v and 1v for the FPGA.
So i located the 5v one and found 3 caps in parallel on its output to add my own simple linear regulator using a potmeter.
Since my two Avago TX units draw only 150mA, a 0.5watt pot will suffice. I set it to 4.5v as i had best performance in that setting.
Next is soldering shielded wires on the scaler's DBNC outputs. I take the signal as close as possible from the BNC pin to prevent reflection on a open end.
This way i leave the BNC's in place so i can still use them with coax.
Then i placed the two Avago TX LED transmitters with the driver PCB. The wires are quite sturdy so it stays in place without screws.
I placed a paper around to prevent possible shortcuts. Later a PCB will be soldered on the Avago units keeping it in place.
I measured the DBNC GND is isolated from the PSU GND, so i DC decoupled my driver's output GND from its power GND.
I will post a circuit schematic of the driver later if there is interest.
Then close the lid and my Mscaler is ready.
Next is modifying my Dave.
I waited with Dave until i was shure my link works.
So offcourse i start by opening it unscrewing the lid. I chose BNC inputs 3 and 4 as they have more room around them and are closer to the PSU.
Dave still keeps BNC's 1 and 2 for coax use.
After taking out the visible PCB bolts i noticed it was still stuck in its casing. It appeared there is another bolt under the display. but the display is glued on the FPGA sink.
So i had no choice then to use a stanley knife to cut through the kit under it. BUT BE CAREFUL not to cut the display bandcable on the underside!
This display type is EOL and a new replacement would require a code change which obviously i cant do.
To get it out, the lockpin of the AES connector has to be removed:
Now only unscrew the headphone jack ring and the PCB is free from its casing.
Lets take BNC's 3 and 4 out by unsoldering them, they are part of a single molded unit with 4 electrical pins and 2 mechanical pins.
note: you need to set your solder iron quite hot on 400° to do this. I used a formed thick massive 2.5mm wire over all pins to heat them all together.
I wanted to build my Avago RX units inside DAVE without nuts on the outside, keeping the wires secure and short so i grabbed my iron saw and cut a L shaped piece out of a metal strip.
The L strip with drilled holes for the RX units and placement on Daves PCB. Two 2mm screws just fit through the PCB holes which before kept the BNC's in place:
The lower unit couldnt fit cause of the strip's screws sticking through, i didnt want to cut those to keep the strip strength so i rasped 2 corners out of the RX unit.
Prior to this i opened the RX unit to find all internal circuitry is sealed inside the tubed part and the housing is almost emty.
Now the second RX unit on top. Since the RX circuit is so simple and has so few components i decided not to make a PCB for this.
The signal DC decouple caps are soldered straight on Dave's PCB. I only used one GND pin since they are shared already.
I want no external PSU or batteries to feed my optical link so i get power from Dave's own 5VDC power rails. The PCB has free solder pins aside the PSU connector.
There are no groundloops and picking up net RF possible this way. So i applied the same solution as in my Mscaler
Now my Dave is ready to receive its dual data optical link and get a Mscaled signal free of any RF noise !
So lets put it back in its casing and make some final pictures of my new stack..
Both units with dual data optical: (i guess i will make my scaler's optical nuts black too)
I already received my short dual fiber cable to neatly fit on my stack.
Thanks for reading my posting
Its finally time to really enjoy my music !!
tears coming.. playing Lord of the Rings 48/24 to 768 what a grand stage..
