Cadet Sync Generator Problem


#1

Hello,
I know LZX does not offer any help with the DIY projects but i figure i might as well ask for some help.
So i built the Cadet sync generator but for some reason i feel the atmega chip might not be programmed.

I connected the h and v outs to a oscope and seem to not get any 1 volt pulses.

I have it connected to the Cadet RGB encoder with the 14 pin sync cable.
I also have looked over the board for any missed solder connections.

any help would be great!


#2

can you try posting hires pics so we can see IC/diodes orientation, and we can do quick solder inspection?

my testing procedure is always is

  1. if you have a bipolar power supply with ampmeter try see how much current your module is pulling, most of the time will be a short or bad orientation component the problem

  2. if the pcb has microcontroller, try testing if it has the requiered power supply, in this case 5v.

  3. check if anything gets too hot, you can do this by gently touching components (you can do this because its a lopower application) or use IP Alcohol.

  4. check for bended legs of ICs

  5. check for cold solder joints

thats at least a starter, its possible that everything is fine and as you said its just the microcontroller but we cant help if we dont get more details or info on your build


#3

hello i have included some pictures.


#4

you have to connect r13! use a small wire or snipped off piece of a resistor leg.

note: in the future, use IC sockets.


#5

Thank you! i will connect it and see if it works out. i will post back with the results.

As for the ic sockets i think i remember something that they would not recommend the ic sockets due to noise interference or something like that?


#6

I thought that was only with the modules that use the TL1251, like the Fader


#7

so the bridge wire on R13 made it come alive!

thanks for eagle eye and help.


#8

it never hurts to help, like Spongebob says


#9

I think Lars recommends not using sockets with all the Cadet (and Castle?) stuff because the sockets can add a small bit of capacitance to these higher-frequency-than-audio-rate circuits. That said, I’ve used sockets on some of the builds and haven’t noticed much issues.


#10

I’ve got some type of issue with my sync generator that’s causing it to fail to genlock. Everything else about the sync generator seems to work - I’m able to sync the ramp generator and RGB encoder over the sync bus as well as some Castle clock VCOs over the power bus, the 1V outputs work, and it’s buffering the RCA input to the RCA output fine.

The patch I’m working with is:

  • Vidiot RCA luma output -> Cadet I input
  • Vidiot 1V luma output -> Cadet II Red input
  • To confirm that the sync bus is working, I’m also patching the horizontal ramp from Cadet IV to the Cadet II Green input.
  • Cadet II video output -> display

The behavior I’m seeing is:

  • The pattern from the Vidiot luma processor scrolls left to right, with a black gap every so often for the horizontal blanking interval.
  • On an oscilloscope, I can see the separated sync from the video input arriving at the SIG_IN input (pin 14) and the generated sync from the ATMega arriving at the COMP_IN input (pin 3) of the 74HC4046AE PLL.
  • I can measure 5V at the Vcc pins of all the 5V ICs.
  • At the PH_COMP2_OUT pin of the PLL, I measure 0V.
  • At the VC input pin of the crystal oscillator, I measure 0V.

Maybe I’ve just got a dead PLL? Makes using sockets in the future sound real appealing. Here are some photos, any thoughts or advice are tremendously appreciated.


#11

so you are syncing the sync generator with the vidiot?

what happens if you leave out the vidiot and only use the sync generator + ramps?


#12

Yeah, with just the ramps on the sync bus patched to the RGB encoder the sync is fine, no “marching”. I also just discovered that if I patch:

  • CCTV camera -> Cadet I input
  • Cadet I output -> Cadet III video input
  • Cadet III luma -> Cadet II Red in

as described in the Cadet I manual, it syncs to the camera! But replacing the CCTV camera with the Vidiot luma out, the image is still marching. Same if I connect Vidiot sync out -> Cadet I sync in and patch an oscillator from the Vidiot to the RGB encoder. Based on this post I was expecting these to work. However I can patch:

  • CCTV camera -> Vidiot camera input
  • Vidiot sync out -> Cadet I sync in
  • Cadet I sync out -> Cadet III video in
  • Vidiot luma out -> Prismatic Ray

and now everything in my rig is synced! However, disconnecting the camera input from the Vidiot makes the Vidiot and Prismatic Ray oscillators start marching again, so I guess that’s the most important thing, at least with my unit. The sync loop thru switch on the Vidiot hasn’t seemed to make a difference for any of the above scenarios.