CADET III VIDEO Input, output level verification

Category: Unknown · Tags: — · Posts: 10

#1 — jestern · 2020-10-09

Hi there after the Vector Hack Festival I’m back to complete my LZX Cadet system. I’m kind of blindly aiming at making work the Video Input, Sync Gen, Ramps. Right now I think my Sync Gen works. The Ramps works only in the top part. So I decided to try the Video Input cause it seems an easy build. I tried inputting video from my Mac -> Extron VSC500 (VID out) -> CADET III top input and measuring the output jack (LUMA) with a scope. I see a rough variation of about 1V in the input if I put a black or white video + Brightness increases the signal turning the pot from 12 o clock counter clockwise or clockwise. Of course there is always the sync signal. Is that supposed to work like that? Only weird thing is I have an offset of about 7.5V. This is regardless of what is plugged in. Uploading a picture just in case.

#2 — reverselandfill · 2020-10-09

you know you have to patch the video into the sync generator first , right?

video -> sync gen in -> sync gen out -> Cadet III video input in

#3 — jestern · 2020-10-09

Hmm I was trying to avoid The Sync Gen in order to test it independently. I will try as you said. Thanks Martijn.

#4 — Robbertunist · 2020-10-10

Ughh, a power cable with two red sides

Not an issue because of the shrowed (typo) header but always a risk. I learned the hard way sadly

#5 — reverselandfill · 2020-10-10

post a pic of the backside too

#6 — jestern · 2020-10-10

Thanks!! I hope the quality is not so bad.

#7 — Fox · 2020-10-10

Is that a TL071? Just off the top of my head, there were no TL071’s in any Cadet BOM.

#8 — jestern · 2020-10-10

aw right!!! true I put the wrong IC!!! thanks!

#9 — Fox · 2020-10-10

ok, that could have caused all sorts of wackiness. Let us know what results you get.

#10 — jestern · 2020-10-11

Changing the IC worked :)))))