Starting Composite Mod
Posted: Sun Nov 11, 2018 12:09 am
OK, on my TS1000...
I was going to start with a basic composite mod. Just the 1 transistor 1 resistor one to start.
I opened it up and have been looking around.
It looks nice. (A little too nice. I had some keys also not working when I started it, but the ribbon cable looks nice... Hmmm. Different issue..)
So since I have the US model, there are 3 wires going into the modulator.
I figured I'd see which is ground, which is 5v and which (the one left) is video.
So I grab my little radio shack multimeter, set it for continuity (where it beeps on continuity) and start poking.
Yes, there is no power anywhere around. Not plugged in!
I touch the ends of the probe together, dial swings and it beeps. (Well, screeches really...)
So far so good. Touch one probe to the RF case (figure ground) and touch the other probe to the far right wire going into the modulator.
The dial swings hard to the side and it screeches. That must be ground.
Move the other probe to the middle wire going into the RF modulator. It still screeches. The dial still swings all the way over, but rests just a bit from the end....
OK, now I am confused.
Touch the probe to the 3rd wire (one on the far left) and there is no screech, and the dial swings a bit over half way...
Obviously I haven't done a lot of electronic work..
I assume there is a reason I am getting some continuity no matter where I touch the probes in the TS1000?
Is there a better way for me to validate what is gnd and what is +5v?
On the good side, all of my chips are socketed. Even the 2k RAM chip. Of course, if I decide to go for the 16k internal mod later I will need to replace the socket with a larger one (or add something to extend it).
I was going to start with a basic composite mod. Just the 1 transistor 1 resistor one to start.
I opened it up and have been looking around.
It looks nice. (A little too nice. I had some keys also not working when I started it, but the ribbon cable looks nice... Hmmm. Different issue..)
So since I have the US model, there are 3 wires going into the modulator.
I figured I'd see which is ground, which is 5v and which (the one left) is video.
So I grab my little radio shack multimeter, set it for continuity (where it beeps on continuity) and start poking.
Yes, there is no power anywhere around. Not plugged in!
I touch the ends of the probe together, dial swings and it beeps. (Well, screeches really...)
So far so good. Touch one probe to the RF case (figure ground) and touch the other probe to the far right wire going into the modulator.
The dial swings hard to the side and it screeches. That must be ground.
Move the other probe to the middle wire going into the RF modulator. It still screeches. The dial still swings all the way over, but rests just a bit from the end....
OK, now I am confused.
Touch the probe to the 3rd wire (one on the far left) and there is no screech, and the dial swings a bit over half way...
Obviously I haven't done a lot of electronic work..
I assume there is a reason I am getting some continuity no matter where I touch the probes in the TS1000?
Is there a better way for me to validate what is gnd and what is +5v?
On the good side, all of my chips are socketed. Even the 2k RAM chip. Of course, if I decide to go for the 16k internal mod later I will need to replace the socket with a larger one (or add something to extend it).