No Luck With The 400 Wiring...

The new diode is in series to #1 post & ready to go but, nothing happens. No power to the coil, starter or lights. I have to be overlooking something. I have the diode wired in 2.5" away from the alt, with the gray band facing the alt. Nuthin'! Re-searched my wiring & everything is connected where it should be. Has to be something simple or it wouldn't be causing so many headaches. Will the gray band facing away from the alt make a difference? It's the only thing I can figure. Same case as before: diode in line = nothing, no diode = starts & runs. The answer has to be right there in that messed up scenario, somewhere. I can't imagine THREE diodes being junk from anywhere! Gotta be me &/or my luck. All there is to it. - Dismayed

Un-plug the two wire plug from alternator and tell us what it does then.

Nothing at all. Are the 2 posts, I disconnected the wires from, supposed to be reading full voltage from the batt? Otherwise I'm not sure what the outcome should be. - Mike

There is a fault in the primary wiring of the tractor. This means that there is no voltage getting to the coil when the key is on. The system is getting its voltage from the Alternator. Not correct.
Use your test light to trace the voltage from the starter relay (little can on starter) to the amp meter, from the amp meter to the ignition switch, from the switch to the coil. There is a break some where.
The #2 terminal should be attached to the Big Bat post on the Alt. The #1 post is connected to the Diode. There should be no voltage on the #1 terminal when the tractor is not running, key off.
This could be part of the problem, If you measure 12+ volts at #1 terminal the regulator in the alternator may be bad. Are you sure it is a 10SI alternator? JimN

Ja, as far as I know it's a 10SI alt. I tried to get a couple pics with my phone. Look ok to you? I'll go chase down that wiring gremlin, in the mean time.

Yup, Sir! All the power is at the alt. All 3 posts are reading 12-13v! So, the piece of junk is a piece of junk, huh? I tell ya what, the next time I go tractor shopping, I do believe I'm goin' with a tool box & doing some diggin'. The way I feel right now, I'll tear the thing apart, right there, on the spot! I'm glad I previously knew the TA was no good on my 400. I'da been there all night!! LOL!

just saw you wondering about diodes. yes they have to be installed one way. current only travels one way through them.didnt really go through all the posts as i hate wrecked 6v systems.

Crazy, the starter, lights, and coil should get power even if no alternator is installed at all!

Power to the lights comes straight from the battery through the Ammeter.

Power to the coil comes straight from the key switch when it is in the ON position.

The starter is a little more complicated. Power goes from the battery to the solenoid to the starter via the big wire. The solenoid is activated by the key switch when you turn it to the start position like a car.

Just hang in there. This problem is able to be solved--just don't get down. You're saying you have 12 volts at the the large terminal on the alt, so that means #2 terminal also has 12 volts. Now is there voltage at the big terminal at all times? or only with the ignition switch on? There should be 12 volts at this terminal at all times. Let's back up a moment---make sure that the points are open before doing any testing.
Now, the #1 terminal--is there voltage present here at all times? Should be voltage here only with ignition switch on. Should be .7 volts less than the battery voltage with the switch on.
No voltage with ignition switch on at #1? Check for voltage at the hot terminal of the ballast resistor coming from the ignition switch which feeds the coil.
If full battery voltage at hot wire to resistor, there is a problem with the wire/diode going to the #1 terminal.
No battery voltage at the hot terminal of the ballast resistor? There is a problem between the battery hot terminal/ignition switch/wiring to the ballast resistor.
If tests above don't show up any problems, likely the regulator will have to be replaced.

Just re-reading your post about no voltage to the starter, coil, or lights. Jim N. is right--either there is a rusty/no ground or a battery cable isn't making contact/ tight. Check this problem out first. Wish I lived closer.

The Alt is in the number category of 10SI alternators. I think the fault may be that the alternator was purchased originally as a one wire setup. These have a regulator designed (kindof) that only uses the BAT wire to the battery to make it work. There is no way to check this unless there is a part number on the regulator inside the alternator. A good electrical service shop will know. If it is, and it is good, it will charge with nothing but the big terminal connected.
If it is (and the regulator is toast -probable-) it will not work. It needs to be taken in. It is quite likely that it is easy to fix with a standard 3 wire regulator (cheap). Unless it has been hooked up backwards (positive ground) it still has 90% of its value. Regulators are in the 20$ range.

The real issue with your electrical system is the wiring from the cable attachment from the battery. (Battery post at the starter relay) to the amp meter (a 10ga wire) and from the amp gauge to the key, and from the key to the ballast resistor. Trace that power.

The alternator (when checked and made into a three wire) will then work with the diode.

This is complex, and will be all OK in the end. And you will know a massive amount about the tractors electrical system. It is in the end game. Seems like the last 2 minutes go on for 8 commercials. JimN
A very fine Delco Model chart and Reality check