TS-570 K2 relay and DIN connector not getting 500 WATTS

[philn]

I'm speaking for a blind ham. He has a seemingly working TS-570. I say that because he's able to go on the air with 100 WATTS and transmit and receive. The problem is going through a SG500 linear amplifier so that he can get 500 WATTS. Of course he has the RF radio out to the RF linear in and the RF linear out to the antenna.
With the linear powered off he gets his 100 WATTS out from the transceiver and goes on the air transmitting and receiving. The way I understand how he would get 500 WATTS is a cable with two wires connecting from the TS-570 DIN to the 10 pin connector on the linear.
I've heard from both Kenwood and SGC. SGC says to make connections to the 2nd from top (ground) and 4th from top (PTT). And when the PTT goes to ground the main relays in the linear will energize and you get your 500 WATTS.
Kenwood says connect pins 2 and 4 of the DIN (note pins 2 and 4 are not the 2nd and 4th from the key counting CW. In fact pins 2 and 4 are the 3rd and 4th pins CW). In any event between Kenwood and SGC instructions, DIN 2 & 4 are connected to 2 (2nd from top ground) and 4 (4th from top PTT). Now if you look at the Kenwood schematic you see that pin 2 and 4 are connected to K2 arm and NO contact. So that the way I see it when K2 energizes, I assume when he transmits, it places a jumper between ground and PTT effectively grounding PTT. But when he transmits the linear relays don't energize. I even grounded PTT and the linear relays don't energize.
I accidentally grounded the 3rd from the top, ALC and heard relays energizing. Further I placed an ohmmeter between 2 &4 of the DIN and when he transmitted I did not get zero resistance. So I have three questions. 1. Am I right that K2 has to energize when he keys the transmitter to start the action? 2. At the linear if I jump ground and PTT should the linear relays energize? 3. What happened when I grounded the ALC on the Linear?

[KM3F]

Go on the internet and key in Kenwood TS 570.
You should come up with the user manuel. Look on page 61.
There you will see the rear remote jack. (It does not count the terminals in straight order).
From the plug location key 'clockwise' you will get the following terminal count. 6, 1, 4, 2, 5, 3, 7.
Connect the amplifier keying line center conductor to pin 4 and shield to the common pin 2.
When the radio is mike keyed, these terminal will shunt and key up the amplifier.
Make sure the amplifier is tuned for max output on the selected band unless it is an auto tune type.
Good luck.