Are you using a Kenwood TL-922A amp?

Dave KD5FX

I'm thinking about getting an HF amp. Found a good deal on a used Kenwood TL-922A in good working condition. Before I buy it I want to be sure it will interface with my FLEX6300. Are you using one with yours? Did you hookup the ALC cable too? The Flex documentation doesn't recommend that.

W1IMD

Dave, do not hook up the PTT output of your 6300 to the Tl922A! Doing so will destroy the keying transistor in the 6300. The 922 has 100 VDC on its key line input. You will need a hardware interface between the 6300 and the amp PTT input. Ameritron makes an interface or you could make your own with a small 12 volt relay. No need to hook up the ALC with a Flex, just don't overdrive the amp.

Dave KD5FX

Thanks for the tip! I have a UKA-3+ interface for my old amp that should work too. 
73, Dave

Steve W6SDM

I agree with all of that. I had a 922A for a couple of years and used it with my 5000 and 6300. It served me well. If I remember, I paid around $900 for it about four years ago. Now, if you're getting a real good deal, go for it. However, I can't say enough in praise of the Elecraft KPA500 when used with a Flex. If you couple it with a KAT500 tuner, it's like having a 500-watt transceiver. Virtually no tuning required. I worked a lot of DX and busted through a few pileups with my 922A. It's a solid amp. I finally parted mine out when the capacitors got too old and failed.

Marty VK2VCC

reading the above ..i am concerned. i run a.922 with my flex 3000. am i in the same boat as the 6300? i am using a heavy duty rca type lead from flex to 922 with no trigger issues. i need to know if im good or if i should be concerned. 100v Dc!! marty

Norm - W7CK

Marty,
Unless someone has modified your 922 to include a low voltage keying circuit internally to the amp, you should NOT be doing what your doing.  you MUST use a separate keying relay that is designed for the higher voltages found in the TL-922.  If you don't, it is only a matter of time before you fry the keying circuit in your 3000.

MFJ (Ameritron) sells a very inexpensive keying circuit model ARB-704.   You can also find cables on ebay that have the relay built into the cable that are capable of handling the voltage.

Ross - K9COX

From the 3000 manual:
(6) External Keying Line This keying line, which can be given a delay, can be used to key an external device such as a linear power amplifier or transverter. The external keying is provided by a relay closure to ground, with a rating of 250 VAC, 220 VDC at 2 A and with a 2.5 ms nominal switching time.