View Full Version : Run a Yaesu FL-2100B with a Kenwood TS-2000

12-08-2003, 02:24 AM
I got a Yaesu FL-2100B CHEAP!! and I would like to use it with my Kenwood TS-2000


12-08-2003, 11:19 AM
(the following text located and blatantly copied via Google)

Subject: [Amps] FL2100B
From: dhearn at ix.netcom.com (Dan)
Date: Mon Aug 4 08:39:26 2003

Hi Carl: I have one of the 2100B amps. The only thing unusual about it is that the LV internal PS for the rig is positive grounded so it can be used for negative bias on the tube. The same PS is used for the internal T/R relay so the rear chassis connection, which must be switched to gnd to transmit, has negative voltage on it instead of positive. If you use an
external relay to do the switching, no problem, but if you use a transistor switch to gnd you need to take the polarity into consideration.

73, Dan, N5AR

12-08-2003, 04:38 PM
I'd use an external amp key line interface.

You can homebrew one easily, and a good set of instructions with schematic and polarity options were published in QST Hints & Kinks (I think) only about two months ago -- probably the October or November issue.

If that's daunting for you, you can buy a pre-built interface which is polarity insensitive from Ameritron or MFJ. The Ameritron P/N was ARB-703, I believe, and I've seen something similar in the new MFJ catalog which just arrived last month.

I would not try keying the FL2100 directly with the TS2000.


12-08-2003, 04:55 PM
I agree with Steve. #I have a TS-570DG that I drive an FL-2100B with using an Ameritron 704 Interface and interface cable. #It works beautifully.
73, K5ENA

12-08-2003, 11:20 PM
IF you are not a builder (for this interface), there are a number of products (Steve mentioned some of them).
Mike Bryce, WB8VGE also has an external interface product (AmpKeyer)

The FL-2100B is similar to the Heathkit SB-200 amplifier (572B tubes). #PLEASE read the RF Parts / Yaesu technical bulletin advisory regarding bias and the usage of Svetlana 572B tubes within this amplifier.
RF Parts has a very inexpensive ($ 2.50) kit of parts to address the bias issue.

Taylor versus Svetlana tube comparison (RF Parts web site)

Given the age of this amplifier -- I would check the power supply (e.g. dried out electrolytic, burnt or dark brown resistors) -- now is the time to replace these suspect components. #As Glen, K9STH has mentioned many times on QRZ, Mouser has a large selection of new electrolytics and at reasonable prices (I use Mouser or Digi-Key for my part orders). #