View Full Version : FT - 101 E

01-15-2007, 07:33 AM
The old FT - 101 E is silent - does not seem to transmit. The receiver is working perfectly and the transmitter does function, but nothing seems to go out - how do I check if the final tubes are bust or if there is something else wrong with the rig?

01-15-2007, 02:34 PM
Got heater voltage?

There's an 11-pin socket on the back of the set - a dummy plug (or accessory cable) mates with it. Two of the pins in the plug are jumpered and carry power to the tube filaments.

Without the jumper...no filament voltage...and no power output.

01-15-2007, 09:57 PM
First, with the top cover open, do you see a nice warm glow from the driver tube and the PA tubes (the PA tubes are inside the cage at the right rear of the rig, but you can see the glow).

As YX points out, there does need to be the plug in the ACC socket...

I'd like to point out that if it seems we're speaking Greek, you might want to consider getting some help locally, since there's 600+ volts DC on the final plates, and there's 300 volts DC running rampant in several places in the rig.

But the very first thing is to make sure you have filament (heater) voltage, and the quick check for that is the nice glow on the tubes.

02-01-2007, 08:51 AM
Thanks Dave and the others - sorry for the delay in replying - was out in the boondocks for a while.

The heater works fine, there is a warm glow in the driver and final tubes.

How does one find out if the finals are actually transmitting? Is there any change in the glow of the tubes while transmitting? Is there some other way of finding out?

Was wondering if there was a problem with the antenna (feedline or elements) and perhaps nothing wrong with the rig. The antenna was tested out with an MFJ antenna analyser and it shows SWR 1.5. Perhaps at higher power would there be some other factors atr play?

Many questions, a lot of confusion!!!! WOuld be grateful for any assistance.


02-01-2007, 11:36 AM
/* from memory ! ! */
the s-meter also serves to measure output "power" [PO], this is really just an indication of RF volts at the output but would seem to meet your requirements. By changing the slide switch to [IC] this meter also measures cathode current on transmit which should sit near 60mA on SSB without modulation and will be seen to dance about as you speak (another indication the valves are doing something and modulation is getting there) - If the standing current is incorrect there is a trimpot inside (from memory under top lid, left side, a skeleton trimpot, logically labelled but I forget what it is labelled as) which allows it to be set over quite a high range however if you are really unlucky it is possible that a coupling cap or something will have gone leaky and need attention. If you place the rig on say 20m and into "tune" mode you can play with the carrier control (2nd function on mike gain pot) and see if you can see anything change on IC or PO meter indications (NB the PO sensitivity is _not_ fixed, there is a pot at rear panel, the shaft is about 1/4" dia {no knob} which allows PO meter sensitivity to be adjusted - at min setting it is pretty useless, at maximum sensitivity it will give large deviations for quite low output powers so if you don't see anything play with the rear pot {probably labelled, most things on the 101 were logically labelled} Take all the above with a grain of salt as it is too long since I played with one of these but if you are really stuck I have the manual here or there "somewhere" though it won't be fast for me to find. If you need more then drop me an email and maybe we can make an echolink sked (I talk better than I type). 73 Frank VK2AKG

02-01-2007, 11:47 AM
/* post script */

just had a horrid thought, I presume you are aware that unlike most modern rigs the FT101 requires manual tuning of the driver and final without which you will not be generating useful output power.

' 73 Frank

02-02-2007, 05:10 AM
Thanks Frank - this gets better - your memory is REALLY GOOD - everything is as you say, very accurately. I do have the user manual and everything is detailed quite accurately - I shall start from the beginning and lets see if it works - seems like I have my work cut out for this weekend - shall get back to you with the results.


02-03-2007, 05:51 AM
Let's take a moment and be sure that there's actually some plate current... (I learned a LOT from a Brit that's very helpful... don't have his call handy, but he's Derek)...

Switch the rig to LSB... make sure the mic gain is at 0 (all the way to the left). The meter switch needs to be in the I.C. position.

Move the MOX/PTT/VOX switch to MOX, and observe the meter. It should move up to the 3rd hash mark... this is 60 milliamps of plate current, the "idle" current necessary in the FT-101 series. If it reads between the 2nd and 3rd hash mark, that's ok, that's approximately 50 ma, and is in a reasonable ballpark (one that some suggest the rig should be run at anyway).

Apparently, it should be obvious, but it's not printed anywhere I could find, the bottom scale of .1, .2, .3, .4 and .5 is what you use to read the plate current.

If you do not show that, then there are problems that will take some sorting out. I have an FT-101E that will only show that with the grid bias turned completely down, which indicates bad tubes. I have an FT-101EE that has no problem with that, and makes a whale of a lot of power.

The E has other issues as well, but I'm working on restoring it.

If you find that you do not get 60 ma (again, third hash mark on the meter) in MOX with the meter switch in I.C. and the mic gain turned completely down, we'll go from there.

02-20-2007, 07:14 PM
Quote[/b] ]How do I check ..... if there is something else wrong with the rig?
Start with the FT-101 manuals! #

FT-101 Service Manual

These are readily available to you from Fox-Tango International - The Yaesu User's Group.

Yaesu FT-101 Web page

PROPER FT-101 Tune-up (final tubes are getting too expensive -- to not perform this step correctly)


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