Radio Preservation Project

[koØm]

My Yaesu FT-101E is sick, the receiver is working properly and, the transmitter tunes up where it should and it has the correct amount of output. When operating, the carrier level is at about 20 watts AM and with the compressor on, the side bands can top 100 watts easy.

This is my bench radio and, is pretty much only used to drive other equipment under repair. While working on another unit, I noticed the power output dropping on the Yaesu. While checking the radio out, I also discovered that the Upper Sideband is screwed up and, the lower SSB frequency isn't where it should be.

Ater talking with some Fox-Tango Folks, I confirmed that the driver is going into oscillation.

In the past, I have eaten dead RL Drake 3-Line and 4-Line equipment for breakfast and have shat out working stations but, I am not (wasn't before now) a Yeasu repairer.

I am Reading TFM........

I've had this radio since 1985, I don't wanna give it up and, I am not going to pay a fortune to get it repaired by someone else.

Any 'Ex-Yaesu' engineers out there?
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[NQ6U]

This always works for me:

http://i815.photobucket.com/albums/zz79/gyrogeerloose/sledgehammer.jpg

[KC2UGV]

I'm not sure of the fix for it, but here are some resources I've found with similar issues:
http://www.foxtango.org/phpBB2/viewtopic.php?t=695
http://www.qsl.net/nw2m/ft101.html

From what I've read (quickly) it appears that the first place to look is the master oscillator crystal(s). Check those with a freq counter, and see if they are on the spot. Do you have access to a service manual that has the alignment procedures?

[koØm]

I'm not sure of the fix for it, but here are some resources I've found with similar issues:
http://www.foxtango.org/phpBB2/viewtopic.php?t=695
http://www.qsl.net/nw2m/ft101.html

From what I've read (quickly) it appears that the first place to look is the master oscillator crystal(s). Check those with a freq counter, and see if they are on the spot. Do you have access to a service manual that has the alignment procedures?

Thanks, I will add these links to my other resources, I have the FT101 Service Manual that is published on the web in .PDF form which I am digesting before I dig any farther into the radio.

As a long time Yaesu owner, I know that one of the most problematic areas of the radio is the mode switch so, after taking off all the skins, I sprayed each and every contact on each and every switch with contact cleaner and then, I rinsed every sprayed area with rubbiing alcohol from a spray bottle. I worked all switches and controls repeatedly while being spray cleaned. I allowed the radio to dry for two days.

On third day, I placed the radio on the bench and, repeated the the process of spraying, soaking, cleaning and working of all contacts in the radio. I set the radio aside for a couple more days to dry. That was last week, I powered the radio on and, I am confident that all contacts on the mode switch and the band switch are clean.

The Fault location tree directed me to the Modulation/Oscillator board and, that is where I am stopped; the book list various voltage measurements on the crystal board but, this radio is most easily T/S by using the extender cards to raise the boards to a servicable level. I don't have the extender card so, I am going to have to connect extender wires to the connection points for measurements.

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[koØm]

I'm not sure of the fix for it, but here are some resources I've found with similar issues:
http://www.foxtango.org/phpBB2/viewtopic.php?t=695
http://www.qsl.net/nw2m/ft101.html

From what I've read (quickly) it appears that the first place to look is the master oscillator crystal(s). Check those with a freq counter, and see if they are on the spot. Do you have access to a service manual that has the alignment procedures?

DANG, look what I found: http://www.foxtango.org/phpBB2/viewtopic.php?f=1&t=663

Look at the date of the posting......

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[KC2UGV]

DANG, look what I found: http://www.foxtango.org/phpBB2/viewtopic.php?f=1&t=663

Look at the date of the posting......

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Looks like you've been going at this for a while, huh?

[koØm]

Looks like you've been going at this for a while, huh?

Just a little over 3 years ago, I became a single parent to my 10 year old. I had forgotten that I had made that post and was a member of that forum as, my attention was needed elsewhere. I have him at a point that I can think about a little "me" time.

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[KC2UGV]

Just a little over 3 years ago, I became a single parent to my 10 year old. I had forgotten that I had made that post and was a member of that forum as, my attention was needed elsewhere. I have him at a point that I can think about a little "me" time.

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That's cool, I just chuckled a little at a problem encountered 3 years ago, forgotten, and then picked back up... Your age is showing OM, you didn't even remember the rig was broken already :lol: Sounds like something I'd do :)

[N8YX]

While working on another unit, I noticed the power output dropping on the Yaesu. While checking the radio out, I also discovered that the Upper Sideband is screwed up and, the lower SSB frequency isn't where it should be.
What does the unit do while in transmit in CW mode?

[koØm]

That's cool, I just chuckled a little at a problem encountered 3 years ago, forgotten, and then picked back up... Your age is showing OM, you didn't even remember the rig was broken already :lol: Sounds like something I'd do :)

My age + 4 years of life changing events will do it every time....I guess, I should have said, "remembered that the Upper Sideband was screwed up".



What does the unit do while in transmit in CW mode?

It turns on the side tone generator and it transmits, probably would not be noticable under normal CW speeds but, "Brick-on-the-key" mode, the output will start to fade.

Still reading the service manual.

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[N8YX]

It turns on the side tone generator and it transmits, probably would not be noticable under normal CW speeds but, "Brick-on-the-key" mode, the output will start to fade.
Bad driver.

I would also have a look at the screen blocking capacitor which couples the driver to the input of the PA stage. On the FT-901 series, for example, this was a mica unit of .001uF; 1KV. They will fail over time and take lots of other stuff out in the process. If the '101B/E/F uses the same type of capacitor, remove and replace with a 1-2KV part of the silver mica variety.

In addition to the driver tube itself being bad, a dropping off of output power is indicative of the capacitor heating up and changing value.

[koØm]

Bad driver.

I would also have a look at the screen blocking capacitor which couples the driver to the input of the PA stage. On the FT-901 series, for example, this was a mica unit of .001uF; 1KV. They will fail over time and take lots of other stuff out in the process. If the '101B/E/F uses the same type of capacitor, remove and replace with a 1-2KV part of the silver mica variety.

In addition to the driver tube itself being bad, a dropping off of output power is indicative of the capacitor heating up and changing value.

I have 2 NOS General Electric 12BY7A due to drop in the mail box from flea-bay.

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[koØm]

Bad driver.

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Bad toob!

Also, bad Tube Checker!

I installed a new tube and, the problem went away; put the old tube back in, the power problem reappears. My tube checker shows "good" indication for both tubes but, the old tube was the problem.

[KG4CGC]

I'd check out that screen blocking cap like Fred said too. Just saying.