FT 101B CLARIFIER control 0/off alignment

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FT 101B CLARIFIER control 0/off alignment

Postby N5AEA » Sun Apr 10, 2016 4:31 am

The FT 101B transceiver works except that the Tx and Rx VFO are not in alignment.
I have done all that I know to do, so I need an new set of eyes on the problem.
The alignment procedure that I am using is to set the Clarifier to "0" and measure voltage at the VFO Clari input.
Next, set the Clarifier to "Off" and use VR4 to set to same volts.
Problem is that in the "Off" position I measure 6.0 volts and VR 4 will not adjust any at all.

If some new eyes will look into this with me, I have a complete set of voltage measurements that I have made that may help.
I have not been able to isolate a bad component.

Just as an unrelated side note. I find that the test point on the PB 1314 Reg Board, pin 14 measures over 17vdc and should be 13.5vdc.
I welcome a comment on this issue also.
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Joined: Sat Apr 09, 2016 5:07 pm

Re: FT 101B CLARIFIER control 0/off alignment

Postby N5AEA » Wed Apr 13, 2016 5:04 am

The alignment problem has been cleared. It helped to just walk away from it for a while then go back to it.
The Clarifier control piggy back switch was not providing the required ground return for diode D13 when in the "off" position.
The switch contacts were bad. So now I have adjusted for 1.4 Vdc in the 0, Off and Zero MOX status.

The next issue was that the unregulated DC voltage was much to high (+17.5 Vdc).
Problem has been cleared. Someone had wired the transformer primary for 100 VAC. My AC line voltage is 122 volts.
I think this is a good way too fry a radio. Also I think it came from the factory wired that way.
I have changed the straps for 117 Vac line power. Now my unregulated supply is 14.0 volts as it should be.
I recommend everyone to check their radios for the proper straps.
I would like some feedback on this issue, how many find it strapped for 100 v and 117 v.
And also if anyone disagrees with the above comments.
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Joined: Sat Apr 09, 2016 5:07 pm

Re: FT 101B CLARIFIER control 0/off alignment

Postby n4qms » Sun Apr 17, 2016 7:00 pm

Sure sounds like you have a handle on it, Ed.

The 100-Volt setting could have been someone's "QRO" strategy to get a higher wattmeter reading, or maybe an honest error.

Good thing you found it before the smoke alerted you to it.

One accurate measurement is worth a thousand expert opinions"
-- Admiral Grace Hopper
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Joined: Thu Sep 25, 2008 4:53 pm
Location: Louisville, KY

Re: FT 101B CLARIFIER control 0/off alignment

Postby KF7GGN » Wed Mar 29, 2017 6:57 pm

Hi Ed,

I just stumbled on your post from last year, as I came across the same issue with the primary taps. My rig, a FT101ZD, was bought in Tokyo, Japan in 1979 by my father, and sat in its original box for 32 years. So when I got a hold of it, it was a brand new 32 year old rig! Anyway, it worked just fine until it was keyed up on a new hb antenna that was not tuned, and no tuner was used, so you can guess the rest. Anyway, the first thing I did was to check the voltages on the RECT B board, only to find them out of spec and too high, both the DC and AC voltages. It really bothered me that the AC voltages were too high, as these gave rise to the high DC voltages. I needed to solve that problem, but could not fathom how that was the case. I thought there was something incorrect about the transformer windings ratio. When I flipped the unit over to check the RECT A board, I noticed that the 100V tap was used for the hot lead. I realized that the turns ratio was too high for 120V, and doing the math I was able to account for the higher than spec voltages that I was measuring.

So by now you may know this, but the line voltage in Japan is 100V, which explains even having the 100V tap available. As the rig I have was bought directly from the Yaesu factory outlet, it was not set up for export, but probably intended at least by default for the Japanese market. At least it was not wired up for North America at the factory. Your rig may have had a similar history. My father may have been warned about that issue, at the outlet, but any warning was apparently long forgotten over time. Anyway, just letting you know about my experience, and that yes, there are other Yaesu xcvr rigs of the FT-101 vintage that are out there and have initially been wired in that manner. I would think by now most of those rigs were changed over to the 117V tap either before being put in service by the factory or by distributors, or somewhere along the line when the rigs had servicing done. Hope you're still enjoying your rig!

Best regards,
Scott KF7GGN
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Joined: Tue Mar 28, 2017 8:44 pm

Re: FT 101B CLARIFIER control 0/off alignment

Postby wa3yre » Sun Jul 23, 2017 6:56 pm

My FT-101B Was bought new in Japan in 1974, but it was strapped for 117V because my dad told the radio dealer that it was going to the USA.

Radios sold in Japan for domestic use were strapped for 100V. The standard line voltage in Japan is 100 VAC 60Hz.
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Joined: Sun Jul 23, 2017 4:14 am

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