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FT-101B Will not go into transmit with the mic or MOX switch

 

Hello all, I recently wanted to try my hand in getting an old rig. I bought an FT-101B on ebay, untested of course.? It does receive pretty good on the bands but it will not transmit.? The mic I have was tested on another Ft-101 and it works.? I've taken it apart, pulled out all the boards, cleaned it as much as possible. I didn't see any burnt components.? I took the relay out of the high voltage box where the tubes are and cleaned the contacts.? I touched it with 12v and it engages.? I checked the light bulb in the back and it reads good on an ohmmeter. The tubes look good.? I cleaned the MOX adjust knob.? My question is which board or part should I look at first.? I'm kind of at a loss where to start.? Thanks in advance all.?
 

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You might also want to post your query on the Facebook group dedicated to the FT-101:



They have over 1800 members and plenty of experience to draw on.? They helped me get my 101EX back up and running.

Good luck,

Richard kn7sfz



On 7/31/2023 6:36 PM, panzermkv@... wrote:

Hello all, I recently wanted to try my hand in getting an old rig. I bought an FT-101B on ebay, untested of course.? It does receive pretty good on the bands but it will not transmit.? The mic I have was tested on another Ft-101 and it works.? I've taken it apart, pulled out all the boards, cleaned it as much as possible. I didn't see any burnt components.? I took the relay out of the high voltage box where the tubes are and cleaned the contacts.? I touched it with 12v and it engages.? I checked the light bulb in the back and it reads good on an ohmmeter. The tubes look good.? I cleaned the MOX adjust knob.? My question is which board or part should I look at first.? I'm kind of at a loss where to start.? Thanks in advance all.?

 

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Also check the other relay in the audio section (not just the antenna relay)

Make sure pins 1&2 on the accessory jack are shorted.That allows heater current to flow.



Mike


-------- Original message --------
From: panzermkv@...
Date: 7/31/23 6:55 PM (GMT-07:00)
Subject: [Yaesu-FT-101] FT-101B Will not go into transmit with the mic or MOX switch

Hello all, I recently wanted to try my hand in getting an old rig. I bought an FT-101B on ebay, untested of course.? It does receive pretty good on the bands but it will not transmit.? The mic I have was tested on another Ft-101 and it works.? I've taken it apart, pulled out all the boards, cleaned it as much as possible. I didn't see any burnt components.? I took the relay out of the high voltage box where the tubes are and cleaned the contacts.? I touched it with 12v and it engages.? I checked the light bulb in the back and it reads good on an ohmmeter. The tubes look good.? I cleaned the MOX adjust knob.? My question is which board or part should I look at first.? I'm kind of at a loss where to start.? Thanks in advance all.?

 

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Hello,

?

Not sure who you are. No name or call sign at end of your message.

?

Download a schematic and start tracing from pin 3 of the microphone connector past the MOX switch. (Does the radio TX when the PTT/MOX/VOX switch is placed in MOX? MOX… manually Operated Relay.) Path then goes thru RL-1 coil and on.

?

You do not mention you have a schematic. The “light bulb” acts as an RX fuse in case of too much RF injected into the receiver.

Make sure it is the correct type bulb,it has nothing to do with TX.

?

Regards,

Tony F.

VA7TF? VE7ACF

?

?

From: panzermkv@...
Sent: July 31, 2023 6:55 PM
To: [email protected]
Subject: [Yaesu-FT-101] FT-101B Will not go into transmit with the mic or MOX switch

?

Hello all, I recently wanted to try my hand in getting an old rig. I bought an FT-101B on ebay, untested of course.? It does receive pretty good on the bands but it will not transmit.? The mic I have was tested on another Ft-101 and it works.? I've taken it apart, pulled out all the boards, cleaned it as much as possible. I didn't see any burnt components.? I took the relay out of the high voltage box where the tubes are and cleaned the contacts.? I touched it with 12v and it engages.? I checked the light bulb in the back and it reads good on an ohmmeter. The tubes look good.? I cleaned the MOX adjust knob.? My question is which board or part should I look at first.? I'm kind of at a loss where to start.? Thanks in advance all.?

?

AE8B17F8B5E445B28420AE006916D943.png

 

Sorry about that I put my call sign in my profile and thought it would be visible on my posts.? KN6WNE Keith.? I do have schematics, I'll check what you've written.? It won't go into transmit with the MOX switch engage either.? I replaced C13 like Buddy says to do in his youtube videos.? His channel is called the radio guy.? I'll pull up the schematic and start tracing.? The Mic was tested on another 101 and it worked.? Thank you very much Tony

Regards,?

Keith B
KN6WNE
 

Thanks Mike, I checked pins 1&2 and they are shorted.? I did pull out the other relay and it looked good, i didn't pull it apart.? When i key up or put it into MOX mode it sounds like it's still in Rx mode, I can hear the noise still.? I don't hear either of the relays clicking or engaging.??

KN6WNE

Keith.?
 

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Keith,

I would make sure the contacts on both relays are not corroded and making good connection. I assume you know how to do that?

Does the 'VFO' red LED stay lit when you key?



Mike


-------- Original message --------
From: panzermkv@...
Date: 7/31/23 7:52 PM (GMT-07:00)
Subject: Re: [Yaesu-FT-101] FT-101B Will not go into transmit with the mic or MOX switch

Thanks Mike, I checked pins 1&2 and they are shorted.? I did pull out the other relay and it looked good, i didn't pull it apart.? When i key up or put it into MOX mode it sounds like it's still in Rx mode, I can hear the noise still.? I don't hear either of the relays clicking or engaging.??

KN6WNE

Keith.?

 

I bet its the switch, try using the other side of the switch that is not used, boom... works

KC6RHE

Don

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