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Author Topic: Yaesu FTdx-3000 RX Drop  (Read 199 times)

VE7GMX

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Yaesu FTdx-3000 RX Drop
« on: January 27, 2023, 10:18:41 AM »

I own a Yaesu FTdx-3000 which has of late been having an issue with the receive dropping down about 10-20% after unkeying from a transmission ( on SSB ) . It lasts until I tap the PTT on the mic and you can hear the static come up again , every time .  Its doing this when the radio gets warmer during operation .  Its nothing to do with any AGC settings as someone else mentioned .  Any ideas ?

Thanks

Jeff
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K6AER

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Re: Yaesu FTdx-3000 RX Drop
« Reply #1 on: January 27, 2023, 11:35:14 AM »

Check the T/R switching circuit. sounds like a bad solder connection.
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VE7GMX

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Re: Yaesu FTdx-3000 RX Drop
« Reply #2 on: January 27, 2023, 12:55:45 PM »

If I knew where that was I would  ;D

Check the T/R switching circuit. sounds like a bad solder connection.
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AJ8MH

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Re: Yaesu FTdx-3000 RX Drop
« Reply #3 on: January 27, 2023, 01:33:33 PM »

First, make sure the problem is in the rig.  I've seen poor connectors, coax and antenna traps cause this type of problem.  You should know what your doing before attempting any radio troubleshooting.

Just to give you an idea, there are a number of relays in the radio.  The following relays are before the transmit/receive (T/R) relay, RL5504 (Ant 1), RL5503 (Ant 2) and RL5502 (Ant 3).  Next is RL5511 (T/R relay).  Move your coax to antenna 2, switch to antenna 2 and see if the problem continues.

For receive, you can even bypass RL5511 (T/R relay), RL5501 (Protection Relay), and both RL1001/RL1002 (Attenuation Relays) by connecting a second antenna for receive only to the micro-tune port (From Micro-Tune J1003-1) and turning it on (Press AND hold MHZ/uT button by the CLAR/VFO B knob). You'll need a PL259 to phono-plug adapter. See page 29 of the manual TO MAKE SURE you plug into the correct plug.  Do NOT plug the receive antenna into the 13.8 VDC or PTT plugs that are right below the micro-tune plugs.

After the micro-tune relay, there is RL1004 (amateur band-general band) and some band-pass filters.

Before attempting a fix, get a service manual. Don't work on this radio unless you have some experience.
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VE7GMX

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Re: Yaesu FTdx-3000 RX Drop
« Reply #4 on: January 27, 2023, 05:26:33 PM »

Appreciate all the information Joe , thanks .

I have 3 different antenna systems and have switched and moved around all of them to different ANT ports , all the same issue .  I do have the service manual for reference .  I have a new SW-A board I'm going to put in next week to fix a long running issue of the FAST tuning turning on and off every time the PTT is pushed , a well know 'glitch' in this radio . Who knows , maybe that bad board is also responsible for the RX issue ??
I'll look at everything you posted here when I get the thing all apart next week .

73

Jeff



First, make sure the problem is in the rig.  I've seen poor connectors, coax and antenna traps cause this type of problem.  You should know what your doing before attempting any radio troubleshooting.

Just to give you an idea, there are a number of relays in the radio.  The following relays are before the transmit/receive (T/R) relay, RL5504 (Ant 1), RL5503 (Ant 2) and RL5502 (Ant 3).  Next is RL5511 (T/R relay).  Move your coax to antenna 2, switch to antenna 2 and see if the problem continues.

For receive, you can even bypass RL5511 (T/R relay), RL5501 (Protection Relay), and both RL1001/RL1002 (Attenuation Relays) by connecting a second antenna for receive only to the micro-tune port (From Micro-Tune J1003-1) and turning it on (Press AND hold MHZ/uT button by the CLAR/VFO B knob). You'll need a PL259 to phono-plug adapter. See page 29 of the manual TO MAKE SURE you plug into the correct plug.  Do NOT plug the receive antenna into the 13.8 VDC or PTT plugs that are right below the micro-tune plugs.

After the micro-tune relay, there is RL1004 (amateur band-general band) and some band-pass filters.

Before attempting a fix, get a service manual. Don't work on this radio unless you have some experience.
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ZS5WC

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Re: Yaesu FTdx-3000 RX Drop
« Reply #5 on: March 03, 2023, 12:09:24 AM »

 :)If you are wired through a linear (even if linear is off) , could be Transmit / Recieve relay in linear with dirty contact.
( The brief RF burst from keying wets the contact for a short time.)
Also could be internal relay contact within the rig.
Make sure if you have aux. cables connected to back of rig you are not getting some voltage back feed.
(Disconnect and test)
73 de William
ZS4L / ZS5WC
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VE7GMX

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Re: Yaesu FTdx-3000 RX Drop
« Reply #6 on: March 03, 2023, 05:31:42 AM »

I have a couple different amps and did the same on both . I did fix the issue , I bought a new 101D   ;D


:)If you are wired through a linear (even if linear is off) , could be Transmit / Recieve relay in linear with dirty contact.
( The brief RF burst from keying wets the contact for a short time.)
Also could be internal relay contact within the rig.
Make sure if you have aux. cables connected to back of rig you are not getting some voltage back feed.
(Disconnect and test)
73 de William
ZS4L / ZS5WC
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