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Yaesu FT-101EE Speech Processor Removal

R

Ranch55

Sr. Member
Jan 18, 2016
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Fredericksburg, Texas
I hope someone reads this post that can help me out.
I need to remove the speech processor board, PB1534, from a Yaesu FT-101EE.
The board has some issues that I am not going to chase and just want to remove it completely. It is a simple procedure to remove it, BUT .......
After the harness wires are disconnected from the board, I do know that some of the harness wires need to be soldered together and the the ends covered with shrink tubing.
Problem is that I have not found any instructions anywhere to tell me which wires to connect and solder. The schematic is no help. It does not show the state of the wiring before a processor board is installed.
If anyone has a FT-101EE and would be willing and kind enough to to remove the top cover, remove the black tubing from the wire harness bundles, and take a couple of detailed photos and description of which pairs or wires to mate together, I would be very grateful.
I don't want to get into a discussion about chasing down the board problems, or repairing it.
I just need to remove it altogether from the radio.
Thanks for any help anyone can provide.
 

Why not just leave it in there and leave switch in the off position? If you must remove it go to fox tango and download the service manual. Look at the install for the processor. On the underside you will see where you remove the jumped out shielded audio cable. You can just reverse this or just snip them at the processor itself and connect them together.
 
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KneeBiter said:
Why not just leave it in there and leave switch in the off position? If you must remove it go to fox tango and download the service manual. Look at the install for the processor. On the underside you will see where you remove the jumped out shielded audio cable. You can just reverse this or just snip them at the processor itself and connect them together.
Click to expand...

I have the full service manual. What you are describing, I am aware of.
But when the speech processor has not been installed, some of the wires are connected together, soldered, then the ends are covered with tubing for insulating purposes.
This is what I need to do.
I need to completely remove the board because it is causing issues whether it is turned on or off.
I know about the jumper wire on the undercarriage.
 
The speech processor only works in the two sideband modes. It's a true RF processor, meaning that the 3.18 MHz output from the radio's balanced modulator feeds into it, and then back out. Your sideband transmit signal passes through this board both when the processing is switched off, and when it's selected.

There are three shielded wires attached to this board. One of them leads to the VFO/Fix switch. Ignore that wire.

Unsolder the the other two shielded wires. Solder the center wire from the one to the other. Solder the shields together.

Voila! You have now fully bypassed the speech processor. Once you are sure that this makes the radio work, you may remove all the other wires on the PB1534 Fix/RF processor board.

Unless you're using a fixed-channel crystal in this radio in place of the VFO.

73
 
KneeBiter said:
Can you describe the issues you are having?
Click to expand...

Since installing the speech processor, it has knocked the power output down to about half of what it was.
When the Processor switch is turned on, the Level control has to be turned fully clockwise to get any power out. If the Level control is reduced CCW slightly, the power output drops to less than 10 watts.
Even with the processor turned off, the output power is reduced substantially from what it was before.
This processor came out of a FT-101E that was experiencing the exact same conditions.
 
nomadradio said:
The speech processor only works in the two sideband modes. It's a true RF processor, meaning that the 3.18 MHz output from the radio's balanced modulator feeds into it, and then back out. Your sideband transmit signal passes through this board both when the processing is switched off, and when it's selected.

There are three shielded wires attached to this board. One of them leads to the VFO/Fix switch. Ignore that wire.

Unsolder the the other two shielded wires. Solder the center wire from the one to the other. Solder the shields together.

Voila! You have now fully bypassed the speech processor. Once you are sure that this makes the radio work, you may remove all the other wires on the PB1534 Fix/RF processor board.

Unless you're using a fixed-channel crystal in this radio in place of the VFO.

73
Click to expand...

Yes, thank you nomadradio . I had already given that a thought.
But there were a couple of pairs of wires that were originally connected and soldered, then covered with tubing for protection. So as to complete a circuit for operation without the processor. I just do not remember which ones.
 
Well I got it. It seems that it was almost a secret.
It took me some heavy duty schematic studying and looking real hard.
The answer was not in plain sight, as the schematic does not show everything.
But I did get it.
The radio will not perform 100% without these two pair of wires, but it would work.
Now everything is back as it should be and the bad processor board has joined the spare parts pile.
 
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Alrighty, be glad to. Maybe it'll help someone else ......

The "unused" white wire (not used when a processor is installed) is connected to PIN 14 on the MJ (3) board connects to the RED 13.5V wire to the processor. (solder together and cover the ends with tubing)
The White/Yellow wire and the White/Grey wire, connect to each other. (solder and cover again)
The rest is just reversing the install process that is in the manual.

Connecting the 13.5V red wire to the "unused" white wire, connects the ALC meter to the ALC VR2 adjusting pot. Without doing this, the radio will still perform, but the ALC meter will not work.

The White/Yellow wire is the ALC. Connecting it to the White/Grey wire, connects it to "E" ground.

It took me a LOT of studying the schematic to figure all this out, as the solid white wire is not shown on the FT-101E schematic. On the schematic, MJ-3 PIN 14 shows to be blank, nothing connected to it. But it shows PIN 14 going to the output of the ALC VR2 adjusting pot.
 
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