Yaesu FT-902DM

Please have patience, this is my first time with a boat anchor radio.

I have a Yaesu FT-902DM.
Following the Instruction manual for Pre-tuning - Page 14
Everything seems to go as expected until I get to, Pre-Tuning
on Item 1 - Adjusting the Preselect control, does not seem to have any effect on receiver noise.
on Item 2 - Rotating the CARR control does not have any effect on the meter reading.

Can anyone point as to what the problem might be?

 

To add some clarification,
Item 1 reads - Adjust the PRESELECT control for maximum receiver noise level.
Item 2 reads - Depress the TUNE button. Rotate the CARR control until the meter reading rises just above the normal idling current of .05 (50ma)

 

To add some clarification,
Item 1 reads - Adjust the PRESELECT control for maximum receiver noise level.
Item 2 reads - Depress the TUNE button. Rotate the CARR control until the meter reading rises just above the normal idling current of .05 (50ma)

 

If you turn the Calibrator (Marker) On, can you hear its signal in the receiver on any band?

 

Before any of this is done, make sure you antenna is hooked up, and if a tuner is used, get it as close as you can by ear or with another rig.

First, make sure you have followed all the steps and settings as outlined in the left hand column on p.14.
Next , make sure the resting cathode current is correct. (50mA)
Then make sure all controls you changed to set the resting cathode current back to where they should be.
Then follow the pre-tune steps.

My guess is one of the controls is set way off to begin with.


Matt

 

Left hand column P14 , Check mark
Cathode resting current 50MA
No turner is being used, antenna is hooked up, antenna is resonant on frequency. ( I did change antennas and try different bands just in case it was band specific)
The ALC wont adjust to full scale deflection (which is all the way to the right side of the meter correct?)
when I press the tune button, the CARR control has no effect on IC it stays right at 50MA

What should I hear when the mark switch is activated?

thanks for the help.

 

You're not being very clear . . .

Can you hear stations on the Receiver OK?

If so, are you saying you can't peak the signals (or noise) on the Preselector?

Is this on ANY band, or just one?

If NOT, then you need to find the fault in the reciver, before you start worrying about the Transmitter fault. (some of the circuits are common to both)

The Mark switch turns on a Crystal Calibrator - an Oscillator to check the frequency dial - you should hear a strong signal every 100kHz.

To be honest, it sounds like you could do with someone to show you how to operate a rig like that. (it's pretty hard just reading the Manual - they presume anyone reading would have some experience of how to tune a rig with a Valve PA - you might do some damage)

Roger G3YRO

 

IF you can hear anything try this .....

-Look closely at the preselect and plate knobs. You'll notice that at the band markings, the bands actually overlap. Set these knobs in the center of the range for the band in question.
-Set the loading at 5
(At this point, you should be able to tune around and hear stations. You should also hear the receive volume change)
-Now start the pre-tune
You might also want to take a few minutes to make sure all antenna and feedline connections are OK.

Most problems with these type of radios are simply lack of experience and understanding how they work.
I have worked with several OPs helping them learn the tuning process.

I have even had them send/post pics of their rig so I could see what they were doing. lol

BTW- What band are you on?

Matt

 

Yes receiver seems to work fine, I have listened to nets and qsos on several different bands.
I have attempted this process with 10m,20m ,75m
CARR control still does not effect the IC (with tune active)

mark does produce tone (that was loud), should it be directly at example 28300 and again at 28400 or can it be off from the zero say 28386?

 

Are the tube heaters lit?

There's a plug which goes in the 11-pin Accessory socket on the back of the rig. It has a jumper between pins 1 and 2, and this jumper allows filament voltage to get to the tubes.

Make sure this is in place. If it is, can you get any idling current indication on the meter when the rig is switched to Transmit? If not, remove the top cover and visually inspect the driver and PA tubes for heater operation.

This is a common gotcha with Yaesu rigs of the era.