The Yaesu FT-901DM & FT902DM

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                                      Yaesu FT-901DM Transceiver                                                  

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FT-901 Specifications    

Type:

Amateur HF transceiver

Frequency range:

10-160 m

Mode:

All-mode

RF Power output:

SSB/CW: 100 W
AM/FM: 80 W

Sensitivity:

N/A

Selectivity:

N/A

Image rejection:

N/A

Voltage:

13.8 VDC or mains

Current drain:

RX: Max ? A
TX: Max ? A

Impedance:

50 ohms

Dimensions (W*H*D):

342*154*324 mm

Weight:

18 Kg

Manufactured:

197x-19xx

Other:

 

Related documents:

 

 

  Click for larger view. Click for larger view. Click for larger view.Click for larger view.

 

Yaesu FT-902DM Transceiver with Gold display

  All band coverage 160~10 meters, Including WARC bands

 

Click for larger view.

FT-902 specifications 

Type:

Amateur HF transceiver

Frequency range:

10-160 m + WARC

Mode:

AM/FM/SSB/CW/FSK

RF Power output:

SSB/CW: 100 W
AM/FM/FSK: 80 W

Sensitivity:

0.25 uV (10 dB S/N)

Selectivity:

SSB: 2.4 KHz (-6 dB), 4 KHz (-60 dB)
CW/FSK: 0.6 KHz (-6 dB), 1.2 KHz
AM: 6 KHz (-6 dB), 12 KHz (-60 dB)

FM: 12 KHz (-6 dB), 24 KHz (-60 dB)

Image rejection:

15-160 m: better than 60 dB
10-12 m: better than 50 dB

Voltage:

13.8 VDC or mains

Current drain:

RX: 1.1 A with heater off, 5 A with heater on
TX: Max 21 A

Impedance:

50-75 ohms, SO-239

Dimensions (W*H*D):

342*154*324 mm

Weight:

18 Kg

Manufactured:

19xx-19xx

Other:

 

Related documents:

 

 

For a detailed summary of most of the information on this page

Down Load the complete Fox Tango FT-901 Survival Guide here

 

**Our sincere thanks to Wim Penders PA0PGA for his contribution to the club

 

 

 

 

FT-901/902 Internal boards & components

 

FT-901/902 Audio Unit PB1705    FT-901A-Rectifier Unit        FT-901 C-Rectifier PB-1717

 

FT-901 Noise Blanker PB-1994   FT-901 Filter Unit PB-1716  FT-901 IFUnitPB-1704

 

FT-901 RF Unit PB-1702              FT-901 PLL PB-1709            FT-901 Keyer PB1728A

 

FT-901_Xtal-Unit                         Tube socket PB-1715             FT-901 Diode board PB-1726 

 

Switch Assy PB-1718c                 LED Bank PBN-1721b          FT-901 VCO PB-1710

 

FT-901 Module cover                 FT-901 Panel meter                FT-901 VFO Unit

 

VOX-marker PB-1846                FT-901 Pre-selector               FT-901 Relays

 

Mains, Power Transformer        PA Plate & Load                    DC-DC converter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

What lurks beneath an Ebay purchase

An FT-901 night mare!

Just wanted to show you what I was doing

while trying to pump some life back into this FT-901

Click for larger view.

 

Bought this one off Ebay, it looks innocent enough.

 

Was told up front it wasn't working, so I didn't expect much in the way of performance.

 

It lived up to my expatiations!

Click for larger view. Click for larger view. Click for larger view. Click for larger view. Click for larger view. Click for larger view.

At first glance the rig doesn't look all that bad except for the obvious! Except where we can see it has bad capacitors on the rectifier "A" unit. The photos above came from the original Ebay auction. Deep down inside this rig was hiding a lot of sins yet to be revealed.  I can only imagine the seller knew something about  this or threw all his bad parts at the problematic rig! The rig has bad capacitors all over the place and a VFO that had been tampered with and wasn't working!

 

After replacing the capacitors on the Rect "A" unit, the rig started coming back to life, we had a red flashing digital display, no audio or signals of any kind were heard giving reason to believe possible PLL problems or more! The transceiver  ran for approximately 45 minutes while I was looking around inside and checking things out before it finally cut loose and bellowed smoke into the shack and revealed another hidden secret that was not visible in the photos above at the time of purchase.

 

The High Voltage Filter caps shot smoke and capacitor cheese all over the place! It's not exactly an easy job getting the filter caps out of this rig!

 

Click for larger view.Click for larger view.

The H.V. filter caps reside just forward of the power transformer, under the rig you need to pull just about everything clear as the capacitors and rectifier board are under PB-1726 diode switching board.  In the two pictures above (Original Auction Pictures) I didn't catch it, but a keen eye might notice from the top photo of the rig that something bleed out of the capacitors onto the chassis just forward of the blue wire on the transformer. 

Click for larger view.Click for larger view. Once the memory unit was removed and the crystal unit was removed, we were ready to go to work digging out our filter capacitors.  The counter unit, PLL unit and RF unit were all removed to get more access to the capacitors from the top.

Click for larger view.

Click for larger view.Click for larger view. PB-1712A the HV rectifier unit resides under the diode switching board and is directly attached to the bottom of the HV filter capacitors.

Click for larger view.

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Now the truth is told once the capacitors were removed, this was not the first time the filter caps have blown their tops!  All of this will have to be cleaned up before the new replacement  capacitors are installed.

 

Before I put any more time into this rig,

 I wanted to see if I could at least get it to receive something.

Click for larger view.

Having gotten lucky by chance I plugged in my spare FV-101Z VFO. This is the same VFO used with the FT-101ZD series and works fine with the FT-901/902. Ta'da we have signals.  We also have a dead VFO ~ Great !  The VFO unit pulls directly out from the front of the FT-901/902. Removing the VFO unit and the counter unit also made it easier when it came to replacing the H.V. filter capacitors.  Someone had already beaten me into the VFO first,  they knew it did not work! Otherwise why would someone have gone into it, the lights were missing from the VFO behind the blue dial and a couple of screws were missing off the VFO shield.  Repairs were made to the VFO unit and it was reinstalled.   The counter no longer runs randomly and we basically have a working receiver.

Click for larger view.Click for larger view. Luckily for me at this point the receiver is working, the display unit is working and counting properly. All of the high voltage AC wiring has been cut loose and secured for safety reasons. Thus the transceiver will actually function as a receiver alone at this point. Even after getting into this mess, I believe we have really had a great deal of success to get the rig up and running to this point.

Click for larger view.

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Along with the VFO lamps that were missing, the meter lamps were dead. Wanting to get a quick look at these, I was afraid I'd be dealing with more peanut bulbs as was the case with the meter lamps in the FR-101 / FL-101 Yaesu twins, that's a story in itself.  Yaesu made an improvement here some 10 years after the 101 series and installed two axial lead lamps in front of the meter, so there is no need to remove the meter movement to replace these lamps.

Lamp, Meter S8100017 Suitable sub - Try PN 620701
from Farnell.com $3.12 OBS-NLA 032704

LAMP, T3.8 AXIAL W/E 8V 0.6W; Lamp fitting type:  Axial wire ended, T3.8; Power rating:0.6W; Current rating:0.1A; Length / Height, external:20mm; Length, lead:15mm; Light output, total:1.9lm; Time, operating life:5000h; Vo

Click for larger view.

It may not look like much right now.

Now with a working VFO and repairs well underway, I was

able to hear signals on 75 meters weak! Good enough

 for now, it was time to go to bed!  Another 4AM night!

 

 

Exploding Rectifier "C" unit

PB-1717A

 

 

Click for a larger view.

PB-1717A resides in the very back of the transceiver

Click for a larger view. Click for a larger view. Click for a larger view.

One problem to watch out for in the FT-901 is the Rectifier "C" unit with the exploding capacitor syndrome!

The FT-901 series starting with production lot No. 8 had the following modifications, the changes  were made in order to provide against the loss of R1803  caused by unbalance in C1802 and C1803.  The failure of R1803 could cause the destruction of the filter capacitors as seen in the photos above.

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Attempting  to rebuild the blown apart circuit board, PB-1717A

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Members Emails regarding PB-1717A problem.

I've rebuilt several rectifier c boards over the years for myself and
friends. I've used both methods listed on page 3-17 of the service manual.
Both seemed to work just fine. The last few I used the second method, adding
the extra diode, exclusively and they have all held up under stress. Yaesu
still has the odd value caps for this board in stock as well. So, if the
caps blew, simply add the extra diode and replace the caps with originals.
Which are very inexpensive by the way. The last time I called they sent them
to me free because the postage was more than the caps! LOL! :)

Tom KB6SSN

 

 April 16, 2005   Subject: The FT-901
Replaced the diode and a resistor in the 190 volt side of the 'C' rectifier board.  I had to replace the resistor R-1809, 470 ohm, it had fried. Also the diode D-1802, the input, was open. I replaced it with a 1N5408, 1000 PIV at 3 amps Mouser part number 5121N5408.   Also did the mods to the board, replacing five resistors and adding a resistor and a diode in series with existing diodes. The mods were shown in the service manual,  Yaesu suggests in the mod section of the service manual on page 3-1.  I followed the mod and replaced the four 470K ohm resistors with 180K ohm resistors, replaced the R-1803 470 Ohm with a 390 ohm, and added the 39 ohm 1 watt resistor in series with diode D-1801. And last I checked the mod on the PB-1715A board located below the final tubes, to make sure mine had the diode added as per the mod on page 3-16 of the manual.  his may have kept the caps from disappearing in a cloud of smoke. I think that this is the most important mod to do.  I got the parts from Mouser Electronics. Phone is 1-800-346-6873. No minimum order and quick service. They had the 2 and 3 watt resistors and the  diode was a replacement for the 10D10. The number of the diodes I used was  1N5408, 1000 PIV at 3 amps Mouser part number 5121N5408.   By the way, the manual I used, I down loaded from Fox Tango site, and it sure made a difference. 

Larry, WB3EUS

 

 

FT-901 AND FT-902 MODEL DIFFERENCES

O = Built-in feature X = Available option - = Not Available*

FEATURE

FT-901D

FT-901SD

FT-901DE

FT-901DM

FT-902D

FT-902SD

FT-902DE

FT-902DM

BAND CRYSTAL 160m

O

O

O

O

O

O

O

O

BAND CRYSTAL 80m

O

O

O

O

O

O

O

O

BAND CRYSTAL 40m

O

O

O

O

O

O

O

O

BAND CRYSTAL 30m

-

-

-

-

O

O

O

O

BAND CRYSTAL 20m

O

O

O

O

O

O

O

O

BAND CRYSTAL 17m

-

-

-

-

O

O

O

O

BAND CRYSTAL 15m

O

O

O

O

O

O

O

O

BAND CRYSTAL 12m

-

-

-

-

O

O

O

O

BAND CRYSTAL 10mA

O

O

O

O

O

O

O

O

BAND CRYSTAL 10mB

O

O

O

O

O

O

O

O

BAND CRYSTAL 10mC

O

O

O

O

O

O

O

O

BAND CRYSTAL 10mD

O

O

O

O

O

O

O

O

VOX/MARKER UNIT

O

O

O

O

O

O

O

O

FM UNIT

O

X

X

O

O

X

X

O

RF SPEECH PROCESSOR

O

O

O

O

O

O

O

O

AM FILTER

X

X

X

X

X

X

X

X

CW FILTER

X

X

X

X

X

X

X

X

FM FILTER

-

-

-

-

X

X

X

X

KEYER UNIT

X

X

O

O

X

X

O

O

MEMORY UNIT

X

X

X

O

X

X

X

O

DC-DC CONVERTER

X

X

X

O

X

X

X

O

COOLING FAN

X

X

O

O

X

X

O

O

POWER OUTPUT

100 W

10 W

100 W

100 W

100 W

10 W

100 W

100 W

Source: Yaesu FT-901DM and FT-902DM Instruction Manual, page 3.

* Except in very late production FT-901DM units.

 

 

 

FT-901 / FT-902 (Update June 1, 2007)

24 Mhz to 28 Mhz Conversion

(FT-901DM  12 Meter conversion,  11 Meter removal)

It was not totally unexpected that an occasional error might be found in some of the documentation on our web site, we strive to bring to you the most current and accurate information available for every Yaesu product.  However some times errors do show up from time to time, so we often depend on those who are actively working on a specific piece of equipment to help find those errors on the web pages and we depend on you the user to help us by forwarding those corrections on to us.   That having been said we have found some minor errors in the 11m / 12m conversion, but not so much that it warrants removing this information.  The intention of providing you this information was for the REMOVAL of the 11 meter modifications which so often can botch up a perfectly good working amateur band transceiver.  On occasion however we do find some folks around the world wishing to put the 11m band into their equipment. While we do not condone this our goal is to be a source of information and to help those of you who own these wonderful old amateur transceivers.  One such correction that should be noted in the downloadable PDF file below is the 11m band Xtals; they should be 41.9875, 41.4875, 40.9875, 40.4875 MHz.   Fox Tango member Jean Pierre ON4AEF has been actively working on his FT-902 in recent weeks and has kindly sent us the follow file for the master oscillator crystals  required for each new WARC band.  Thank you for your time on this Jean.  The green portion of the chart represents the eleven meter band and is NOT LEGAL for use in the United States, however this information is being provided to you should you have those crystals in your FT-901 / FT-902 crystal unit you will not be totally surprised by what they are. Simply reorder new crystals for 10A/B/C/D bands and you rig should be once again original with a slight retuning of the master oscillator coil for those particular bands.   Keep in mind too, simply changing the master oscillator crystal will not show the correct display frequency, as the display may require further modification to reflect any new band installations.

Note the following chart:

BAND CRYSTAL FREQ MID - FREQUENCY VFO HAM FREQ BAND FREQ DISPLAY LOCAL VCO
M MHZ IF(Mhz) RANGE 5,0 - 5,5 Mhz RANGE(Mhz) READOUT(Mhz) RANGE(Mhz)
10A 42.4875 8.9875 5.000 5.500 28.000 28.500 28.000 28.500 36.9875 37.4875
10B 42.9875 8.9875 5.000 5.500 28.500 29.000 28.500 29.000 37.4875 37.9875
10C 43.4875 8.9875 5.000 5.500 29.000 29.500 29.000 29.500 37.9875 38.4875
10D 43.9875 8.9875 5.000 5.500 29.500 30.000 29.500 30.000 38.4875 38.9875
11A 40.4875 8.9875 5.000 5.500 26.000 26.500 26.000 26.500 34.9875 35.4875
11B 40.9875 8.9875 5.000 5.500 26.500 27.000 26.500 27.000 35.4875 35.9875
11C 41.4875 8.9875 5.000 5.500 27.000 27.500 27.000 27.500 35.9875 36.4875
11D 41.9875 8.9875 5.000 5.500 27.500 28.000 27.500 28.000 36.4875 36.9875
12M 38.4875 8.9875 5.000 5.500 24.895 24.950 24.000 24.500 33.8825 33.9375
15M 35.4875 8.9875 5.000 5.500 21.000 21.500 21.000 21.500 29.9875 30.4875
17M 32.4875 8.9875 5.000 5.500 18.065 18.165 18.000 18.500 27.0525 27.1525
20M 28.4875 8.9875 5.000 5.500 14.000 14.500 14.000 14.500 22.9875 23.4875
30M 24.4875 8.9875 5.000 5.500 10.100 10.130 10.000 10.500 19.0875 19.1175
40M 21.4875 8.9875 5.000 5.500 7.000 7.100 7.000 7.500 15.9875 16.0875
80M 17.9875 8.9875 5.000 5.500 3.500 4.000 3.500 4.000 12.4875 12.9875
160M 15.9875 8.9875 5.000 5.500 1.500 2.000 1.500 2.000 10.4875 10.9875

Everything has been calculated by the next formula as:

 Frequency of Operation (display) = Crystal frequency-(IF frequency +VFO frequency)

 
The VFO frequency is a variable between 5.0 MHz and 5.5 MHz (MANUAL DIAL)
The IF frequency is a C(is always 8.9875 MHz)

 Crystal frequency depends on crystals installed in the FT901 / FT-902DM transceiver.

 

 Downloadable PDF file for 11m /12m conversion

 

 

 

 

FT-901/FT-902 Accessories

 Cooling Fan and DC-DC Converter

The optional cooling fan can easily be installed on the FT-901.

If you use another fan than the original Yaesu fan, see to it that the voltage is 110 Volt ac.

         DC Converter

DC-DC Converter

The DC-Dc converter allows the mobile use of the FT-901, on a 13.8 Vdc source. The unit is installed on the back of the transceiver and uses the internal transformer to obtain the proper voltages. The power connection is made by a special DC cord, delivered together with the DC-DC converter.

 

 

FV-101Z external VFO

Click for a larger view.

FV-101DM external VFO

The FV-101Z external VFO is a compact remote VFO for the FT-101ZD. The VFO has a analog frequency display. If you use it with a FT-101ZD, the frequency is displayed on the digital display from the FT-101ZD. The VFO has a precision tuning mechanism with a silky-smooth operation. Clarifier for transmit, receive or transceive frequency is included. The VFO shift range is +/- 8khz. Up to 6 crystal-controlled channels may be installed. The necessary crystals have to be in the 5 - 5.5 Mhz range.

The FV-101DM external VFO has twelve memories, up/down scanning, keyboard frequency entry and receiver offset tuning in 10hz steps. This provides smooth and precise tuning for SSB and CW. Either the keyboard, main tuning knob or up/down scanning buttons can be used for quick (QSY) changing of frequency to your preferred operation frequency. Up to four of you most used memory channels can be protected from overwriting, when you store frequencies. The two-loop PLL circuit is designed to produce a crisp, clean output signal for a spurious-free receiver and transmitter. This VFO can only be used with the FT-101ZD MK3, serial numbers above 240001

 

FL2100Z Linear Amplifier

The FL-2100 is special designed for the FT-101ZD transceiver. It uses two rugged 572B/T160 transmitting triodes in a class AB2 grounded grid configuration. Power input is 1200 watts PEP on SSB and 1KW on CW, on all bands, including the W.A.R.C. bands 10, 18 and 24 Mhz. The linear has 2 fans for cooling the final tubes, and special protection circuits for the output tubes and the tank circuit. During standby is the antenna switched to the transceiver and the built-in SWR meter allows monitoring of the feed line during either amplifier or exciter-only operation. The heavy-duty power supply requires no warm-up time and has excellent regulation.

 

Click for a larger view.

FT-101ZD & FT-901DM accessories

Left to Right

The FT-101ZD can use accessories of the FT-901DM, but there are some restrictions at their use.

 

FV-901DM external VFO:

This is a external VFO that provide a synthesized control system for your FT-101ZD. It has a 3-speed scanner, which will take you instantly everywhere in the band, and the auto-scan feature sweeps the band until it finds a signal. The synthesizer has a separate of 100 hz and is coupled to a 40-memory bank for storing the frequency. Fine tune is done with the TX/RX clarifier. Because there is no frequency display on the FV-901DM, use of this VFO in combination with the analog FT-101Z is not possible, as the operating frequency cannot determined.

 

FTV-901R transverter:

The FTV-901R is a 3-band VHF/UHF transverter, all in one compact case. The basic FTV-901R comes equipped for 144 – 148 Mhz. 6 meter and 70 centimeter modules may be added. The satellite 1-3 bands provide operation on OSCAR modes A/B/J on full duplex, when a external receiver is used. Repeater split is provided on 6 and 2 meters.

 

YO-901 Multiscope:

The YO-901 Multiscope provides superb monitoring capability, with a instant interface to the FT-101ZD and can be used to monitor the output signal with trapezoidal and two-tone tests, general oscilloscope measurements are also possible. A panoramic adapter is a available option for a quick band activity examination. IF rx and tx monitoring is not possible with the FT-101ZD combination.

 

SP-901P speaker/hybrid phone patch:

The SP-901P features a shaped-response loudspeaker and a hybrid phone patch, allowing efficient operation during patches. Styling and size match the FT-101ZD and FT-901DM series.

 

FC-901 Antenna coupler:

The FC-901 antenna coupler presents a 50 ohm load to your FT-101ZD transceiver, all across the band. 3 coax-fed and one random-wire antenna may be accommodate (SWR) standing wave radio meter and power metering to allow for quick determination of proper matching conditions.

 

YR-901 Morse / RTTY Keyver converter unit:

 

 

 

Photo Courtesy of Kay DL5OAQ

 

 YR-901 MORSE CODE / RTTY TELETYPE READER

 
The YR 901 is a high performance computerized translator which will allow display on a video monitor of incoming Morse Code and teletype (RTTY) signals. The YR-901 and YVM-1 Video Monitor are options a.
 

I get this question at least once every six months her at the  Fox Tango club, so I'm posting this Email we received from N9ZF with may thanks to him forfinding this for the club!
Best 73 Carol W4CLM
_____________

Keyboard for YR901 RTTY keyer converter unit, what one to use?
_____________

I now remember. The Wyse ASCII Keyboard is what this unit works with.
I found one advertised on Amazon:
http://www.amazon.com/Wyse-Technology-Keyboard-Type-Ascii/dp/B00006BA61

Good luck. I have also seen theses on occasion up on EBay.
Cheers, N9ZF

_____________

Another thought from WD4CQ Ken Sanders of Stanley North Carolina.

"That is right, the Wyse Terminal.....wow those may be hard to find anymore.
 
A PC running terminal emulator will work." Ken Sanders / WD4CQ

Wyse Technology Keyboard Type A - Ascii

 

 


 

 

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Fox Tango Members contributions. (c) Fox Tango International

 Http://www.foxtnago.org

 

W4CLM