Yaesu FT-901DM & FT-902DM

Just wanted to show you what I was doing while trying to pump some life back into this FT-901.

Bought off eBay — sold as not working, which was accurate. At first glance bad capacitors on rectifier "A" were visible; deeper inside hid blown HV filter caps, a tampered dead VFO, and more.

After replacing Rect "A" caps the rig briefly showed life, then bellowed smoke when the HV filter capacitors failed — not the first time those caps had blown their tops.

Getting the receiver working

A spare FV-101Z VFO (FT-101ZD series, compatible with FT-901/902) proved the receiver could hear signals. The internal VFO had been tampered with; after repair and counter unit work, a working receiver emerged even with HV AC wiring secured for safety.

Meter lamp substitute: S8100017 / PN 620701 (8 V 0.6 W axial, T3.8). VFO lamps were also missing behind the blue dial.

PB-1717A sits at the very back of the transceiver. Watch for the rectifier "C" unit exploding-capacitor syndrome. From production lot 8, Yaesu modified the board to prevent R1803 failure from unbalanced C1802/C1803, which could destroy filter capacitors.

Tom KB6SSN

I’ve rebuilt several rectifier C boards using both methods on page 3-17 of the service manual. The second method (extra diode) has held up under stress. Yaesu still had the odd-value caps in stock — inexpensive, sometimes sent free.

Larry WB3EUS (April 2005)

Replaced diode and R-1809 on the 190 V side; added the factory mod resistors and diode per service manual page 3-1. Verified PB-1715A mod below the finals. Parts from Mouser (1N5408 for D-1802). Manual downloaded from Fox Tango made the difference.

Models include FT-901D, FT-901SD, FT-901DE, FT-901DM, and matching FT-902 variants. Legend: O = built-in, X = option, − = not available (* except very late FT-901DM production).

The full feature comparison table (160 m crystal, FM, digital display, memory channels, etc.) spans eight model columns and is preserved in the original manual and the Survival Guide PDF.

• FT-901D / FT-902D — base digital-display models
• SD suffix — speaker/stand configuration variants
• DE suffix — European market versions
• DM suffix — full-featured models with memory and expanded options

Information provided primarily for removing illegal 11 m modifications that botch otherwise good transceivers. Corrections noted: 11 m band crystals should be 41.9875, 41.4875, 40.9875, and 40.4875 MHz (not as previously listed). Chart contributions from Jean Pierre ON4AEF.

Note Eleven-meter operation is not legal in the United States. Reorder correct 10A/B/C/D crystals and retune the master oscillator coil; changing crystals alone may not update the frequency display without further counter modification.

Frequency formula: Display frequency = Crystal frequency − (IF frequency + VFO frequency). IF is 8.9875 MHz; VFO ranges 5.0–5.5 MHz on the manual dial.

Optional cooling fan installs easily on the FT-901; use 110 VAC if substituting a non-Yaesu fan. The DC-DC converter mounts on the rear for 13.8 V mobile operation.

• FV-101Z — analog remote VFO for FT-101ZD; works with FT-901/902 for split operation
• FV-101DM — synthesized VFO with memories (FT-101ZD MK3, serial >240001)
• FL-2100Z — 572B linear for FT-101ZD/901 series, WARC capable
• FV-901DM — synthesized VFO with 40-memory bank (digital FT-101ZD/901 only)
• FTV-901R — VHF/UHF transverter (144 MHz base, 6 m and 70 cm modules)
• YO-901 — multiscope monitor; SP-901P speaker/phone patch; FC-901 antenna coupler

The FT-101ZD shares many FT-901DM accessories with noted restrictions (FV-901DM requires digital frequency readout).

The YR-901 displays incoming Morse and RTTY on a video monitor (with YVM-1 monitor option). Keyboard question answered by N9ZF: the unit works with a Wyse ASCII keyboard (also seen on eBay). Ken Sanders WD4CQ notes a PC running a terminal emulator can work too.

Carol L. Maher W4CLM — Rev. 2016 update. Web page by Fox Tango International and member contributions.