Yaesu FT-101E — Parts Substitution & Sourcing Reference
Common failure points, modern equivalents and procurement notes for the FT-101E hybrid transceiver (12BY7A driver + 2×6JS6C finals; otherwise solid-state, dual conversion: 5 MHz 1st IF, 9 MHz VFO, 3.18 MHz 2nd IF).
- 20Tracked Parts
- 7Critical / Safety Items
- 14Part Categories
- 12Procurement Sources
Parts Substitution Table
Designators follow the FT-101E service manual where verified; check your sub-model board variant before ordering board-specific parts.
| Category | Designator | Original & Specs | Severity | Modern Replacement | Alternative Mods | Sourcing | Typical Price | References |
|---|---|---|---|---|---|---|---|---|
Tube |
V1, V2 |
6JS6C (Toshiba “Green Band” / NEC)Beam-power sweep tube (12-pin compactron), ~30 W plate dissipation, 6.3 V heater. Two run in parallel (grounded-cathode) into the pi-network — not a push-pull or “common-base” pair. |
Critical |
Matched-pair NOS 6JS6C (GE, RCA, Sylvania)Long out of production (sweep-tube manufacturing wound down through the 1980s as TVs went solid-state). U.S.-brand subs require the C125 neutralization mod (see below) and re-neutralization per manual. |
Full conversion to 6146B/6146W or 6883B (12.6 V-heater 6146 variant) — well-documented; ~70–100 W out. Requires heater rewiring, screen-feed/zener changes and the R30 47k→470k screen-protection swap. |
Hard |
$120–$220 / matched pair NOS |
|
Tube |
V3 |
12BY7AVideo pentode used as RF pre-driver. 12.6 V / 0.3 A heater (series), ~6.5 W plate dissipation. |
Common |
12BY7A NOS (GE, RCA, Sylvania, Toshiba)Direct drop-in, no neutralization concerns. A soft 12BY7A is frequently misdiagnosed as weak PA tubes — test it first. |
None recommended. (12GN7A etc. differ in pinout/characteristics — not a drop-in for this socket.) |
Easy |
$15–$35 NOS |
|
Electrolytic Cap |
HV doubler pair |
2 × 100µF / 500V (axial)Filter for the PA voltage-doubler supply (~+600–750 V no-load). Each cap sees roughly half the doubled output, so the 500 V rating is correct in this topology. |
Critical |
2 × 150µF / 500V + 470kΩ equalizing resistorsThe well-documented upgrade — uprated capacitance “stiffens” the supply and reduces voice-peak sag. 35 mm bodies fit the original clamps. Never power up an un-restored unit — a failed HV cap can take out the HV rectifiers and the power transformer. |
Keep a 10kΩ/10 W bleeder; discharge fully before any work. |
Easy |
$25–$45 / pair |
|
Electrolytic Cap |
All PB modules |
Mixed 1–100µF, 10–50V (1970s)Board electrolytics on the plug-in modules — dried, leaky or high-ESR after 45+ years. |
Critical |
Nichicon UKL/UPM, Panasonic FC/FR (105°C low-ESR)Recap the regulator, IF, audio and processor boards first (e.g. PB-1314A/1547A regulator, PB-1183C IF, PB-1315B audio, PB-1494/1534A processor — per sub-model). |
Tantalum acceptable only for low-voltage signal-coupling positions; never on HV rails. |
Easy |
$30–$80 full recap |
|
Mica Cap |
C125 |
100pF / 1kV mica (neutralization)In series with the ~10 pF variable neut cap off the plate circuit, in the HV PA compartment. |
Critical |
10pF / 1kV dipped mica (or 2×20pF mica in series)Mandatory when fitting U.S.-brand 6JS6C in place of the original Japanese (NEC/Toshiba) tubes. Mica/silver-mica only — heat in the PA cage shifts ceramic. Short leads, identical orientation, then re-neutralize. |
For a 6146 conversion, C125 is set to 82pF/1kV mica instead. |
Easy |
$2–$5 each |
|
Mica Cap |
C13 |
80pF / 1kV (driver coupling)Couples the 12BY7A anode to the 6JS6C grids. The original 1 kV rating is marginal — a classic G3LL-documented failure that can take out the tubes and HV supply. |
Critical |
80–100pF mica, uprated to ≥3kV (6kV ideal)Replace pre-emptively even if working; uprating the voltage cures the recurring failure. Silver/dipped mica only. |
None — mica only. |
Easy |
$3–$8 |
|
Mica Cap |
C131 |
1000pF / 1kV (low-band tank)Switched into the PA tank on 160/80 m. Same marginal-voltage failure mode as C13. |
Critical |
1000pF mica, uprated to ≥3kV (6kV ideal)High RF current position — use transmitting-grade mica, not a generic film cap. |
None — transmitting mica only. |
Medium |
$4–$10 |
|
Mica Cap |
C11 (10m) |
~200pF / 1kV silver micaDriver compartment, hidden inside the band-switch; critical to 10 m output. |
Common |
200pF / 1kV silver micaLow/no power on 10 m often traces here. Realign after replacement. |
None — silver mica only (RF stability). |
Medium |
$4–$8 |
|
Film Cap |
Mylar (various) |
Coupling / bypass mylars (1970s)Coatings split and peel; values drift. Splitting mylars are near-universal on these rigs. |
Common |
Polypropylene film (Wima MKP, Kemet R82, Panasonic ECQ)Match or exceed the voltage rating; modern polypro is electrically superior. |
Orange Drop 715P/716P for audio-quality positions. |
Easy |
$0.50–$3 each |
|
Resistor |
R5 (driver) |
5.1kΩ / 3W carbon compScreen/dropping resistor in the 12BY7A driver compartment — runs hot, frequently cooked open. |
Common |
5.1kΩ / 5W wirewoundUpsize wattage. Vishay/Dale RH-5 is the gold-standard. |
2×10kΩ/3W metal film in parallel as a field repair. |
Easy |
$2–$6 |
|
Resistor |
PA bias net |
Carbon comp, ½W (various)Bias network for the 6JS6C control grids — drifts high with age, causing red-plating. |
Common |
Vishay/Dale CMF or PR02 metal film 1%Keep carbon/carbon-film where the schematic shows non-inductive RF positions. |
Yageo CFR carbon film for RF-critical spots. |
Easy |
$0.10–$0.50 each |
|
Transistor |
Q3 (RF unit) |
2SC784R (Toshiba NPN RF)RF mixer/driver, NLA from Toshiba. Low gain with age, intermittent on receive. |
Common |
2SC1923 (closest), 2SC2026, S9018S9018 reported working (MW0UZO) but higher gain and different pinout — insulate/twist leads and recheck alignment. |
Verify gain and pinout against the schematic before substituting. |
Medium |
$0.50–$5 |
|
Regulator |
PB-1314A |
Discrete regulator (early) / IC (late)Provides the regulated low-voltage rail (≈6 V) for oscillators/IF. Drifts on early discrete versions. |
Common |
78xx / LM317 retrofitClean upgrade with better load regulation; match the original rail voltage and re-set per manual (precision 6 V rail). |
LM2940 low-dropout for more headroom. |
Easy |
$1–$3 |
|
MOSFET (RX mod) |
1st RF amp |
3SK39 / 3SK40 dual-gate MOSFETThe factory front end is already a dual-gate MOSFET; it can struggle with strong adjacent signals. |
Performance |
Fox Tango “FT-MOSFET” upgrade boardDrop-in improved dual-gate MOSFET (diode-protected, lower noise) — Fox Tango members report better linearity and weak-signal recovery. |
Equivalent BF981 / 3SK-series MOSFET swap; Sherwood SE-3 synchronous detector for ultimate RX. |
Medium |
$3–$10 / device |
|
Diode |
LV rectifier/signal |
1970s small-signal / rectifier diodesAround the bias/regulator board; occasionally fail and drop a low-voltage rail. |
Common |
1N4148/1N914 (signal), 1N4007 (rectifier)Cheap pre-emptive replacement in critical paths. |
Schottky (1N5817/19) for low-drop spots. |
Easy |
$0.10–$0.25 each |
|
Switch |
Band selector |
Multi-wafer rotaryRoutes DC, oscillator, crystal and tank RF — the most complex single part in the radio. Dirty contacts = intermittents. |
Common |
Clean — DeoxIT D5 then Gold G5No modern equivalent; replace only from a donor radio. Never use carbon-tet. |
None — irreplaceable; salvage only. |
Very Hard |
$0 (clean) – $150+ donor |
|
Knob |
Tuning / aux knobs |
Yaesu brass-insert plasticLost/cracked knobs common; the main-tuning reduction drive can seize from old grease. |
Cosmetic |
Donor-radio originalsFor a seized drive: flush, then light synthetic grease (Super Lube). |
3D-printed (PETG) substitutes exist but never match cosmetically. |
Hard |
$10–$45 each |
|
Meter |
S / IC meter |
Yaesu proprietary dual-scale movementS-meter + cathode-current (IC) scale. Movements rarely fail; the meter lamp burns out routinely. |
Uncommon |
Donor unit (face artwork won’t match generics)Refurbish: warm-white LED + dropper to keep the period look; re-zero with the shunt trim. |
Generic movements available but restoration value drops. |
Very Hard |
$45–$150 donor |
|
Lamp |
Dial / meter / VFO |
Incandescent dial lampsRoutine burn-out. A separate protection bulb guards the receiver front end — do not jumper it out. |
Common |
Direct incandescent or warm-white LED (2700–3000K) + dropperKeep the protection bulb incandescent for its fusing behaviour. |
Sealed LED wedge modules with built-in resistor. |
Easy |
$1–$3 / lamp |
|
Trimmer Cap |
Plate trimmers |
Ceramic/mica compression trimmersLow output on a single band (often 20/10 m) frequently traces to a bad plate trimmer. |
Common |
Sprague-Goodman GMA or Johnson pistonMatch the original range; piston trimmers give the best long-term stability. |
Multi-turn trimmers for finer adjustment. |
Medium |
$5–$15 each |
|
Crystal Filter |
PB-1183 IF |
Yaesu 3180 kHz crystal filtersAt the 3.18 MHz 2nd IF. Standard SSB filter XF-30A (~2.4 kHz); CW option XF-30C, 600 Hz; AM option XF-30B (~6 kHz). Filters rarely fail — a missing CW filter is the common shortcoming. |
Rare |
INRAD 3180 kHz aftermarket filtersINRAD lists 3180 kHz SSB/CW units for the FT-101/FR-101 (e.g. 1.8 kHz SSB; verify the current part number). INRAD #2011 is the 6 kHz AM filter. Fox Tango narrows (1.8 kHz SSB / 250 Hz CW) are NLA except secondhand. |
Outboard DSP (Timewave DSP-9+) for filtering without internal mods. |
Medium |
INRAD $130–$200; used $80–$250 |
|
Power Cord |
AC mains cord |
2-wire non-grounded factory cordLeaves the chassis ungrounded — a real safety hazard with HV present. |
Safety |
3-wire grounded cord + chassis groundAdd a green ground from the cord to the rear-apron grounding point. |
IEC C13 chassis-mount conversion for modern serviceability. |
Easy |
$8–$20 |
Procurement Source Directory
Where to actually find the parts — ordered roughly from easiest to source through to specialist outlets.
Mouser / DigiKey
Very EasyBest for: modern components — caps, resistors, diodes, regulators, MOSFETs.
Volatility: Very Low
Stable pricing, datasheet-verified, fast delivery, low minimums.
ProsTraceability, quality, speed.
ConsNo vintage/cosmetic parts.
Build a full BOM to clear the free-shipping threshold; cap kits are cheaper from cap specialists.
RF Parts Company
EasyBest for: verified NOS tubes (6JS6C matched pairs), PA components.
Volatility: Low
Premium but tested/matched; year-to-year stable; US-only sales.
ProsTested, matched, real RF expertise.
ConsCosts more; limited stock.
Call ahead for matched pairs — limited on-hand stock.
ft101repair.com
EasyBest for: professional repair, alignment, cold-cathode neutralization.
Volatility: Low
Service rates stable; parts often included with service.
ProsFactory extender cards, calibrated gear, parts rigs.
ConsBacklog; turnaround can be months.
If the rig is beyond DIY scope, this is the go-to US service shop.
Best for: tubes, sockets, vintage hardware, cap kits, supplies.
Volatility: Low
Tube prices crept up 2020–2025; common types still reasonable.
ProsWide selection, ships internationally.
ConsMatched-pair selection less rigorous than RF Parts.
Bundle resistors/caps with a tube order to save shipping.
Hayseed Hamfest
EasyBest for: pre-built electrolytic recap kits for vintage radios.
Volatility: Low
Kit pricing stable; built for boatanchor restorers.
ProsNo BOM building, US-based, ham-friendly.
ConsMay not cover every FT-101 board.
Confirm FT-101 coverage; otherwise individual caps from Mouser are easy.
INRAD
EasyBest for: 3180 kHz crystal-filter replacements for the FT-101 series.
Volatility: Low
Stable; some models occasionally back-ordered.
ProsNew manufacture, drop-in for original sockets.
ConsLimited model coverage.
Call to verify the exact 3180 kHz model fit for your IF board.
eBay
EasyBest for: NOS tubes, donor radios, original knobs, parts lots.
Volatility: High
6JS6C pairs trending up ~15–20%/yr since 2020; parts radios $150–$400 by condition.
ProsLargest inventory, sold-price history, returns.
Cons“NOS” scam risk; shipping damage to meters/glass.
Filter by Sold listings to gauge real prices; prefer sellers with hi-res tube-box photos.
QRZ Swapmeet
MediumBest for: donor radios, parts hauls, scarce mechanical parts.
Volatility: Medium
Typically 10–25% below eBay; ham-to-ham pricing.
ProsCommunity trust, callsign verification, negotiable.
ConsNo buyer protection; check feedback.
Watch both Wanted and For-Sale; reach out to listed FT-101 collectors directly.
Groups.io — Yaesu-FT-101
MediumBest for: advice, hard-to-find parts via members, alignment support.
Volatility: Low
Fair-market, friend-of-friend pricing; often traded not sold.
ProsDeep expertise, helpful community, free advice.
ConsSlower; depends on member generosity.
Post a polite WTB with photos and your serial range — veterans often hold donor stock.
Fox Tango International
MediumBest for: documentation, board schematics, the FT-MOSFET upgrade, occasional member parts.
Volatility: Low
Fox Tango filters very rare now ($150–$300 when available).
ProsDefinitive reference; full board-variant archive.
ConsArchival first; parts not the main mission.
Use the library PDFs to confirm your processor-board variant before sourcing.
Best for: donor radios, parts lots, knobs, cabinets, accessories.
Volatility: High
Best prices of the year (often 30–60% below eBay); inventory unpredictable.
ProsHands-on inspection, no shipping damage, negotiation.
ConsSchedule-bound; travel cost; no guarantees.
Bring a printed wishlist; arrive at flea-market opening for best pick.
Best for: the SE-3 synchronous detector for top-tier receive.
Volatility: Low
Stable; built to order.
ProsDramatic AM/SSB RX improvement, outboard (no internal mods).
ConsPremium price; an add-on box, not a repair part.
Best paired with a recapped, well-aligned radio — it won’t fix a sick IF strip.
Restoration Notes & Safety
- Never power up an un-restored FT-101E. Inspect/replace the HV voltage-doubler electrolytics first — a failed cap can take the HV rectifiers and power transformer with it.
- High voltage present: the PA voltage-doubler runs roughly +600 to +750 V no-load, plus ~165 V screen, the −100/−180 V bias rail and filaments. Discharge filter caps with a 10kΩ/10 W bleeder and use only non-metallic tools in the HV PA compartment.
- C125 neutralization mod is mandatory for any U.S.-brand 6JS6C fitted in place of the original NEC/Toshiba tubes: 100pF→10pF (or 2×20pF in series), 1 kV mica, then re-neutralize per the service manual.
- Uprate the marginal 1 kV caps. C13 (driver coupling, ~80pF) and C131 (low-band tank, 1000pF) are known to fail from undersized voltage rating — replace with ≥3 kV mica.
- R30 screen-protection resistor: if doing a 6146 conversion, change R30 from 47k to 470k (½ W) — this prevents PA flash-over when screen voltage is removed and is vital.
- Verify your sub-model before ordering board-specific parts. Early (S/N <15,000, PB-1494 processor), Mid (15,001–20,500, PB-1534), and Late (>20,501, PB-1534A processor, PB-1547A regulator, PB-1183C IF, PB-1315B audio, PB-1582 blanker) differ. Check the Fox Tango library.
- Cold-cathode neutralization (offered by shops such as ft101repair.com) is the definitive method versus dipping the plate circuit.
Compiled and fact-checked against
Fox Tango International,
the NW2M FT-101 Archive,
ft101repair.com,
the MW0UZO repair log,
K3JLS 6146 conversion,
Wikipedia and the
Groups.io Yaesu-FT-101 community.
Mike Peace VK6ADA · r-390a.net Administrator
Mike Peace VK6ADA · r-390a.net Administrator