YAESU FT-7 MODIFICATIONS - 15 June 2020 - BF961 pin corrections on RX RF Amplifier PCB

Sep 22, 2026

Document content describes Yaesu FT-7 transceiver modifications with an emphasis on RX RF amplifier changes, including BF961-related pin corrections on the RX RF Amplifier PCB. It provides background on ownership and usage, explains why certain improvements are possible, and outlines specific circuit adjustments such as replacing or modifying input RF amplifier stages, tuning decoupling values for frequency bands, and adding CW signal rounding and stabilization components. Additional troubleshooting notes cover anti-microphone click updates, capacitor polarity issues, and buffer/front-end considerations.

LanguageEnglish

CategoryPresentations

FormatPDF

Pages2

Reading Time1 min

AccessFree to download

RX RF Amplifier

CW rounding, stabilization

Anti microphone click

Incorrectly installed tantalum ELCO

Buffer amplifier in front of mixer

Continue Yaesu ft-7 mods The Yaesu FT-7 was first released in Australia in the late 1970’s and proved to be a hit with the then new Novice “N” calls. The Yaesu FT-7 – photograph by Mark VK3PI Rugged and simple to operate, the FT-7 was a “no frills” offering from Yaesu, with around 10 watts output. Additionally for those with a technical mind, the FT-7 was constructed with a series of plug in boards, making fault finding and circuit identification relatively simple, if required. I can recall I first purchased an FT-7 in 1979 for a cost of $379 . It is remarkable to say that the value of the FT-7 has actually increased since that time, with some units, in excellent condition, fetching up to $500 . The FT-7 is the mainstay of my portable operations, fitting neatly into an aluminium tradesman type case, padded with foam from Clark Rubber. The FT-7 is transported in one case, with peripherals such as a morse key, power cable, speaker and coaxial patch leads transported in another. Specifications Frequency Range 3.5 – 4.0MHz, 7.0-7. 5MHz, 14.0 – 14. 5MHz, 21.0-21. 5MHz, 28.5-29.0MHz**Other crystals to operate on lower portions of the 10m band are available Modes SSB (USB,LSB), CW Receiver sensitivity 0. 25uV for S/N 10dB Transmitter Input power 20 watts DC Image ratio Better than 50dB IF rejection Better than 50dB Selectivity-6dB at 2.4KHz – 60dB at 4KHz Audio out 3 watts @10% THD Antenna impedance 50 ohms Microphone 500 ohms nominal Power Consumption 13.5 V DC Transmit 3A 13.5 V DC Receive 0.4A Dimensions 230 (W) x 80 (H) x 290 (D) mm Weight 5 kg Programming interface schematics for Yaesu : Programming software for Yaesu FT-7 (FT 7 FT7) : PDF User Manual for Yaesu FT-7 (FT 7 FT7) : PDF Service Manual for Yaesu FT-7 (FT 7 FT7) : Yaesu FT-7 (FT 7 FT7) technical specifications : Yaesu FT-7 (FT 7 FT7) technical specifications date post13-Dec-2015CategoryDocumentsview82download3Embed Size (px)344 x 292429 x 357514 x 422599 x 487description ft 7b modificaciones. Modifying The FT- 7image002image003image004image005image006image007image008image009image010 YAESU FT-7 MODIFICATIONS 15 june 2020 BF961pin corrections on RX RF Amplifier PCB. INTRODUCTION Since 1982 I am in possession of a 2ndhand YAESU FT-7 . The 10 W set did well service at home, on holiday and during a UN mission abroad. With a freely suspended home-made FD4 antenna across a Wadi in Lebanon American hams could hardly believe that I was transmit with low power. Furthermore, the receiver is one of the quietest of its kind with low self-noise and the transmitter only draws about 3 A! Currently there is a revived interest in this rather small and well-built transceiver and modifications are possible to those of interest to you. More output is possible (some sets even 25 W) but do not go to extremes. With 10 W output, the transceiver is well protected even with high SWR to the load. Furthermore, this power remains constant with 13.8 V, but also with 15 V or 11 V when the battery needs to be charged. Yaesu has produced a transistor amplifier FL-110 (fig») for the transceiver and this PA is sometimes offered as 2ndhand. A large portion of the device consists of plug-in boards that facilitate modification, repair or installation of your own design. If your circuit don't work just replace the original PCB. Pretty soon I installed my ideas because in my opinion"improvements" were possible. You recognise the tinkering for some DIY! The set was a long time used as backup and for this article removed from a dusty shelf. I had forgotten why some modifications were installed, hi! After some searching in the mess of my shack, all documents found. RX RF AMPLIFIER Almost immediately after the purchase (in 1982) the receiver input RF amplifier Q104 (3SK40M) was replaced by a BF900 . A modern BF961 will also work in this circuit. Even with the original transistor the gain was too much for the low bands. So the source decoupling capacitor (C113) of was reduced to 100 pF. This value is suitab

FAQs

What RX RF amplifier change is recommended after acquiring the FT-7?

The receiver input RF amplifier Q104 is replaced (e.g., with a BF900), and the source decoupling capacitor value (C113) is reduced to 100 pF to avoid overloading while supporting 10 m, 40 m, and 80 m performance.

How is the “blocky” CW envelope addressed in the document?

CW rounding is achieved by modifying the pre-drive PCB PB-1632, including adding a diode in parallel with a resistor and replacing capacitor values, or using an alternative resistor network plus a parallel resistor approach.

What update helps reduce the annoying click when pressing PTT?

The document recommends changes in the MOD/DEM unit PB-1624: replacing R507 with 2.2k2, inserting an RFC (220 µH) between R507 and D505, and adding 1N4148 in series with R507 while decoupling with 10 nF and 47 nF.

Sep 22, 2026

Upload by Taylor Morgan