?

Hi all, I have a rather strange issue with my '847 that I haven't yet figured out the cause for: It doesn't receive or transmit between 420 MHz and 459..9995 MHz.

Background info: I'm 3rd owner of my nearly mint condx.? My understanding is that it has never been modded or altered in anyway.? An examination of some of the circuit boards shows no signs of tampering/repair or component damage. The radio functions perfectly in every sense, transmits and receives in all 5 modes without issues on all amateur bands (except 440 MHz band of course) and receives perfectly fine on HF and VHF general coverage receive, and receives perfectly fine at 460 MHz up to 512 MHz.? No other anomalous functionality except that I just discovered during my trouble shooting session that I cannot enable the Alaska 5167 kHz emergency channel in the menu, and that my radio will transmit at 460 Mhz and up.? That last bit piques my attention as my understanding is that these radios cannot transmit out of band unless someone has done a mod?

When I select any 70 cm frequency and key the radio, the speaker audio cuts off normally and I hear the cooling fan step up in speed from it's normal stand-by cooling speed like it normally does on any other band.? "Transmit" appears on the display, but no PO level, nothing, no matter what mode I use.? Using a couple of dual band radios confirmed to be working (I hear them perfectly on a pair of Icom R7000's) there is a definite gap between 420 MHz and 459.9995 MHz where nothing is heard or can be sent.? But the moment I go to 460 MHz and higher it will receive and transmit.? I do not hear a change in the receive static in the affected frequency region as I scroll up in frequency.? I've performed the CPU reset with no resulting change in behaviour.? Owned the radio for over 5 years but i've never used it on 440 MHz before so I do not know how long this issue has existed.

Any ideas before I break out the magnifying glasses and schematics?

?

I have further read this, and it makes no sense, it seems you have a corruption, or an illegal settings near the CPU

?

Check this site and let me know what you find:

?

?

73

?

Andrew

?

?

Hi all, I have a rather strange issue with my '847 that I haven't yet figured out the cause for: It doesn't receive or transmit between 420 MHz and 459..9995 MHz.

Background info: I'm 3rd owner of my nearly mint condx.? My understanding is that it has never been modded or altered in anyway.? An examination of some of the circuit boards shows no signs of tampering/repair or component damage. The radio functions perfectly in every sense, transmits and receives in all 5 modes without issues on all amateur bands (except 440 MHz band of course) and receives perfectly fine on HF and VHF general coverage receive, and receives perfectly fine at 460 MHz up to 512 MHz.? No other anomalous functionality except that I just discovered during my trouble shooting session that I cannot enable the Alaska 5167 kHz emergency channel in the menu, and that my radio will transmit at 460 Mhz and up.? That last bit piques my attention as my understanding is that these radios cannot transmit out of band unless someone has done a mod?

When I select any 70 cm frequency and key the radio, the speaker audio cuts off normally and I hear the cooling fan step up in speed from it's normal stand-by cooling speed like it normally does on any other band.? "Transmit" appears on the display, but no PO level, nothing, no matter what mode I use.? Using a couple of dual band radios confirmed to be working (I hear them perfectly on a pair of Icom R7000's) there is a definite gap between 420 MHz and 459.9995 MHz where nothing is heard or can be sent.? But the moment I go to 460 MHz and higher it will receive and transmit.? I do not hear a change in the receive static in the affected frequency region as I scroll up in frequency.? I've performed the CPU reset with no resulting change in behaviour.? Owned the radio for over 5 years but i've never used it on 440 MHz before so I do not know how long this issue has existed.

Any ideas before I break out the magnifying glasses and schematics?

?

I have further read this, and it makes no sense, it seems you have a corruption, or an illegal settings near the CPU

?

Check this site and let me know what you find:

?

?

73

?

Andrew

?

From: [email protected] <[email protected]> On Behalf Of Richard via
Sent: 04 September 2022 05:16
To: [email protected]
Subject: [YaesuFT847] UHF Range: Partial RX/TX Issue.

?

Hi all, I have a rather strange issue with my '847 that I haven't yet figured out the cause for: It doesn't receive or transmit between 420 MHz and 459..9995 MHz.

Background info: I'm 3rd owner of my nearly mint condx.? My understanding is that it has never been modded or altered in anyway.? An examination of some of the circuit boards shows no signs of tampering/repair or component damage. The radio functions perfectly in every sense, transmits and receives in all 5 modes without issues on all amateur bands (except 440 MHz band of course) and receives perfectly fine on HF and VHF general coverage receive, and receives perfectly fine at 460 MHz up to 512 MHz.? No other anomalous functionality except that I just discovered during my trouble shooting session that I cannot enable the Alaska 5167 kHz emergency channel in the menu, and that my radio will transmit at 460 Mhz and up.? That last bit piques my attention as my understanding is that these radios cannot transmit out of band unless someone has done a mod?

When I select any 70 cm frequency and key the radio, the speaker audio cuts off normally and I hear the cooling fan step up in speed from it's normal stand-by cooling speed like it normally does on any other band.? "Transmit" appears on the display, but no PO level, nothing, no matter what mode I use.? Using a couple of dual band radios confirmed to be working (I hear them perfectly on a pair of Icom R7000's) there is a definite gap between 420 MHz and 459.9995 MHz where nothing is heard or can be sent.? But the moment I go to 460 MHz and higher it will receive and transmit.? I do not hear a change in the receive static in the affected frequency region as I scroll up in frequency.? I've performed the CPU reset with no resulting change in behaviour.? Owned the radio for over 5 years but i've never used it on 440 MHz before so I do not know how long this issue has existed.

Any ideas before I break out the magnifying glasses and schematics?

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Just chucking this out there but surely the signal passes through the 70cm BPF? If anything in the 70cm BPF has come adrift then the radio will have a broken signal path. Is it possible soon as you go to 460mhz a relays (pin diodes) on nearly all radios switch out the BPF and onward. If the switching at 460mhz has switched out the bad BPF then this may be why it suddenly bursts into life.

? I believe the diodes (noisy diodes are 1N5711 or BAT85’s) so may be worth checking those and the BPF relays.

? I’m trying to find a schematic for the FT847 but only find the technical supplement.

? I will tune my FT847 near 460mhz and listen to any switching but I’m sure it does as it’s the beginning of band IV tv transmissions here in the UK before DVB-T

de Spence M0STO

Sent while portable! please excuse typos.

On 4 Sep 2022, at 15:02, Andrew Lenton <a@...> wrote:

I have further read this, and it makes no sense, it seems you have a corruption, or an illegal settings near the CPU

?

Check this site and let me know what you find:

?

?

73

?

Andrew

?

From: [email protected] <[email protected]> On Behalf Of Richard via
Sent: 04 September 2022 05:16
To: [email protected]
Subject: [YaesuFT847] UHF Range: Partial RX/TX Issue.

?

Hi all, I have a rather strange issue with my '847 that I haven't yet figured out the cause for: It doesn't receive or transmit between 420 MHz and 459..9995 MHz.

Background info: I'm 3rd owner of my nearly mint condx.? My understanding is that it has never been modded or altered in anyway.? An examination of some of the circuit boards shows no signs of tampering/repair or component damage. The radio functions perfectly in every sense, transmits and receives in all 5 modes without issues on all amateur bands (except 440 MHz band of course) and receives perfectly fine on HF and VHF general coverage receive, and receives perfectly fine at 460 MHz up to 512 MHz.? No other anomalous functionality except that I just discovered during my trouble shooting session that I cannot enable the Alaska 5167 kHz emergency channel in the menu, and that my radio will transmit at 460 Mhz and up.? That last bit piques my attention as my understanding is that these radios cannot transmit out of band unless someone has done a mod?

When I select any 70 cm frequency and key the radio, the speaker audio cuts off normally and I hear the cooling fan step up in speed from it's normal stand-by cooling speed like it normally does on any other band.? "Transmit" appears on the display, but no PO level, nothing, no matter what mode I use.? Using a couple of dual band radios confirmed to be working (I hear them perfectly on a pair of Icom R7000's) there is a definite gap between 420 MHz and 459.9995 MHz where nothing is heard or can be sent.? But the moment I go to 460 MHz and higher it will receive and transmit.? I do not hear a change in the receive static in the affected frequency region as I scroll up in frequency.? I've performed the CPU reset with no resulting change in behaviour.? Owned the radio for over 5 years but i've never used it on 440 MHz before so I do not know how long this issue has existed.

Any ideas before I break out the magnifying glasses and schematics?

This email has been scanned by BullGuard antivirus protection.

For more info visit

From: [email protected] [mailto:[email protected]] On Behalf Of Richard via groups.io
Sent: Sunday, September 04, 2022 9:35 PM
To: [email protected]
Subject: Re: [YaesuFT847] UHF Range: Partial RX/TX Issue.

?

Bill K2WH-> Hi Bill, I only just discovered the inability to enable the Alaska emergency frequency during a complete functionality check of the radio.? I went thru all the settings to see what was & what wasn't working on my radio.? I needed a full picture of what the radio could & couldn't do.? But yeah, I have no need for it.

Andrew-> I'm unsure about actual power out as I have no way of measuring VHF & UHF at the moment.? I've been looking at some cross needle SWR/PWR meters for those bands but haven't made a decision on which one to get.? I did get a neighbour to walk down the street to a park about 200m away with an FRS radio and he reports full quieting on minimum power.

I followed your link and sure enough it's been opened up.? I'm not too impressed, I? actually said "oh, bloody hell" as I specifically asked about this and the seller assured me it was untouched.? Oh well.? I'll be restoring it back to factory original.? Looks like all I have to do is remove the solder-shorts on pads #2 and #3 and put a chip resistor back on pad #6.

I feel like an idiot as I've had the radio this long and never noticed it could go out of band.? Never had a need to so I never tried.? Heh.

Spence M0STO -> I had the same thought about the relays.? I had my ear to the radio case listening for the tell-tale "click" as I tuned up & out of a BPF and into the next one.? I heard none.? That's when I had the thought that i'd need to look in this area.? Ah-ha!? look at that, "420 - 460 MHZ" circled in red on that schematic snapshot.? Dead-on the problem i'm having.? Thank-you for narrowing it down for me.

I do plan to replace the HF BPF diodes with low noise Schottky type as explained here:?

------

Examining the bottom board, I did see left of X1001 a soldering job that looked non-original and there was still a bit of flux around it.

On 5 Sep 2022, at 18:46, Andrew Lenton <a@...> wrote:

?

The current drawn from the power supply is also a good indicator, ideal current on UHF TX on min RF? is aroubd 2.5 Amps, at 50 Watts expect 12-15 Amps on FM or CW. PA is around 50 % efficient.

Most ham shacks should have what I call the minimum amount of kit:

Power supply 30 A with Voltage and current meters. Also a small variable 0 to 30V 2Amp with current limit.

DVM I/P to 20 A and 1 mV/A 750V AC/ DC

Oscilloscope 100MHZ? bandwidth (very cheap now days)

SWR meter or and an ATU that is metered?

50 ohn load 100 watts

Tina SA Spectrum Analyser (?60)

SDR RX SDR Play 1A

SMA, Pl259, BNC and N adapter set

Various hook up cables

With the above list you can repair and fault find a lot of radios, all costing less than one rig!!

73 Andrew G8UUG

Get

On 5 Sep 2022, at 19:34, Robin Burke <robinsburke@...> wrote:

?

Rob Burke

137 bd de la République

92420 Vaucresson FRANCE

Mobile: +33 (0)6 30 33 18 48

eMail: robinsburke@...

On 5 Sep 2022, at 18:46, Andrew Lenton <a@...> wrote:

?

The current drawn from the power supply is also a good indicator, ideal current on UHF TX on min RF? is aroubd 2.5 Amps, at 50 Watts expect 12-15 Amps on FM or CW. PA is around 50 % efficient.

Most ham shacks should have what I call the minimum amount of kit:

Power supply 30 A with Voltage and current meters. Also a small variable 0 to 30V 2Amp with current limit.

DVM I/P to 20 A and 1 mV/A 750V AC/ DC

Oscilloscope 100MHZ? bandwidth (very cheap now days)

SWR meter or and an ATU that is metered?

50 ohn load 100 watts

Tina SA Spectrum Analyser (?60)

SDR RX SDR Play 1A

SMA, Pl259, BNC and N adapter set

Various hook up cables

With the above list you can repair and fault find a lot of radios, all costing less than one rig!!

73 Andrew G8UUG

Get