HR2510,

[DavidD]

Carrier on FM, AM, CW but no modulation on voice on any band, FM,AM,LSB,USB? Checked mic, seems okay, Power out good, just no modulation on voice tx.

 

[sp5it]

Apply some audio to leg 2 of IC104 and come back with result.
Mike

 

[DavidD]

Apply some audio to leg 2 of IC104 and come back with result.
Mike

hard to read my schematic but applied a 1kh tone at R85 which I think connects to IC104 pin2. Heard a very, very faint 1k tone in the speaker but did not see any modulation in the output

 

[DavidD]

hard to read my schematic but applied a 1kh tone at R85 which I think connects to IC104 pin2. Heard a very, very faint 1k tone in the speaker but did not see any modulation in the output

WEAK AUDIO IN THE SPEAKER, NO MODULATION OF CARRIER

 

[DavidD]

Apply some audio to leg 2 of IC104 and come back with result.
Mike

DID, GOT WEAK AUDIO OUT OF SPEAKER, NO MODULATION

 

[DavidD]

Apply some audio to leg 2 of IC104 and come back with result.
Mike

hard to read my schematic but applied a 1kh tone at R85 which I think connects to IC104 pin2. Heard a very, very faint 1k tone in the speaker but did not see any modulation in the output

 

[sp5it]

Increase level of that audio.
SSB path goes different way than FM, so check both.

 

[DavidD]

applied tone but just week output. Put tone directly onto the mic input leads and got mod reading on the internal radio meter and onthe output

 

[DavidD]

Increase level of that audio.
SSB path goes different way than FM, so check both.

applied the tone to the mic input pins and got modulation on the internal meter on all selections, on the output RF appeared to be modulated.

 

[DavidD]

Increase level of that audio.
SSB path goes different way than FM, so check both.

assuming mic element is bad as audio applied to the mic voice input pins shows modulation on all bands now.

 

[nomadradio]

Sounds like a 50-50 tossup. Bad cord or bad mike element.

Cords break more frequently than the cartridge/element.

73