20-05-2020, 08:25 PM
(This post was last modified: 20-05-2020, 08:37 PM by Mike Watterson.)
The AM & FM working and over driven on SSB suggests the SSB alignment is faulty. I'm not familiar with how SSB is done on this model. In general the carrier has to be nulled (DC offset on a double balanced mixer and then a ceramic filter blocks the unwanted side band). The FM uses class C, no DC bias on the FETS. The AM mode biases the FETS at 1/2 current. Hence power on AM is typically 1/4 of FM power. SSB only has an average power if fed a tone. Otherwise you should be seeing a peak power similar to FM. With no audio there should be almost no RF out and almost no supply current to the output stage on SSB.
It's normal that the output stage, the "finals" run straight of the supply, hence 12V gives less power than 14.2, a fully charged car battery. The 13.6 or so +/- 10% is "traditional" for a bench supply for something intended for a vehicle.
I'd remove the supply to the output FETS and see what is happening on the drive / gates with a 'scope, DC coupled to see any bias. Compare AM, FM and SSB.
These radios are sold as 10m Ham rigs to get round import controls as they are really CB rigs with more power for 11m than is licensed anywhere. They are sold under different brands. There is no comparison with Kenwood, Yaesu, Icom etc.
You need the service manual, any version, to see how the SSB works and is aligned. It depends who you bought it off as to the warranty situation, and if a qualified 3rd party says it's inherently faulty, (sounds like it's never been right), then what ever version of the SOGA applies unless you imported personally from outside the EU (UK doesn't leave till 31st Dec, just has no votes since 31st January).
The contract / warranty that counts is with the retailer that sold it. It sounds like you are describing the maker or importer's warranty.
Edit:
reasonable overview https://hamgear.wordpress.com/2013/03/04...s6900n-v6/
He says no service info or schematic.
About €195 from the Netherlands, so it's a very cheap radio really for the illegal CB market, which used to be mostly Italy due to poor enforcement, some CBers there with 1kw in the past.
It's normal that the output stage, the "finals" run straight of the supply, hence 12V gives less power than 14.2, a fully charged car battery. The 13.6 or so +/- 10% is "traditional" for a bench supply for something intended for a vehicle.
I'd remove the supply to the output FETS and see what is happening on the drive / gates with a 'scope, DC coupled to see any bias. Compare AM, FM and SSB.
These radios are sold as 10m Ham rigs to get round import controls as they are really CB rigs with more power for 11m than is licensed anywhere. They are sold under different brands. There is no comparison with Kenwood, Yaesu, Icom etc.
You need the service manual, any version, to see how the SSB works and is aligned. It depends who you bought it off as to the warranty situation, and if a qualified 3rd party says it's inherently faulty, (sounds like it's never been right), then what ever version of the SOGA applies unless you imported personally from outside the EU (UK doesn't leave till 31st Dec, just has no votes since 31st January).
The contract / warranty that counts is with the retailer that sold it. It sounds like you are describing the maker or importer's warranty.
Edit:
reasonable overview https://hamgear.wordpress.com/2013/03/04...s6900n-v6/
He says no service info or schematic.
About €195 from the Netherlands, so it's a very cheap radio really for the illegal CB market, which used to be mostly Italy due to poor enforcement, some CBers there with 1kw in the past.
