HLA 300V Plus Problem

[Michael Barrett]

I have an HLA 300 amplifier that I am trying to fix.

When keyed with 10watts the power out is ok but when I de key the out put goes off no problem but the Tx light on the amplifier stays on untill I turn off the power then when I turn it back on it's ok till I tx again then the light locks on again.

Any help would be greatly appreciated.

 

[Shockwave]

I have an HLA 300 amplifier that I am trying to fix.

When keyed with 10watts the power out is ok but when I de key the out put goes off no problem but the Tx light on the amplifier stays on untill I turn off the power then when I turn it back on it's ok till I tx again then the light locks on again.

Any help would be greatly appreciated.

Can you confirm with an external watt meter that the output power actually drops to zero when you unkey? Do you have any noise level or receive signal meter reading while the amplifier is still locked keyed? What is the SWR while the amplifier is running into the antenna? Has the amplifier worked properly in the past with another antenna or radio? Your symptoms sound as though this amplifier may be oscillating. Answering some of these questions will help identify the problem.

 

[magnuman]

Those are prone to dry solder joints on the filter section. Especially if it was one of the older ones. Very susceptible to RF getting back in as well. Test with dummy load.
I have found the kl500 505 series to be far more reliable in use. Those HLA 300 with all the shut down circuitry and filters were not very reliable. Now the newer 305 series are a whole lot better. They do work well.

 

[magnuman]

Reflow the filter section is what I was trying to say!