[Amps] Problems with HLA300

[DH5HV]

Hello

 

I got a HLA300 to repair and I have a very funny failure.


The guy who used it pushed a bit too much power on 11m into the amp and
blows up something.

The final transistor looking good.

The manual band switching is working also. The relais are clicking and
switching the correct band pass filters.

 

 

 

BUT:

 

I connect 13,8V and no transceiver.

Just a Cinch connector to push PTT manual to see the basic functions.

 

The band switch is on "automatic".

 

If I close the PTT connection the amplifier goes on transmit.

 

 

Now I switch from automatic to 10-12m.

Again closing the PTT connection but the amplifier does not go on transmit.

 

Switching of 13,8V and back on makes it working again.

 

Now I switch from 10-12m to 15-17m.

Again the PTT does not work !

Just switching off and on the amplifier makes it working again.

 

If I now go further down the bands it works perfect !!!

Switching back from 160m via all bands up to 15-17m is working fine.

 

If I switch to 10-12m the PTT does not work !
Just pushing it off and on again makes it working.

 

And if I switch further to "automatic" the PTT fails again until I switch
off and on the 13,8V again.

 

 

It seems to be a problem somewhere in the band switching.

Anyway the SWR on the input is bad.

 

I changed the IC3 allready but this makes no difference.

 

 

Any suggestions ?

 

 

Thanks in advance.

 

 

Jochen van Heek

DH5HV

 

This ist he manual:

http://www.rmitaly.com/download/manuals/HLA300-manual_rel_100.pdf