Fast Protection with a Linear:
For complaints of fast protection, such as when operating CW semibreak-in
with a linear, check C73 at the base of Q1 on the LPF unit X51-1180-00.
If it is a 1uf, change to 3.3 uf, 25v or greater. This will compensate
for slow linear relay closure.
The radio should protect at 3:1 SWR, or at 24W open (no) load. To
test the protection circuit, load the radio at 24W into a know 500 ohm
dummy load through a Bird 43 wattmeter. Disconnect the load from the
wattmeter. The protection light should just lite. Adjust the protection
pot VR1 on the LPF unit for protectio at 24W with no load.
For complaints of VOX CYCLING, MEMORY JUMP, READOUT JUMP, or TONE
"BEEP" at key up or down with a linear amp, suspect linear induced relay
transients entering the radio via the ASSY relay wiring.
For example, DRAKE L4B linears before Serial Number 5500 do not have a
quench diode across the DC operated relay. Install a 1N4005 or equivalent
across the relay in the linear to eliminate the back EMF induced by the
linear into the TS-180S. Similarly, Henry linears also don't have a diode
across the relay and may give these symptoms when operated with a TS-180S.