Icom 718 weak receive

[K4PIH]

My Icom 718 took static/lightning hit? Transmit is fine but receive is weak. Maybe gas discharge tube is bad, or other filter board part? How do you check a gas discharge tube?

[N8YX]

Sorry for not noticing this before.

A GDT is not in "series" with the receiver's front end. Rather, it's shunted to ground and will conduct excessive voltage to same when its breakdown threshold occurs.

I have a 718 plus servicing info. What do you have in the way of test equipment?

[K4PIH]

Thanks, I have the usual fluke and access to an HP spectrum analyzer and a portable O Scope. Also have a nice shop at home and at work.

[N8YX]

Thanks, I have the usual fluke and access to an HP spectrum analyzer and a portable O Scope. Also have a nice shop at home and at work.
Any sort of RF generator?

[K4PIH]

That I do not have. I suppose I could use another low power rf generator of some kind, or throw one together out of the parts box.

[N8YX]

That I do not have. I suppose I could use another low power rf generator of some kind, or throw one together out of the parts box.
I'd look into a NanoVA or similar low-cost signal source. An amplitude/frequency stable unit is going to be very helpful in troubleshooting things.

[K4PIH]

Gping through my stash of old equipment, I did find an ancient Eico grid dip meter.

[N8YX]

Gping through my stash of old equipment, I did find an ancient Eico grid dip meter.
That has AC on the chassis, depending on how you plug it in. Steer clear for DC-powered equipment.

[K4PIH]

Yep, it does have an AC cord.