Johnson Courier

[N2DTS]

Its got mercury vapor rectifiers, no?
Solid stating wont get you anything there....
They do have plug ins, so you dont have to mod anything, but its not going to improve things much.

Brett

[Pete, WA2CWA]

Pete, Dave

I haven't SS'd the power supply but I did for quite for some time run mine at 100 watts AM carrier but after carefully looking at the envelope on a scope and getting a report of flattopping (thanks Dirk) I decided 70 was a better place to have things.  At no time did I experience any  blush on the plates.

I just cannot bring myself to making those kind of changes (possibly SSing the power supply) but it's close to a 50 year old machine and it just aint worth it to me to even try.  She's a grand old girl and I expect she will outlive me.

Al

As Dave indicated, got rid of the choke, added a string of diodes in the power supply, and added a pair of 572B's. When I got the Courier ($25), one 811 and 866 were missing. The other 811 had a open filament. Since I'm not fond of mercury vapor tubes to start with, I sold the remaining one for $5. Courier has been running this way since the late 80's both on AM and SSB. It rocks on SSB.

[w1vtp]

Its got mercury vapor rectifiers, no?
Solid stating wont get you anything there....
They do have plug ins, so you dont have to mod anything, but its not going to improve things much.

Brett

Brett. I have the direct SS plugins - made em myself.  Pete - I bet it does rock. What kind of PEP do you get?

[W2VW]

Its got mercury vapor rectifiers, no?
Solid stating wont get you anything there....
They do have plug ins, so you dont have to mod anything, but its not going to improve things much.

Brett

I suggested cap input and forget the choke to allow more voltage for the 572Bs and hopefully keep the plate load where it started.

Rectifier requirements go way up with cap input.

Fortunately we have Pete to tell us his numbers.

[Pete, WA2CWA]

On SSB, the PEP output was somewhere around 600 or 650 watts, I seem to remember the last time I measured it back around 1989. On AM, I generally adjust the RF exciter feeding the Courier for a Courier RF output of about 100 to 110 watts. Still using the same 572B's I put in back in the 80's.