KRIS 600 SSB-New Project

[Dmans]

All,
So a good friend of mine asked me to look at his Kris Amp for him. (It had been sitting in a Truck Stop CB shop for about 6 months) I love a challenge and never pass up an opportunity to learn something-So it is on!

The initial issue he had with it was that the SSB delay was not working. I'm not sure what if anything the CB s
Shop did to it but upon initial inspection, I found it has been "screwdrivered" to DEATH.

It has a decent face. The undercarriage-not so much.

Sketchy wiring and soldering.

First thoughts are to lose the 115v relay and convert it to a 12vdc relay, lose the microscopic coax jumpers, recap it, new bleeder resistors, new SO239's, 3 prong power cord.....................................

Stay tuned!

73's
David

 

[Dmans]

Update to the Kris 600SSB

Removed the lamp cord and installed a 3 wire power cord.

It does not have a 115v relay but does have a 12vdc relay.

Found that the standby switch (a DPDT) had the center terminals shorted together and the medium voltage supply line was hooked across both poles of the switch. One side of the one of the "On" poles was wired to the 12vdc relay, the other "On" pole was wired to ground! Glad I never plugged this thing in!!

I removed the relay and using jumper wires to a 12vdc power supply tested it. It seems to work well. So it can stay.

New S0239 connectors arrived as well as some Rg316 coax. (I tried Rg58U but it was a little too stiff to make some of the turns and bends required in this chassis)

This afternoons project was cleaning up the awful high voltage supply board.
A couple of before pictures.

And a couple of after pictures.

Stay tuned!

73's
David

 

[kopcicle]

So, no explosions yet?

 

[Dmans]

Not yet.

But there is still plenty of time!

73's
David

 

[Hurricane145]

Neat project.
I knew a couple people that had Kris amps back in 1970. Probably not the best designed amplifiers but they have nostalgic value to me although I never had one. That and the Hy-gain Afterburner amps which were common at the time.

 

[Dmans]

Hurricane145,

Probably not the best designed amplifiers

Agreed. And not unlike today. Makers use as cheap a part/component as they can find to maximize their profit.
I still like resurrecting them though!

I spent some time on the Kris project today and rewired the standby switch so that it doesn't ground the medium voltage output meant for the driver tube. NOW when switching the Standby switch to the "On" position, it grounds half the bridge rectifier so that the high voltage/bridge rectifier circuit is complete. The other pole of the switch NOW supplies 12vdc to the keying relay-As designed. All the internal coax jumpers were replaced. The relay was also completely rewired. I did find that the way it was wired when I disassembled it would never let the unit operate. It is correct now and has been tested. I suppose after about 50 years of this things life, many a screwdriver has been inside of it. I'm not surprised at anything I have come across.

I am just trying to return it to it's as built condition with an eye on safety measures. I.e. Metal Oxide Varistors on the 115Vac lines, 3 prong power cord, fast blow fuse between the high voltage winding and bridge rectifier, a proper safety choke and cleaning up a heap of poor connections, poor wires and terrible solder joints.

So far, so good. I'm waiting on some components to rebuild the keying circuit (should have been here last Friday) but all in all it has been a fun project and a great learning experience.
(I did go through a Hygain Afterburner recently. Repaired some of my own damage and made some mods to extend tube life and give a cleaner output. It is in a thread under the "Amplifiers" heading on the forum. Now the amp sits on a shelf and collects dust. Time well spent!)

73's
David

 

[kopcicle]

 

[Dmans]

kopcicle,
Makes me want to homebrew an amp. Been thinking about it for a while. Got some hand drawn schematics from some sleepless nights. PAOFRI's is much better than the products of my sleep deprived ventures.
Parts collecting may be the next step along with many more sleepless nights!

73's
David

 

[kopcicle]

Cary 4x Gilded 9pin Ceramic Vacuum Tube Socket Gold Valve Base for El504 El519 Audio

 

[kopcicle]

1500VA 950V + 950V & 6.3V 5A x2 Tube Amp Transmitter Power Transformer AS-15T950

 

[kopcicle]

<----enabler

 

[nomadradio]

And that toroid transformer is rated for 1500 VA at 50 Hz. At 60 Hz it's 20% more, or 1800VA.

John builds 'em mean.

73

 

[Tallman]

My wife who has never soldered on a circuit board saw that HV board and said, "I could do a better soldering job than that!" She can, I had her help me when I needed a fourth hand on a chassis and she did it perfectly. I did not have to reheat it or anything. I guess I'm going to put her to work now.

 

[Dmans]

Tallman,
I hope she was talking about the "Before" pictures??

73's
David

 

[Tallman]

Tallman,
I hope she was talking about the "Before" pictures??

73's
David

Yep, I don't let her look at my computer very often. She might take over and kick me off.