Siltronics VFO/MK III

[gator7]

I am in the process of installing a model 90 into my MK III. I see it states to solder the center (copper) wire to the channel 23 socket. And the shield to the ground. I was wondering if anyone has tried to do this with a solid wire the correct gage to fit in the socket. This would eliminate the need for the solder to the socket. You would need to be sure that you had the right fit so that the connection didn't loose contact.
It would be a cleaner install, and wouldn't mess up the crystal socket.
What do you think?

[Tombstone (R.I.P.)]

You don't need to solder to the socket at all. You'll see a tab just next to the socket that extends over and rides on the center ring that selects each crystal on the rotary switch. Just solder to that tab, it has a hole in the center so you can slip the wire in it.

Tombstone

[gator7]

OK, I guess that would work. I was looking at getting away from doing any solder to the selector.

Thanks.

[Tombstone (R.I.P.)]

You probably can get away with cutting a short piece of a paper clip or something else that will fit snugly into one of the empty crystal connections.

Tombstone

[Marc]

If you have an old crystal laying around. just remove the top cover and remove the internals solder to the two pins inside and plug it in.

I have used a drumal tool to cut the top off leveing about 1/8th inch of the top case. works very well.

Marc

[gator7]

That is also a good idea. I guess i have enough to go with now.

Thanks.

[2600]

The used crystal-can idea has a fatal flaw. Each crystal socket has two pins. The inner pin is the "hot" side. The side that feeds through the switch to V6. The outer pin is NOT ground. It leads to the "VFO" knob on the front.

Not the same thing as ground.

Here's the pic from my web page on this subject. Click on it for the full-size version.



I recommend soldering the coax center conductor to the switch lug, and NOT to the crystal socket itself. Lap-solder an insulated wire to the shield of the slider coax and pass this wire through the grommet in the deck alongside the yellow wire. There is a handy ground lug near this hole underneath the deck.

Well, what I really recommend is to install our buffer board so the radio won't keep burning up R34 and V6. The Siltronix 90 does not have sufficient drive level for a tube-type radio. It's a good match for a solid-state 23-channel radio. But the crystal oscillator in a solid-state radio runs at a lower signal voltage than a tube-type radio requires.

Here's the page showing how to install it.

www.nomadradio.com/OldNomadWebPages/SBinstall/index.htm

Sooner or later I'll get around to posting the setup to install it inside the slider, rather than inside the transmitter.

It's 30 bucks prepaid, and includes USPS Priority Mail shipping.

73

[gator7]

Thanks 2600, I'll look into that install option.

73's

[Tombstone (R.I.P.)]

Hey, Gator7, I didn't mention the slider buffer kit because I thought that you knew about it. I use it with my Mark III and the Siltronix 90 and everything is installed like 2600 recommends. It's an easy install and will save you from having problems. Without it you may notice a lower wattage output from the transmitter when on the slider compared to using the crystals. This is what stresses the components that 2600 describes. Good luck.

Tombstone

[gator7]

Yes, i remember it being discussed in the past. Sounds like that is the way to go.


Thanks.