From: Eric Webner 
Subject: Re: [drakelist] R4C xtal bank bad


Eric Webner  made an utterence to the drakelist gang
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Garey et al,
 
I appreciate your comments. Perhaps I did a little too much work on my T-4XC. 
 
I just finished restoring my transmitter, and during my work I found a few
problems with wafer misalignment and too much "play" on certain
wafers. Can you comment on the best ways to correct these problems?
 
I would also like to know what typical settings for plate and load controls
should be when loading into a dummy load. I have never owned a working
C-line before, so I am not sure what "normal" is. Suffice it to
say, I believe my plate control is turned relatively high. I just about
"run out of room" on 10 meters.
 
Also, what kind of output power should I be getting. When I follow the
tuning procedure given in an errata sheet indicating that I should limit my
plate current to 340 mA in order to meet FCC regs, I only get about 85
watts out on 80 and 40 meters. When loading to full power, what is the
maximum plate current I can load to without melting my new finals?
 
For those of us that were discussing how to obtain knobs for the Drake: I
called Caltronix today and they confirmed that the 50-133 knob is only
available from the manufacturer if they buy 500 pieces. They are looking
for another vendor who will sell in more reasonable quantities. In the
meantime, they have available the 50-123 knob, which is 1.04" in
diameter vs. the 50-133, which is 0.93" diameter. Has anybody had any
luck with other vendors? I still need to replace one knob.
 
I hope to chat with you guys this Sunday during the CE Contest.
 
73,
 
Eric KA8FAN


Garey Barrell  wrote:

Garey Barrell made an utterence to the drakelist gang
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Most switching problems in Drake gear are a result of wafer misalignment 
or wafer center hole wear. Making sure the switch assembly hardware is 
tight and properly aligned and keeping shaft bearing surfaces lubricated 
will correct the first and help mitigate the last.

Silver "cleaners" clean by removing, either by chemical or mechanical 
means, silver (di?)sulfide. This is the black stuff seen on silver 
items. Unfortunately, when you remove silver disulfide, you are by 
definition removing "some" silver. The thing is, silver disulfide is 
very soft, and easily displaced by the spring action of the switch 
contacts. You can see this by looking closely at the blackened area of 
a switch. You will see a bright silver line where the contact has been 
wiping. By the way, the black deposit is essentially as conductive as 
silver.

The bad news is that any chemical or mechanical abrasive that is left 
behind on the switch after "cleaning" continues to work.

DeoxiT is excellent at removing minute amounts of corrosion at the 
contact points without attacking the _thin_ silver layer, restoring 
electrical conductivity. Liquid DeoxiT (Was D100L under old 
nomenclature) is best, since you want it only on the contact area, NOT 
all over everything in the general area to attract and hold dust.

The only reason I see for "cleaning" switch silver is for appearance, 
which is perhaps important if you are competing in a concours show! 
The inherent hazards, not to mention the danger of "springing" or 
otherwise damaging small contact elements by poking around them with 
tools, far outweigh any positive effects.

73, Garey - K4OAH
Atlanta

Drake C-Line Service Manual




Eric Webner wrote:

> Hi Joe,
> 
> Have you made any progress on your radio? I didn't see any responses 
> on drakelist.
> 
> It seems the crystals are ok, so it must be a wire or more probably, a 
> switch contact. The wafer switches on these radios seem to corrode a 
> bit, with the metal parts turning black. You might be able to clean 

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