Re: [drakelist] R4C xtal bank bad

[Eric Webner]

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 <[EMAIL PROTECTED]> wrote:

Garey Barrell <[EMAIL PROTECTED]>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
> the rotary switch contacts sufficiently with De-Oxit, but I used a
> more thorough method on all the switches in my T-4XC. Check out
> http://www.wb4hfn.com/DrakeArticles/CleaningSwitches/CleaningSwitches.htm for
> details.
>
> BTW, this web site is very well done and you will want to explore the
> other articles on it. Good luck.
>
> 73,
>
> Eric KA8FAN
>
> */Joe Roth <[EMAIL PROTECTED]>/* wrote:
>
>
> "Joe Roth" made an utterence to the drakelist gang
> ----------------------------------------------------------------------
> I've added a lot of xtals to my R4C. I began to use position 11
> which is now
> in the 3 (bottom most) row. The entire row for positions 11-15
> will not
> work. The receiver acts as if the xtal sockets are empty. The xtal
> works
> fine in other positions. I've swapped all combinations around and
> I know
> there is a problem with the row. I looked at the obvious solder
> joints on
> the switch and traced the connections of 3 wires going to the
> underside of
> the chassis. Everything appears to be okay.
> I now need to get in to it deeper and trace some lines with the
> VOM. Does
> anyone have suggestions to narrow things down?
> TNX
> Joe/N4ARI
> www.n4ari.net
>
>
>

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