Re: [Drakelist] Drakelist Digest, Vol 33, Issue 7

[Ken Winterling]

Howard,

When rebuilding AC-4s I have used both discrete replacements for the caps,
resistors, and diodes as well as the Heathkit Shop AC-4R boards.  The
boards are very good and the kit is easy to follow.  Just take your time
and note where the original wires were connected.  If you have a  digital
camera (or one on your phone) take pictures of the original wiring to use
as a reference during the rebuild.

If you do nothing else you should replace the bias supply capacitors and
diode as well as check the values of the resistors in the bias supply.  If
the bias supply fails it will toast your finals even if the transmitter is
in standby.

You mentioned "a voltmeter capable of 1000 volts to be used in the testing"
which leads me to believe you do not have such a meter.  If you do not have
one I would add that to the top of your "must get" list.  You don't need an
expensive, precision instrument but be sure it will measure 1000 VDC.
Many are limited to 600 VDC or 750 VDC.  You should be able to find one for
$50 or less.  Even my venerable Simpson 260 (analog) meter will measure
1000 VDC.

Good luck (and be careful)!

Ken
WA2LBI


On Fri, May 30, 2014 at 1:52 PM, Mike Williams  wrote:

> Hello Howard,
>
> I reworked an AC-4 with the Heathkit shop kit a couple of years ago.  It
> worked just fine and took me about 3 hours or so to complete taking my
> time.  The Hayseed kit may be easier since they use elecrolytic cans  with
> new caps inside so they are probably a unit for unit replacement I believe.
>  I don't know for sure since I have not used the latter.  In either case, a
> rebuild will probably save you a bunch of headaches especially if you were
> to lose the grid bias supply for your finals!
>
> 73 & DX,
>
> W4DLMike
> Tallahassee & Pompano Beach, FL USA
>
>
>
>
>> --
>>
>> Message: 1
>> Date: Thu, 29 May 2014 21:36:15 -0400 (EDT)
>> From: choward...@aol.com
>> To: drakelist@zerobeat.net
>> Subject: [Drakelist] TR-4 Audio Hum Question
>> Message-ID: 
>> Content-Type: text/plain; charset="us-ascii"
>>
>> Thanks to Gary and John for their response to my  audio  hum question. I
>> plan to accomplish the easy one first; cleaning the pins on the  AC-4
>> power
>> plug.
>> If that does not work, I will go to #2: re-cap the power  supply.  In
>> fact,
>> I may that in any case. But, I would like some advice. I  am 74 years old
>> and the only real electronic work I have done was to build a  Viking
>> Adventurer transmitter when I was 14.  It worked the first  time.
>> I have found 2 different products for the AC-4.
>> The first is from "Hayseed Hamfest". It is a kit that replaces  all five
>> electrolytic capacitors with new ones. It is $72.00.
>> The second is from "The Heathkit Shop".  The Drake  AC-4R kit includes a
>> new PCB that replaces the old Caps and diodes.  Only  the transformer and
>> the
>> bias adjusting pot from the old power supply are used.  It also requires a
>> voltmeter capable of 1000 volts to be used in the testing.
>> My question is to anyone who has knowledge of these products  and which
>> they recommend for someone with limited electronic skills.
>> As usual, Thanks for any help you folks can provide. You have  helped in a
>> couple of previous situations, which turned out just as you  suggested.
>> Howard - N0KOE
>>
>
>>
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Re: [Drakelist] T4XB output

[Ken Winterling]

Peter,

Check the manual again.  You will see that 200W is the INPUT power.

Assume a realistic 60% efficiency and you get 120W.

Ken
WA2LBI



On Sat, Jan 21, 2012 at 07:18, Peter Ravn  wrote:

> **
> Acccording to the factory specifications the T4XB should run 200 watts on
> all bands. My recent acquired T4XB runs 120 watts on 80 and 40 meters, 140
> watts on 20 meters, 100 watts on 10 meters and 75 watts on 15 meters. SWR
> is low on all the antennas used. After some 30-45 minutes of operation the
> output will fall app. 10 watts. Any idea why? Thanks in advance.
>
> 73 OZ8CTH, Peter
>
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Re: [Drakelist] T4XB output meter control

[Ken Winterling]

Peter,

If you have verified continuity through the switch then look at the
schematic and you will see there is a 1N270 diode between the output meter
control pot and the antenna.  If that diode is defective, missing, or has a
cold solder joint you will not get any reading.

Ken
WA2LBI



On Sun, Jan 15, 2012 at 10:34, Peter Ravn  wrote:

> **
> When I press and rotate the output meter control on my T4XB, nothing
> happens. I have checked the switch and the 68 0hm resistor on it. They are
> Ok.
>
> 73 Peter, OZ8CTH
>
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Re: [Drakelist] L4 vs. L4B

[Ken Winterling]

I consider it like a bench power tool switch.  You pull "ON" and push
"OFF".  This is done so you can punch the switch in the event of a disaster
rather than having to carefully aim and grab.  So to me, pulling to put the
amp on line and pushing to put into standby makes sense.  OTOH, I like big,
easily visible toggle switches for operate and standby.  If they have
lights, so much the better!

Ken
WA2LBI



On Fri, Jan 13, 2012 at 11:08, Garey Barrell  wrote:

> Hi Greg -
>
> You ever get that T-4X(?) running??
>
> Those type of control switches were typically used to turn equipment on
> and off, pulling 'OUT' to turn the gear 'ON'.  So Drake's implementation
> makes sense from that standpoint.  That said, I too have trouble keeping it
> straight, even with it printed right there on the panel!!  :-)
>
>
> 73, Garey - K4OAH
> Glen Allen, VA
>
> Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
> and TR-4/C Service Supplement CDs
> 
>
>
> Greg Roecker wrote:
>
>> Of all the ham gear I've owned and operated, the position of the ALC
>> switch on my L-4B for 'standby / operate' seems the most counter-intuitive
>> function to me - and one I screw up more times than I care to admit.  From
>> just a human factors perspective, pushing the switch in would logically
>> mean 'on' or 'in-line', and pulling it out would mean 'off' or
>> 'off-line'when it fact it's the other way around.
>>
>> You can train dogs to do tricksbut I think I'm just too thick to
>> learn this one!
>>
>> Thanks for the insight Garey.
>>
>> 73,
>>
>> Greg Roecker/n4osj
>> Roswell, GA.
>>
>> -Original Message- From: Garey Barrell
>> Sent: Friday, January 13, 2012 10:01 AM
>> To: m coffey
>> Cc: drakelist@zerobeat.net
>> Subject: Re: [Drakelist] L4 vs. L4B
>>
>> Mike -
>>
>> Couple of things.
>>
>> 1.  The L-4 never was sold with 4-400s.  I assume you mean 3-400Zs.
>>
>> 2.  Electrically, yes, you can replace the 3-400s with 3-500Zs.  The
>> problem is that the '500s are a
>> little taller and won't fit in some of the chimneys Drake supplied.
>>  There really isn't any reason
>> to replace 'good' 3-400s with 3-500s as long as you stay within the
>> original power specs.  This is
>> about the limit of the power supply anyway.  Yes, you can get close to
>> today's legal limit, if you
>> really need that one quarter of an S-Unit increase.
>>
>> The main 'significant' difference between the two is that the "B" moved
>> the ALC level control from
>> the rear panel, and made it a 'push-pull' switch control to put the
>> amplifier in standby.  Pushing
>> the knob "IN" takes the amplifier off line without turning it off.  With
>> the L-4, you have to switch
>> the AC power off to bypass the amplifier.  The 3-400/500Zs are 'instant
>> on' tubes so not an
>> operating problem, but you could argue about turning the amp on and off
>> multiple times.
>>
>> 73, Garey - K4OAH
>> Glen Allen, VA
>>
>> Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
>> and TR-4/C Service Supplement CDs
>> 
>>
>>
>> m coffey wrote:
>>
>>> Can anyone tell me the difference between the L4 and L4B ?  Can one
>>> replace the 4-400s with 3-500s? Mike
>>>
>>
>>
>>
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Re: [Drakelist] Yet another AC-4 rebuild (now :-) completed

[Ken Winterling]

Here are a couple examples that may also give you some ideas.
http://www.mcmelectronics.com/product/28-11161
http://www.mcmelectronics.com/product/28-11585

Ken
WA2LBI



On Tue, Jan 10, 2012 at 19:28, Garey Barrell  wrote:

> Mark -
>
> Here's a suitable one.   Rated at 15A, so should handle a couple of T-4X
> and a receiver or two without problems.
>
> Lots more out there, 'computer power center'.
>
>
> 73, Garey - K4OAH
> Glen Allen, VA
>
> Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
> and TR-4/C Service Supplement CDs
> 
>
>
> Mark Pilant wrote:
>
>> Hi Garey.
>>
>>
>>
>>
>> I like the idea of individually switched outlets.  But I haven't seen
>> any that weren't network/LAN controlled.  A little to pricey for me
>> at home.  (Although I have used them plenty at work.)
>>
>> 73
>>
>> - Mark  N1VQW
>>
>> _
>>
>
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Re: [Drakelist] problem with deoxit

[Ken Winterling]

In addition to the "wooden stemmed tightly woven Q tips that are
made especially for electrical cleaning" mentioned by Dennis, AE6C, I also
use the brushes listed below.  A drop of DeoxIT on either goes a long way.

These brushes are great for cleaning 7 & 9 pin tube sockets:
http://www.gumbrand.com/interdental-brushes/products/gum-go-betweens-proxabrush-cleaners-wide/872rn/

These brushes are good for cleaning RCA connectors, 8 pin and other larger
tube sockets, etc:
http://www.mcmelectronics.com/product/CAIG-LABORATORIES-AB-50-/200-288

Ken
WA2LBI



On Fri, Dec 23, 2011 at 13:06, Dennis Monticelli <
dennis.montice...@gmail.com> wrote:

> I have found that 100% DeOxit dries more slowly than the 5% stuff
> because the latter is mostly carrier.  So allow a little extra time
> before powering up, especially with pots.   A few hours should have
> been enough, so it seems that you applied too much.  I almost always
> use the 100% stuff but I avoid droplets.  Instead I apply the DeOxit
> to one of those wooden stemmed tightly woven Q tips that are made
> especially for electrical cleaning.  The Q tip then does double duty
> of applicator and scrubber.  This works really well for wafer switches
> and tube pins.  For socket pins, I use a wooden toothpick that is
> coated with DeOxit.  Once again it serves as applicator and scrubber.
> The Q tip and toothpick end up with a satisfying dark coloration of
> oxides with this method.  Sufaces will glisten after cleaning but you
> won't see any red pooling.
>
> With DeOxit a little goes a very long way.  Mild scrubbing with a
> rough absorbant surface such as wood or tightly woven Q tip physically
> removes the dissolved oxides.
>
> Dennis AE6C
>
>
> On 12/23/11, y...@aol.com  wrote:
> > Today I put a totally dead R-4a on the bench,replaced the fuse and off
> she
> > went. The rig was fairly clean considering its age. The rig lit up and
> got
> > some audio out and all functions seemed to basically work. Cleaned the
> > chassis of dust ,damp cloth  and proceeded to pull all the tubes and
> > test,all were good. I took a emery board and cleaned all tube pins then
> > wiped the pins with Deoxit and dried with a cloth, also cleaned all the
> > wafer switch contacts with deoxit,using the tiny needle bottle  being
> VERY
> > careful to keep the deoxit to the very small amount, also cleaned all the
> > pots with the deoxit  spray for pots.
> > Any way let the rig sit for a few hours working all the switch's and
> > pots. Reassembled the rig and powered up. The radio lite up and that was
> > about all ,nothing seemed to work, rechecked the tube install,all
> correct,
> > put back on the bench flipped the rig over  and ALL the tube sockets and
> > wafer switch's looked like they were flooded with deoxit. I was careful
> to
> > use as Little as you could of the deoxit,while cleaning everything.  I
> then
> > proceeded to clean EVERYTHING with 100 %alcohol, tube pins,sockets, all
> > wafer switch's and pots,made sure everything was dry, using a hair drier.
> > Put the rig back together and turned on,the R4A works as well as my B
> line
> > receiver,even without a alignment.
> >   Has there been a change in Deoxit? I have used this procedure on
> lots
> > of Boat anchors and up till now always worked fine. Can't believe the
> TINY
> > amount I used, crawled all over everywhere I didn't want it to go. Unless
> > someone else had used some other substance to clean before me and the the
> > deoxit ,I haven't got a clue. Anyone else run across anything like this?
> The
> > deoxit was brand new a week ago. I think I will star with the 100%
> > alcohol,like I used to use.
> > everybody  have a Merry Christmas
> > dale wt4t
> >
>
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Re: [Drakelist] What is he best way to test the N-4B noise blanker?

[Ken Winterling]

Lee,

Wire up a relay to act like a buzzer.  That should generate some good
ignition-like sparking at the contacts.

Ken, WA2LBI


On Sun, Feb 6, 2011 at 02:00,  wrote:

> Gang,
> I need to test the noise blanker in my R-4CIs there an easy way to test
> it?
> No ignition noise here, no electric fences
> Tried the hair dryer, and an electric drill
> 73,
> Lee
>
>
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Re: [Drakelist] GUF-1 Filter

[Ken Winterling]

Paul,

Years ago I read all of the Drake mods and other available information
regarding the GUF-1 and the recommendation was to install the 8 kHz GUF-1.
 I have one in my R-4C and it makes a significant difference with adjacent
channel rejection compared to the original factory filter.

Ken, WA2LBI


On Tue, Feb 1, 2011 at 16:33, Paul Christensen  wrote:
>
> I'm planning on adding a GUF-1 filter to my R-4C receiver.  Any comments
as to the selection of either the 6 kHz or 8 kHz filter version of the
GUF-1? One comment on the web indicated that the 4NB is more effective with
the 8 kHz GUF-1.  Perhaps it's a decision that balances NB effectiveness
versus narrower Rx bandwidth.
>
> Paul, W9AC
>
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Re: [Drakelist] Wanted 4NB Noise Blanker

[Ken Winterling]

To All,

The R-4C noise blanker is effective depending on the type of noise.  In my
case it handles the 20 over S9 raucous, pulsing hash generated by defective
street lights that try to restart every minute or so from dusk to dawn.  It
is far less useful on other types of noise.

Ken, WA2LBI


On Tue, Feb 1, 2011 at 15:50, Don Jones  wrote:

>  OK – I am going to stir the pot some.
>
> I have one of those 4NB noise blanker’s installed in my R-4C. To be honest
> that noise blanker is largely ineffective and over rated. I have seen them
> sell for over $200 on e-bay. I scratch my head and wonder why? In My Humble
> Opinion they are a over rated vessel of fertilizer and none may abide by the
> odor there of.
>
> Would I sell my 4NB noise blanker? NO. As you might recall I have one of
> those Sherwood / Drake R-4C’s (late production SN), the service receipt for
> it from Sherwood totals more than $900.
>
> Bottom line, be prepared to be disappointed if you pay high dollar for a
> 4NB noise blanker and it does little or nothing. Experiencing what I have
> with my R-4C and 4NB, I would never throw away money on buying one for my
> TR-4C.
>
> Be careful what you wish for.
>
> Don Jones KO7i
>
> ps – my heavily modified R-4C has been outperforming my Ten Tec OMNI VI in
> every way. The OMNI VI has a full load of filters. Plus the INRAD roofing
> filter mod. I have trying to get the VP8O logged and I have had to resort to
> using the R-4C to copy his very weak signal here in Western WA.
>
> Message: 1
>
> Date: Mon, 31 Jan 2011 10:21:01 -0800
>
> From: "Kevin Nathan" <*k...@comcast.net* >
>
> To: <*drakelist@zerobeat.net* >
>
> Subject: [Drakelist] Wanting to Buy
>
> Message-ID: 
> <*mailman.599.1296569921.2744.drakel...@zerobeat.net*
> >
>
> Content-Type: text/plain; charset="us-ascii"
>
> Hi All,
>
>  I went to a vintage radio even over the weekend and was able to sell some
> heavy metal and come back with much lighter cash.Now, I would like
> to find the noise blanker for my R4C.  Does anyone on the list have one and
> what would you need for it?
>
>  Thanks much and very 73.
>
>  Kevin :)
>
> Amateur Radio:  K7RX
>
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Re: [Drakelist] T-4XB LSB vs USB

[Ken Winterling]

Garey,

Of course, you are correct.  I was thinking of the PTT for SSB.  Sorry for
misleading you, Frank.

Ken, WA2LBI


On Mon, Mar 22, 2010 at 10:13, Garey Barrell  wrote:

> Ken -
>
> Re-read that page..   The Carrier Balance is adjusted in CW MODE, BUT
> with PTT closed instead of the KEY so the SIDETONE is NOT generated.
>
> This puts the Carrier Oscillator within the LSB passband so as to have a
> larger output to null.
>
>
> 73, Garey - K4OAH
> Glen Allen, VA
>
> Drake 2-B, 4-B, C-Line&  TR-4/C Service Supplement CDs
> 
>
>
> Ken Winterling wrote:
>
>> Frank,
>>
>> The carrier balance adjustment is made in SSB, not CW.   See page 15 of
>> the T-4XB manual under "CARRIER BALANCE ADJUSTMENT".
>>
>> Ken, WA2LBI
>>
>>
>> On Mon, Mar 22, 2010 at 09:42, iz oos > izo...@gmail.com>> wrote:
>>
>>Hi!
>>
>>I did my homework! Indeed, the carrier oscillator crystal frequency
>>was not exactly set to 5.645 MHz, mainly due to C2 which was offest by
>> 30 degree and a bit also to T14 which was not completely peaked.
>>Switching sideband switch back and forth it was easy to note
>>difference in plate current and Adjust C-2 to make the current and
>>output of the sidebands equal. Current was about 0.8 and output zero
>>or close to zero.
>>
>>
>>Plugging the mike, both sidebands now sound much more the same,
>>however I had still to rebalance the carrier balance control which was
>>set fully counter clockwise. Setting the function switch to CW and and
>>PTT on mic ON the relative output meter stays at zero for whatever
>>adjustment of the carrier balance control  So, I CAN'T rebalance
>>the Carrier Balance control 
>>
>>Why is that???
>>
>>73,
>>
>>Frank IZ2OOS
>>
>>
>>
>>
>>2010/3/21 Garey Barrell ><mailto:k4...@mindspring.com>>:
>>
>>> Frank -
>>>
>>> Start with the Carrier Oscillator, Filter Match & Balanced Modulator
>>> alignment in Section VII, Section B.  The idea is to get the Carrier
>>> Oscillator "centered" in the valley between the two filters as
>>shown at "0"
>>> on Page 37.
>>>
>>> 73, Garey - K4OAH
>>> Glen Allen, VA
>>>
>>
>>
>>
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Re: [Drakelist] T-4XB LSB vs USB

[Ken Winterling]

Frank,

The carrier balance adjustment is made in SSB, not CW.   See page 15 of the
T-4XB manual under "CARRIER BALANCE ADJUSTMENT".

Ken, WA2LBI


On Mon, Mar 22, 2010 at 09:42, iz oos  wrote:

> Hi!
>
> I did my homework! Indeed, the carrier oscillator crystal frequency
> was not exactly set to 5.645 MHz, mainly due to C2 which was offest by
>  30 degree and a bit also to T14 which was not completely peaked.
> Switching sideband switch back and forth it was easy to note
> difference in plate current and Adjust C-2 to make the current and
> output of the sidebands equal. Current was about 0.8 and output zero
> or close to zero.
>
>
> Plugging the mike, both sidebands now sound much more the same,
> however I had still to rebalance the carrier balance control which was
> set fully counter clockwise. Setting the function switch to CW and and
> PTT on mic ON the relative output meter stays at zero for whatever
> adjustment of the carrier balance control  So, I CAN'T rebalance
> the Carrier Balance control 
>
> Why is that???
>
> 73,
>
> Frank IZ2OOS
>
>
>
>
> 2010/3/21 Garey Barrell :
> > Frank -
> >
> > Start with the Carrier Oscillator, Filter Match & Balanced Modulator
> > alignment in Section VII, Section B.  The idea is to get the Carrier
> > Oscillator "centered" in the valley between the two filters as shown at
> "0"
> > on Page 37.
> >
> > 73, Garey - K4OAH
> > Glen Allen, VA
> >
>
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Re: [Drakelist] T-4XB Transceive Frequency Offset

[Ken Winterling]

Curt,

See pages 15 and 16 in your T-4XB manual.  It is the section labeled
"TRANSCEIVE ALIGNMENT".

Have fun!

Ken, WA2LBI


On Sun, Nov 8, 2009 at 12:59, Curt  wrote:

>  I had been using my T-4XB and R-4A in separate mode since buying them.
> Recently hooked up injection cable and tried "transmitter" control.  Folks
> with the 40M net said I was off frequency, about 300 Hz low. Maybe am just
> not seeing it, but the manual doesn't mention correcting th.
>
> Appreciate advice about correcting this problem.
>
> 73, Curt KB5JO
>
>
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Re: [Drakelist] trouble with c-line

[Ken Winterling]

Yash,

Be sure the receiver is to to EXT MUTE.

Ken, WA2LBI



On Thu, Oct 29, 2009 at 12:04,   wrote:
> Just set up my c-line,everthing worked fine Except .. when you key the
> transmitter  ssb   you hear yourself thru the speaker. Changed the mute
> cable just to be sure,problem still occurs. Read the manual,gather when the
> transmitter is keyed it causes a relay in the receiver, thru the mute line
> to shut off the ant to the r4c? Been running a Heath 301/401 line for a few
> years and this is my first drake line. Iam asking before I get into the 2
> rigs ,maybe I have a adjustment I passed over while setting up the 2. sure
> would welcome any suggestions on this.
> thanks
> dale wt4t
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Re: [drakelist] AM Filter R4C

[Ken Winterling]

Frank,

INRAD sells new R-4C AM filters for either $110 or $120 USD.  The asking
prices for any used filters I have seen for sale are usually in the same
vicinity or higher.  I also need (want) an AM filter to complete the filter
selections in my R-4C.  Considering the used prices I will buy a new one
from INRAD if I absolutely must have one.  They will give you a guarantee
that you won't receive from a used item seller.

73,

Ken, WA2LBI


On 3/25/07, Frank Woolfe <[EMAIL PROTECTED]> wrote:


 Gents,



After an AM filter for a R4C can anyone help, if so what would it be
worth?



Cheers.



Frank H Woolfe, Dip EE. VK5MFW

36 Coolaroo Street Woomera

South Australia 5720

Ph 08 8673 7725

Mb 0408 100 707

Re: [drakelist] AC-4R upgrades

[Ken Winterling]

"Ken Winterling" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
According to Tom this supply also had an open 10K HV bleeder/load
resistor.  Whatever caused it to fail may have caused the 220K
resistor to fail.  I'm waiting for Tom's response to see what he
found.

Ken, WA2LBI

On 1/15/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:


An open 220k bleeder resistor makes sense. I guess you could check that by
disconnecting it and checking the resistance. Makes me wonder what would
cause it to fail. Assuming 250 volts it would need to dissipate 0.28 watt.
If it's a 1/2 watt carbon composition resistor, it might have increased in
value over time. Those resistors are known to do that.
-- Original message --
From: "Ken Winterling" <[EMAIL PROTECTED]>

>
> "Ken Winterling" made an utterance to the drakelist
> gang
>
--
> Tom,
>
> There is a 220K bleeder/load resistor, R8, across the medium B+, 250V,
> supply to ground. If it is open the medium B+ will be pulled up
> toward the HV. Let us know what you find.
>
> Ken, WA2LBI
> >
> > On 1/14/07, Tom Taylor wrote:
> > > Still working on the AC-3... The drakelist wisdom was the 20k load
resistor
> > > didn't present enough of a load, compared to the original 10k
resistor, and
> > > that was the reason the HV kept climbing. I ordered a 10k 10w re
sistor and
> > > it recently arrived and I installed it in place. Note that this
resistor
> > > connects the HV+ with the medium voltage B+ (which seems odd). With
this new
> > > resistor, the HV now reads a reasonable and respectable 720v (no
load).
> > > That's good. But the medium voltage now reads 570v !!! I can't explain
it.
> > > What's different about the medium voltage supply is I replaced the two
100
> > > uf caps with 330 uf caps and the 80 uf cap with a 120 uf. That's what
I had
> > > in my junk box. Why is that supply so over-voltage now? Perhaps I have
a
> > > wiring error, though I carefully checked for errors.
> > >
> > > Thanks,
> > > Tom n7tm
> > >
> >
>
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Re: [drakelist] AC-4R upgrades

[Ken Winterling]

"Ken Winterling" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Tom,

There is a 220K bleeder/load resistor, R8, across the medium B+, 250V,
supply to ground.  If it is open the medium B+ will be pulled up
toward the HV.  Let us know what you find.

Ken, WA2LBI


On 1/14/07, Tom Taylor <[EMAIL PROTECTED]> wrote:
> Still working on the AC-3... The drakelist wisdom was the 20k load resistor
> didn't present enough of a load, compared to the original 10k resistor, and
> that was the reason the HV kept climbing. I ordered a 10k 10w resistor and
> it recently arrived and I installed it in place. Note that this resistor
> connects the HV+ with the medium voltage B+ (which seems odd). With this new
> resistor, the HV now reads a reasonable and respectable 720v (no load).
> That's good. But the medium voltage now reads 570v !!! I can't explain it.
> What's different about the medium voltage supply is I replaced the two 100
> uf caps with 330 uf caps and the 80 uf cap with a 120 uf. That's what I had
> in my junk box. Why is that supply so over-voltage now? Perhaps I have a
> wiring error, though I carefully checked for errors.
>
> Thanks,
> Tom n7tm
>


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[drakelist] Drifting T-4XC PTO

[Ken Winterling]

Happy holidays to all!

I have a T-4XC on the bench that has a drifting PTO.   I am monitoring it
with a freq counter and it never settles down, even after hours on the
bench.  The 11 VDC supply is stable.  Have any of you folks run across this
and, if so, what was the cure?

Thanks,

Ken, WA2LBI

Re: [drakelist] parts

[Ken Winterling]

Rob,

The original feet for the AC-4, when used stand alone, had a 6-32 stud
projecting from a rubber "bumper" that protected the table top.  These were
removed when the AC-4 was inserted in a MS-4 speaker cabinet.  The feet were
then used to secure the AC-4 to the MS-4 cabinet which had its own feet that
were longer.

Below is one site where you can get these AC-4 feet.  I have no interest in
Donny's site other than as a satisfied customer.  I have purchased the B and
C line blue filters and white diffusers from him.

http://www.wa9tgt.com/Drake_Cabinet_Feet_Bumpers.html

As for crystals, everybody has their favorite source.   I use JAN Crystals
for the B and C lines I own/repair.  I don't buy used crystals because you
don't know what you are getting and most sellers want close to what JAN
charges for a new one.  Also, JAN provides a guarantee and will replace a
defective xtal.  How many sellers of used xtals will do that?

73,

Ken, WA2LBI


On 12/9/06, R. Ton <[EMAIL PROTECTED]> wrote:



"R. Ton" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
It's a standard 6-32 machine thread in the AC-4.  1/4" screw should work
fine -- these are available in any hardware store.  (I'm not aware of
any rubber coating).

73, Rob (KFØRT)
> Anyone out there have a source for the screws that hold the MS4 power
> supply to the AC4 cabinet? Think the heads are covered with rubber. If
> not,how about the size for them?
> Also am in need of a 100khz calibrator crystal.
> Thanks
> Rusty
> WB9FIU

Re: [drakelist] D-104 Mic.

[Ken Winterling]

"Ken Winterling" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Dave,

Check the function switch on the R-4C.  Be sure it is in the "EXT.
MUTE" position. That position allows the transmitter to mute the
receiver during transmit.

If the switch is in the "ON" position the mute function is bypassed
and the receiver remains operational during transmit and you will
experience the feedback you described.  I use this "feature" on
occasion to check my transmitted audio while wearing headphones and
cranking down the RF gain control.

Ken, WA2LBI

On 12/4/06, David Abbott <[EMAIL PROTECTED]> wrote:


"David Abbott" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Good evening, I have another problem with my twins -- R4C not muting when I
key my mic. I am using a D104 mic. I checked the wiring diagram and
everything appears to be wired correctly. I have it plugged into a T4XC.
When I key it, I get major feedback from the receiver. I have adjusted the
antivox gain,the ssb vox delay, and the vox gain. I checked the mute cable
connected to the receiver and the xmitter for continuityIt reads alright
. So my question is, has anyone had this problem b-4. I am wondering if I am
using the wrong mic. I used the same mic on my Hallicrafters HT-32B and it
works just find. I am in the dark on this one .Thanks for your time in
reading this and your help. 73's Dave WB6BIL.


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[drakelist] Late Version AC-4 Schematic

[Ken Winterling]

"Ken Winterling" <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
I am looking for an electronic copy of the latest version of the AC-4
power supply schematic that shows the wiring of the dual voltage
primary switch.

Thanks,

Ken, WA2LBI
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Re: [drakelist] Excessive PTO free play

[Ken Winterling]

Ken Winterling <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Keith,

Here are two sites that may help.  The PTO has an internal adjustment
screw for the ball bearing race.  The first site describes the
procedure while the second one provides a picture of an open PTO and
where the adjustment screw is located.  Some PTO covers have an access
hole in the rear, others do not.  You must remove the cover to adjust
a PTO that does not have an access hole.  You will need a long 3/32"
allen (hex) wrench.

http://www.dproducts.be/drake_museum/nouvelle48.htm
http://www.jvgavila.com/tr3.htm

Be careful not to disturb anything in the PTO or you will affect its
tracking.   Do not over tighten the adjuster or you will ruin the dial
drive ball bearings and race.

Good luck!

Ken, WA2LBI


On 1/31/06, Keith Hamilton <[EMAIL PROTECTED]> wrote:
>
> Keith Hamilton <[EMAIL PROTECTED]> made an utterance to the drakelist gang
> --
> I have an R-4C receiver with metal gears in the PTO
> assembly. I have too much free play in the PTO
> assembly. The knob can move up and down at least an
> 1/8 of an inch (maybe more) There is no free play in
> and out. I need some sugestions about where to adjust
> the gear train or bearings to eliminate the up and
> down play.
> The PTO bearings had been heavily greased and it took
> a lot of work to clean out the grease and loosen up
> the PTO. I lightly oiled only the bearings and it now
> turns freely like it should, but I would like to
> eliminate the annoying free play.  (it had the free
> play problem before I "ungreased" it.)
> 73  Keith, N8QO
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Re: [drakelist] T-4XC microphone

[Ken Winterling]

Ken Winterling <[EMAIL PROTECTED]> made an utterance to the drakelist gang
--
Keith,

Over the years I have used the following, listed in no particular
order, with "B" and "C" lines:
Shure 444D
Shure 404C
Shure 520SL
Astatic D-104
Astatic 10-DA
Electro-Voice 664

Ken, WA2LBI

On 1/25/06, Keith Hamilton <[EMAIL PROTECTED]> wrote:
>
> Keith Hamilton <[EMAIL PROTECTED]> made an utterance to the drakelist gang
> --
> I would like to ask the group for some advise
> concerning a microphone for my T-4XC? Has anyone tried
> using the Heil GM Vintage microphone? What do you use?
>  Keith, N8QO
>
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