Re: [Drakelist] Drakelist Digest, Vol 67, Issue 1

[Dieter Horst]

Hello Demis,

you may want to try reseating the DR7 first. I would say that EXACTLY 2 
MHz offset indicate a digital problem. The relevant circuitry sits on 
the DR7. The connector is on the upper left when the front looks to you, 
9 Pins. If you have an intermittent there, it could cause the problem 
you described. A little bit of Deoxit may help prevent further contact 
issues.


As always... whenever there is something strange happening on a TR7 or 
R7, reseat the boards first before you do any alignment.


Best 73s

Dieter DL5RDO




Am 10.10.2017 um 19:02 schrieb Demis Bertoni:

Hello Dick,
thaks for your very quickly reply, I will do wath you told me next 
weekend!


73, Demis IZ4ORS


2017-10-10 18:00 GMT+02:00 >:


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Today's Topics:

   1. DRAKE R7A jump the frequency (Demis Bertoni)
   2. Re: DRAKE R7A jump the frequency (DW Harms (Dick))


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Message: 1
Date: Tue, 10 Oct 2017 10:55:01 +0200
From: Demis Bertoni >
To: drakelist@zerobeat.net 
Subject: [Drakelist] DRAKE R7A jump the frequency
Message-ID:
       
>
Content-Type: text/plain; charset="utf-8"

Hi All,
I've problem with my R7A, this morning during a QSO at 14,222, the
reception frequency jumped directly to 12,222 for a few seconds to
return
to 14,222. I tried to rotate the band switch, the up and down
buttons, but
occasionally the frequency jumps. Where's the problem?

Do you have a solution to this problem?

Many thanks for possible help.

My best 73's
--
IZ4ORS - Demis Bertoni
Via Rebecchi, 13 - 41015 Nonantola
(Modena) - Italy
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Message: 2
Date: Tue, 10 Oct 2017 13:42:15 +0200
From: "DW Harms (Dick)" >
To: Demis Bertoni >
Cc: drakelist@zerobeat.net 
Subject: Re: [Drakelist] DRAKE R7A jump the frequency
Message-ID: >
Content-Type: text/plain; charset="us-ascii"

Hello Demis,

Guess the PLL needs adjustment, check the procedure in the service
manual. I had something similar in my TR7 which was solved that way.

73, Dick PA2DW



Verstuurd vanaf mijn iPhone

> Op 10 okt. 2017 om 10:55 heeft Demis Bertoni > het volgende geschreven:
>
> Hi All,
> I've problem with my R7A, this morning during a QSO at 14,222,
the reception frequency jumped directly to 12,222 for a few
seconds to return to 14,222. I tried to rotate the band switch,
the up and down buttons, but occasionally the frequency jumps.
Where's the problem?
>
> Do you have a solution to this problem?
>
> Many thanks for possible help.
>
> My best 73's
> --
> IZ4ORS - Demis Bertoni
> Via Rebecchi, 13 - 41015 Nonantola
> (Modena) - Italy
> ___
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Re: [Drakelist] Connecting Signalink to TR-7?

[Dieter Horst]

Hello Gary,

I am not particularly familiar with the Signalink but it seems to have 
the usual connections like AF-out, AF-in and PTT.
The TR7 is not at all uncommon in this respect. Keying is low-voltage 
positive and the audio connections are not different from other 
transceivers.

I used mine for WSPR without any trouble.

If nothing at all works you may want to check whether the GND connection 
is good. At least PTT should work straight away.


73s, Dieter DL5RDO




Am 09.10.2013 02:09, schrieb Gary Watson:
I would like to give some diital modes a try, but I have not been 
successful in connecting the Signalink to my(new to me)  TR-7. I have 
the jumpers set correctly on the Siglink, but I am not able to pick-up 
signals on the waterfall (JT-65) nor am I able get it to key the PTT. 
Can someone point me to a working connection diagram?


Gary, K6PDL


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Re: [Drakelist] R7 AGC issues

[Dieter Horst]

Thanks Paul for sharing this!

I found the fast AGC on the R7 useless, too. I will try the proposed mod 
on my R7.


@Jim, would you say that the service manual describes the right methode 
for aligning the AGC?
I have had my doubts about it in the past, mostly because 'fast' would 
always create trouble.


73 de Dieter DL5RDO



Am 11.05.2013 21:17, schrieb Jim Shorney:

Wow, nice detective work Paul! I've had correspondence with John too, but it
was mostly about the AGC alignment and the subject of the fast AGC never came
up. I would agree with the assessment that it is useless, the poppy-ness on
noise alone is just to annoying to put up with, and manual intervention with
the RFG control shouldn't be needed. I have another R7 I am working on for
someone that exhibits the same behavior, and I have heard similar tales from
other users. I just figured that it was the nature of the beast, and haven't
taken the time to look deeply at the circuit.

I agree with doing the alignment by the book at this point. I tied various
alignment methods, and after discussing the how and why of the book method with
John, that seems to be the best way to do it.

I'll file your notes and try it out the next time I have one or the other of
the radios on the bench - a couple of other projects have temporarily sidelined
Drake tech-ing for me.

Many thanks to John also, for sharing his wisdom!

73

-Jim
NU0C

On Sat, 11 May 2013 11:39:52 -0500, Paul wrote:


Have had issues with the R7 AGC in fast mode in that the AGC would go
into a low frequency oscillation excited by noise.  Looking at the AGC
line showed a triangular waveform.  This caused distortion on AM and SSB
signals.  This problem went away when the RF gain control was turned
counterclockwise (reduced IF gain).  Medium AGC also had this problem
but to a lesser degree.  Slow AGC worked fine.

  Contacted John Kriner and he was kind enough to share his thoughts and
suggestions on fixing the R7 AGC problem.  I made the modifications to
the IF/AGC/Audio board per John's suggestions and they did help.  There
was no more issues with medium AGC and much less problem with fast AGC.
On no noise the fast AGC did not oscillator anymore, but when high noise
or signals present AGC did go into the low frequency triangular wave
oscillation.  By turning the RF gain control down (less IF gain) the
problem went away and the fast AGC was usable.  Since I don't really use
fast AGC for anything, I'm quitting while ahead.  Proper alignment of
the R7 IF/AGC/Audio board is important.

Has anyone had a similar problem with the R7 AGC in fast and/or medium
modes?  Anyone come up with a better solution then John's below?  I
think that the R7 AGC circuit has too much gain and becomes unstable
when excited by noise or signals.  My TR7 doesn't suffer from the
aforementioned problems.

Excepts of the emails:

To: John,
I have a Drake R-7A that works very well except when using fast AGC
and/or the audio distorts when the RF gain is all the way up (in all
speeds of AGC).  I have aligned the IF/AGC/audio board per the manual
and your instructions below:

(John's alignment instructions -  AGC pedestal is left all the way CW.
I have argued with some folks who claim it must be re-adjusted.  But
this is the way I have always left it.  And the S-meter calibration
turns out to be perfect, and S+N/N far exceeds the specifications.  10dB
drop in generator level equals an exact 10dB drop on the 'S' meter. )

My S-meter calibration is perfect for microvolt inputs, but audio
distortion at high RF control (IF) gain is horrible.  When I turn down
the RF (IF) gain control the receiver works well with no distortion or
AGC pumping in fast AGC.  I tried adjusting the AGC pedestal, R1127,
just to see if it made any difference, it didn't.

I could not find any obvious circuit or component failures.  Scoping the
AGC circuit in Fast AGC shows a triangular waveform oscillation excited
by noise.  When the RF (IF) gain knob is turned down this triangular
waveform oscillation goes away and the receiver works fine.  I think the
audio distortion is being caused by the AGC circuit modulating the IF
signal.  The distortion is mainly on AM detection but I can tell that
the SSB demodulated signal also doesn't sound quite right.  There also
is popping of the SSB signal at the beginning of voice peaks even with
slow AGC.  All of this goes away when I reduce the RF gain control.

Is this a circuit component(s) malfunction or a design problem?  My TR-7
doesn't act like this.

 From John:
Fast AGC on the R7/A is useless.

It always has been.  No tweaking can correct it.

I had a customer with a RR3 complain about this as well.  He sent me the
radio (basically a ship R7) and I worked with a designer at Drake.  This
is the fellow who designed the SW8, Eton E1, and R8A/B.  He said he too
knew that fast was worthless.I took a schematic to him and he said that
the time variance between fast and medium was such that fast was 10
times faster 

Re: [Drakelist] Removing the Load Variable Capacitor on a L-7

[Dieter Horst]

Hello Roger and group,

I had the same problem with an L-7 I bought some time ago. It came 
without P/S, was cheap and had 3-500ZG with graphite anodes from RF 
Parts. But I was aware of a short in the load cap because you could hear 
it when turning even without RF applied. I bought the whole thing anyway.


To fix the problem, I had to get the cap out of the L-7. That is not the 
nicest job you can imagine but can be done. There was some melted 
aluminum on 2 plates. I used a Dremel with a sanding disc to get between 
the plates and sand out the aluminum. Luckily the short was not further 
inside. I would have had a hard time if this had been the case.


The cap can be aligned so that the plates are centered. Maybe yours has 
been mistreated by a previous owner.


73s Dieter DL5RDO


Am 30.07.2012 03:53, schrieb Roger White:
I have had a Drake L-7 sitting on the shelf unused for a few years now 
and recently decided to sell it. It has had the power supply updated 
and the ON/OFF switch disassembled and cleaned. It had functioned OK 
the last time I had used it (2 years ago) with the only problem being 
an erratic reading Plate Amp meter (an quick tap on the meter made it 
come from zero to the correct reading).
The problem I am having now (and one that has never occurred before) 
is the Load Variable Capacitor is appearing to short some of its 
plates over a narrow arc of operation (say 10-20 degrees of arc). I 
can hear the plates touching and, of course, the resultant negative 
effect of the power out going to zero, etc. I have only had the amp 
open once to clean the power switch, I could tell it may have been 
worked, on as far as the screws on the bottom cover(s) appear to have 
been removed at few times.
One thing I have noticed as I looked at the cap with the cover removed 
is that I can hear the plates unshort if I torque the chassis a 
little bit or loosen the screw that holds the front half of the Load 
Cap to the floor. Has anyone had this sort of problem with one of the 
variable caps? Can the Load var. cap be removed easily?

Thanks for any help in advance.


Roger White W5RDW
Murphy, Texas



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[Drakelist] Connector for L7-PS

[Dieter Horst]

Gentlemen,

I am currently after an L7 missing the power supply. It will not be a 
big problem to build a decent p/s but will I be able to get that 8-pole 
connector? Especially here in Germany it is probably hard to get. Can 
you give me some sourcing hint?


Thanks and 73

Dieter Sam DL5RDO

TR-7/R7

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[Drakelist] WTB MS-7

[Dieter Horst]

Hello Drake community,

my R-7 is always jealous because the TR-7 sitting next to it has an MS-7 while 
the R-7 only has the internal speaker.

So I am after another MS-7 to restore full fairness on the table again.

Should anyone of you have one for sale, please let me know.

Thanks

Dieter DL5RDO




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Re: [Drakelist] List Downtime

[Dieter Horst]

Another 2 cents from across the atlantic. I have been on this list for
many years now and I really appreciate the knowledge about Drake gear
being present in the community here. 

I have joined several activities initiated by group members such as
- Drake replacement feet
- extender boards
- Drake book
- Drake log book

To me, this is real amateur radio. 

And Thom, you were not really serious, right? Thanks for all your effort
over many years.

Best regards from Germany

Dieter DL5RDO





 Thom,

  I'll throw in my 2 cents.  I don't post very often, but I have a
 separate Drakelist folder in my Outlook Express that automatically catches
 all the postings and I read them every single day.  The list already
 helped
 me fix a TR-7 and I'm thankful for the list and archives.  It's a great
 asset and I appreciate it like everybody else who has responded.

 Dave / K8JDC

 - Original Message -
 From: Thom LaCosta k3...@zerobeat.net
 To: drakelist@zerobeat.net
 Sent: Sunday, June 14, 2009 7:37 AM
 Subject: Re: [Drakelist] List Downtime


 At 07:32 AM 06/12/09, Thom LaCosta wrote:
Apologies for the recent list downtime.  An automated update to the
server
software did not restore the settings for the mailing lists.

 Is anyone here?

 Just wondering if I should continue the list, or simply remove it from
 the
 server?

 Thom


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Re: [drakelist] Pondering RF Feedback (TR7/SP75)

[Dieter Horst]

Dieter Horst [EMAIL PROTECTED] made an utterance to the drakelist gang
--
I agree with the ferrite idea. Whenever I go to the club station DL0AO for a 
major
contest, I have a few ferrites with me. And they did help a lot in the past.

Not only RF pickup in Mics and Headphones but also lots of computer problems
like strangely behaving keyboards, mice etc. can be cured. 

At the last meeting of the Bavarian Contest Club a presentation was given
on this subject by Hans DK3YD.

The slides can be found here: 

http://www.bavarian-contest-club.de/storage/med/papers/linden2008/79_Linden2008_dk3yd.pdf

(Sorry, all in German but you can see from the pictures how the ferrites are 
mounted.
I may help with a translation if needed.)

73, Dieter DL5RDO







 When and where to ground is not as simple as it sounds at first thought.?
 Depending on circuit design, several grounding schemes for microphones
 might have to be tried to ensure proper shielding while at the same time
 not creating a ground loop.? Too, ferrite beads on each and every lead
 going to/from the rig might help.



 Just some random thoughts from a fellow Drake enthusiast...


 -Original Message-
 From: Jim Shorney [EMAIL PROTECTED]
 To: drakelist@zerobeat.net drakelist@zerobeat.net
 Sent: Wed, 2 Jul 2008 10:35 pm
 Subject: [drakelist] Pondering RF Feedback (TR7/SP75)




 Jim Shorney [EMAIL PROTECTED] made an utterance to the drakelist
 gang
 --

 Some readers may recall that last year I was plagued by RF feedback at
 Field Day
 with the TR7/SP75
 combination. Careful balancing of the mic gain and SP75 input and output
 levels
 could eliminate it most of
 the time, but not always.

 This year, I connected a ground strap from the SP75 to the TR7 chassis, as
 was
 suggested here. Well, that
 helped quite a bit. However, I was still seeing some RF feedback this
 year. It
 was happening with the Yagi
 (4-el 20 meter monoband) pointed generally southwesterly, which would have
 been
 pretty much over my
 head. As usual, were stationed in an EMCOMM trailer on a concrete parking
 lot,
 with no station ground
 available. The feedback could be mostly eliminated, depending on the
 actual
 position of the Yagi, by
 reducing the TR7 mic gain. I couldn't nail down exactly where it was
 getting in,
 but it seemed to have
 something to do with the microphone wiring - a Telex Echelon 150 aircraft
 active
 noise-cancelling headset
 with a homebrew interface box. The box was solid aluminum, mic cable to
 the SP75
 was RG-174/U coax,
 and power for the ANC amplifier and mic bias was well bypassed. Sort of a
 puzzler.

 Then I found this surfing the web:
 http://www.audiosystemsgroup.com/RFI-Ham.pdf

 This may be old news to some of you, but what caught my eye was the
 author's
 description of what is called
 the Pin 1 problem. I recalled from having been inside these boxen that
 the mic
 ground connection inside
 both the TR7 and the SP75 is not tied to the chassis at the point of
 entry, but
 rather, is wired to the circuit
 board. According to the referenced article, this is bad.

 I've made wiring changes to both the TR7 and SP75 to establish proper
 grounding,
 as described in the
 article. There is also a tech note on Heil's web site regarding this
 problem:
 http://www.heilsound.com/amateur/tips/rfi_removal_mics.htm

 Heil provides a method of grounding at the mic connector that is pretty
 easy,
 but I have a lot of microphones
 and I like to try out different things.

 It seems possible that this may be where my feedback was entering, but I
 have no
 way of duplicating the
 Field Day conditions at home (and I doubt the radio club will want to drag
 out
 the trailer, Yagi, and tower just
 to test my rig). I don't recall ever seeing this sort of RF feedback at
 home, so
 it will have to wait for next year
 to test out the Pin 1 problem theory. I'm thinking I will take along
 some
 snap-on ferrite chokes next time as
 well - or maybe I can get the club to add some to the Field Day kit.

 Any thoughts from the gallery?

 73

 -Jim
 NU0C

 (BTW, the Echelon headset knocked the generator noise right out of the
 headphones...)



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Re: [drakelist] Re: TV-3300LP Help?

[Dieter Horst]

Dieter Horst [EMAIL PROTECTED] made an utterance to the drakelist gang
--
Steve,

my TV-3300 works just fine and I wonder why yours has the cut-off frequency 
already on 10 meters.

If you know someone who has good measurement equipment like a network analyzer, 
you may give it to him and have it properly measured and hopefully aligned if 
possible. 

I could do this for you as I have equipment like this but shipping the thing to 
Germany would probably cost you more than you paid for it.

In any case, the TV-3300 is a good piece of gear and very well designed. 

73, Dieter DL5RDO





 Steve Berg [EMAIL PROTECTED] made an utterance to the drakelist gang
 --
 Hi Bob,

 Thanks for the tip.  I got it apart and tightened up the bolts holding
 in the capacitors.  It still attenuates on 10 meters, but seems to be
 fine other than that.  I hate to take a crowbar to a piece of gear
 unnecessarily.

 73,

 Steve WA9JML

 Robert Ladden wrote:

 Robert Ladden [EMAIL PROTECTED] made an utterance to the drakelist gang
 --
 I have one and have opened it. I still use it. It opens easily by
 removing the screws you can remove (the bolts are not removable) and
 sliding it apart.

 73,
 Bob WW3QB





 At 08:45 PM 5/15/2008, you wrote:

 Steve Berg [EMAIL PROTECTED] made an utterance to the drakelist gang
 --
 I bought a Drake TV-3300-LP filter off of the e-place.  I find that it
 starts to attenuate and cut off at the lower end of the 15 meter band.
 I tried to take it apart, and it has resisted valiantly.  How do I get
 this thing apart so that I can take a look inside?

 73,

 Steve WA9JML

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Re: [drakelist] TR-7 AF control

[Dieter Horst]

Dieter Horst [EMAIL PROTECTED] made an utterance to the drakelist gang
--
Hello Ken,

I am afraid, it is normal. Reason is that when audio is completely muted, the 
radio is off because the on/off switch is activated by then...

There is only one cure I once tried: you add a resistor to decrease the max. 
volume and therefore also the min. volume. But I removed it again and use the 
method you described i. e. RF control.

Enjoy your TR-7 !

73, Dieter DL5RDO


 I recently acquired TR-7 SN 3173, my first.  Is it normal for the AF
 control to provide enough volume to still hear easily when full
 counter-clockwise or is the pot changing value with age?  Only way I have
 of cutting audio volume down lower is by use of RF control.  Doesn't
 bother me but I have a picky XYL who's not all that fond of my hobby.

 Thanks,
 Ken - N0VA


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Re: [drakelist] ham equip for sale

[Dieter Horst]

Dieter Horst [EMAIL PROTECTED] made an utterance to the drakelist gang
--
...and I am still after a nice WH7...

73

Dieter DL5RDO


 Thom LaCosta [EMAIL PROTECTED] made an utterance to the drakelist gang
 --
 If anyone here does buy the entire collection...I am very interested in
 the
 Brown Brothers combination.

 Thom

 www.baltimorehon.com/Home of the Baltimore Lexicon
 www.tlchost.net/hosting/ Web Hosting as low as 3.49/month
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Re: [drakelist] L75 burning smell

[Dieter Horst]

Dieter Horst [EMAIL PROTECTED] made an utterance to the drakelist gang
--
Dick,

look at the VHF suppressor directly at the anode. It is usually made of 
carbon resistors with a coil wound around. 

Under some circumstances (mismatch, near oscillation...) these resistors 
dissipate a lot of power.
Maybe too much in your case...

Your description of not having the effect when a dummy is connected made me 
think of this.
I have no L75 though.

73, Dieter DL5RDO


 Dick Harms PA2DW [EMAIL PROTECTED] made an utterance to the drakelist
 gang
 --

 Hi all,

 I am using the L75 for some time now and since recently I have this
 strange
 smell when I run the PA for a while at max power. My wife then says have
 you started smoking cigars again, you promised not too yaghhh! And yes it
 smells like a mixture of burned resistors and cigars. Something has to
 be
 done about it hi!
 The problem is, I CANNOT locate where it comes from! Has anyone ever seen
 (smelt...) this before? I recall have seen a message related to a L7?

 There is something strange that I notice along. If I run the L75 on my
 dummy-load, it runs fine and no smell at all. Also the fan turns on much
 later then if I run it on the antenna, so obviously smoothing becomes less
 hot.
 The SWR is the same though and the plate-current is same too.

 Any suggestions are highly appreciated!

 73, Dick/PA2DW

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Re: [drakelist] TR-7 Receiver Noise

[Dieter Horst]

Dieter Horst [EMAIL PROTECTED] made an utterence to the drakelist gang
--
Hi Vic and group,

some years ago I replaced a 'semi-faulty' transistor in the audio chain which 
caused some
kind of noise or rumble.

Unfortunately, I don't remember which transistor it was. It most likely was 
located on
the 2nd IF / Audio board. 

In general, try to find out whether your noise is caused by the audio amp or 
some other source.

What happens if you disconnect the antenna? 

BTW, the hum from the switch line for the PS7 mentioned by other list members, 
I encountered
here as well. 

73, Dieter DL5RDO



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 Greetings.
 I recently put a TR-7 on the air that I purchased several months ago. All
 is fine except that there is what I can best describe as a low frequency
 rumble noise that is most noticable when using headphones. It is very
 audible even with the RF gain set to max and the audio gain set to min. I
 have listed with another receiver and do not hear this noise, so I don't
 think I have any interference in the shack.
 When tuning in signals, there does not appear to be any distortion, but
 the background noise is very noticable.
 Any suggestions greatly appreciated.
 Vic K5TAG
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Re: [drakelist] tr7 oscillation, predrivers blown.. My drake b-line twins are laughing!!!

[Dieter Horst]

Hello Craig and group,

I had problems with oscillation on my TR7. Setting the predriver to minimum gain 
did not help so I removed R2209 which is in parallel with the gain pot of the 
predriver.
(I have board #2 with one MRF476). This further reduced gain and my problem was solved.
I am still getting full output power so gain is still enough.

Concerning your driver board, I doubt that the two transistors (SRF2281) must be 
matched
because they are not in parallel but one after the other. Check if reducing your driver
gain changes something. There might be a similar problem just like described above.

73, Dieter DL5RDO


 Hello,

 I remember why I like tubes now.. :)

 My tr7 failed one night when I turned it on.  It had been performing fine
 with no apparent problems.  I noticed that output power was down (all
 other functions are ok), then as I continued troubleshooting (checking
 feedlines etc), it went into oscillation even when unkeyed. We have been
 tinkering with it, and it appears to start oscillating when we key it (and
 unkey)after replacing the drivers with a set similar to what was in it.
 Question:  Are these supposed to be a matched set (mrf475)?  And, will the
 pin diodes everyone refers to in the high pass filter cause oscillation?
 The set (predrivers) that was in it, was not a matched set (not mrf475 or
 drake stock), and they were not high quality (someone had replaced them
 before, and done it poorly).  The rig did work for quite a while (2
 years).. so maybe a matching pair wasn't critical.  Looking for thoughts.
 My service manual doesn't do step by step troubleshooting..

 thanks,

 Craig
 kc5pgz

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