Re: R-4C Low audio output
Either amp, the original or mine, should clip on a typical signal about 3 or 4 o¡¯clock. ?The IF signal into the protect detector should be about 600 mV P-P above the AGC threshold. If the audio amp can¡¯t clip, suspect the product detector and then the amp.
Rob, NC0B?
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On Mar 19, 2024, at 4:19?PM, Steve Wedge, W1ES/4 via groups.io <w1es@...> wrote:
?
Either stock or with the Sherwood amp, it should be plenty before 12 o¡¯clock. ?You could have component drift or someone used a different pot.
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Tue, Mar 19, 2024 at 1:17 PM, Malcolm G4TJK via groups.io < charlie.porter1@...> wrote:
Thanks for your thoughts! I get audio, but not the level that I¡¯ve had with other examples. The AF gain is at around the 3pm position all of the time.
Vol with headphones is also low-level.
M
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Re: R-4C Low audio output
Not necessarily. The mod is great if done well. ?I would simply look at how well it was installed.?
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Tue, Mar 19, 2024 at 1:19 PM, Malcolm G4TJK via groups.io < charlie.porter1@...> wrote: Steve,
Are you suggesting the removal of the AF mod? Do you have instructions?
Many thank,
Malcolm.
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Re: R-4C Low audio output
Either stock or with the Sherwood amp, it should be plenty before 12 o¡¯clock. ?You could have component drift or someone used a different pot.
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Tue, Mar 19, 2024 at 1:17 PM, Malcolm G4TJK via groups.io < charlie.porter1@...> wrote: Thanks for your thoughts! I get audio, but not the level that I¡¯ve had with other examples. The AF gain is at around the 3pm position all of the time.
Vol with headphones is also low-level.
M
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Re: Soft Rubber Eqp't Feet
This is a perennial topic. Museum putty - or 3M or Gorilla mounting putty works very well.
However, a better solution I've used for many years allows instant moving or changing of the telegraph instrument on the desk.
It is slip-resistant tape, sold my 3M as "Safety Walk" heavy duty anti-slip tread. A small piece of it under each foot of a key will keep it in place. It should be the heavy duty version.
This stuff is designed for walkways around swimming pools and such. Since it's thin it won't raise the key very much. Other brands probably will be inferior.
My local Ace Hardware sells it in a roll, by the foot, so I buy one foot 3 or 4 inches wide, good for dozens of keys. If you mail order it the price for a 60 foot roll is about $45.
Pete
WB2QLL
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-----Original Message----- From: < [email protected]> Sent: Mar 17, 2024 2:32 PM To: < [email protected]> Subject: Re: [DRAKE-RADIO] Soft Rubber Eqp't Feet Okay, apparently a lot of people are unfamiliar with the undercarriage on Vibroplex keys :-) See the 1st picture attached. From L-R those are the bottom sides of an Iambic, a Vibrokeyer, and a standard bug. There's a lot of stuff going on under there. Double sided tape, gluing on rubber sheets, etc., aren't an option. (And though it probaly won't work here, either, "museum putty" sounds very cool and deserves further exploration. It could be useful for keeping things like watt meters from wandering about.) At the bottom of the 1st pic is the butt side of the road warrior key I put together. Those stick-on bumpers stick like glue! If I could find a taller version of those, I could just remove the feet from all the keys and replace them with the bumpers. I did come up with a workaround for the main offender, though. (See 2nd picture attached.) I found some small stick-on bumpers I had forgotten about. These keep the key nicely stuck to the desk, but they elevate it to where the finger pieces are higher up than I like. It will work for now, but it's not a long term solution. Anyway, still searching ... :-) --lyndon
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Re: R-4C Low audio output
Working as it did before the change¡.
M
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Re: R-4C Low audio output
Steve,
Are you suggesting the removal of the AF mod? Do you have instructions?
Many thank,
Malcolm.
|
Re: R-4C Low audio output
Thanks for your thoughts! I get audio, but not the level that I¡¯ve had with other examples. The AF gain is at around the 3pm position all of the time.
Vol with headphones is also low-level.
M
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Re: R-4C Low audio output
Implementation of the mods is my suspect No. 1. ?I will assume that the audio amp mod was done. ?Look around the work done to install that amp. ?Cold solder joints, broken wires, etc.
The extreme variability of the installation of these various mods has caused me to do what others who work on these sets have done and avoid working on them any more.
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Tue, Mar 19, 2024 at 11:45 AM, Damien Mannix < damienmannix@...> wrote:
Sorry, Damien G3XER
Hello Malcolm,
I am sure you will get plenty of good advice but, for what it is worth, I do not think changing all the tubes was a good idea!
73 Damien B3XER
Just obtained an R-4C from eBay (I don¡¯t recommend this as a source!). The radio appears to have Sherwood mods (see photo). The radio works on all band, but with the RF Gain on Max, and the AF Gain almost on max, the audio output is rather low. Have changed
all of the tubes.
Not a Drake expert so any thoughts would be valued.
Malcolm.
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Re: What's the best way to learn tube electronics?
M0HKG - Martin via groups.io writes: I did think that maybe they'd replaced the 'z' in words with 's' but that's=
not the case. It's not a proper Britishization if they didn't insert all the missing 'u's :-) --lyndon (whose view on this is coloured by being Canadian)
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Re: What's the best way to learn tube electronics?
From my cursory flick through, I'd say that the adaptions for British and Commonwealth Usage comprise replacing the work tube with valve, and 110 VAC / 60 Hz with 240 VAC / 50 Hz.
I did think that maybe they'd replaced the 'z' in words with 's' but that's not the case.
Seems they only did 2/3 rds of the job ;-)
Martin
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Re: R-4C Low audio output
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Hello Malcolm,
I am sure you will get plenty of good advice but, for what it is worth, I do not think changing all the tubes was a good idea!
73 Damien B3XER
Just obtained an R-4C from eBay (I don¡¯t recommend this as a source!). The radio appears to have Sherwood mods (see photo). The radio works on all band, but with the RF Gain on Max, and the AF Gain almost on max, the audio output is rather low. Have changed
all of the tubes.
Not a Drake expert so any thoughts would be valued.
Malcolm.
|
Re: R-4C Low audio output
Hello Malcolm,
I am sure you will get plenty of good advice but, for what it is worth, I do not think changing all the tubes was a good idea!
73 Damien B3XER
toggle quoted message
Show quoted text
Just obtained an R-4C from eBay (I don¡¯t recommend this as a source!). The radio appears to have Sherwood mods (see photo). The radio works on all band, but with the RF Gain on Max, and the AF Gain almost on max, the audio output is rather low. Have changed
all of the tubes.
Not a Drake expert so any thoughts would be valued.
Malcolm.
|
Re: R-4C Low audio output
Hi, Malcolm.?
I presume the S-meter is moving in time with any input signal(s). If yes, check the?1/4" headphone jack in the front of the radio. There may be sufficient corrosion to prevent the shorting contacts of the jack from sending the audio to the speaker jack on the back.
The tension on the RCA jack for the speaker may have lessened (a lot). You can retension it by carefully compressing the portion that makes contact with the center pin of the speaker cord RCA plug.
73 ES GL,
Bob Loving K9JU
Maryville, TN
On Tuesday, March 19, 2024 at 11:22:45 AM EDT, Malcolm G4TJK via groups.io <charlie.porter1@...> wrote:
Just obtained an R-4C from eBay (I don¡¯t recommend this as a source!). The radio appears to have Sherwood mods (see photo). The radio works on all band, but with the RF Gain on Max, and the AF Gain almost on max, the audio output is rather low. Have changed all of the tubes.
Not a Drake expert so any thoughts would be valued.
Malcolm.
|
Just obtained an R-4C from eBay (I don¡¯t recommend this as a source!). The radio appears to have Sherwood mods (see photo). The radio works on all band, but with the RF Gain on Max, and the AF Gain almost on max, the audio output is rather low. Have changed all of the tubes.
Not a Drake expert so any thoughts would be valued.
Malcolm.
|
Re: What's the best way to learn tube electronics?
Boy did you hit a nerve asking about learning Vacuum tubes. I did not know there were still dinosaurs around. Remember first The UK uses Valves not Tubes. My laugh for today Don licensed 1963
WOW! What a response!
Thanks for all the collective wisdom, and the suggestions.
I've jumped on a few web sites and admired the author's workshops and their projects - especially Dr. Greg Latta's...
I've ordered, and received, a copy of the 1957 ARRL Handbook which, as Michael and others have said, is full of some gems.
Searching around ?I found a series called 'RIGHT - From the Start' in the 1956/57 editions of The Radio Constructor - a UK magazine of the era. It takes an amateur (like me) through the basics up to more complex theory in a series of 21 articles - it certainly looks to be a useful reference piece.
Lastly, I bought the 6-Parts that make up 'Basic Electronics - A Course of Training Developed for the United States Navy'; although my set says it is 'Adapted to British and Commonwealth Usage' which made me smile.
So I think I'm there for reference material, and I've now started working through Basic Electronics and filling in the gaps with The Radio Constructor as needed.
Thank you again for all of the input, I'm so grateful to all of you who took the time to share your suggestions.
73
Martin
m0hkg
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Re: What's the best way to learn tube electronics?
WOW! What a response!
Thanks for all the collective wisdom, and the suggestions.
I've jumped on a few web sites and admired the author's workshops and their projects - especially Dr. Greg Latta's...
I've ordered, and received, a copy of the 1957 ARRL Handbook which, as Michael and others have said, is full of some gems.
Searching around ?I found a series called 'RIGHT - From the Start' in the 1956/57 editions of The Radio Constructor - a UK magazine of the era. It takes an amateur (like me) through the basics up to more complex theory in a series of 21 articles - it certainly looks to be a useful reference piece.
Lastly, I bought the 6-Parts that make up 'Basic Electronics - A Course of Training Developed for the United States Navy'; although my set says it is 'Adapted to British and Commonwealth Usage' which made me smile.
So I think I'm there for reference material, and I've now started working through Basic Electronics and filling in the gaps with The Radio Constructor as needed.
Thank you again for all of the input, I'm so grateful to all of you who took the time to share your suggestions.
73
Martin
m0hkg
|
Re: Soft Rubber Eqp't Feet
Try McMater-Carr...
They have a multitude of various rubber feet and bumpers available.? Not the cheapest around, but a large variety.
A lower "durometer" number means softer, higher indicates harder (or firmer).
HERE:
73,
~Alan
W5ARM
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Re: Dumb question of the day.
Paul,
Thanks for sharing the information about the Fluke 8060a. I also?have an 8060a and would like a copy of the instructions and bom for replacing the electrolytic caps.
73,
Bob AD3K
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The 8060A was quite an achievement for a 1980s DMM design.? After graduating from college, I worked for RKO Radio in Chicago.? We depended on it for a litany of precision
audio measurements.?
?
I¡¯m in the minority, but I prefer manual-ranging DMMs and its one reason I keep the 8060A and one that¡¯s NOS in the box. ?Even the fastest auto-ranging DMMs slow me down when
working through a problem.
?
A while back, I did correspond with Dr. Taylor though EEVBlog. Searching though the same message board is a complete set of instructions for electrolytic cap replacement and
a B.O.M.? Today, many 8060A stability issues are a result of failed low WVDC caps.? If anyone would like a copy, let me know.
?
The ultra-high Z tool you mentioned may have been the first implementation in a DMM.? Nice for DC work, but of course, an isolating-tip probe is still needed for many Hi-Z
RF measurements.
?
Paul, W9AC?
?
?
?
Paul, you may already know this, but the 8060A has a special high impedance mode for DC voltage measurements. However, it only works in 2V and 200mv ranges. To put it in high impedance mode, you select either 2V or 200mv range and leave
all the other switches out. If I remember correctly it offers several hundred Megohms of impedance. With a shunt you could use 100:1 to cover a more useful voltage range. May not offer much in the way of resolution though.
I love that meter. I was issued a brand new one in my Eastman Kodak toolkit in 1982 when I went to work for them as a service rep in 1982. When I saw an 8060A on eBay a few years ago I snagged it. It has become my go to meter around the shack. This is at least
partly for nostalgic reasons, but it is also a fine meter. The guy who designed it used to hangout on EEVblog I think his name is Dr. Taylor. That is where I learned about the High impedance mode. It is in the manual, but you know how that goes.
73,
Bob ? N0GGO
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Re: Soft Rubber Eqp't Feet
Just looked on Amazon...lots of "soft rubber feet? for Cutting Board"....maybe depends on whose "soft" tho
Jim
On Sun, Mar 17, 2024 at 12:32?PM Lyndon VE7TFX < lyndon@...> wrote: Okay, apparently a lot of people are unfamiliar with the undercarriage
on Vibroplex keys :-)? See the 1st picture attached.? From L-R those
are the bottom sides of an Iambic, a Vibrokeyer, and a standard
bug.? There's a lot of stuff going on under there.? Double sided
tape, gluing on rubber sheets, etc., aren't an option.? (And though
it probaly won't work here, either, "museum putty" sounds very cool
and deserves further exploration.? It could be useful for keeping
things like watt meters from wandering about.)
At the bottom of the 1st pic is the butt side of the road warrior key
I put together.? Those stick-on bumpers stick like glue!? If I could
find a taller version of those, I could just remove the feet from
all the keys and replace them with the bumpers.
I did come up with a workaround for the main offender, though.? (See
2nd picture attached.)? I found some small stick-on bumpers I had
forgotten about.? These keep the key nicely stuck to the desk, but
they elevate it to where the finger pieces? are higher up than I
like.? It will work for now, but it's not a long term solution.
Anyway, still searching ... :-)
--lyndon
|
Re: Dumb question of the day.
Still have my 77 from the days at Digital, where in the location closing they said "you can take your tools with you if you want". Works fine (the intermittent displays seemed to come with the 8x series meters)
(My friend in Metrology rolled out his giant Kennedy stack)
:-)
John
On Sun, Mar 17, 2024 at 6:20?PM Steve Wedge, W1ES/4 via <w1es= [email protected]> wrote: Now that I'm back at my shack, I can attest that the 70 series meter that I have is the 77.? It's in excellent shape and is still holding its calibration, as far as I can tell without having a traceable standard...
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with Proton Mail secure email.
On Sunday, March 17th, 2024 at 4:44 PM, Jim Shorney <jimNU0C@...> wrote:
> The speed factor that I look at for DMMs is how quickly the beep reacts when doing continuity testing. The Flukes seem to be mostly pretty fast. Cheaper DMMs (yes I have some of those too) less so. We had quite a few 77s at my former workplace and they were acceptable.
>
> 73
>
> -Jim
> NU0C
>
> On Sun, 17 Mar 2024 18:39:25 +0000
> "Steve Wedge, W1ES/4 via " w1es=[email protected] wrote:
>
> > I have a Fluke 17B (Chinese-made and for foreign markets) that I bought new on eBay a few years ago. I found the delay in getting a stable reading to be something that really bugs me.
> >
> > I have an old Fluke 77 or 73 that auto ranges that is still plenty fast enough. Of course these cost around $300 in ¡®83 and the newer one was $125 in 2020.
> >
> > Yes, sometimes I¡¯ll set the 73 at manual ranging.
> >
> > I bought it at a hamfest a couple years ago for $15.
> >
> > Steve Wedge, W1ES/4
> >
> > Time flies like an arrow. Fruit flies like a banana.
> >
> > Sent from Proton Mail for iOS
> >
> > On Sun, Mar 17, 2024 at 12:50, Ralph Mowery via <[ku4pt=[email protected]](mailto:On Sun, Mar 17, 2024 at 12:50, Ralph Mowery via <<a href=)> wrote:
> >
> > > I have two of the 8060A but have not used them in a while. Usually use the newer auto ranging ones . Could you send me the file about replacing the capacitors so I will have it if my 8060 fails I could try replacing them.
> > >
> > > ralph ku4pt
> > >
> > > On Sunday, March 17, 2024 at 11:37:39 AM EDT, Paul Christensen w9ac@... wrote:
> > >
> > > The 8060A was quite an achievement for a 1980s DMM design. After graduating from college, I worked for RKO Radio in Chicago. We depended on it for a litany of precision audio measurements.
> > >
> > > I¡¯m in the minority, but I prefer manual-ranging DMMs and its one reason I keep the 8060A and one that¡¯s NOS in the box. Even the fastest auto-ranging DMMs slow me down when working through a problem.
> > >
> > > A while back, I did correspond with Dr. Taylor though EEVBlog. Searching though the same message board is a complete set of instructions for electrolytic cap replacement and a B.O.M. Today, many 8060A stability issues are a result of failed low WVDC caps. If anyone would like a copy, let me know.
> > >
> > > The ultra-high Z tool you mentioned may have been the first implementation in a DMM. Nice for DC work, but of course, an isolating-tip probe is still needed for many Hi-Z RF measurements.
> > >
> > > Paul, W9AC
>
>
>
>
> --
>
> 73
>
> -Jim
> NU0C
>
>
>
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Rob Sherwood
M0HKG - Martin
Alan - W5ARM