Re: R-4B AGC Issues, Part Trois
David, I agree with Gary¡¯s response. ?I liked your comments.
73, Bill KJ5BNE ++++++++++++++++ Bill Blodgett Arlington, Texas
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On Jan 6, 2024, at 10:05?AM, wb6ogd <garywinblad@...> wrote:
?Whoa David.
Not sure what this refers to but I am pretty sure we all appreciate your insight and help.
In fooling with broken old radios, nobody has an exact answer, we have to work around the problem till we find it, any knowledge and help
is very much appreciated at least by me!
73,
Gary
WB6OGD
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Re: R-4B AGC Issues, Part Trois
Whoa David.
Not sure what this refers to but I am pretty sure we all appreciate your insight and help.
In fooling with broken old radios, nobody has an exact answer, we have to work around the problem till we find it, any knowledge and help
is very much appreciated at least by me!
73,
Gary
WB6OGD
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Re: R-4B AGC Issues, Part Trois
Yup, sometimes you gotta savor the victories!
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Richard,
YES, you are da man.? I have learned a lot of valuable info from your posts, keep them coming!
73,
Gary
WB6OGD ?
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Drake SW4A AGC issues part three
Hi everyone,
I wanted to update the progress on my SW4A problems with the AGC causing distortion with strong signals.
Over the Christmas holiday, I installed the tri-section electrolytic capacitor I got for Hayseed Hamfest.
I don¡¯t know if I scared the bejesus out of the radio with my 100W soldering iron, or perhaps a wire got moved? For whatever the reason, the old Drake SW4A is working fine. No distortion at all.
Chalk that one up to the unexplained.
Mike, WB8VGE
The Heathkit shop
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Re: R-4B AGC Issues, Part Trois
Great Steve.? I love it when we find a solution and save an old Drake!
Darn, I sure wish we could? go down to the store and buy a new tube.? I am suspicious of any tube now, they are all as old and creaky as I am.
73,
Gary
WB6OGD
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Re: R-4B AGC Issues, Part Trois
Richard,
YES, you are da man.? I have learned a lot of valuable info from your posts, keep them coming!
73,
Gary
WB6OGD
?
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Re: TR7 Getting ready to sell. But have to deal with the dastardly DR7 board again. I thought.
Update:
First, thank you all for the info and help.
I took the DR7 out and cleaned it with deoxit. Especially the pins and contacts in the rear corner, that I knew were causing problems. That fixed that part of my problem.?
The TR7 will run properly in all? bands and modes. Putting out as hi as 140 watts. Made several contacts and as usual everyone seems to like the audio. Receive is as good as is expected. Not as good as my FT-950 :-)
No issues. Until I operate the Aux Program switch. Then more than 50 % of the time the display will go erratic. All digit's are present but not on frequency. Rotating the switch will restore proper operation.?
To a much lesser extent the Band Switch causes the same problem. Bottom line:
I can create the erratic display with either the Aux Program or Band Switch. And I can fix the erratic display with either the Aux Program or Band Switch. If I stay on one band I can operate all afternoon with no problem!
Any ideas or suggestions please?
Thanks
Bill
W4WCS
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Re: CW Operation with T4XC & R4C
My first rig was a Swan 500. Shortly afterwards, my Elmer also sold me an R-4A that didn¡¯t work. That was my first piece of Drake gear and I wish I¡¯d kept it but I didn¡¯t. I used a Johnson TR switch that I got for $5 at a fest. I even did my first CW contest with that setup, as it only took me a couple months to get my general. That was back when you had to go to the FCC for the test.?
73,
Steve Wedge, W1ES/4
Time flies like an arrow. Fruit flies like a banana.
On Fri, Jan 5, 2024 at 10:49, N3WM - Bill via groups.io < n3wm@...> wrote:
Gary & Steve,
RRRR Understand. I just ran a on air test with my friend Marty, KK4RF....it worked flawlessly running separate. I have a counter monitoring my transmit frequency which help when doing a sanity check hi hi. I use a "magic Tee" to sample the RF out.?
?I ran a DX60 with a SX99...had to net them so you could hear ourself on CW.. this was back around 1964 as a novice.
Cheers,
Bill N3WM
On Friday, January 5, 2024 at 10:20:11 AM EST, wb6ogd <garywinblad@...> wrote:
Bill,
The offset is so high because the carrier oscillator signal has to go through the crystal filter.? As John's mod lowered the offset, going farther outside the filter
reduces the drive and therefore power out.
Drake should have somehow routed the signal around the filter.
But Collins did it even worse on the S-Line (unitl the 3 series).? They used and audio oscillator to generate the CW carrier.? Due to audio harmonics causing
close in spurs, they had to make the offset really high (1.8KHz I think it was).
Transceive CW is very nice for contests!? Otherwise, SEPARATE mode is probably nicer.? If you calibrate both PTOs, you can just set the dial without doing
the SPOT thing...maybe.? I always leave the receiver ON and listen to my real on the air signal.. slight adjustment is easy then.? Back in the '60s when I was
a teen age super ham I didn't have a T-4X so I had to do it that way with my Hammarlund HX-50.
73,
Gary
WB6OGD
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Happy new year dear friends! Had some time to spend, the TR7 is now fixed. As Jim suggested, I could not find any obvious fault in the VCO board. I think the fault was due to the very tight boards compartments which likely resulted in erratic contacts at the bottom of VCO and TX exciter boards. I corrected them by inserting a cartoon insulator at bottom of each board. The PLL now works perfectly Another interesting? finding is that the 500 Khz signal from the programmable divider to the phase comparator, pin 5/11, is not a square wave, as the manual suggests,? but a 2 uS pulse of variable width. The higher the band, the shorter the pulse. Please have a look at photos posted here: /g/DRAKE-RADIO/album?id=292102
Vr Giuliano, IV3DLW?
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I missed a point about tubes. All tubes will drift when warming up. Simply the the spacing of the electrodes and their dimensions change with temperature. Most things expand when they get warm, so do the tube components. The characteristics of the tube depend on the dimensions and spacing so they will change a little until the tube warms up enough to stabilize. Probably, there is also some change due to age. For instance some elements can sag especially when they are elastically mounted. In some tubes, notably those with high Gm, the spacing of the grids, both turn spacing and the spacing of the grid from other electrodes, can be very small so that any change in size w. ill significantly affect the characteristics. Mechanical shock, such as dropping a tube, can cause permanent change. So, the answer is _yes_ tubes can change with temperature. Age can also affect the quality of the emission, true of both directly heated and indirectly heated cathodes. Sometimes ageing can be compensated, as when increasing the voltage and thus temperature of a pure tungsten cathode (found mostly in large old style transmitting tubes). Running at overvoltage for a time can also partially restore some thoriated tungsten cathodes by boiling some of the thorium to the surface but such tubes may get weak again after a relatively short time and should be run at normal temperature after regenerating. For the most part indirectly heated cathodes, such as are common in receiving tubes, can't be regenerated and have very short lives if run at higher than normal temperature.
I have not mentioned out-gassing. This can happen when tubes are run at serious overload. Residual gas in the electrodes, notably the plate, is driven off and may be too much for the getter to absorb. Some tubes, mainly transmitting types, are made with plate materials like tantalum silicon which absorb gasses at high temperatures. For more on metals for use in vacuum systems see:
<>
The tube manufacturers have published material on tube life over the years, most of it is on line somewhere.
Oh, gee, another essay. Hey, catch those run-away fingers...
--
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998
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Re: R-4B AGC Issues, Part Trois
UPDATE
One very bad tube (V5, I think. I should have marked them when I removed them!). Three that weren't great but had passed on the tube tester. V3, V4 and V9.
There is still a change in voltage between AGC off, fast and slow, but these are on the order or 100 mV or thereabouts. Totally within tolerances of the parts.
Thanks to all for the comments and for being the second - nth set of eyeballs and brains on this.
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with Proton Mail secure email.
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On Friday, January 5th, 2024 at 7:29 PM, Willy - LU5WE via groups.io <guiye8@...> wrote: I seem to have written an essay. Didn't mean to. Sometimes my
fingers just run away.
And it's very welcome. Thanks.
Regards
Guillermo - LU5WE.
On 1/5/2024 8:36 AM, David wrote:
Based on my limited experience, knowledge and baloney quotient, I
offer the following:
Anytime I have a difference in cold vrs warmed up as regards to
performance, I suspect:
First of all tubes: Even a good tube will "drift" when warmed. If
the inner surface around the getter is silvery, then it may mean the
insides of the tube are not pristine as the getter material is
exhausted. The tube life is dependent on many things, cleanliness of
the insides is one of them.
Capacitors: As they age, the ability to hold and pass on charge
varies. Generally, I have found, the warmer a cap, the better it works.
Resistors: If a circuit changes current boldly when it warms, then a
marginal resistor could be at fault. Drake did not spend a lot of
money on the quality of their resistors.
Lastly, Soldered connections: Another current sensitive issue, with
cold being the least current and warm the greater current.
I suppose I should include transistors as well as they are affected by
temperature changes, In either state, they may function, but at
different points on the curve.
I hope you can resolve this dilemma. As you have done in the past,
your findings are valuable to those of us who insist on fixing these
radios. As none of us have an infinite time frame to do so, sharing
the results of our victories is a valuable tool in keeping the old
stuff working. Now if anyone has a solution for creaky knees, I would
be interested to know.
this as well.
David Assaf III
W5XU, VP8RXU
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Re: R-4B AGC Issues, Part Trois
well, it was not my intention to draw people from addressing the problem, but it appears that intended helpful comments based on nearly 60 years of radio repair experience was not taken as intended.?? I will no?longer be a source of intended help where the intention is reversed.
Sorry.
David Assaf III W5XU, VP8RXU ?
>? ??? I seem to have written an essay. Didn't mean to. Sometimes my
> fingers just run away.
And it's very welcome. Thanks.
Regards
Guillermo - LU5WE.
>
> On 1/5/2024 8:36 AM, David wrote:
>> Based on my limited experience, knowledge and baloney quotient, I
>> offer the following:
>>
>> Anytime I have a difference in cold vrs warmed up as regards to
>> performance, I suspect:
>>
>> First of all tubes:? Even a good tube will "drift" when warmed.? If
>> the inner surface?around the getter is silvery, then it may mean the
>> insides of the tube are not pristine?as the getter material is
>> exhausted.? The tube life is dependent on many things, cleanliness?of
>> the insides is one of them.
>>
>> Capacitors:? As they age, the ability to hold and pass on charge
>> varies.? Generally, I have found, the warmer a cap, the better it works.
>>
>> Resistors: If a circuit changes current boldly when it warms, then a
>> marginal resistor could be at fault.? Drake did not spend a lot of
>> money on the quality of their resistors.
>>
>> Lastly, Soldered connections:? Another current sensitive issue, with
>> cold being the least current and warm?the greater current.
>>
>> I suppose I should include transistors as well as they are affected by
>> temperature changes,? In either state, they may function, but at
>> different points on the curve.
>>
>> I hope you can resolve this dilemma.? As you have done in the past,
>> your findings are valuable to those of us who insist on fixing these
>> radios. As none of us have an infinite time frame to do so, sharing
>> the results of our victories is a valuable tool in keeping the old
>> stuff working. Now if anyone has a solution for creaky knees, I would
>> be interested to know.
>> ??this as well.
>>
>> David Assaf III
>> W5XU, VP8RXU
>
>
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Re: R-4C S-Meter Going Backwards?
That is a good place to start.? I will have to pull the tubes this weekend.
TNX
-73 de Chris KQ6UP
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On 1/5/2024 4:34 PM, Steve Wedge, W1ES/4 via groups.io wrote: Because this has bitten me so recently, check to tubes for gas.
Does the receiver behave normally for the first few minutes?
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with Proton Mail secure email.
On Friday, January 5th, 2024 at 7:16 PM, Christopher KQ6UP <christopher.maness@...> wrote:
I was playing with my R-4C today, when after a few hours on he meter
started reading slightly negative. It went back after powering off, and
even after turning it back on. However, again after being on for a
couple of minutes it stated drifting back in the negative (below the S 1
indication). This is one of my favorite receivers, it works nice save
for some dial slop that I need to look into.
TNX es 73 de Chris KQ6UP SK ..
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Re: R-4C S-Meter Going Backwards?
Because this has bitten me so recently, check to tubes for gas.
Does the receiver behave normally for the first few minutes?
73,
Steve Wedge, W1ES/4
Time flies like an arrow.? Fruit flies like a banana.
Sent with Proton Mail secure email.
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Show quoted text
On Friday, January 5th, 2024 at 7:16 PM, Christopher KQ6UP <christopher.maness@...> wrote: I was playing with my R-4C today, when after a few hours on he meter
started reading slightly negative. It went back after powering off, and
even after turning it back on. However, again after being on for a
couple of minutes it stated drifting back in the negative (below the S 1
indication). This is one of my favorite receivers, it works nice save
for some dial slop that I need to look into.
TNX es 73 de Chris KQ6UP SK ..
|
Re: R-4B AGC Issues, Part Trois
??? I seem to have written an essay. Didn't mean to. Sometimes my fingers just run away. And it's very welcome. Thanks. Regards Guillermo - LU5WE. On 1/5/2024 8:36 AM, David wrote:
Based on my limited experience, knowledge and baloney quotient, I offer the following:
Anytime I have a difference in cold vrs warmed up as regards to performance, I suspect:
First of all tubes:? Even a good tube will "drift" when warmed.? If the inner surface?around the getter is silvery, then it may mean the insides of the tube are not pristine?as the getter material is exhausted.? The tube life is dependent on many things, cleanliness?of the insides is one of them.
Capacitors:? As they age, the ability to hold and pass on charge varies.? Generally, I have found, the warmer a cap, the better it works.
Resistors: If a circuit changes current boldly when it warms, then a marginal resistor could be at fault.? Drake did not spend a lot of money on the quality of their resistors.
Lastly, Soldered connections:? Another current sensitive issue, with cold being the least current and warm?the greater current.
I suppose I should include transistors as well as they are affected by temperature changes,? In either state, they may function, but at different points on the curve.
I hope you can resolve this dilemma.? As you have done in the past, your findings are valuable to those of us who insist on fixing these radios. As none of us have an infinite time frame to do so, sharing the results of our victories is a valuable tool in keeping the old stuff working. Now if anyone has a solution for creaky knees, I would be interested to know.
??this as well.
David Assaf III
W5XU, VP8RXU
|
R-4C S-Meter Going Backwards?
I was playing with my R-4C today, when after a few hours on he meter started reading slightly negative.? It went back after powering off, and even after turning it back on.? However, again after being on for a couple of minutes it stated drifting back in the negative (below the S 1 indication).? This is one of my favorite receivers, it works nice save for some dial slop that I need to look into.
TNX es 73 de Chris KQ6UP SK ..
|
That's a great reminder, thank you
Joe ki5o?
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And, as always, look for bad solder joints or broken wires.
Bob K9JU
On Friday, January 5, 2024 at 07:01:00 PM EST, Joe KI5O <ki5ojoe@...> wrote:
Bob that is a great place to start. I had a bad potentiometer on the Q-multiplier that was a problem. I'll check it out.
Any other thoughts are greatly appreciated?
Joe ki5o?
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Bob that is a great place to start. I had a bad potentiometer on the Q-multiplier that was a problem. I'll check it out.
Any other thoughts are greatly appreciated?
Joe ki5o?
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Re: R-4B AGC Issues, Part Trois
On 2024-01-05 15:45, R W Gould via groups.io wrote: Thank you, great article...
WD4AGG *** Thanks from me too. I saved it. - Jerry, KF6VB
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Gary WB6OGD
Bill
David