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Re: SX-117 Power transformer Voltage
开云体育Hello Wolfgang, From the schematic and the “normal” voltages chart in the SX-117 manual, the primary +B voltage at C117B looks to be 200V. Which means a transformer HV secondary of 280Vct (140-0-140). There is also a replacement transformer specified in the attached document, but the secondary voltage rating seems to high, IMHO. ? 73, Jacques, VE2JFE in Montreal ? Hello, I am restoring a SX-117. A former owner replaced the original transformer by a transformer with a primary voltage of 220 Volt. The secondary voltage of this transformer is much too high. I would like to know if there is any info on the secondary voltage of the original transformer as I am looking for getting a replacement. 73s Wolfgang dk7cy |
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
MEA CULPA!!? SORRY!! SORRY!! SORRY!! SORRY!! SORRY!!?
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As Jacques suggested I had to double check the measuring setup.
Nothing strange in there but a leap of imagination on my part: for convenience I connected the probe tip to the sample point via 15cm of coaxial cable.
What a mistake!! By removing that cable and positioning the tip of the probe very close to the sampling point, all the numbers immediately turned out to be spot on where they had to be.
So, no bad or wrong parts.
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I was also been able to isolate the "sudden signal level decrease" problem: it's a fault in the TG circuit of my Spectrum Analyzer. So the cleaning the spring contacts of C7 I performed yesterday, even if did some good anyway, had nothing to do with that problem.
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Reconnecting C33 to the V1 grid dropped the peak frequency a bit, but I was able to easily recover it to the correct values by slightly tweaking the TRIMCAPs.
So, with this setup, in order to bring C3 and C4 close to the alignment points, I tweaked them so that the peaks are (visually) located exactly on the frequencies required by the alignment procedure (a sort of "prealignment" procedure).
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Then I turned the rig ON and performed an accurate alignment as per service manual.
Everything went well with no further problems.
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My conclusion is that some previous owner played with the tuning without any test gear and screwed it up in all stages and completely.
With my "prealignment" procedure, done using the spectrum analyzer, I brought things closer and closer to where they had to be, allowing me to perform the final alignment as per service manual without any further problem.
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Once again: SORRY for my mistakes, .. many mistakes!
I can declare this post CLOSED and problem SOLVED.
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THANK YOU VERY MUCH INDEED TO ALL YOU GUYS!!!!!!!!!!!!!!!
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--
Emanuele (IU1KNR). |
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
Since you are having strange problems I would suggest not trusting rivets to make a good ground connection.? Much better to solder the riveted grounds to the chassis at the tube sockets and the single ground point near the wafer switch.?? There appears to be ample room as shown in Jim's photos to get a large 100 or so watt soldering iron in there to solder the ground terminals to the chassis.? Nokorode solder paste works well for me.? A little fine grit sandpaper held by a hemostat to roughen up the area would help prepare the joint for soldering. Regards, Jim Logic: Method used to arrive at the wrong conclusion, with confidence.? Murphy
On Saturday, February 22, 2025 at 04:01:20 PM CST, JThorusen <jthorusen@...> wrote:
Hi Emanuele!
?
?? It takes me a bit of time to respond to these things... I had a serious fall in January and broke my back in 3 places so I am hobbling around in a back brace and cannot lift anything myself, but must get my care giver to do it.?? However, it has been done; here are the results:
?
?
?
?
?
?
I hope this is of some help.?? I am not able to take the radio any further apart at this time.
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73,
--
Jim T.
KB6GM |
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
开云体育Hi Emanuele, I do not understand why the measurement of the L3 and C7A values can be good and the combination of the two so wrong. The only thing I do not see correct in your setup is the use of the RTMA “dummy” antenna which can screw up the whole measurement setup by adding more parallel capacitance to the whole circuit. If you try to measure one of the L3 sections ALONE with the C7A parallel capacitor + trimmer the results HAVE TO BE DIFFERENT. OK for the active fet probe, but those things are not magical and often present an input impedance lower than a 10:1 low cap probe. Which model of fet probe are you using ? The signal source used to measure the parallel resonance should have a resistive only impedance at least 100 times more high than the reactance of the coil or the capacitor, and this is why I put a 100k ohms in the setup I suggested to use. Using a SA as the signal source is OK, I think, but just try a scope with a low cap probe instead of the fet probe, just to see if there is a difference. ? It just makes no sense that the whole parallel resonant circuit, when measured, performs that way off compared to what it should. ? 73, Jacques, VE2JFE in Montreal ? Jacques, I repost the measuring setup: The RF probe is an with 1500MHz bandwidth. Do you see anything wrong here? please let me know! I repeat that actually C33 has been disconnected from V1 pin4 and the probe moved to the now free terminal of C33 so that the ANT circuit has become completely standalone. I also tried to change the antenna connection between the following configurations: RTMA, a 0.01uF cap, pure induction (air): the signal levels change, but the peaks are steady at the wrong too low values. C7 and L3 were measured out of circuit using a DE-5000 LCR meter. If everything is ok as I suppose it to be, your question remains unanswered: where does the excess capacitance come from? I can only think of wrong parts or a miswiring problem. ? Jim, thank you very much indeed for your effort! I am going to have a close look at your pictures tomorrow. First impression: your radio is much better preserved than mine! ? I have a news: during today's tests I saw the signal going up and down for no apparent reason, without me doing anything. Also, when going up and down in band 1 by rotating the main tuning knob, the signal showed a significant drop in the lower half of the band (something I had never seen before). This gradual increase in contact resistance as the tuned frequency decreases could explain the problem of the significant decrease in sensitivity the radio shows at these frequencies. ? Unfortunately, the effect of the hidden capacitance has remained the same. I think I have to tear C7 down and bring it somewhere to give it an ultrasonic treatment. -- Emanuele (IU1KNR). |
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Re: SR-500 Tornado
开云体育
For the 160-500 conversion, the correct power supply is the P-500 or the PS-500-AC. The PS-500A-AC does not have the bias adjustment. If you want to use later versions of the PS-500XXXXX then you will need?to install the bias divider network.
Walt Cates, WD0GOF
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From: [email protected] <[email protected]> on behalf of Robert Kembel <rwkembel@...>
Sent: Saturday, February 22, 2025 6:14 PM To: [email protected] <[email protected]> Subject: Re: [HallicraftersRadios] SR-500 Tornado ?
Hi All,
To wrap up part of this discussion, Walt Cates' repair guide for the SR-160/SR-500, section 9.11, lists the changes needed to convert the SR-160 to an SR-500. Other than some component changes, the main change would be to change
the power supply from the PS-120-150 (a 150 watt transmitter supply) to the PS-120-400 power supply. This supply has a higher B+ for the finals (800v vs 550v) and higher current capabilities. This is the same supply as is used for the SR-400.
In the case of the SR-500 (or converted SR-160), either the 8236 tubes or the 6DQ5 tubes can be used. The 8236 tubes are much more rugged (but in short supply), but the 6DQ5 tubes will work fine although I am in agreement with
using a cooling fan in either case.
The SR-150 is a bit of a different beast, and while it could be modified to use different finals and power supply, it is not as straightforward and would involve a PA socket change and rewiring. There was a bit of a "how much
peak power" can I get out of a given pair of tubes that took place during the 70s's. The sweep tubes provide high peak current capabilities, but with limited average power dissipation (typically 35 watts). In my humble opinion, I think it would be best to
leave the SR-150 as it is rather than make significant modifications to obtain a few more watts of output. Remember, it take a 4x increase in power to provide a one "S" unit difference. If you are wanting more power, maybe a better solution is to look at using
an external linear amplifier.
Just my two cents (oops, no more pennies) worth,
Bob,? K7DYB
On 2/20/2025 4:42 PM, HF via groups.io wrote:
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Re: SR-500 Tornado
开云体育Hi All,
To wrap up part of this discussion,
Walt Cates' repair guide for the SR-160/SR-500, section 9.11,
lists the changes needed to convert the SR-160 to an SR-500. Other
than some component changes, the main change would be to change
the power supply from the PS-120-150 (a 150 watt transmitter
supply) to the PS-120-400 power supply. This supply has a higher
B+ for the finals (800v vs 550v) and higher current capabilities.
This is the same supply as is used for the SR-400.
In the case of the SR-500 (or converted
SR-160), either the 8236 tubes or the 6DQ5 tubes can be used. The
8236 tubes are much more rugged (but in short supply), but the
6DQ5 tubes will work fine although I am in agreement with using a
cooling fan in either case.
The SR-150 is a bit of a different
beast, and while it could be modified to use different finals and
power supply, it is not as straightforward and would involve a PA
socket change and rewiring. There was a bit of a "how much peak
power" can I get out of a given pair of tubes that took place
during the 70s's. The sweep tubes provide high peak current
capabilities, but with limited average power dissipation
(typically 35 watts). In my humble opinion, I think it would be
best to leave the SR-150 as it is rather than make significant
modifications to obtain a few more watts of output. Remember, it
take a 4x increase in power to provide a one "S" unit difference.
If you are wanting more power, maybe a better solution is to look
at using an external linear amplifier.
Just my two cents (oops, no more
pennies) worth,
Bob,? K7DYB
On 2/20/2025 4:42 PM, HF via groups.io
wrote:
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
Jacques,
I repost the measuring setup:
The RF probe is an with 1500MHz bandwidth.
Do you see anything wrong here? please let me know!
I repeat that actually C33 has been disconnected from V1 pin4 and the probe moved to the now free terminal of C33 so that the ANT circuit has become completely standalone.
I also tried to change the antenna connection between the following configurations: RTMA, a 0.01uF cap, pure induction (air): the signal levels change, but the peaks are steady at the wrong too low values.
C7 and L3 were measured out of circuit using a DE-5000 LCR meter.
If everything is ok as I suppose it to be, your question remains unanswered: where does the excess capacitance come from?
I can only think of wrong parts or a miswiring problem.
?
Jim, thank you very much indeed for your effort! I am going to have a close look at your pictures tomorrow. First impression: your radio is much better preserved than mine!
?
I have a news: during today's tests I saw the signal going up and down for no apparent reason, without me doing anything.
Also, when going up and down in band 1 by rotating the main tuning knob, the signal showed a significant drop in the lower half of the band (something I had never seen before).
So I decided to thoroughly clean the spring contacts between the rotor and the frame of the variable capacitor and the problem disappeared. This gradual increase in contact resistance as the tuned frequency decreases could explain the problem of the significant decrease in sensitivity the radio shows at these frequencies.
?
Unfortunately, the effect of the hidden capacitance has remained the same.
I think I have to tear C7 down and bring it somewhere to give it an ultrasonic treatment.
--
Emanuele (IU1KNR). |
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
开云体育Jim Sorry about your fall, but you still take really good pics. R31 must have been a last minute addition, so no terminal block was available. Maybe parasitic resonance? ? From: [email protected] [mailto:[email protected]] On Behalf Of JThorusen
Sent: Saturday, February 22, 2025 5:01 PM To: [email protected] Subject: Re: [HallicraftersRadios] S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak! ? Hi Emanuele! ? ?? It takes me a bit of time to respond to these things... I had a serious fall in January and broke my back in 3 places so I am hobbling around in a back brace and cannot lift anything myself, but must get my care giver to do it.?? However, it has been done; here are the results: ? -- Jim T. _._,_._,_
-- don??? va3drl |
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
开云体育Hi Don, Speaking of slide rules… I used one in my first year at the technical school, but the next year, the HP-35 and the TI hand calculators came in (halleluiah !). Just making a series-parallel conversion with the slide rule was a pain in the … you know what. And yep, world is full of mysteries, but I believe we can solve this one. ? 73, Jacques, VE2JFE in Montreal ? De?: [email protected] <[email protected]> De la part de don Root ? Hi Jacques?? I also had a similar concern/thought, but since the alignment had indicated too much capacitance, both were in general agreement, so not so much need to ask. I think the original sweeps were mostly intended just to get some sort of look at the response. I would not want to expect accuracy unless the probe does not disturb the circuit . ??It would be good to understand how much error can creep in. and…I hope your slide-rule is well lubricated too. Mystery continues. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jacques_VE2JFE via groups.io
Sent: Saturday, February 22, 2025 2:33 PM To: [email protected] Subject: Re: [HallicraftersRadios] S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak! Importance: High ? Hello Emanuele, One time again, I performed some calculations from your test results below. IF there is no error in the C7A capacitor and L3 sections measurements, your test results constantly shows an effect of EXCESS capacitance in the tested antenna circuits. Could that be induced by the test setup you use ?? The attached .pdf contains the calculated “excess capacitance” values (that are not constant, btw). And also the kind of test setup I will use to perform such tests. ? Maybe I missed something from the (very) long thread of exchanges about this problem, but the test setup you used is still not clear to me. I just want to mention that measuring the resonant frequency of a parallel circuit requires high impedance from both the RF source used and the instrument displaying the result. ? As one of my colleagues already mentioned: “Nothing is more useful than a good theory”. And I still believe that it is true. ? Let us know ! ? 73, Jacques, VE2JFE in Montreal
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
开云体育Hi Jacques?? I also had a similar concern/thought, but since the alignment had indicated too much capacitance, both were in general agreement, so not so much need to ask. I think the original sweeps were mostly intended just to get some sort of look at the response. I would not want to expect accuracy unless the probe does not disturb the circuit . ??It would be good to understand how much error can creep in. and…I hope your slide-rule is well lubricated too. Mystery continues. ? From: [email protected] [mailto:[email protected]] On Behalf Of Jacques_VE2JFE via groups.io
Sent: Saturday, February 22, 2025 2:33 PM To: [email protected] Subject: Re: [HallicraftersRadios] S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak! Importance: High ? Hello Emanuele, One time again, I performed some calculations from your test results below. IF there is no error in the C7A capacitor and L3 sections measurements, your test results constantly shows an effect of EXCESS capacitance in the tested antenna circuits. Could that be induced by the test setup you use ?? The attached .pdf contains the calculated “excess capacitance” values (that are not constant, btw). And also the kind of test setup I will use to perform such tests. ? Maybe I missed something from the (very) long thread of exchanges about this problem, but the test setup you used is still not clear to me. I just want to mention that measuring the resonant frequency of a parallel circuit requires high impedance from both the RF source used and the instrument displaying the result. ? As one of my colleagues already mentioned: “Nothing is more useful than a good theory”. And I still believe that it is true. ? Let us know ! ? 73, Jacques, VE2JFE in Montreal -- don??? va3drl |
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
开云体育Hello Emanuele, One time again, I performed some calculations from your test results below. IF there is no error in the C7A capacitor and L3 sections measurements, your test results constantly shows an effect of EXCESS capacitance in the tested antenna circuits. Could that be induced by the test setup you use ?? The attached .pdf contains the calculated “excess capacitance” values (that are not constant, btw). And also the kind of test setup I will use to perform such tests. ? Maybe I missed something from the (very) long thread of exchanges about this problem, but the test setup you used is still not clear to me. I just want to mention that measuring the resonant frequency of a parallel circuit requires high impedance from both the RF source used and the instrument displaying the result. ? As one of my colleagues already mentioned: “Nothing is more useful than a good theory”. And I still believe that it is true. ? Let us know ! ? 73, Jacques, VE2JFE in Montreal ? Some additional info: disconnecting BS variable condenser doesn't change things significantly. Here are measurements (ANT circuit only): ? ? I then disconnected C33 from V1 pin4 and moved the probe to C3 but, again, nothing significant happens. Now the ANT circuit is completely alone and ... still resonating too low. I also tried to switch the input connection between; RTMA, a 0.01uF cap, pure induction (air). The signal levels change, but the peak is steady at the wrong values. ? Here you can see the variables: I cannot see any sign indicating not being Halli's originals. ? The last resort idea is to check wiring and all part numbers of my not working ANT circuit against someone else working one. ? -- Emanuele (IU1KNR). |
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
Some additional info:
disconnecting BS variable condenser doesn't change things significantly. Here are measurements (ANT circuit only):
?
?
I then disconnected C33 from V1 pin4 and moved the probe to C3 but, again, nothing significant happens.
Now the ANT circuit is completely alone and ... still resonating too low.
I also tried to switch the input connection between; RTMA, a 0.01uF cap, pure induction (air). The signal levels change, but the peak is steady at the wrong values.
?
Here you can see the variables: I cannot see any sign indicating not being Halli's originals.
?
The last resort idea is to check wiring and all part numbers of my not working ANT circuit against someone else working one.
Should anyone else had an S-85 open on the ?bench, your input would be greatly appreciated (Jim, are you still there?). ?
--
Emanuele (IU1KNR).
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
开云体育Emanuele, as you seek out more and more long-shot ideas for your original problem set, sometime you might contemplate the probability that an “almost same” C7 ?somehow managed to get the right S-85 part number put on it [ but only the min capacitance was not as low] and then ?put in your radio, and perhaps it got passed along as a shelf queen all this time, passing from one SWL to another. Without having Jim undo his wires maybe you two can visually measure/compare the rotor to stator gaps when wide open or something? ? -- don??? va3drl |
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Re: S-85 refurbish: I've got a problem during the RF alignment of bands 1 and 2 - trimcaps don't peak!
开云体育Emanuele the? side view of L3, and L6 shows more spacing between coils than the earlier? “almost end views” did, and consequently in my mind, the mutual coupling and trimmer tuning interaction will not be much. ? ? Some bug has me, but I am up for a bit.. staring at C33 , which is needed to let the AVC control the RF grid, while allowing RF to also couple from the left. Since C33 is hung on the tuning condensers and switch the other end of it will need to maintain High resistance 1 Meg ofr R1 ????.very long shot but . ?? ? Whaterever it is that is wonky, it does the same thing to the RF and Mixer. ??I keep wondering what would happen with the BS wires lifted ? -- don??? va3drl |
Jacques_VE2JFE
Emanuele Girlando
Jim Whartenby
waltcates
Robert Kembel
don Root