[Flexradio] blown SDR-1000 final opamp
Some months ago I blew the final opamp in my 1W SDR-1000 whilst matching it to a linear. Wasn't happy about that but since I accidentally hooked up the attenuator resistors wrong I wasn't too surprised since the rig saw a very high impedance. Worked fine ever since. Unfortunately I'm less happy about blowing the amp this morning, about a half year after that first incident, whilst trying it on six meters for the first time. Without the linear which doesn't cover six. Just wanted to see if I could work a couple locals. As far as the MFJ-269 showed there was a perfect match into the ATU but when I increased the power beyond about a tenth of a watt output the opamp popped again. Besides the time and money aspect, the circuit board clearly can't take a lot of parts replacements. Has anyone figured out how better to protect this part? Or some better solution. This is a four stack including the rfe board, older version with nylon spacers. Thanks. -Pete WB2QLL Somers, WI ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] blown SDR-1000 final opamp
Pete, The very old SDR-1000 units have OPA2677 as the final amplifier and cannot stand short circuit. The newer radios use OPA2674 that has internal short circuit protection. Anyhow, ask Flex people directly, they know better the difficulties with some of the first production units. 73, Ahti OH2RZ On 09/12/2008, Pete Ferrand [EMAIL PROTECTED] wrote: Some months ago I blew the final opamp in my 1W SDR-1000 whilst matching it to a linear. Wasn't happy about that but since I accidentally hooked up the attenuator resistors wrong I wasn't too surprised since the rig saw a very high impedance. Worked fine ever since. Unfortunately I'm less happy about blowing the amp this morning, about a half year after that first incident, whilst trying it on six meters for the first time. Without the linear which doesn't cover six. Just wanted to see if I could work a couple locals. As far as the MFJ-269 showed there was a perfect match into the ATU but when I increased the power beyond about a tenth of a watt output the opamp popped again. Besides the time and money aspect, the circuit board clearly can't take a lot of parts replacements. Has anyone figured out how better to protect this part? Or some better solution. This is a four stack including the rfe board, older version with nylon spacers. Thanks. -Pete WB2QLL Somers, WI ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Update from W1aw/W5gi
Just a quick note to report on my activities at the ARRL. At 1800 UTC I was joined at W1AW by about 15 employees of the ARRL, including Dave Summer. I officially handed over a FLEX-5000 (an upgraded beta unit) for use at their station. Following the official presentation, I spent about 90 minutes demonstrating the radio and discussing the world of software defined radio. I was then invited to take a tour of the ARRL complex, which was very interesting. I returned to the station at 2000hrs UTC to begin operating ( a hour later than promised). I experienced high SWR problems, which turned out to be a bad coax cable run from the antenna box to the F5K operating position. I began operating as soon as the problem was repaired but had to cease operation at 2047 UTC so that the regular broadcast could begin. I worked about 50 stations in about 30 minutes despite terrible band conditions. The F5K performed flawlessly and was fun to use with their monster antenna system. I worked several FLEXERS but Dudley, WA5QPZ had, by a large measure, the strongest signal of any station worked. The 5000 is now a permanent part of W1AW/ARRL and available to anyone to use when visiting there. I recommend a visit to the ARRL-it's like a Smithsonian museum for amateur radio. 73 John P. Basilotto W5GI VP Amateur Division (NA) ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Update from W1aw/W5gi
UHMMM, wonder what beta upgrades are included in this 5K? Jim K4JAF - Original Message - From: John [EMAIL PROTECTED] To: 'Flex Radio' FlexRadio@flex-radio.biz Sent: Tuesday, December 09, 2008 9:20 AM Subject: Re: [Flexradio] Update from W1aw/W5gi Just a quick note to report on my activities at the ARRL. At 1800 UTC I was joined at W1AW by about 15 employees of the ARRL, including Dave Summer. I officially handed over a FLEX-5000 (an upgraded beta unit) for use at their station. Following the official presentation, I spent about 90 minutes demonstrating the radio and discussing the world of software defined radio. I was then invited to take a tour of the ARRL complex, which was very interesting. I returned to the station at 2000hrs UTC to begin operating ( a hour later than promised). I experienced high SWR problems, which turned out to be a bad coax cable run from the antenna box to the F5K operating position. I began operating as soon as the problem was repaired but had to cease operation at 2047 UTC so that the regular broadcast could begin. I worked about 50 stations in about 30 minutes despite terrible band conditions. The F5K performed flawlessly and was fun to use with their monster antenna system. I worked several FLEXERS but Dudley, WA5QPZ had, by a large measure, the strongest signal of any station worked. The 5000 is now a permanent part of W1AW/ARRL and available to anyone to use when visiting there. I recommend a visit to the ARRL-it's like a Smithsonian museum for amateur radio. 73 John P. Basilotto W5GI VP Amateur Division (NA) ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
[Flexradio] Second Receiver Observations
I questioned whether I would find the second receiver in the 5K of much use in my station. I have a K9AY loop as well as the usual dipole and a quarter wave 80 meter vertical. The diversity reception on very weak signals while linking the 2 receivers is amazing.. I have one receiver on the left speaker and one on the right speaker and you can tell when each receiver is the dominant one.. Amazingly, it can occur in a very short space of time (milliseconds). You can see it on the panadapter also but it is not as apparent as listening... Just my thoughts if any are considering the second receiver for use with 2 antennas. Jim K4JAF ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Update from W1aw/W5gi
I was more concerned over John's latest promotion the Vice President of the Amateur Division! I would imagine he is on the short list of any number of Obama staff positions. I would hate to lose him! 73 Lee K9WRU - Original Message - From: Jim Cox [EMAIL PROTECTED] To: John [EMAIL PROTECTED]; 'Flex Radio' FlexRadio@flex-radio.biz Sent: Tuesday, December 09, 2008 9:40 AM Subject: Re: [Flexradio] Update from W1aw/W5gi UHMMM, wonder what beta upgrades are included in this 5K? Jim K4JAF - Original Message - From: John [EMAIL PROTECTED] To: 'Flex Radio' FlexRadio@flex-radio.biz Sent: Tuesday, December 09, 2008 9:20 AM Subject: Re: [Flexradio] Update from W1aw/W5gi Just a quick note to report on my activities at the ARRL. At 1800 UTC I was joined at W1AW by about 15 employees of the ARRL, including Dave Summer. I officially handed over a FLEX-5000 (an upgraded beta unit) for use at their station. Following the official presentation, I spent about 90 minutes demonstrating the radio and discussing the world of software defined radio. I was then invited to take a tour of the ARRL complex, which was very interesting. I returned to the station at 2000hrs UTC to begin operating ( a hour later than promised). I experienced high SWR problems, which turned out to be a bad coax cable run from the antenna box to the F5K operating position. I began operating as soon as the problem was repaired but had to cease operation at 2047 UTC so that the regular broadcast could begin. I worked about 50 stations in about 30 minutes despite terrible band conditions. The F5K performed flawlessly and was fun to use with their monster antenna system. I worked several FLEXERS but Dudley, WA5QPZ had, by a large measure, the strongest signal of any station worked. The 5000 is now a permanent part of W1AW/ARRL and available to anyone to use when visiting there. I recommend a visit to the ARRL-it's like a Smithsonian museum for amateur radio. 73 John P. Basilotto W5GI VP Amateur Division (NA) ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] Update from W1aw/W5gi
The best way to keep him is to BUY MORE FLEX RADIOS! Neal Campbell Abroham Neal Software Programming Services for Windows, OS X and Linux (540) 242 0911 - Try Spot for OS X, the intelligent DXCluster Client at www.abrohamnealsoftware.com - $15.99 - For a great dog book, visit www.abrohamneal.com - See the FlexRadio Systems Flex-5000a in action at www.flex-videos.com On Tue, Dec 9, 2008 at 11:21 AM, Lee Mushel [EMAIL PROTECTED] wrote: I was more concerned over John's latest promotion the Vice President of the Amateur Division! I would imagine he is on the short list of any number of Obama staff positions. I would hate to lose him! 73 Lee K9WRU - Original Message - From: Jim Cox [EMAIL PROTECTED] To: John [EMAIL PROTECTED]; 'Flex Radio' FlexRadio@flex-radio.biz Sent: Tuesday, December 09, 2008 9:40 AM Subject: Re: [Flexradio] Update from W1aw/W5gi UHMMM, wonder what beta upgrades are included in this 5K? Jim K4JAF - Original Message - From: John [EMAIL PROTECTED] To: 'Flex Radio' FlexRadio@flex-radio.biz Sent: Tuesday, December 09, 2008 9:20 AM Subject: Re: [Flexradio] Update from W1aw/W5gi Just a quick note to report on my activities at the ARRL. At 1800 UTC I was joined at W1AW by about 15 employees of the ARRL, including Dave Summer. I officially handed over a FLEX-5000 (an upgraded beta unit) for use at their station. Following the official presentation, I spent about 90 minutes demonstrating the radio and discussing the world of software defined radio. I was then invited to take a tour of the ARRL complex, which was very interesting. I returned to the station at 2000hrs UTC to begin operating ( a hour later than promised). I experienced high SWR problems, which turned out to be a bad coax cable run from the antenna box to the F5K operating position. I began operating as soon as the problem was repaired but had to cease operation at 2047 UTC so that the regular broadcast could begin. I worked about 50 stations in about 30 minutes despite terrible band conditions. The F5K performed flawlessly and was fun to use with their monster antenna system. I worked several FLEXERS but Dudley, WA5QPZ had, by a large measure, the strongest signal of any station worked. The 5000 is now a permanent part of W1AW/ARRL and available to anyone to use when visiting there. I recommend a visit to the ARRL-it's like a Smithsonian museum for amateur radio. 73 John P. Basilotto W5GI VP Amateur Division (NA) ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] John had to shut down..
I did speak with John, using my 5000a here in Dallas (100 watts). The Flex radio at W1AW has the cleanest audio of anything I have heard from there. I have been looking forward to this for some time. When I was at W1AW last Summer I discovered there was nothing resembling a software defined radio there. I sent Gerald Youngblood an EMail about it. He responded that he would donate a radio. What we heard on Monday was the result. I look forward to hearing this radio on the air often in the years to come. There are so many other 'new' radios that appear to be little more than boat anchors when compared to it. Dudley Hurry wrote: John had to shut down, really brief on W1AW.. -- Regards, TOM BLACKWELL, PO Box 25403, Dallas, Texas 75225 N5GAR. ARRL SM - NTX. http://www.arrl.net/sections/NTX.html ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] John had to shut down..
I spoke with Gerald briefly during the Flex QSO party and I heard unbelievably smooth, clear audio. I had meant to ask him to post the settings and if any external processing was required to sound like that. Incredible!! Edwin Marzan AB2VW === Date: Tue, 9 Dec 2008 10:07:12 -0600 From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] CC: FlexRadio@flex-radio.biz Subject: Re: [Flexradio] John had to shut down.. I did speak with John, using my 5000a here in Dallas (100 watts). The Flex radio at W1AW has the cleanest audio of anything I have heard from there. I have been looking forward to this for some time. When I was at W1AW last Summer I discovered there was nothing resembling a software defined radio there. I sent Gerald Youngblood an EMail about it. He responded that he would donate a radio. What we heard on Monday was the result. I look forward to hearing this radio on the air often in the years to come. There are so many other 'new' radios that appear to be little more than boat anchors when compared to it. Dudley Hurry wrote: John had to shut down, really brief on W1AW.. --Regards, TOM BLACKWELL, PO Box 25403, Dallas, Texas 75225 N5GAR. ARRL SM - NTX. http://www.arrl.net/sections/NTX.html ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ _ Send e-mail anywhere. No map, no compass. http://windowslive.com/Explore/hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_anywhere_122008 ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] [SPAM] Re: John had to shut down..
I am fairly sure that Gerald was just using a Heil PR-781 directly into the balanced input on the FLEX-5000 and using just the PowerSDR EQ and Compander for audio processing. -Tim -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Edwin Marzan Sent: Tuesday, December 09, 2008 12:22 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: flexradio@flex-radio.biz Subject: [SPAM] Re: [Flexradio] John had to shut down.. I spoke with Gerald briefly during the Flex QSO party and I heard unbelievably smooth, clear audio. I had meant to ask him to post the settings and if any external processing was required to sound like that. Incredible!! Edwin Marzan AB2VW === Date: Tue, 9 Dec 2008 10:07:12 -0600 From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] CC: FlexRadio@flex-radio.biz Subject: Re: [Flexradio] John had to shut down.. I did speak with John, using my 5000a here in Dallas (100 watts). The Flex radio at W1AW has the cleanest audio of anything I have heard from there. I have been looking forward to this for some time. When I was at W1AW last Summer I discovered there was nothing resembling a software defined radio there. I sent Gerald Youngblood an EMail about it. He responded that he would donate a radio. What we heard on Monday was the result. I look forward to hearing this radio on the air often in the years to come. There are so many other 'new' radios that appear to be little more than boat anchors when compared to it. Dudley Hurry wrote: John had to shut down, really brief on W1AW.. --Regards, TOM BLACKWELL, PO Box 25403, Dallas, Texas 75225 N5GAR. ARRL SM - NTX. http://www .arrl.net/sections/NTX.html ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ _ Send e-mail anywhere. No map, no compass. http://windowslive.com/Explore/hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_anywhere_122008 ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] [SPAM] Re: John had to shut down..
John did the setup on the Flex QSO party but as I recall, Tim is correct on the setup we had. Gerald Gerald Youngblood, K5SDR President FlexRadio Systems 13091 Pond Springs Rd. #250 Austin, TX 78729 Phone: 512-535-4713 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tim Ellison Sent: Tuesday, December 09, 2008 11:39 AM To: Edwin Marzan; [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: flexradio@flex-radio.biz Subject: Re: [Flexradio] [SPAM] Re: John had to shut down.. I am fairly sure that Gerald was just using a Heil PR-781 directly into the balanced input on the FLEX-5000 and using just the PowerSDR EQ and Compander for audio processing. -Tim -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Edwin Marzan Sent: Tuesday, December 09, 2008 12:22 PM To: [EMAIL PROTECTED]; [EMAIL PROTECTED] Cc: flexradio@flex-radio.biz Subject: [SPAM] Re: [Flexradio] John had to shut down.. I spoke with Gerald briefly during the Flex QSO party and I heard unbelievably smooth, clear audio. I had meant to ask him to post the settings and if any external processing was required to sound like that. Incredible!! Edwin Marzan AB2VW === Date: Tue, 9 Dec 2008 10:07:12 -0600 From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] CC: FlexRadio@flex-radio.biz Subject: Re: [Flexradio] John had to shut down.. I did speak with John, using my 5000a here in Dallas (100 watts). The Flex radio at W1AW has the cleanest audio of anything I have heard from there. I have been looking forward to this for some time. When I was at W1AW last Summer I discovered there was nothing resembling a software defined radio there. I sent Gerald Youngblood an EMail about it. He responded that he would donate a radio. What we heard on Monday was the result. I look forward to hearing this radio on the air often in the years to come. There are so many other 'new' radios that appear to be little more than boat anchors when compared to it. Dudley Hurry wrote: John had to shut down, really brief on W1AW.. -- Regards, TOM BLACKWELL, PO Box 25403, Dallas, Texas 75225 N5GAR. ARRL SM - NTX. http://www .arrl.net/sections/NTX.html ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ _ Send e-mail anywhere. No map, no compass. http://windowslive.com/Explore/hotmail?ocid=TXT_TAGLM_WL_hotmail_acq_anywher e_122008 ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] blown SDR-1000 final opamp
Ahti: Thank you for taking the time to reply. My radio has the OPA2674 and that is what it had originally. The issue is not one of a short circuit, but most probably one of dealing with a high impedance load which would send the voltage up beyond what the part can handle. At least that's what I'm guessing; I'm not sure of the correct troubleshooting procedure for this kind of fault. My hope was that someone has figured out how to make the circuit more robust but since yours was the only reply and there's no mention of it in the archives I suppose that hasn't happened. 73, -Pete WB2QLL Somers, WI -Original Message- From: Ahti Aintila [EMAIL PROTECTED] Sent: Dec 9, 2008 4:54 AM To: Pete Ferrand [EMAIL PROTECTED] Cc: flexradio@flex-radio.biz Subject: Re: [Flexradio] blown SDR-1000 final opamp Pete, The very old SDR-1000 units have OPA2677 as the final amplifier and cannot stand short circuit. The newer radios use OPA2674 that has internal short circuit protection. Anyhow, ask Flex people directly, they know better the difficulties with some of the first production units. 73, Ahti OH2RZ On 09/12/2008, Pete Ferrand [EMAIL PROTECTED] wrote: Some months ago I blew the final opamp in my 1W SDR-1000 whilst matching it to a linear. Wasn't happy about that but since I accidentally hooked up the attenuator resistors wrong I wasn't too surprised since the rig saw a very high impedance. Worked fine ever since. Unfortunately I'm less happy about blowing the amp this morning, about a half year after that first incident, whilst trying it on six meters for the first time. Without the linear which doesn't cover six. Just wanted to see if I could work a couple locals. As far as the MFJ-269 showed there was a perfect match into the ATU but when I increased the power beyond about a tenth of a watt output the opamp popped again. Besides the time and money aspect, the circuit board clearly can't take a lot of parts replacements. Has anyone figured out how better to protect this part? Or some better solution. This is a four stack including the rfe board, older version with nylon spacers. Thanks. -Pete WB2QLL Somers, WI ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] blown SDR-1000 final opamp
Pete, You did not mention what sound card you are using, but if the sound card output is too high you can easily overdrive the low level driver, particularly the PreSonus can drive more than 4 volts peak to peak.. 73, Dudley WA5QPZ Pete Ferrand wrote: Ahti: Thank you for taking the time to reply. My radio has the OPA2674 and that is what it had originally. The issue is not one of a short circuit, but most probably one of dealing with a high impedance load which would send the voltage up beyond what the part can handle. At least that's what I'm guessing; I'm not sure of the correct troubleshooting procedure for this kind of fault. My hope was that someone has figured out how to make the circuit more robust but since yours was the only reply and there's no mention of it in the archives I suppose that hasn't happened. 73, -Pete WB2QLL Somers, WI -Original Message- From: Ahti Aintila [EMAIL PROTECTED] Sent: Dec 9, 2008 4:54 AM To: Pete Ferrand [EMAIL PROTECTED] Cc: flexradio@flex-radio.biz Subject: Re: [Flexradio] blown SDR-1000 final opamp Pete, The very old SDR-1000 units have OPA2677 as the final amplifier and cannot stand short circuit. The newer radios use OPA2674 that has internal short circuit protection. Anyhow, ask Flex people directly, they know better the difficulties with some of the first production units. 73, Ahti OH2RZ On 09/12/2008, Pete Ferrand [EMAIL PROTECTED] wrote: Some months ago I blew the final opamp in my 1W SDR-1000 whilst matching it to a linear. Wasn't happy about that but since I accidentally hooked up the attenuator resistors wrong I wasn't too surprised since the rig saw a very high impedance. Worked fine ever since. Unfortunately I'm less happy about blowing the amp this morning, about a half year after that first incident, whilst trying it on six meters for the first time. Without the linear which doesn't cover six. Just wanted to see if I could work a couple locals. As far as the MFJ-269 showed there was a perfect match into the ATU but when I increased the power beyond about a tenth of a watt output the opamp popped again. Besides the time and money aspect, the circuit board clearly can't take a lot of parts replacements. Has anyone figured out how better to protect this part? Or some better solution. This is a four stack including the rfe board, older version with nylon spacers. Thanks. -Pete WB2QLL Somers, WI ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
Re: [Flexradio] blown SDR-1000 final opamp
Dudley and Pete, The absolute maximum differential input voltage for OPA2674 is +/-1.2V. For that reason I used clamping diodes for protection in one instrumentation application of SDR-1000 when I was not sure the operators remember to keep the sound card output at reasonable level. Be careful though not to distort the signal. 73, Ahti OH2RZ On 10/12/2008, Dudley Hurry [EMAIL PROTECTED] wrote: Pete, You did not mention what sound card you are using, but if the sound card output is too high you can easily overdrive the low level driver, particularly the PreSonus can drive more than 4 volts peak to peak.. 73, Dudley WA5QPZ Pete Ferrand wrote: Ahti: Thank you for taking the time to reply. My radio has the OPA2674 and that is what it had originally. The issue is not one of a short circuit, but most probably one of dealing with a high impedance load which would send the voltage up beyond what the part can handle. At least that's what I'm guessing; I'm not sure of the correct troubleshooting procedure for this kind of fault. My hope was that someone has figured out how to make the circuit more robust but since yours was the only reply and there's no mention of it in the archives I suppose that hasn't happened. 73, -Pete WB2QLL Somers, WI -Original Message- From: Ahti Aintila [EMAIL PROTECTED] Sent: Dec 9, 2008 4:54 AM To: Pete Ferrand [EMAIL PROTECTED] Cc: flexradio@flex-radio.biz Subject: Re: [Flexradio] blown SDR-1000 final opamp Pete, The very old SDR-1000 units have OPA2677 as the final amplifier and cannot stand short circuit. The newer radios use OPA2674 that has internal short circuit protection. Anyhow, ask Flex people directly, they know better the difficulties with some of the first production units. 73, Ahti OH2RZ On 09/12/2008, Pete Ferrand [EMAIL PROTECTED] wrote: Some months ago I blew the final opamp in my 1W SDR-1000 whilst matching it to a linear. Wasn't happy about that but since I accidentally hooked up the attenuator resistors wrong I wasn't too surprised since the rig saw a very high impedance. Worked fine ever since. Unfortunately I'm less happy about blowing the amp this morning, about a half year after that first incident, whilst trying it on six meters for the first time. Without the linear which doesn't cover six. Just wanted to see if I could work a couple locals. As far as the MFJ-269 showed there was a perfect match into the ATU but when I increased the power beyond about a tenth of a watt output the opamp popped again. Besides the time and money aspect, the circuit board clearly can't take a lot of parts replacements. Has anyone figured out how better to protect this part? Or some better solution. This is a four stack including the rfe board, older version with nylon spacers. Thanks. -Pete WB2QLL Somers, WI ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
