Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
I don't think there are any drain plugs on this antenna. connection seals were checked and re-done. I am not familiar with the desense tests, but both repeater and duplexer were replaced. New duplexer tested at more than 100 db isolation and power is about 75 watts .Problem must be with hard line (replaced already), tower or antenna. In a message dated 8/10/2010 12:09:39 A.M. Eastern Daylight Time, petedcur...@gmail.com writes: Hi, Juts a thought: Sometimes certain antennas have a drain plug at the bottom and sometime one at the top. You should remove the drain plug at the bottom for normal mounting or the one at the top for inverted mounting.If you don't water can ingress, then can't escape and build up.Another thing to check is the connector sealing. Peter On Mon, Aug 9, 2010 at 4:49 PM, Kevin Custer _kug...@kuggie.kug_ (mailto:kug...@kuggie.com) wrote: _radi...@aol.rad_ (mailto:radi...@aol.com) wrote: Hi Kevin, The desense is a staticy reception of weaker signals( ie an HT at 25 miles) It had gotten worse as it started to affect strong signals too. If the transmitter was turned off, the repeater could hear just fine. Problem is intermittent and often followed a rainy day. We replaced EVERYTHING A UHF repeater on the same tower is unaffected. At this point we think the new antenna is failing. Tower sections have been bonded grounds improved etc etc To know whether or not the problem is the antenna system, do a desensitization test directly at the antenna port of the duplexer using a good load and a lossy tee or other acceptable method like a coupler slug installed into the Bird Watt meter. If you don't know how to perform a desense test, there are several articles on the website that will assist you. If this proves good, then you have more work to do on the outside. Let us know... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Have you swept the Antenna and Transmission Line with a Site analyzer or a Comms Analyzer / RF Bridge? Peter On Tue, Aug 10, 2010 at 8:35 AM, radi...@aol.com wrote: I don't think there are any drain plugs on this antenna. connection seals were checked and re-done. I am not familiar with the desense tests, but both repeater and duplexer were replaced. New duplexer tested at more than 100 db isolation and power is about 75 watts .Problem must be with hard line (replaced already), tower or antenna. In a message dated 8/10/2010 12:09:39 A.M. Eastern Daylight Time, petedcur...@gmail.com writes: Hi, Juts a thought: Sometimes certain antennas have a drain plug at the bottom and sometime one at the top. You should remove the drain plug at the bottom for normal mounting or the one at the top for inverted mounting.If you don't water can ingress, then can't escape and build up.Another thing to check is the connector sealing. Peter On Mon, Aug 9, 2010 at 4:49 PM, Kevin Custer kug...@kuggie.com wrote: radi...@aol.com wrote: Hi Kevin, The desense is a staticy reception of weaker signals( ie an HT at 25 miles) It had gotten worse as it started to affect strong signals too. If the transmitter was turned off, the repeater could hear just fine. Problem is intermittent and often followed a rainy day. We replaced EVERYTHING A UHF repeater on the same tower is unaffected. At this point we think the new antenna is failing. Tower sections have been bonded grounds improved etc etc To know whether or not the problem is the antenna system, do a desensitization test directly at the antenna port of the duplexer using a good load and a lossy tee or other acceptable method like a coupler slug installed into the Bird Watt meter. If you don't know how to perform a desense test, there are several articles on the website that will assist you. If this proves good, then you have more work to do on the outside. Let us know... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Yes it has been swept. (not by me, by someone who knows the commercial repeater business) Nothing found. But remember this is an intermittant thing. In a message dated 8/10/2010 9:50:44 A.M. Eastern Daylight Time, petedcur...@gmail.com writes: Have you swept the Antenna and Transmission Line with a Site analyzer or a Comms Analyzer / RF Bridge? Peter On Tue, Aug 10, 2010 at 8:35 AM, _radi...@aol.rad_ (mailto:radi...@aol.com) wrote: I don't think there are any drain plugs on this antenna. connection seals were checked and re-done. I am not familiar with the desense tests, but both repeater and duplexer were replaced. New duplexer tested at more than 100 db isolation and power is about 75 watts .Problem must be with hard line (replaced already), tower or antenna. In a message dated 8/10/2010 12:09:39 A.M. Eastern Daylight Time, _petedcur...@petedcurt_ (mailto:petedcur...@gmail.com) writes: Hi, Juts a thought: Sometimes certain antennas have a drain plug at the bottom and sometime one at the top. You should remove the drain plug at the bottom for normal mounting or the one at the top for inverted mounting.If you don't water can ingress, then can't escape and build up. Another thing to check is the connector sealing. Peter On Mon, Aug 9, 2010 at 4:49 PM, Kevin Custer _kug...@kuggie.kug_ (mailto:kug...@kuggie.com) wrote: _radi...@aol.rad_ (mailto:radi...@aol.com) wrote: Hi Kevin, The desense is a staticy reception of weaker signals( ie an HT at 25 miles) It had gotten worse as it started to affect strong signals too. If the transmitter was turned off, the repeater could hear just fine. Problem is intermittent and often followed a rainy day. We replaced EVERYTHING A UHF repeater on the same tower is unaffected. At this point we think the new antenna is failing. Tower sections have been bonded grounds improved etc etc To know whether or not the problem is the antenna system, do a desensitization test directly at the antenna port of the duplexer using a good load and a lossy tee or other acceptable method like a coupler slug installed into the Bird Watt meter. If you don't know how to perform a desense test, there are several articles on the website that will assist you. If this proves good, then you have more work to do on the outside. Let us know... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Hi Kevin, The desense is a staticy reception of weaker signals( ie an HT at 25 miles) It had gotten worse as it started to affect strong signals too. If the transmitter was turned off, the repeater could hear just fine. Problem is intermittent and often followed a rainy day. We replaced EVERYTHING A UHF repeater on the same tower is unaffected. At this point we think the new antenna is failing. Tower sections have been bonded grounds improved etc etc In a message dated 8/8/2010 9:57:09 P.M. Eastern Daylight Time, kug...@kuggie.com writes: _radi...@aol.rad_ (mailto:radi...@aol.com) wrote: Hi Kevin, I have confirmed that 2 of the 4 finals are bad. both are on one side of the push pull. Both open base connection One has collector to emitter short. The other open emitter. I have not yet checked the drivers I might be able to test them without removal. I have a friend trying to scare up a Mitrek Aside from the transistors which I know are hard to find, and the cooked 12 ohm resistors, Is there something else I need to look for? I doubt it. Usually the resistors go because of the imbalance from one or more of the transistors failing. I recommend replacing all of the output together with matched gain transistors, if you choose to repair the PA. We think it was an intermittent Duplexer or antenna issue that caused it to blow. We have since replaced the repeater, amp, and duplexer but a desense condition has returned after a few weeks. The antenna is a 4 bay folded dipole on a 100 foot tower. this Antenna replaced a Stationmaster only about 3 years ago. Tower is Rohn 45? guyed with Phillystrand. Thanks for your help. Marty What kind of desense? Does the repeater properly duplex on a known good dummy load? Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
radi...@aol.com wrote: Hi Kevin, The desense is a staticy reception of weaker signals( ie an HT at 25 miles) It had gotten worse as it started to affect strong signals too. If the transmitter was turned off, the repeater could hear just fine. Problem is intermittent and often followed a rainy day. We replaced EVERYTHING A UHF repeater on the same tower is unaffected. At this point we think the new antenna is failing. Tower sections have been bonded grounds improved etc etc To know whether or not the problem is the antenna system, do a desensitization test directly at the antenna port of the duplexer using a good load and a lossy tee or other acceptable method like a coupler slug installed into the Bird Watt meter. If you don't know how to perform a desense test, there are several articles on the website that will assist you. If this proves good, then you have more work to do on the outside. Let us know... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Hi, Juts a thought: Sometimes certain antennas have a drain plug at the bottom and sometime one at the top. You should remove the drain plug at the bottom for normal mounting or the one at the top for inverted mounting.If you don't water can ingress, then can't escape and build up.Another thing to check is the connector sealing. Peter On Mon, Aug 9, 2010 at 4:49 PM, Kevin Custer kug...@kuggie.com wrote: radi...@aol.com wrote: Hi Kevin, The desense is a staticy reception of weaker signals( ie an HT at 25 miles) It had gotten worse as it started to affect strong signals too. If the transmitter was turned off, the repeater could hear just fine. Problem is intermittent and often followed a rainy day. We replaced EVERYTHING A UHF repeater on the same tower is unaffected. At this point we think the new antenna is failing. Tower sections have been bonded grounds improved etc etc To know whether or not the problem is the antenna system, do a desensitization test directly at the antenna port of the duplexer using a good load and a lossy tee or other acceptable method like a coupler slug installed into the Bird Watt meter. If you don't know how to perform a desense test, there are several articles on the website that will assist you. If this proves good, then you have more work to do on the outside. Let us know... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
radi...@aol.com wrote: Hi Kevin, I have confirmed that 2 of the 4 finals are bad. both are on one side of the push pull. Both open base connection One has collector to emitter short. The other open emitter. I have not yet checked the drivers I might be able to test them without removal. I have a friend trying to scare up a Mitrek Aside from the transistors which I know are hard to find, and the cooked 12 ohm resistors, Is there something else I need to look for? I doubt it. Usually the resistors go because of the imbalance from one or more of the transistors failing. I recommend replacing all of the output together with matched gain transistors, if you choose to repair the PA. We think it was an intermittent Duplexer or antenna issue that caused it to blow. We have since replaced the repeater, amp, and duplexer but a desense condition has returned after a few weeks. The antenna is a 4 bay folded dipole on a 100 foot tower. this Antenna replaced a Stationmaster only about 3 years ago. Tower is Rohn 45? guyed with Phillystrand. Thanks for your help. Marty What kind of desense? Does the repeater properly duplex on a known good dummy load? Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Hi Kevin, I have confirmed that 2 of the 4 finals are bad. both are on one side of the push pull. Both open base connection One has collector to emitter short. The other open emitter. I have not yet checked the drivers I might be able to test them without removal. I have a friend trying to scare up a Mitrek Aside from the transistors which I know are hard to find, and the cooked 12 ohm resistors, Is there something else I need to look for? We think it was an intermittent Duplexer or antenna issue that caused it to blow. We have since replaced the repeater, amp, and duplexer but a desense condition has returned after a few weeks. The antenna is a 4 bay folded dipole on a 100 foot tower. this Antenna replaced a Stationmaster only about 3 years ago. Tower is Rohn 45? guyed with Phillystrand. Thanks for your help. Marty
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
I have a brand new - never used - TLD 1693 VHF amp that I purchased as a back up for a local club. I tried to find - buy - and substitute other final transistors and discovered - there are no more around. They had the MSR2000 repeater and this amp has the M1131 - M1133 - M1134 transistors in the same configuration as the MSR2000. It was something that I purchased with my own money - They have changed repeaters and I was stuck with this extra amp. Should be exactly what you are looking for I am in PA -- Ron rt...@yahoo.com On 8/7/2010 6:52 PM, radi...@aol.com wrote: Hi Kevin, I have confirmed that 2 of the 4 finals are bad. both are on one side of the push pull. Both open base connection One has collector to emitter short. The other open emitter. I have not yet checked the drivers I might be able to test them without removal. I have a friend trying to scare up a Mitrek Aside from the transistors which I know are hard to find, and the cooked 12 ohm resistors, Is there something else I need to look for? We think it was an intermittent Duplexer or antenna issue that caused it to blow. We have since replaced the repeater, amp, and duplexer but a desense condition has returned after a few weeks. The antenna is a 4 bay folded dipole on a 100 foot tower. this Antenna replaced a Stationmaster only about 3 years ago. Tower is Rohn 45? guyed with Phillystrand. Thanks for your help. Marty Yahoo! Groups Links * To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ * Your email settings: Individual Email | Traditional * To change settings online go to: http://groups.yahoo.com/group/Repeater-Builder/join (Yahoo! ID required) * To change settings via email: repeater-builder-dig...@yahoogroups.com repeater-builder-fullfeatu...@yahoogroups.com * To unsubscribe from this group, send an email to: repeater-builder-unsubscr...@yahoogroups.com * Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
radi...@aol.com wrote: Sucess! I completely cleaned and re tinned my Weller 8100 tip, added some solder, and got heat transfer to pop it up. I was not aware of the fish paper that the wires came thru. Now to troubleshoot the amp. It probably has some blown transistors as well as the cooked caps and 12 ohm resistors across some of the finals. We do have a Motorola test set, I have done component level work in the past, but this is out of my league. Kevin, I may take you up on your offer for further help. Thanks to all who responded. 73, Marty Consider obtaining a used MICOR mobile (usually can be gotten for $5 to $50) having a power amplifier board of the desired size and transplant it onto your heatsink. The PA assembly for this mobile radio is identical to the one(s) used on the continuous duty MICOR and MSR2000 power amplifiers. Or, just figure out which stage is bad and replace the transistor(s) that have failed. There is a process I use to easily see which stage is bad. Reply if you need more help. Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Tom Parker wrote: Why has no one suggested replacing the guts of this beast with a Mitrek PA? Why? Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Sucess! I completely cleaned and re tinned my Weller 8100 tip, added some solder, and got heat transfer to pop it up. I was not aware of the fish paper that the wires came thru. Now to troubleshoot the amp. It probably has some blown transistors as well as the cooked caps and 12 ohm resistors across some of the finals. We do have a Motorola test set, I have done component level work in the past, but this is out of my league. Kevin, I may take you up on your offer for further help. Thanks to all who responded. 73, Marty In a message dated 8/2/2010 8:29:32 P.M. Eastern Daylight Time, kug...@kuggie.com writes: _radi...@aol.rad_ (mailto:radi...@aol.com) wrote: OK Kevin, I had already tried the desoldering with a really good Pace unit, but the heat did not transfer well. I will get a buddy to help and use my Weller guns. I have a big 250 watt one here somewhere. Marty Let us know how you make out - or, if you need more help... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Why has no one suggested replacing the guts of this beast with a Mitrek PA? radi...@aol.com wrote: Sucess! I completely cleaned and re tinned my Weller 8100 tip, added some solder, and got heat transfer to pop it up. I was not aware of the fish paper that the wires came thru. Now to troubleshoot the amp. It probably has some blown transistors as well as the cooked caps and 12 ohm resistors across some of the finals. We do have a Motorola test set, I have done component level work in the past, but this is out of my league. Kevin, I may take you up on your offer for further help. Thanks to all who responded. 73, Marty In a message dated 8/2/2010 8:29:32 P.M. Eastern Daylight Time, kug...@kuggie.com writes: radi...@aol.com wrote: OK Kevin, I had already tried the desoldering with a really good Pace unit, but the heat did not transfer well. I will get a buddy to help and use my Weller guns. I have a big 250 watt one here somewhere. Marty Let us know how you make out - or, if you need more help... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Thanks Kevin, I think you are on to something. The areas that are pinned down seem to be close to where the power supply wires enter the board from the underside. I am wondering if the wires are glued down with RTV or something. Cautious prying is still not getting me anywhere. Marty
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
radi...@aol.com wrote: Thanks Kevin, I think you are on to something. The areas that are pinned down seem to be close to where the power supply wires enter the board from the underside. I am wondering if the wires are glued down with RTV or something. Cautious prying is still not getting me anywhere. Marty Get a friend. Using two solder guns (Weller 8200 or like) heat both joints where the feed-through pins come through. Pull straight up when you have both heated well enough that the solder is fully molten. This process can be done with one gun/iron, but it's difficult at best; as you have to alternately heat and pry which puts a good bit of strain on the board until it becomes free. You could also try a de-soldering tool cleaning out the holes where the feed-throughs protrude from the board, but again, this can be difficult to remove the solder that lays under the board depending on the amount of heat you apply and the quality of your de-soldering pump. Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
OK Kevin, I had already tried the desoldering with a really good Pace unit, but the heat did not transfer well. I will get a buddy to help and use my Weller guns. I have a big 250 watt one here somewhere. Marty
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
radi...@aol.com wrote: OK Kevin, I had already tried the desoldering with a really good Pace unit, but the heat did not transfer well. I will get a buddy to help and use my Weller guns. I have a big 250 watt one here somewhere. Marty Let us know how you make out - or, if you need more help... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Motorola didn't do anyone any favors with that design. Same thing on the Micor PA. Chuck WB2EDV - Original Message - From: Kevin Custer To: Repeater-Builder@yahoogroups.com Sent: Monday, August 02, 2010 8:29 PM Subject: Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How? radi...@aol.com wrote: OK Kevin, I had already tried the desoldering with a really good Pace unit, but the heat did not transfer well. I will get a buddy to help and use my Weller guns. I have a big 250 watt one here somewhere. Marty Let us know how you make out - or, if you need more help... Kevin
Re: [Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
martinfriedman67 wrote: Our Amateur radio club's Motorola MSR 2000 continuous duty amp needs repair. I cant figure out how to remove the amp board from the heat sink. I removed all screws from corners as well as the transistors. It seems to be held by the center, just below the tall air variable cap. I tried heating the solder in the area but, no joy. I don't want to crack the board. The drawings in the manual I found here do not show even the screw holes. Thanks in advance, 73, Marty (WB2BEW) Look for the via that carries the power supply connections to the board. Sounds like they are holding you back. Kevin
[Repeater-Builder] Dissasembly of msr 2000 continuous duty amp. How?
Our Amateur radio club's Motorola MSR 2000 continuous duty amp needs repair. I cant figure out how to remove the amp board from the heat sink. I removed all screws from corners as well as the transistors. It seems to be held by the center, just below the tall air variable cap. I tried heating the solder in the area but, no joy. I don't want to crack the board. The drawings in the manual I found here do not show even the screw holes. Thanks in advance, 73, Marty (WB2BEW)
