Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
On May 22, 2010, at 9:29 AM, Mike Besemer (WM4B) wrote: Every Tech Order I ever used in the Air Force started with 'Perform a through visual inspection'. Often times, that was good advice. Thorough, even. ;-) If you can see through it, the aircraft probably took a few rounds the pilot didn't know about. ;-) -- Nate Duehr n...@natetech.com facebook.com/denverpilot twitter.com/denverpilot
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
Nate Duehr wrote: If you can see through it, the aircraft probably took a few rounds the pilot didn't know about. ;-) --- That reminds me of a story Kevin told about when he worked in a CB shop. A guy came in and said he mounted his radio and now it didn't work. Kevin went out to investigate and found the guy drilled two holes right straight through the radio and used two lag bolts to fasten it to the dash!! It sure wasn't going anywhere in a crash!! Next.. Scott Scott Zimmerman Amateur Radio Call N3XCC 474 Barnett Road Boswell, PA 15531
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
Scott Zimmerman wrote: --- That reminds me of a story Kevin told about when he worked in a CB shop. A guy came in and said he mounted his radio and now it didn't work. Kevin went out to investigate and found the guy drilled two holes right straight through the radio and used two lag bolts to fasten it to the dash!! It sure wasn't going anywhere in a crash!! Yup..Radio was a week old - and totally ruined. Dude comes in to the CB shop I was working at when I was 14; wants a CB right now, and doesn't have the time to have it installed. So, we ran the power and antenna wires and laid it on the passenger seat until he could return to have it mounted. He comes back a week later to 'complain' that the radio no longer works. He had taken some time at his delivery lay-over to professionally mount his new radio to the under side of the dash. I went out and saw the bolt heads (with nice washers I might add) on the under side of the case of the radio. He drilled 2 mounting holes right through both sides of the case (and circuit board) and mounted that radio to the dash. It sure looked good, and it wasn't going anywhere, but the radio failed to operate after he wiped out most of the VCO and audio amplifier components with the 1/2 drill bit. True story - sigh Kevin
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
On 5/24/2010 7:43 AM, Scott Zimmerman wrote: --- That reminds me of a story Kevin told about when he worked in a CB shop. A guy came in and said he mounted his radio and now it didn't work. Kevin went out to investigate and found the guy drilled two holes right straight through the radio and used two lag bolts to fasten it to the dash!! It sure wasn't going anywhere in a crash!! Next.. Scott Here's your sign. - Bill Engvall :-) Nate WY0X
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
On 5/24/2010 11:38 AM, Kevin Custer wrote: I went out and saw the bolt heads (with nice washers I might add) on the under side of the case of the radio. He drilled 2 mounting holes right through both sides of the case (and circuit board) and mounted that radio to the dash. It sure looked good, and it wasn't going anywhere, but the radio failed to operate after he wiped out most of the VCO and audio amplifier components with the 1/2 drill bit. Great example of applying the rule: Safety First! You have to see the Dirty Jobs episode and Mike Rowe's speech in it titled,Safety Third -- to really understand that comment... http://dsc.discovery.com/videos/dirty-jobs-rocky-safety-third/ Nate WY0X
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
There were more *commercials* than the actual video - but it was pretty good to watch. Don, KD9PT - Original Message - From: Nate Duehr To: Repeater-Builder@yahoogroups.com Sent: Monday, May 24, 2010 3:25 PM Subject: Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater On 5/24/2010 11:38 AM, Kevin Custer wrote: I went out and saw the bolt heads (with nice washers I might add) on the under side of the case of the radio. He drilled 2 mounting holes right through both sides of the case (and circuit board) and mounted that radio to the dash. It sure looked good, and it wasn't going anywhere, but the radio failed to operate after he wiped out most of the VCO and audio amplifier components with the 1/2 drill bit. Great example of applying the rule: Safety First! You have to see the Dirty Jobs episode and Mike Rowe's speech in it titled,Safety Third -- to really understand that comment... http://dsc.discovery.com/videos/dirty-jobs-rocky-safety-third/ Nate WY0X
RE: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
I would look for a shorted tantalum capacitor hanging somewhere on the 10V rail. I agree. If you hook 10V from an outside source to the 10V buss, you'll probably find it's drawing all kinds of current. The 10V regulator circuit will go into fold back before burning up. This is by design. I usually hook a source of 10V at about 1.5A and look for smoke. It's usually one of the tantalum capacitors that starts to smoke. Once it's done smoking, problem solved!! Put a DMM on the 10V line, then start disconnecting things until you narrow it down, divide and conquer. Pull all of the cards out of the cage (except the 10V reg card obviously), disconnect the exciter, remove the receiver, etc. With a good ohmmeter that measures fractions of an ohm, you should be able to narrow it down further once you've found the suspect module/board. I have lost track of how many shorted tantalums I have had over the years. When they occur in the B+ of the high current PA supply, they simply burn up and th problem fixes itself. They make a cool purple smoke with lots of sparks when they flame out! --- Jeff WN3A
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
And sometimes scare the crap out of you! And they stink. Chuck WB2EDV - Original Message - From: Jeff DePolo j...@broadsci.com To: Repeater-Builder@yahoogroups.com Sent: Saturday, May 22, 2010 9:35 AM Subject: RE: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater They make a cool purple smoke with lots of sparks when they flame out! --- Jeff WN3A
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
On Sat, 22 May 2010, Chuck Kelsey wrote: And sometimes scare the crap out of you! And they stink. They make a cool purple smoke with lots of sparks when they flame out! IIRC they contain an element you're not supposed to breathe because it only causes cancer in the state of California. -- Kris Kirby, KE4AHR Disinformation Analyst
RE: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
Whenever you have a shorted component, such as a tantalum capacitor, the current drawn by that short might burn out a PC board trace before burning up the capacitor. If that happens, finding the original problem becomes much more difficult. Perhaps a better and safer tack would be to use a small current-limited power supply to energize the 10 volt buss, but with the current limit set to 1/4 ampere or so. Following Jeff's suggestion, start unplugging and/or disconnecting loads until the buss voltage jumps up to 10 volts. I don't know what current is normally drawn from the 10 volt regulator in a properly-operating station, but that value should be measured and recorded for future troubleshooting efforts. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo Sent: Saturday, May 22, 2010 6:36 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater I would look for a shorted tantalum capacitor hanging somewhere on the 10V rail. I agree. If you hook 10V from an outside source to the 10V buss, you'll probably find it's drawing all kinds of current. The 10V regulator circuit will go into fold back before burning up. This is by design. I usually hook a source of 10V at about 1.5A and look for smoke. It's usually one of the tantalum capacitors that starts to smoke. Once it's done smoking, problem solved!! Put a DMM on the 10V line, then start disconnecting things until you narrow it down, divide and conquer. Pull all of the cards out of the cage (except the 10V reg card obviously), disconnect the exciter, remove the receiver, etc. With a good ohmmeter that measures fractions of an ohm, you should be able to narrow it down further once you've found the suspect module/board. I have lost track of how many shorted tantalums I have had over the years. When they occur in the B+ of the high current PA supply, they simply burn up and th problem fixes itself. They make a cool purple smoke with lots of sparks when they flame out! --- Jeff WN3A
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
At 5/22/2010 07:28, you wrote: On Sat, 22 May 2010, Chuck Kelsey wrote: And sometimes scare the crap out of you! And they stink. They make a cool purple smoke with lots of sparks when they flame out! IIRC they contain an element you're not supposed to breathe because it only causes cancer in the state of California. I thought they were perfectly safe because there's no prop. 65 warning label on the radio ;) Bob NO6B
RE: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
This is also a good place for the 'finger test'. If there are suspect components you can get to that can't easily be removed (by pulling boards, etc.) then a calibrated finger will often lead you to the defective component. If it's really a cap, it should be generating a lot of heat. Sometimes your nose is a good indicator of what's getting hot too, but you really don't want to be sniffing the cap when the purple smoke and sparks decide to leak out! Every Tech Order I ever used in the Air Force started with 'Perform a through visual inspection'. Often times, that was good advice. 73, Mike WM4B From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Eric Lemmon Sent: Saturday, May 22, 2010 10:48 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater Whenever you have a shorted component, such as a tantalum capacitor, the current drawn by that short might burn out a PC board trace before burning up the capacitor. If that happens, finding the original problem becomes much more difficult. Perhaps a better and safer tack would be to use a small current-limited power supply to energize the 10 volt buss, but with the current limit set to 1/4 ampere or so. Following Jeff's suggestion, start unplugging and/or disconnecting loads until the buss voltage jumps up to 10 volts. I don't know what current is normally drawn from the 10 volt regulator in a properly-operating station, but that value should be measured and recorded for future troubleshooting efforts. 73, Eric Lemmon WB6FLY -Original Message- From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Jeff DePolo Sent: Saturday, May 22, 2010 6:36 AM To: Repeater-Builder@yahoogroups.com Subject: RE: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater I would look for a shorted tantalum capacitor hanging somewhere on the 10V rail. I agree. If you hook 10V from an outside source to the 10V buss, you'll probably find it's drawing all kinds of current. The 10V regulator circuit will go into fold back before burning up. This is by design. I usually hook a source of 10V at about 1.5A and look for smoke. It's usually one of the tantalum capacitors that starts to smoke. Once it's done smoking, problem solved!! Put a DMM on the 10V line, then start disconnecting things until you narrow it down, divide and conquer. Pull all of the cards out of the cage (except the 10V reg card obviously), disconnect the exciter, remove the receiver, etc. With a good ohmmeter that measures fractions of an ohm, you should be able to narrow it down further once you've found the suspect module/board. I have lost track of how many shorted tantalums I have had over the years. When they occur in the B+ of the high current PA supply, they simply burn up and th problem fixes itself. They make a cool purple smoke with lots of sparks when they flame out! --- Jeff WN3A
[Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
I was up on the hill this afternoon loading new firmware into a controller when my UHF Master II went down. Didn't even touch the thing... The PS is working with 15 volts out and the 3 fuses in the front are fine. The 10 volt card checked OK in my spare repeater No 10 volts at all. Any ideas? Ben-W4WSM
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
Could be a dirty contact on the backplane. Chuck WB2EDV - Original Message - From: w4wsm b.run...@insightbb.com To: Repeater-Builder@yahoogroups.com Sent: Friday, May 21, 2010 4:45 PM Subject: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater I was up on the hill this afternoon loading new firmware into a controller when my UHF Master II went down. Didn't even touch the thing... The PS is working with 15 volts out and the 3 fuses in the front are fine. The 10 volt card checked OK in my spare repeater No 10 volts at all. Any ideas? Ben-W4WSM Yahoo! Groups Links No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.819 / Virus Database: 271.1.1/2887 - Release Date: 05/21/10 02:26:00
RE: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
Or it could be one of the jumpers on the 10 Volt card has a cold joint-I have seen this before on these cards From: Repeater-Builder@yahoogroups.com [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey Sent: Friday, May 21, 2010 1:59 PM To: Repeater-Builder@yahoogroups.com Subject: Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater Could be a dirty contact on the backplane. Chuck WB2EDV - Original Message - From: w4wsm b.run...@insightbb.com mailto:b.runner%40insightbb.com To: Repeater-Builder@yahoogroups.com mailto:Repeater-Builder%40yahoogroups.com Sent: Friday, May 21, 2010 4:45 PM Subject: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater I was up on the hill this afternoon loading new firmware into a controller when my UHF Master II went down. Didn't even touch the thing... The PS is working with 15 volts out and the 3 fuses in the front are fine. The 10 volt card checked OK in my spare repeater No 10 volts at all. Any ideas? Ben-W4WSM Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.819 / Virus Database: 271.1.1/2887 - Release Date: 05/21/10 02:26:00
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
i have no idea at all on what systems you run, or what they are, other than, a repeater, but just an idea maybe, to try. the Controller, you refer to, that you were uploading new firmware, is that, anything to do with the uhf system, in anyway. if not, perhaps try shutting down the system, with the controller in it, for a couple of seconds, maybe and see, if it is not radiating, some kind of interference, that interfares with your UHF system i only say this out of course, since occassonly i have to upload new firmware to Tait Mobile units and desktop computers ( firmware here = bios upgrades ) and now and again one interfares with the other just a thought maybe worth looking at Marcus On Sat, May 22, 2010 at 8:45 AM, w4wsm b.run...@insightbb.com wrote: I was up on the hill this afternoon loading new firmware into a controller when my UHF Master II went down. Didn't even touch the thing... The PS is working with 15 volts out and the 3 fuses in the front are fine. The 10 volt card checked OK in my spare repeater No 10 volts at all. Any ideas? Ben-W4WSM
Re: [Repeater-Builder] Lost 10 volts in a Master II UHF Repeater
I would look for a shorted tantalum capacitor hanging somewhere on the 10V rail. If you hook 10V from an outside source to the 10V buss, you'll probably find it's drawing all kinds of current. The 10V regulator circuit will go into fold back before burning up. This is by design. I usually hook a source of 10V at about 1.5A and look for smoke. It's usually one of the tantalum capacitors that starts to smoke. Once it's done smoking, problem solved!! I have lost track of how many shorted tantalums I have had over the years. When they occur in the B+ of the high current PA supply, they simply burn up and th problem fixes itself. The 10V regulator doesn't have enough guts to burn them up, so they stay shorted and wait for someone to find them. Often times it is a cap on the mixer board. Those are fed though a resistor of a few ohms. Good luck, Scott Scott Zimmerman Amateur Radio Call N3XCC 474 Barnett Road Boswell, PA 15531 w4wsm wrote: I was up on the hill this afternoon loading new firmware into a controller when my UHF Master II went down. Didn't even touch the thing... The PS is working with 15 volts out and the 3 fuses in the front are fine. The 10 volt card checked OK in my spare repeater No 10 volts at all. Any ideas? Ben-W4WSM Yahoo! Groups Links
