MSF5000 dead
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MSF5000 dead
I went to check a VHF MSF5000, secure, tone remote, 1990 model, and found that it did not transmitt or receive. All indicator leds looked normal. I unplugged the AC cord for 3 or 4 minutes and replugged it. Station reset and came up normal. What's happening with it?
"The world runs on radio."
Well,
Not to be smart or condesending, But I would start with the basics.
Plug in the MSF full feature diagnostic panel, this will give you a better understanding of what is going on. It will visually show you what is happening. If the radio is not rx'ing, it won't be tx'ing.
If you don't have the diag panel, plug your computer in and use the "interactive" one in the software.
Check to see the radio is on the right channel. Bring your service monitor and start taking some measurements.
P.S. Grab a service manual... The MSF book is not all that bad, it will start you in the right direction.
Now, you say that the MSF LED's indicate "normal". You should see the indicators, when tx'ing with a subscriber unit such as RX Lock, PA FULL, PA ON, TX Lock lighting up, at least this will let you know minimally whats is going on. Usually if the pa takes a crap it will give you a series of low audible beeps, it think 3 or 4 in a row to let you know you are on exciter power, or reduced power.
Good Luck.. Post more as you go.
P.S. Try a service monitor or power meter to the output and depress the TX micro switch, you should make dead carrier and full power (or whatever it was last set to)
Not to be smart or condesending, But I would start with the basics.
Plug in the MSF full feature diagnostic panel, this will give you a better understanding of what is going on. It will visually show you what is happening. If the radio is not rx'ing, it won't be tx'ing.
If you don't have the diag panel, plug your computer in and use the "interactive" one in the software.
Check to see the radio is on the right channel. Bring your service monitor and start taking some measurements.
P.S. Grab a service manual... The MSF book is not all that bad, it will start you in the right direction.
Now, you say that the MSF LED's indicate "normal". You should see the indicators, when tx'ing with a subscriber unit such as RX Lock, PA FULL, PA ON, TX Lock lighting up, at least this will let you know minimally whats is going on. Usually if the pa takes a crap it will give you a series of low audible beeps, it think 3 or 4 in a row to let you know you are on exciter power, or reduced power.
Good Luck.. Post more as you go.
P.S. Try a service monitor or power meter to the output and depress the TX micro switch, you should make dead carrier and full power (or whatever it was last set to)
The model number would be helpful, as there are analog-only models and digital-capable ones, and the controller can either be programmed with a PC and RSS or require new EPROMs to be installed. Can you describe the station a bit more?
If the radio has the 3-digit 7-segment display (CXB or RLB model), is any error code showing up there as it powers up and does its self-test? Depending on how it's programmed, it should sit idle with just the decimal points showing.
When you try to key it up, do any other LEDs come on? There are an awful lot of them for the transmitter, but unfortunately none for the receiver, so you really do need the digital metering panel, if your station supports one. I've only played with UHF models and they've all had the display on the front and a place to plug the metering panel into.
Could the secure board be interfering with the radio's operation? Maybe it's looking for some special signal.
The CXB/RLB models have a manual XMIT momentary switch on the front panel. Pressing it should cause the transmitter to come on with no modulation. Hooking a wattmeter and dummy load to the antenna connector should give you some indication, even if it's only a momentary spike.
With any metering panel attached (one with a speaker), if you raise the ACC DIS switch on the front panel, then the front panel front volume and squelch pots should work and you should hear squelch noise from the speaker.
Any metering panel can be used to measure the five receiver metering points and a few on the transmitter. Having these would be helpful.
If the station has a power amp on it, perhaps someone reversed the input and output coax connectors. That would certainly keep it from transmitting. Also, VHF stations have a "peripheral box" that contains a T/R relay and some transmitter filtering. This would need to be working properly for signals to get to the station.
Last minute thought - check ALL the power supply outputs and fuses. I had one station that seemed quite dead - it was a blown fuse and a shorted power supply cap (probably). Two new fuses later and the problem went away and it worked just fine. Now I also had tons of other unrelated errors on the station (it was a CXB) but everything went away once the voltages came back.
Bob M.
If the radio has the 3-digit 7-segment display (CXB or RLB model), is any error code showing up there as it powers up and does its self-test? Depending on how it's programmed, it should sit idle with just the decimal points showing.
When you try to key it up, do any other LEDs come on? There are an awful lot of them for the transmitter, but unfortunately none for the receiver, so you really do need the digital metering panel, if your station supports one. I've only played with UHF models and they've all had the display on the front and a place to plug the metering panel into.
Could the secure board be interfering with the radio's operation? Maybe it's looking for some special signal.
The CXB/RLB models have a manual XMIT momentary switch on the front panel. Pressing it should cause the transmitter to come on with no modulation. Hooking a wattmeter and dummy load to the antenna connector should give you some indication, even if it's only a momentary spike.
With any metering panel attached (one with a speaker), if you raise the ACC DIS switch on the front panel, then the front panel front volume and squelch pots should work and you should hear squelch noise from the speaker.
Any metering panel can be used to measure the five receiver metering points and a few on the transmitter. Having these would be helpful.
If the station has a power amp on it, perhaps someone reversed the input and output coax connectors. That would certainly keep it from transmitting. Also, VHF stations have a "peripheral box" that contains a T/R relay and some transmitter filtering. This would need to be working properly for signals to get to the station.
Last minute thought - check ALL the power supply outputs and fuses. I had one station that seemed quite dead - it was a blown fuse and a shorted power supply cap (probably). Two new fuses later and the problem went away and it worked just fine. Now I also had tons of other unrelated errors on the station (it was a CXB) but everything went away once the voltages came back.
Bob M.
...
i would add that if you aren't familiar with the MSF, now is probably not a good time to learn about the basic operation of the station.
call someone who knows the station and learn from them. priority is getting the machine back on the air - not teaching yourself how to fix it.
(assumption is that this is not a "hammy" MSF)
doug
call someone who knows the station and learn from them. priority is getting the machine back on the air - not teaching yourself how to fix it.
(assumption is that this is not a "hammy" MSF)
doug
BRAVO MIKE JULIET ALPHA
"You can do whatever you want, there are just consequences..."
IF SOMEONE PM'S YOU - HAVE THE COURTESY TO REPLY.
"You can do whatever you want, there are just consequences..."
IF SOMEONE PM'S YOU - HAVE THE COURTESY TO REPLY.
Re: MSF5000 dead
The local school district here has a UHF model, and it has done the same thing. Doing the old "hard reset" (unplug, wait, plug in) has fixed it on two seperate occasions. And it will hum along just fine for a couple of years, then do it again. It's done it twice in 5 years. Haven't had the opportunity to shut it down and take the time to determine what problem, if any, it has.arlojanis wrote:I went to check a VHF MSF5000, secure, tone remote, 1990 model, and found that it did not transmitt or receive. All indicator leds looked normal. I unplugged the AC cord for 3 or 4 minutes and replugged it. Station reset and came up normal. What's happening with it?
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If at first you don't succeed,.....then maybe skydiving isn't for you.
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If at first you don't succeed,.....then maybe skydiving isn't for you.
Sometimes, very rarely, the logic gets confused. This could happen due to a nearby or distant lightning strike or even a lot of static electricity. Make sure the station is properly grounded using the stud provided on the right side of the cabinet.
Other than pulling the plug and waiting several minutes for all the DC voltages to reach zero, there's probably very little you can do to isolate this type of intermittent, once-in-a-blue-moon type of occurance.
But glad it's working now.
Bob M.
Other than pulling the plug and waiting several minutes for all the DC voltages to reach zero, there's probably very little you can do to isolate this type of intermittent, once-in-a-blue-moon type of occurance.
But glad it's working now.
Bob M.
The 1000 cap is on the Control board in the upper left corner. It is the output filter cap for the 5 volt switching power supply that runs the Control board logic.
If I remember there is a fuse and a choke in the reg circuit.
Some may use two caps in paralell, like two 470uF. I do not have the later programmable control board roadmap, so am going from memory.
I use what are called Low ESR caps, low equivillant series resistance. I get them from my wholesale electronics parts supplier like I do the Spectra caps. NOT from Motorola, theirs are all dryed out and old stock.
Cost, about $3 for the 1000uf, 20 v.
Check ALL the electrolitic caps on the Control, interconnect boards, and in the power supply for ANY signs of leaking.
If the date code on any of them is older than 10 years on a electrolitic cap, replace it.
If I remember there is a fuse and a choke in the reg circuit.
Some may use two caps in paralell, like two 470uF. I do not have the later programmable control board roadmap, so am going from memory.
I use what are called Low ESR caps, low equivillant series resistance. I get them from my wholesale electronics parts supplier like I do the Spectra caps. NOT from Motorola, theirs are all dryed out and old stock.
Cost, about $3 for the 1000uf, 20 v.
Check ALL the electrolitic caps on the Control, interconnect boards, and in the power supply for ANY signs of leaking.
If the date code on any of them is older than 10 years on a electrolitic cap, replace it.