Garmin GMR 18 Marine Radar Magnetron error

[obelisk]

Hey all,

I installed a Garmin GMR 18 4kw radar scanner on my sailboat and it worked beautifully until the multistage regulator on my hi output alternator failed and the voltage spiked to 15.5V while the radar was turned on. Now I get "Error Message 6" when I try to turn the unit on. Garmin tech support told me this means that there is an error with the magnetron. The problem is that I am now in southern Argentina and Garmin only repairs units at a facility in Kansas. I don't have the time to ship it back and even if I did the shipping cost would be equal to the cost of the unit itself.

Does the magnetron need to be replaced completely, or does it just need an adjustment (possible?)? Are magnetrons brand-specific or are they like refrigeration compressors and nearly all made by one company, despite the brand? Is the repair possible with a well-equipped but standard tool set?

Any help would be greatly appreciated!

Jesse

 

[Resqueline]

I have some doubts that the magnetron itself is damaged, it's quite robust, and the voltages it needs are converted from the 12V and would be regulated/stabilized.
I'm more inclined to believe it's the voltage converters or some other electronics relating to the magnetron that have taken a dive.
You'd need a multimeter to check for the presence of internal power supplies first. Sometimes there used to be printed some values on terminal strips inside. If not then you'll need a service manual.

I think many magnetrons have cross-references like other vacuum tubes. It's 15 years since I did any work on radars so I forget if there would be any need for adjustments after an exchange. I don't think any special tools would be needed.

 

[obelisk]

thanks resq., i'll crack the unit open and see what's inside!

 

[obelisk]

so, i pulled the unit apart and found that there was water inside! it was not a lot of water and it appeared not to be soaking anything *important*. all of the seals looked uncompromised--could this just be condensation?

looking at the circuit boards, i wasn't able to immediately identify and fuses or test points. can anyone point me in the right direction? across which points should i be checking voltage? could it be that i have just blown fuse or is it more likely that the boards and/or magnetron are fried?

thanks!

 

[Resqueline]

Moisture is an electronics killer, especially if there's a grain of salt involved.. If it leaves white spots after drying then it's salt-water, if not then it could be rain water or condensation.
I found a document describing the error codes and it seems the high-voltage supply for the magnetron is the cause of your problems. Check for salt-deposits, corrosion, and carbon tracks around there.

Error-
Code - Description --------------------------- Notes
0 ------ Antenna rotation error -------------- Antenna has stopped rotating or is rotating at the wrong speed.
1 ------ Magnetron heater current error -- The heater current is either too high or too low.
2 ------ Magnetron current error ------------ The anode current is out of specification.
3 ------ Over temperature error ------------- The circuit board temperature is too hot.
4 ------ Limiter error --------------------------- The diodes in the receiver limiter circuit have failed.
5 ------ AFC error ------------------------------- The software has been unable to tune the receiver for maximum sensitivity.
6 ------ Magnetron high voltage error ----- The high voltage power supply for the magnetron is out of specification.
7 ------ 36 volt dc-dc converter error ------- The voltage from the external voltage converter is too low.
8 ------ Motor error
9 ------ Motor stall error
10 ---- Motor hardware error
11 ---- Motor start error
12 ---- Motor stop error
13 ---- General motor fault

 

[obelisk]

The unit was mounted 25 feet off the water on the mast, so it was not salt water--at least there was no salt residue. Around certain, isolated parts of the circuit board there appeared to be oxidation like the kind that occurs on aluminum. I cleeaned all that of and the unit is now good and dry. Should I remount it, turn it on and just keep my fingers crossed?

The "Error Code 6" means that the "high voltage power supply for the magnetron is out of spec." but I cannot see anything on the boards that could be adjusted, short of plugging it into a specialized computer. Am I missing something?

Thanks much for all the help so far!
Jesse

 

[Resqueline]

Ok, good to hear there was no salt spray in there. I used to live 1200 feet from the shoreline but the car was better off outside than in the garage due to salt in the air getting inside. After a winter in the garage the bumpers were all green on top..

Some whitish residue around solder pads could be due to the solder resin flux not being cleaned completely away during manufacture. It's supposed to be harmless but who knows when it gets moist, it could very well throw off sensitive electronics.
Oxide/residue on contact surfaces is more of a problem and all available contacts should be unplugged and inspected.
I'm quite confident that it'll work after being dried out and "worked on". Just try.

Out of spec. means just that. The voltage could be too high, too low, or missing altogether. One would have to measure to know. Perhaps there's a computer port on it for diagnostics & adjustments, like there is on cars.

 

[Jjem77]

Hello. My radar Gmr 18 Garmin showme error code 0 and radar need repair..:..can you helpme whit tris problem....tanks. Regards...i'm from mazatlan México.

 

[debe]

If were going to repair a Radar there should be some clear pictures of what we are looking at.

 

[obelisk]

Hey guys,

I started this post back in 2009 from Argentina (see first post) and it turned out that I had to send my radome back to Garmin in Kansas. They did not attempt to repair it, just sent me a new unit. Now its a couple years later and I am in Tonga and the unit has gone down again. This time it is "Error Code 2" Current to anode is out of spec. It is nearly impossible for me to ship it out of here. Is there any troubleshooting advice. The unit worked at the beginning of a watch and when I went to check it at the end of the watch, without changing a thing, it gave me this error. Battery voltages were the same, weather was fair, no engine running either time and no extra electronics were turned on. There is no visible damage. Where should I start? Should I just throw it in the trash and buy a more reliable unit (Simrad, Koden) and would a different radome work with my Garmin chartplotter or is it all proprietary info sentences?

Thanks for any help,

 

[debe]

Anode current out of spec sounds like the Magnetron has failed or very low emmision.

 

[(*steve*)]

It's pretty likely that the problem is the same.

After reviewing this thread, I think that there *is* salt getting in. Check it again and see if there are signs of corrosion. If there are, then I would suspect a common cause.

If at all possible, when/if you get a replacement, can you fit it inside another sealed box with sealed ports for cables?

If there is a coaxial cable (or a waveguide) feeding the signal out of the box, then this may be the route for water getting in as these can be hollow inside (a waveguide certainly is) and a problem with sealing the antenna can get water inside an attached device.

Depending on the cost of this unit, and its importance, maybe carrying a spare would be useful as I imagine you don't often sail into Kansas.

Sorry I can't comment on the compatibility of different radomes. If the frequencies are quite close, and the connections compatible, it may well be, but radar is more critical than a simple transceiver, and you may find that performance is not up to spec. In addition, if you're getting leakage via the coax connected to the radome you're just going to sacrifice another unit to the salt gods.

I'm not an expert in this field. Maybe someone else can give you more specific or useful advice.

 

[debe]

This type of Radar the transmitter & reciever & HV powersuply are all in the Radome. It should be waterproof & no corosion inside. The only wires going to it are the powersupply & Network Data. The only time ive seen corosion in a Radome is when there is damage to the outer shell.

 

[JMW]

Could be rainwater. If there is as much water as you state, I doubt it can be repaired, at your level. It will have to be taken apart, dried and tested. Garmin is an extremely good product. Even if you had a unit with a good network, no one outside of the factory is going to attempt a repair. It just won't hold up. They will replace boards until it starts to work. The maggie is probably the only thing that is usable, if you can get the salt from the insulators. Typically they run at -4KV or so, and the insulators have to be in good shape.
If you really like RADAR and want it, buy a R/T unit either rebuilt or new, and send this one back to the factory.
There has been a great deal of discussion of the need for the condensation drain plug, this might be a case against it.
I know this isn't what you want to hear. What are doing in Argentina in the winter anyway? You're supposed to be in the Caribbean, I think you need GPS instead of RADAR

 

[obelisk]

Sorry, Tonga is located in the South Pacific...and this is a new and different problem.

I guess it will just ride around with me until I get to New Zealand in late November and send it back from there.

Thanks for all the input.

 

[Jotto]

All radar antenna units have a drain plug at the bottom of the unit for marine radars. I have installed many types from Furuno to JRC, I have never seen one without a drain for condensation. I have seen when they weren't installed.

I got out of the business when phased array were just starting. No more tuning the gun oscillator, no longer require FCC license to install and tune. Garmin wasn't in business at that time, Goldstar had tried to get into the business but the first radar as a piece of junk.

If the unit was installed improperly that could be why you are having failures.

 

[Jazzycat]

This same radar , I have and it is having trouble with error code : 1. ( temperature) so to get to it , I warmed the unit up with a blow dryer, and it worked. It seems that maybe this garmin 18 is best in the lower north to Southern Hemispheres. I need to make it do it warms up before trying to warm up.
Hmm..
relay.. ( like a glow plug)
..?
Northern hemisphere.