MX-300 Revisited

MX-300 Revisited

I need to repair my MX-300 and my cessna radio (720 channel).  The MX-300 has channeling problems intermittently, i.e. the function buttons intermittently stop working in that I can't swap frequencies from standby to in-use.  This occurs on the COM and NAV.  The squelch stops working as well.  So it is not the buttons (switches).  It also fails to transmit and receive on the COM channel intermittently.  This occurs at the beginning of the flight, but after about 5-10 minutes it operates reliably the rest of the flight. 

The ARC radio has the following problems:
The VOR suddenly went way off as compared to my GPS and other VOR (MX-300).  It never came back. (I don't know if its the radio, antenna or indicator at this point, but I'm checking.) Periodically, it fails to recieve communications.

I spoke with a shop, who works on MX-300's.  He believes the MX-300 could be fixed for about $175 - %200.

I told the shop I am considering buying another MX-300.  He said that he has found the MX-300s do not have longevity (failures such as mine are common after a few years).  He ask if I considered repairing the Cessna radio.  They fix them as well and it usually can be fixed for under $300.  I know that avionic shops do not make money on the MX-300 so they have a vested interest in keeping the ARC business going.  This guy sounded pretty straight, but who knows.

The ARC radio seems to work well, but is is very old 33 plus years.  The other option is very expensive and that would be to upgrade the entire avionics panel, rewire etc.  I'm not going to do that at this time, the plane needs to be painted first. (priorities)

What do you think? 
1) Get another a new or used MX-300 and fix my existing MX-300

2) Fix my existing MX-300 and fix the ARC radio.

I'm considering both of these options at this time. Feedback would be helpful.

If option 2 is viable, why wouldn't I buy a working ARC radio for $200?  Well, I would not go back to having 2 ARC radios, so I am leaning toward option 1.

(Note: I've searched the forum already for this topic.)

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Hello Barry;

Just a note on repairs.  I was having exactly the same problem with my MX-170B, which is the King version.  TKM is currently 2 months turn-around time for repairs.  They referred me to a company in Wichita, Bevan Rabell.  At the date of this message, they have had it for three weeks, and I have not received a call from them yet telling me what the cost of the repairs will be or when it will be fixed. Bevan Rabell's number is 316-946-4870.

I just bought the plane last September, so I don't know how old the radio is, but the log book indicates it was installed as yellow tagged (used) in my airplane in 2003.  Also, the radio was acting up when I bought the plane, so I don't know how long this problem existed before I sent the radio out for repair.  I have a second MX-170B that was installed new at the same time, and it is functioning very well.

Because of the relative low cost of these radios, and the long turn around time for repairs, I might consider buying another used unit and keeping it as a spare.  I have not had any of the other problems mentioned by some in the forums.

Jon

Jonathon Plaxton
jplaxton00
useravatar
Offline
186 Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Jon,

Thanks for the reply.  I had called Bevan prior to posting the message.  They told me about to expect $175 to $200 based on my discription of the problem - they referred to as channeling.

I bought the radio new in 2001 and it has been acting up intermittently for about 1 to 2 years - I hate sending something out for repair that may not act up for them.

I'm considering installing a Garnin GNC 300XL, which is a Com and IFR certified GPS (good for point to point and non-precision approaches.).  The GPS kit and CDI would set me back about 4800 + installation.  I'm thinking about it.  Not sure how wise that is might be one with a precission approach but then I need to upgrade the transponder to digital (I guess).

Not sure what to do... a used MX300 just sold on e-bay for  $961 & no installation.  Maybe it's time to bite the bullet and update to a GPS with Com.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Barry, The VFR 250XL and IFR 300XL GPS/Coms are great units (if you put the two together, there does nor appear to be much difference!) I've had two 300XL's and one 155XL and no problems of the type you mention with your MX300. However, I would not bother running a 300XL IFR. You need external switching/annunciators (a real pain) altitude encoder and a very expensive CDI The IFR installation costs about 3 times more than the VFR. The 300XL is not really a state of the art IFR unit anyway not being WAAS compatible and probably will be outmoded when ADS-B and all that catch up. Great for en-route though and the com radio side is very good - certainly will not give you any of those channeling problems.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Peter,

Thanks for the input.  I need to check to do more thinking and research.  I need to find some literature that will describe the GPS technology today and where it is going.

This was my understanding.  This GPS is good for point to point operation and non-precision approaches and I could use it to substitute for DME.  I'm not hooking up altitude capability so precision approaches are out.  For precision approaches I have an LOC/GS so I can do the ILS approaches. Based on that, I thought it would make a nice addition and add good capability in my plane and a good COM.  I could use it to substitute for DME (my understanding) and do all the approved ADF/GPS and VOR/GPS approaches.  I've got an old ARC Transponder (not digital).

I didn't know it was not compatible with WAAS and how that affects my plan for having the capability to do non-precision approaches, DME substitution, and I don't know what "ADS-B" is, so its time to do more research.

In today’s post 9/11 world, it's probably good to keep some radio navigation that is not solely dependent on the satellites for navigation.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Hi Barry;

Just an update.  Bevan Rabell called to let me know my radio is fixed and they will be shipping it today.  The cost was $200, including UPS ground shipping.  Tom at BR told me it was a channeling switch, which he replaced.  He also replaced one of the frequency selector switches, which I broke while taking the radio out of the tray.  Be careful with that as they are plastic and very easily broken, and the locking mechanism is troublesome.  I had to slide a thin piece of metal between the tray and the radio to disengage the lock before I could pull the radio out.

Jon

Jonathon Plaxton
jplaxton00
useravatar
Offline
186 Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Barry,

You are right you can do that with the 300XL -  but as I understand it, for NPA, you will need the CDI, annunciator control unit, encoder and either a King KNI 520, KI202, KI206 or Garmin CDI (all of which are quite expensive, even used). Then it will not be able to do precision appraoaches. The Garmin 430 can and does not need external switching and is the way to go but even more expensive) I reckon the 300XL is unbeatable for the price, especilly the 'newly overhauled' factory version  but would not bother with the NPA part because it adds considerable cost and is not upgradeable. It also has a display that is a bit pedestrian these days. ADS B is automatic dependent surveilance - broadcast, (I thought you already had that there? its being commissioned here now - maybe you call it something else?) which is a data link that displays all kinds of information (like traffic) on your GPS map and sends information back telling ATC and everyone else what you are doing and  where you are - kind of a radar replacement. Not sure the 300 will be much use for any of that. PS let me know if you need a KNI 520 and a Mid Continent MD41 424  annunciator control unit. I have decided not to bother with them and just stick to en-route nav!

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Peter,

I've been extremely busy lately.  I'll get back with you as soon as I can free up some time.

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Barry,
I have 2 used MX300 removed from my 1977 182 recently. We purchased both new a number of years ago to replace the ACR radios. Now we have updated again. I also have both indicators, one with glideslope. I will sell the radios for $600 and the indicators for $250.
Danny

Danny Morgan
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Danny,

Thanks, but I've already upgraded my ARC radio.

Barry

Barry Schneidman
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Danny,

I know this is a long shot but I am looking for 1 or 2 used MX300 radios for a 1977 C180.  do yu still have yours?

Thanks!

Monte Mabry

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

HI, I HAVE A 1974 CESSNA 150 WITH THE MX-300 NAV COM. IT HAS BEEN WORKING FINE FOR YEARS. TODAY, HOWEVER, WHEN I TURNED IT ON, THE FREQUENCY WINDOWS DID NOT LIGHT UP. ALSO WHEN I PRESS THE PUSH TO TALK SWITCH ON THE YOLK A LOUD BEEP IS HEARD IN THE HEADSET. I CHECK THE FUSES AND THEY ARE FINE. THE RADIO WILL NOT TURN ON. I CANNOT XMNT OR RECIEVE.  ANY HELP WOULD BE MOST APPRECIATED.

THANKS,

CHUCK

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

Has anyone had a problem similar to this?  I'm crusing along with the OBS set to track a VOR station, the needle is nicely centered.  All of a sudden the needle swings to full deflection.  I have to reset the OBS 10 degrees off course to re-center the needle.  In other words, suddenly the VOR NAV reception is 10 degrees in error.  The next time I fly the plane (a few days later) all is normal again. This process repeats every so often.  If anyone had a similar encounter, how was it fixed?

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Re: MX-300 Revisited

I have a MX 300 in my Tomahawk.It broadcast weak. Does anyone know how to adjust the 3 screws on back of radio to boost?

Guest
Guest
useravatar
Offline
Posts
User info in posts
Only registered users or members can reply or post

Board Info

Board Stats:
 
Total Topics:
6045
Total Polls:
1
Total Posts:
16356
Dormant:
User Info:
 
Total Users:
2546
Newest User:
boyerwood@gmail.com
Members Online:
0
Guests Online:
2445

Online: 
There are no members online

Forum Legend:

 Topic
 New
 Locked
 Sticky
 Active
 New/Active
 New/Locked
 New Sticky
 Locked/Active
 Active/Sticky
 Sticky/Locked
 Sticky/Active/Locked

ankara escort ankara rus escort ankara escort bayan ankara bayan partner ankara escort kizlar escort ankara ankara escort ankara eskort ankara escort bayan ankara bayan partner ankara escort kizlar escort ankara