mikeyhaley Posted January 27, 2017 Report Share Posted January 27, 2017 Hello all. I have a 14V KX-165 with Glide Slope. The frequencies don't commit to memory consistently when I turn the power off. Most of the time the unit starts up on 120.00 and 110.00, sometimes the previous frequencies will be there and sometimes a combination of both. I had it fixed once and it worked fine for a few months. Now the problem is back. I was told that there was repair bulletin put out by King/Bendix and you can only get the a repair kit from them. But apparently they don't sell and/or make them anymore and of course, no one has one (That I can find anyway).. The other day, a new issue popped. I was leaving AZ in the morning (55ish degrees OAT, plane was hangared that night) and the COM knob wouldn't change the frequency. The white button to swap the frequencies wouldn't work either. The NAV knob changed both COM & NAV frequencies. Once I filled up and taxied to the run-up, it started working. Weird stuff.... I know it's not the end of the world if the radio always defaults to 120.00/110.00 on start-up....it is just annoying! The latter issue is more of a concern. Has anyone run into either of these issues? Does anyone have one for sale?! Thanks for your help! Quote Link to comment Share on other sites More sharing options...
carqwik Posted January 27, 2017 Report Share Posted January 27, 2017 Call Bevan-Rabell in Wichita. Ask them if they can fix your -165. (I had a 15 year on-going problem on the NAV side...no other avionics shop seemed capable of fixing. Their guy at Bevan-Rabell knew what the problem was and fixed it at a very reasonable cost...about 0.5 AMU. 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 27, 2017 Report Share Posted January 27, 2017 It's a digital radio. They typically work or don't work. - expect that a battery is involved with keeping the memory alive. Find out why it loses connection with the battery. - knobs and buttons and connections get dirty and oxidized. Cleaning them properly is probably a good idea. - How are the display segments. I saw an ad for LCD replacement displays recently. That's about all i know about BK radios... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
mikeyhaley Posted January 27, 2017 Author Report Share Posted January 27, 2017 19 minutes ago, carqwik said: Call Bevan-Rabell in Wichita. Ask them if they can fix your -165. (I had a 15 year on-going problem on the NAV side...no other avionics shop seemed capable of fixing. Their guy at Bevan-Rabell knew what the problem was and fixed it at a very reasonable cost...about 0.5 AMU. I'll reach out to them tomorrow. I'm new so forgive me but what does AMU stand for? I've seen it a bunch on the site. Quote Link to comment Share on other sites More sharing options...
mikeyhaley Posted January 27, 2017 Author Report Share Posted January 27, 2017 10 minutes ago, carusoam said: It's a digital radio. They typically work or don't work. - expect that a battery is involved with keeping the memory alive. Find out why it loses connection with the battery. - knobs and buttons and connections get dirty and oxidized. Cleaning them properly is probably a good idea. - How are the display segments. I saw an ad for LCD replacement displays recently. That's about all i know about BK radios... Best regards, -a- I would agree - work or don't work. I thought battery as well but when they fixed it, they replaced the memory. The frequencies get written to the memory. I think they are ROM boards and for some reason they either stop retaining the memory or the unit can't read the memory. The display looks good. I would have assumed the they cleaned the knobs when they had it apart but probably a bad idea to assume in this business. ha! Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 27, 2017 Report Share Posted January 27, 2017 A whole bunch. It is a unit of monetary amounts used for aviation. There are similar proper methods used to openly discuss the costs of sports cars, boats and hunting trips. Any more detail, somebody will have to sell you a decoder ring. Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted January 27, 2017 Report Share Posted January 27, 2017 3 hours ago, mikeyhaley said: I'll reach out to them tomorrow. I'm new so forgive me but what does AMU stand for? I've seen it a bunch on the site. You are up to 10 posts now - we can let you in on it . . . . AMU=$1000 1 Quote Link to comment Share on other sites More sharing options...
Hector Posted January 27, 2017 Report Share Posted January 27, 2017 AMU = Aviation Monetary Unit = $1000Sent from my iPad using Tapatalk Quote Link to comment Share on other sites More sharing options...
thinwing Posted January 27, 2017 Report Share Posted January 27, 2017 It's been a while but I seem to recall a keep alive input to these radios that needed to be powered up... Quote Link to comment Share on other sites More sharing options...
Vance Harral Posted January 27, 2017 Report Share Posted January 27, 2017 Long shot, but you might also check your battery bus voltage (i.e. what is your regulator putting out when the alternator/generator is running), as well as your power connections. Nonvolatile memory of the era during which the KX-165 was designed and produced (typically EEPROM) requires a programming voltage higher than the operating bus voltage for the device. Typically this is generated by a charge pump, but the pump can only achieve so much of an increase. If the bus voltage is low or the power connection weak, the device can "work", but fail to update NVRAM due to low programming voltage. I've seen this behavior in a couple of different avionics gizmos over the years, most notably our Shadin Miniflo fuel totalizer. When fuel is added, the totalizer must be updated with the engine running and the alternator driving the bus to about 13.6V. If you just turn on the master, program the Shadin with the bus voltage at ~12.8V, and turn the master off, there is a 50/50 chance it will fail to "remember" the new fuel level on the next power up. I'm no expert on the KX-165, but I wouldn't be surprised if it works the same way, particularly given the user manual description Hyett6420 posted above. 1 Quote Link to comment Share on other sites More sharing options...
Jerry 5TJ Posted January 27, 2017 Report Share Posted January 27, 2017 36 minutes ago, thinwing said: It's been a while but I seem to recall a keep alive input to these radios that needed to be powered up... I don't see that input on the wiring diagram. The manual says the non-volitile memory is EEPROM, as Vance says. Quote Link to comment Share on other sites More sharing options...
thinwing Posted January 27, 2017 Report Share Posted January 27, 2017 My faulty memory ,must have recalled that from an old narco or apollo install Quote Link to comment Share on other sites More sharing options...
mikeyhaley Posted January 28, 2017 Author Report Share Posted January 28, 2017 21 hours ago, LANCECASPER said: You are up to 10 posts now - we can let you in on it . . . . AMU=$1000 10 posts. I'm on a roll! ha. I figured it was 1,000 just couldn't figure out the Acronym. Thanks for all the info. I haven't had a chance to call anyone so it's a next week project. Quote Link to comment Share on other sites More sharing options...
mikeyhaley Posted January 28, 2017 Author Report Share Posted January 28, 2017 I just found the invoice from Mike's Avionics in Van Nuys, CA which repaired it back in May. It reads "removed and soldered in a new microprocessor". At idle, it isn't producing much Voltage. I think around 12.0 volts. Any RPM over 900-1,000 it produces right around 14v. Maybe it makes sense to send it into King since they are the ones that made it originally. Quote Link to comment Share on other sites More sharing options...
Vance Harral Posted January 28, 2017 Report Share Posted January 28, 2017 2 hours ago, mikeyhaley said: At idle, it isn't producing much Voltage. I think around 12.0 volts That doesn't sound right. Especially for an airplane equipped with an alternator, which I presume your M20K has. If it's really that low at idle, that lends a little more credence to the programming voltage theory. But again, I'm no expert on the KX-165. In particular, I don't know when/how often it writes the "current" frequencies to nonvolatile memory. Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 28, 2017 Report Share Posted January 28, 2017 Vance, thanks for that technical explanation... An alternator at idle produces less voltage. Enough less voltage that my alternator red light comes on, on the annunciator panel. In order to taxi at low speeds, the engine is usually at idle... increasing the throttle to douse the light is a fast way to the run-up area. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Vance Harral Posted January 28, 2017 Report Share Posted January 28, 2017 Sure, every charging system has some minimum RPM, below which it can not provide enough current to sustain system load. But the whole "trick" about alternators (vs. generators) is they can increase current to the field circuit as RPM decreases, providing more charging "oomph" and sustaining the desired system voltage at lower RPMs. In our F model, the alternator can sustain a system voltage of around 13.7 volts all the way down to an RPM below which we don't idle anyway (oil splash to the camshaft isn't very effective much below 800-900 RPM). I've read stories here and elsewhere about aircraft system voltage warnings at idle RPM, but I look on them with something of a raised eyebrow. The problem makes sense in older airplanes equipped with generators. But in "modern" airplanes with alternators - including the M20K - I frankly don't get it. It seems to me either the charging systems in those airplanes aren't working properly (bad diodes, improperly adjusted regulator, etc.), or they're grossly under-designed. I'm happy to be corrected on the latter point, I do understand aircraft electrical systems have constraints automotive systems don't - e.g. weight. But I'm still inclined to think if you're constantly getting low voltage warnings at idle in an alternator-equippped airplane, you shouldn't automatically assume it's "normal", even if others report the same thing. Quote Link to comment Share on other sites More sharing options...
mikeyhaley Posted January 31, 2017 Author Report Share Posted January 31, 2017 Vance I kind of agree with you. That is the entire purpose of an alternator over a generator. I came from the automotive world and I upgraded my VW bug from a generator to an alternator for that reason. Not sure it translate but logic says it should. Then again I've learner logic goes out the window in the aviation world! Quote Link to comment Share on other sites More sharing options...
mikeyhaley Posted January 31, 2017 Author Report Share Posted January 31, 2017 Does anyone have a way to determine when the unit was made based on the serial number? Quote Link to comment Share on other sites More sharing options...
wiguy Posted February 10, 2017 Report Share Posted February 10, 2017 On 1/30/2017 at 10:22 PM, mikeyhaley said: Does anyone have a way to determine when the unit was made based on the serial number? I was looking too, also what year were they last made? I have one I was going to swap in, the last two digits are '42' on the long serial number. Something lead me to believe it may of been made in 2002, Singapore it says in the back. I don't know if that's accurate, they seemed to have a real long run with manufacturing? Quote Link to comment Share on other sites More sharing options...
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