Kenwood NX-700K No Power-on Issue

[762mm]

Hello,

I've recently bought two "untested" TK-7180H radios, both having their harnesses cut and in quite a rough shape cosmetically (dirty + scratches). I have the Kenwood wire harness connectors and pins from DigiKey and so I made new harnesses for both units. The first unit required that I connect the ignition sense to the 12V source, and so I made a fused (3A) "ignition sense bypass" inside the unit. It fits great under the hood and works fine.

The second radio however will not power on. I made the same ignition sense bypass for it (thinking this was the issue), but it is still dead - nothing showing on the display, no beeping, power switch unresponsive, nothing when connecting the mic and pressing TX. Interestingly, both units have different motherboards and different components on them. I looked on the tag and the radio that won't power on is actually a NX-700K... but the front head is numbered 18560, like a TK-7180H.

Here are my observations with the unit that won't power on :

1. Someone's been in there before. The front panel's ribbon was loose and the cable connector on the motherboard was missing the dark brown securing tab. I re-inserted the ribbon cable tight and put a piece of scotch tape to hold it in place. I'm pretty sure it's making a connection, but can't test it.
2. The radio is getting power at the main power terminals on the motherboard, measured at 13.84V. The same power supply powers all my other radios without issue.
3. The tiny F401 SMD fuse on the motherboard has continuity and measured at 0.16V when radio is receiving power
4. The radio's speaker comes "alive" when radio gets power. I can hear a very faint hum noise from the speaker when I put it against my ear. When I disconnect power, the speaker makes a faint "click" and goes silent.

Does anyone have any idea of what this could be? I looked in the service manual to find fuses that I could test, but not being an electronics tech it's all like Chinese to me. Is it possible that this unit has had its head swapped and that the TK-7180 display head doesn't work with it? The seller advertised both these radios as TK-7180H units, but one of them is obviously a NX-700K.

Here are some pictures :

(Voltages measured. Ignore the missing screw on the positive terminal, it was removed for the picture only)

 

[kd4efm]

If its a nx700 by label on the rf deck, then that's the wrong control head on it. Period.

 

[762mm]

If its a nx700 by label on the rf deck, then that's the wrong control head on it. Period.

I see... thank you for the quick reply.

So, despite Kenwood claiming in their advertising that these units are "identical" minus the digital capability of the NX-700, the display heads won't work despite fitting the body and connector of either deck?

I guess I'll need to contact the seller and see if they have the proper head for it...

 

[tlemke940]

The size and footprint are identical along with most of the accessory. as far as kenwood saying it is identical i have not heard that one, i have head it called a drop in replacement. and yes the control head is very different from the 7180 as the display is not even the same kind of display.

 

[762mm]

The size and footprint are identical along with most of the accessory. as far as kenwood saying it is identical i have not heard that one, i have head it called a drop in replacement. and yes the control head is very different from the 7180 as the display is not even the same kind of display.

I'm fairly new to the UHF/VHF radio world. I've been using mobile and portable radios at work for 20+ years, but never actually tried to figure out how they work and how to program them until recently, so please forgive my ignorance.

The identical claim was in some advertising pamphlet I've read about the TK-7180/8280 series vs. the Nexedge NX variants. I realize that they might've meant that it's identical for the user experience, not necessarily in regards to parts interchangeability.

Thank you for the reply. I will see if I can get my hands on the proper control head!

 

[762mm]

After some checking on Google images, the NX series appear to have the 18560 front control head as well.

How can I tell if I have the 7180H or NX-700 control head? The one on my NX-700K looks identical to the one on my 7180H, so I assumed it had the wrong one.

I still suspect as much, as the front buttons on mine are also different from the NX-700 series.


Here is another (working) NX-700K from Google images :

 

[mmckenna]

I used to have a 7180 in my wife's truck. Got a NX-700 and I thought "Hey, I can save some work by just leaving the 7180 head in place and replacing the RF deck!"

Didn't work.

While the control heads look similar (except for the buttons), they are not the same and you cannot run a 7180 control head on an NX-700 or vice/versa. Will not work.

It's possible that who ever you bought these radios from had a box of parts and just tossed stuff together without knowing that. We already know that the 762 you had was technically molested.

As for being "Identical", I've never hear that either. Likely what was said was in relation to the foot print/installation of the radio. The body is the same size. The power, RF and audio connectors are the same. The mounting brackets are the same. You can unplug a dash mount TK-7180 and put an NX-700 in place and it plugs right in. But they are not identical under the hood.

 

[hill]

Yea, the NX-700/800 and TK-7180/8180 heads/displays are way different.

The NX has more display digits for naming channels, zones and startup messages. The display on the NX radios have the receive antenna display on right. While the TK radios have this antenna display on left.

 

[762mm]

I used to have a 7180 in my wife's truck. Got a NX-700 and I thought "Hey, I can save some work by just leaving the 7180 head in place and replacing the RF deck!"

Didn't work.

While the control heads look similar (except for the buttons), they are not the same and you cannot run a 7180 control head on an NX-700 or vice/versa. Will not work.

It's possible that who ever you bought these radios from had a box of parts and just tossed stuff together without knowing that. We already know that the 762 you had was technically molested.

As for being "Identical", I've never hear that either. Likely what was said was in relation to the foot print/installation of the radio. The body is the same size. The power, RF and audio connectors are the same. The mounting brackets are the same. You can unplug a dash mount TK-7180 and put an NX-700 in place and it plugs right in. But they are not identical under the hood.

Thanks for the confirmation. The buttons on this NX-700 are definitely the same as my 7180 and 8180. The control heads looks identical.

At least now I know what is the most likely issue with this unit.

 

[762mm]

Yea, the NX-700/800 and TK-7180/8180 heads/displays are way different.

The NX has more display digits for naming channels, zones and startup messages. The display on the NX radios have the receive antenna display on right. While the TK radios have this antenna display on left.

Quest updated : Find a working NX-700 control head.

(My latest "note to self", lol.... thank you for the confirmation!)

:|

 

[mmckenna]

Thanks for the confirmation. The buttons on this NX-700 are definitely the same as my 7180 and 8180. The control heads looks identical.

At least now I know what is the most likely issue with this unit.

Then someone has swapped parts. Based on your other radios, that's not a surprise.

TK-x180 mobile:


NX-x00 mobile:

 

[762mm]

Thank you for the information.

In all fairness, I did not buy these units from the same seller as my TK-762HG.... So I guess you could say that "based on my luck, that's not a surprise".

Buying used equipment online is always a shot in the dark. It's not like this is something sold at the local Wal-Mart or Costco, where you can inspect it, try it and then decide to buy it.

 

[mmckenna]

If it will help narrow it down:

The part number for the NX-x00 display unit circuit board is:
X54-404K-02

The part number for the TK-x180 display unit circuit board is:
X54-3480-10

 

[mmckenna]

Buying used equipment online is always a shot in the dark. It's not like this is something sold at the local Wal-Mart or Costco, where you can inspect it, try it and then decide to buy it.

Yeah, it is. Likely someone chucking together parts. Not uncommon to get Frankenstein'd radios sometimes.

Not sure which of your radios have the ignition sense bypass, but when you get to the point you can program it, you can uncheck the ignition sense box and you won't need that jumper. It's under the "Optional Feature" tab in the programming software for both the NX-700 and the TK-7180.

Both the TK-7180 and NX-700 are nice compact radios with a lot of good features. The KPG-89 software for the TK-x180 series radios is probably one of the nicest, easiest to learn softwares on the market. The KPG-111 for the NX-700 is close behind, especially if you are not going to be using the trunking features.

I've got about 50 of the NX-900's at work (800MHz version) and those have been running for 13 years without any issues in all kinds of environments from garbage trucks, buses to police cars. They make nice 2 meter radios. Add the external speaker and they sound really good. Grabbing good condition TK-7180's when you can find them is always a good idea.

 

[hill]

A lot confusion on different between TK/NX heads by many people.

The seller on Flybay lists 2 TK faceplates, but one in link below is an NX one due to button layout. Now someone is purchase then and won't work on a TK.

LOT TWO KENWOOD TK-7180H-K FACEPLATE ONLY FOR PARTS AS IS READ W3C5 | eBay

Find many great new & used options and get the best deals for LOT TWO KENWOOD TK-7180H-K FACEPLATE ONLY FOR PARTS AS IS READ W3C5 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[762mm]

A lot confusion on different between TK/NX heads by many people.

The seller on Flybay lists 2 TK faceplates, but one in link below is an NX one due to button layout. Now someone is purchase then and won't work on a TK.

LOT TWO KENWOOD TK-7180H-K FACEPLATE ONLY FOR PARTS AS IS READ W3C5 | eBay

Find many great new & used options and get the best deals for LOT TWO KENWOOD TK-7180H-K FACEPLATE ONLY FOR PARTS AS IS READ W3C5 at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Very true.

That said, if Kenwood in their infinite wisdom didn't label both of them 18560 and hadn't made them physically interchangeable to save on manufacturing costs no doubt, 100% of this "confusion" would've been avoided.... and I would have the proper control head on my unit today, lol.


Story time : At work about a year ago, we bought new Kenwood radios (the NX-5000 series) and needed some other older Kenwood mobile radios re-programmed for a new frequency, so that all the radios old & new could talk to each other. The Kenwood dealer's technician kept trying different Kenwood softwares on our old radios, as he didn't know which model was which due to the radios looking identical to a few known models and not having a model number on the front of the units (the radios were mounted in vehicles and the tags at the bottom couldn't be seen without extensive disassembly). The lack of a model number at the front of the units for quick identification / servicing is something I always found stupid with Kenwood.

Of course we got charged per the hour. So, him fiddling around with different software versions and Googling images of radios to figure out which one would work was all billable time. Even though it was their dealership who installed the old units as well, years earlier. It was quite hilarious that even their own technicians get confused by Kenwood's mysterious radio design and lack of proper labelling.

This is the reason why when I program my own Kenwood radios nowadays, the "power on message" of each of my units is the exact radio model! This is perhaps something Kenwood themselves should start doing, instead of the default power on message being "Kenwood".




Here's a good example. Try and guess which Kenwood radio model and variant that is, lol :

 

[AM909]

The 18560 is just the OSHA sticker number and is used on multiple models (NX-x0x and TK-x180).

Looks like the top radio is NX-x0x because of the icons instead of S/A/B/C on the middle buttons.

I don't remember, but it is possible that the keytops are interchangeable like the black ones in the TK-x80 that fail and the white ones for something like it that have the wrong lettering on them but are more available and last longer. The lesson is that you can't tell without looking at the numbers on the boards, but that usually works.

I remember working with Motracs and such as a kid, where near everything we saw was either an actual SP model or just different enough from the manuals we had to cause grief.

 

[mmckenna]

All of the NX-x00 series radios I've ever purchased at work had a "NEXEDGE" sticker on top of the control head above the screen. The TK-x180 do not have that sticker:

As for the radios not being marked, they are. Anyone who's been doing this for a while and installs a radio where the tags are not visible has usually learned their lesson and put a P-Touch label somewhere visible with the serial number, ESN, model and property number on it. Usually only takes having to uninstall a radio once or twice to learn that lesson.

 

[762mm]

UPDATE : I reached out to the seller and he actually had a TK-7180 with a NX-700 control head on it for sale as well. So, I bought that other radio too at a slight discount and it arrived in the mail.

I promptly swapped the control heads on the two units and voila! Both are powering on now!

Both radios' motherboards are missing the dark brown retaining clip for the ribbon cable, though. I guess someone must've pulled the cable hard and it popped off. Does anyone know what is the part number or compatible replacement of that retainer clip? Is it a generic part like for a laptop, or is it proprietary?

I have the ribbon cables on both units holding on by friction pressure + a piece of scotch tape... it works, but it's not "pro grade", lol.

 

[mmckenna]

There isn't a part number for -just- the clip.
There is a part number for the entire connector:
E40-6558-05

You can order them here:

JVC/Kenwood KEN-E40-6558-05

buy JVC/Kenwood KEN-E40-6558-05 online

www.pacparts.com