TK-3312 Not Enough Power

[kenwoodgeek]

I've got a TK-3312 portable that is used in the school bus office that stopped working, supposedly.

The radio appears to be transmitting with very little power, not enough to hit the large, powerful repeaters that they have that I can more than easily hit with my TK-380.

When I took it outside in the bus yard and held it up, I could then hit it.

They tried charging the battery up all the way, and also changing the battery, but to no avail. I changed the antenna out with the stubby one on my 380, and that didn't do the trick.

I ordered a programming cable, which should be here by Monday, so I'll check out the programming file, but I doubt that is the issue, assuming it truly was working before.

Any ideas?

Thanks in advance!

 

[Motoballa]

The radio appears to be transmitting with very little power, not enough to hit the large, powerful repeaters that they have that I can more than easily hit with my TK-380.

I have a Motorola XTS5000 VHF that is having the same exact issue, I can receive fine but when I transmit it just doesn't even put out hardly anything, not even enough to hit a repeater practically next door to me.

You might check out this thread and get some ideas from it, there are a few suggestions. This guy talks about TX and RX issues, but there are some posts just for just the TX issues. I've just never gotten around to really looking into mine, since I use it for receive only anyway it doesn't really bug me.

https://forums.radioreference.com/motorola-forum/210967-xts2500-700-800-low-power-tx.html

(also, aren't you that guy from YouTube.. Ugh.. Really can't remember your username.)

 

[mmckenna]

Any ideas?

If it worked fine before, and suddenly does not, I'd expect a component failure.

Question is, does is receive ok and just not transmit, or is it both transmit and receive?

One common issue with portable radios is either it gets dropped/abused, or someone is carrying it around by the antenna. Antenna jack failures are something that happens when knucklehead users carry radios around by their antenna (pull it out of the charger, etc), or the radios get repeatedly dropped.

To test, you'd need to have some test equipment, and based on your job, it might be a good idea to have these items anyway:
-Spare known/good antenna, like you did with your 380 antenna.
-Spare known/good battery.
-Watt meter, 50Ω dummy load, appropriate adapters for the radios you work on, and some test cables.
-multimeter

For basic go/no go testing, this will tell you a lot. If I was in your place, I'd hook up a watt meter to the radio and the meter to a 50Ω load and check power output. That would tell you if it's a transmitter/antenna jack issue.

If it fails, it's going to the shop. Not something you can fix easily.

 

[kenwoodgeek]

Thanks, guys.

Matt, it does receive loud and clear, as good my 380 units. On talk around, it transmits loud and clear to nearby radios.

With regards to the radio being dropped, that has more than likely happened to it more than once. The shop uses TK-3173 units that work just fine, yet look like they need to be tossed in the garbage because they've been dropped thousands of times.

I don't have a watt meter or multimeter (I realize those are tools I should probably have for my own radios, anyway), and I'm really just doing programming for them and doing quick checking on radios that they tell me are having problems.

I have received the programming cable, and I will have the unit back in my hands tomorrow. I'll mess around with the file and see if I can spot anything like low power settings, just for the heck of it.

If there's nothing wrong there, I'll bring it back to the contract manager and tell her it needs to go into a shop for inspection and more than likely repair. And at that point, it will probably just be tossed in the garbage or given to me.

The company doesn't send radios in for repair; they just toss them.

 

[mmckenna]

TK-3312's are inexpensive radios. Considering bench time can run around $85/hr plus parts, it would probably make more sense to just purchase a new radio for this sort of application. Taking the time to send it in, pick it up when repaired, all the hassle, costs labor hours for the bus company.
Since portable radios have a limited life span, spending money to repair an older radio may not make financial sense.
Finding a new replacement model that they can start transitioning to might be a good idea. You'd probably make them pretty happy if you did the research about which model is comparable and makes sense for their future needs, get pricing, etc.
As you know, the NX-300 would use the same programming software.
NX-3000 would put them well ahead of the curve and allow for future NXDN or DMR transition (if that's in their plans)
NX-320 might be a good option, too. I've started ordering a few of the NX-420's at work for users that don't need the full capability of the NX-410's.

All those cost more than a 3312, but having something that will last them another 5-7 years it may pay off in the long run.

 

[kenwoodgeek]

Wow, that much for bench time? That's crazy. But thank you for those recommendations!

Today, I did an experiment with the radio, since like I said, I don't have those tools. I programmed the 3312 up for GMRS and took it on a long walk down the street from the bus company, along with my 380. I had my GMRS buddy, Randy, sitting back in the break room with his radio.

When I had walked a good distance from base, I called Randy on the 3312, and he said it was scratchy. I then keyed up my 380, and he said it was loud and clear.

I walked even farther and tested again. The 3312 was breaking up so badly he couldn't understand me, even though I was receiving a good signal from him. The 380, once again, was loud and clear.

I think it is safe to assume the radio is bad. Now to bring it to the contract manager and hope they let me have it for free. I'm sure it would be good for short distance communication! Lol.

 

[mmckenna]

OK, that's good info.

Some ideas:
-Antenna jack to circuit board connection would be suspect. Might be fixed by opening it up and re- soldering the connection.

-Final RF stage damaged due to wrong antenna, missing antenna, component failure, broken antenna jack connection.

-Bad antenna.

Might be an easy fix if it's just the antenna jack. If it's the amp, then it's costly.

 

[KK6ZTE]

Keep in mind that radio repair, hell--any electronic repair for that matter, is a dying art and very specialized. I would expect $85/hr to be on the bargain side. You can't get your car fixed properly for that, and I've worked in both industries.

Since you can hear just fine with it but he can't hear you, it's on the TX side of the radio. I have a TK-2180 with a bad amp/transistor with the same complaint. Upon disassembly, the PA was melted. It works great for receiving, so it's a dedicated scanner. Maybe you can do the same.

Wow, that much for bench time? That's crazy. But thank you for those recommendations!

Today, I did an experiment with the radio, since like I said, I don't have those tools. I programmed the 3312 up for GMRS and took it on a long walk down the street from the bus company, along with my 380. I had my GMRS buddy, Randy, sitting back in the break room with his radio.

When I had walked a good distance from base, I called Randy on the 3312, and he said it was scratchy. I then keyed up my 380, and he said it was loud and clear.

I walked even farther and tested again. The 3312 was breaking up so badly he couldn't understand me, even though I was receiving a good signal from him. The 380, once again, was loud and clear.

I think it is safe to assume the radio is bad. Now to bring it to the contract manager and hope they let me have it for free. I'm sure it would be good for short distance communication! Lol.