Remote (L3145A) - HELP!

RESCUE161 · Post by **RESCUE161** » Thu Feb 09, 2006 6:49 am

We have one of these just sitting around and need to hook it up. We already have two "Command Series" (L1475A) hooked up to our base which is about a mile away.

Is the L3145A compatable with the other two remotes? Does anybody have the dip switch settings for this thing? It looks like it can control up to 4 radios, but we only need one channel.

We already have the dedicated private pair going to the tower, so that's all taken care of. I just need the settings for the remote itself.

Thanks in advance for the help.

Scott

Post by **wavetar** » Thu Feb 09, 2006 11:05 am

I believe the L1475 was the C100 DC remote, and the L3145 is the C200 DC remote, so yes, they should be compatible. I'm not at work until Monday, so I can't get you the dip-switch configuration before then. I believe from the factory, all switches are set either 'up', or 'down'...can't remember which at the moment.

You should be able to hook into the terminal strip 'L1' position & have it work with no extra configuration needed, other than choosing the 'F1' button on the front.

Todd

RESCUE161 · Post by **RESCUE161** » Thu Feb 09, 2006 11:20 am

You are correct in that the one we're trying to add is a C200.

When I do hook it up, I can barely here any audio and no audio comes through when I press the PTT.

This remote has been sitting in a storage closet for a long time, so I'm not even sure if it works or not.

switch 1 on the dip switch is off and the rest are on, so that might be it. I can wait until Monday. We just need it for an exercise by Thursday. The EOC is trying to use a hand-held for EOC ops inside an rf "vaccuum", so this would definitely help. Thank you again.

RESCUE161 · Post by **RESCUE161** » Thu Feb 09, 2006 11:25 am

Are these concidered "tone-Remotes" or "DC Remotes"?

Post by **wavetar** » Thu Feb 09, 2006 11:40 am

I believe the L1475 & L3145 are 'DC' remotes, while the L1476 & L3146 are 'tone' remotes.

It could be that you have the phone line polarity reversed as the reason why you can't PTT. Try switching the phone line wires around & see what happens.

You should be able to hear the receive audio either way though. Is it low in both the handset earpiece & handsfree speaker?

Todd

RESCUE161 · Post by **RESCUE161** » Thu Feb 09, 2006 11:44 am

Yep. Extremely low volume even with it turned all the way up.

When I press the PTT, the TX light comes on, but it does not key up the radio at the tower.

Post by **wavetar** » Thu Feb 09, 2006 11:49 am

RESCUE161 wrote:Yep. Extremely low volume even with it turned all the way up.

When I press the PTT, the TX light comes on, but it does not key up the radio at the tower.

The handset earpiece volume is controlled by a pot on the board, and is a separate circuit from the handsfree volume, so if they're both low, it points to a common source. IIRC, there is an RX line adjust pot inside...it should be labeled as such. You could try adjusting that.

And yes, the TX light will come on regardless if the wiring is correct or not. With DC remotes, you have to have the polarity correct (with tone remotes polarity doesn't matter). So, try switching the wires & see if it keys the radio.

Do you have any line testers to compare the RX audio level coming down the line to the level at one of the existing remotes? If needed, you could get by with an AC millivolt meter.

Todd

RESCUE161 · Post by **RESCUE161** » Thu Feb 09, 2006 11:55 am

I do not have any test equipment for these or do I know much about them. We have two that work right now, so I unhooked one and hooked this one up in it's place to "test" it. I couldn't get it to work other than it lighting up. Hopefully it's the dip switch settings.

RESCUE161 · Post by **RESCUE161** » Thu Feb 09, 2006 11:57 am

When I say low volume, it VERY low and VERY scratchy at best. If you didn't know when and what to listen for, you'd miss the rx audio altogether. I'll try the POT tomorrow.

RKG · Post by **RKG** » Fri Feb 10, 2006 5:57 am

Most DC remotes have a terminating resistor to maintain line impedence. When you parallel DCs, you have to remove this resistor from all remotes but one.

RESCUE161 · Post by **RESCUE161** » Fri Feb 10, 2006 9:41 am

Okay, the phone company came out and installed another "leased line" into the room where the radio coverage sucks. We tried the L2145A on that line and it worked, well sort of...

It received very well any radio or other remote, but when transmitting, it failed to transmit to individual radios. It will only tx to the other remotes. We moved the known good remote from a location that has a stand alone radio (Maxtrac with a local antenna) and it works flawlessly.

We still would like to have the L3145A work, but can live without it. I tried switching all of the dip switches to on and off and tried switching the polarity of the wires, but nothing seemed to work. Is there anything else that I can try?

k2hz · Post by **k2hz** » Fri Feb 10, 2006 10:23 am

RESCUE161 wrote: I tried switching all of the dip switches to on and off and tried switching the polarity of the wires, but nothing seemed to work. Is there anything else that I can try?

Have you checked the line current during keying to see if it is correct polarity and matches the proper current for your system? Usual values are either 5.5 or 12.5 mA for F1 transmit depending on if the base is configured for 1 or 2 frequency. What current and polarity did the known good remote generate when the base keyed ok?

I believe the L3145 is capable of 4 frequency operation so it would generate different currents and polarity depending on the frequency selected.

Default DC control currents for most systems are:

+12.5 F1 TX (1 frequency system)
+12.5 F2 TX (2 frequency system)
+ 5.5 F1 TX (2 Frequency system)
- 2.5 Monitor

-5.5 and -12.5 usually would be special functions or F3/F4 TX

The remote must generate the proper polarity and current to match the base station control unit for the desired function.

RESCUE161 · Post by **RESCUE161** » Fri Feb 10, 2006 10:43 am

We're only using one frequency.

I don't have any way of measuring amps. I do have a volt/ohm meter. I'm not at work right now, but do have the remote in question with me. I just tried to measure voltage (both A/C and D/C) and get the following when hooked to line 1.

While set to A/C: 0 VAC until the PTT is pressed, then it goes to 16.5 mVAC.

While set to D/C: -9 mVDC until the PTT is pressed, then it goes to 136.5 VDC.

k2hz · Post by **k2hz** » Fri Feb 10, 2006 11:21 am

DC remote control is based on current so voltage readings are of no value. The remote acts like a current source to generate the specified current so the voltage will vary with the loop resistance of the control circuit.

If you have a one frequency base, the controller at the base site still could be set for either +5.5 or +12.5 for F1 TX. You need to determine the correct current for your system.

A simple DC base controller may respond to either +5.5 or +12.5 but a more sophisticated unit will only work if the current is what it expects to see for F1 TX.

If the polarity and other settings in the remote are correct, and it has F1/F2 capability, try both F1 and F2 to see if either works. If F2 works, your base probably needs +12.5 for keying.

RESCUE161 · Post by **RESCUE161** » Fri Feb 10, 2006 12:12 pm

Do you happen to have a dip switch setting chart for the L3145?

Does changing the dip switch change the current? There is an 8 position dip switch inside of it. What does it do?

k2hz · Post by **k2hz** » Fri Feb 10, 2006 1:24 pm

I don't have any access to a service manual for the L3145. There may be internal jumpers as well as the dip switch. If the line polarity is correct and you have a single frequency base, if the F1 function does not key the base then F2 should work.

RESCUE161 · Post by **RESCUE161** » Fri Feb 10, 2006 1:29 pm

When we hooked it up I tried the F1, F2, F3 and F4 buttons. I'll take it in Sunday and try to reverse the polarity. What was Wavetar talking about using an A/C millivolt meter to read? What should I look for on A/C once I hook it up? Where should I measure the millivolts? On the line while a known good remote is hooked to it? Sorry for the stupid questions. Thanks.

Post by **wavetar** » Fri Feb 10, 2006 1:41 pm

RESCUE161 wrote:What was Wavetar talking about using an A/C millivolt meter to read?

That was for reading the audio level going into the unit. Now that you don't have the RX audio problem anymore, it's not needed.

I tried looking on MOL, but they only have the manuals for the MC series, not the older C200 series. I'm not even positive I have a C200 DC manual...I know I have the local & tone versions...won't know for sure 'til Monday. But I DO have a known working C200 DC remote in the shop, so I can just look at the switch config on that one.

RESCUE161 · Post by **RESCUE161** » Fri Feb 10, 2006 1:45 pm

I just wish I knew for sure if this one was good. The guy in charge of the radios took me to the radio room and said have at it, take what you need... There were boxes of Astro Sabers, shelves of Maxtracs and Astro Spectras, base stations and antennas and most of it was on the way to DRMO. Sad.

There was only one remote, so I took it hoping it would help us out.

Post by **wavetar** » Fri Feb 10, 2006 1:51 pm

If you have a digital voltmeter that can measure milliamps, you can easily test it by putting the meter in-line with the L1+ lead, and then jumper it over to the L1- lead with a 1K resistor. Then measure the current when keyed, see if you're getting the 5.5mA or 12.5mA needed. Then compare it to one of your working units, see if it's the same.

If you just have a voltmeter, you can verify voltage across the open leads to be somewhere around 120-170 volts DC, dropping to about 10-11 volts across a 1K load.

Todd

k2hz · Post by **k2hz** » Fri Feb 10, 2006 4:55 pm

RESCUE161 wrote:I just wish I knew for sure if this one was good.

The fact that you read 136VDC when you keyed it into an open circuit means that the DC current generator circuit is working so the only issue is to get the proper current setting and polarity. You are really just spinning your wheels messing with switch settings if you do not know what the keying current should be. If for some reason you can not find out how the controller at the base station is configured, the best soultion is to open one side of the control pair at a working remote and insert a milliammeter in series to measure the current. Then you will at least know how you need to configure this unit if you do get the dip switch setting information.

For a quick check with just a DC voltmeter without opening up the line- Connect the known good remote in place of the 3145 and read the keying voltage across the control pair and note the polarity. Then connect the 3145 and be sure the polarity is correct. If the polarity is not correct, then reverse the line connection on the 3145. If polarity is correct, try selecting F1, then F2, F3, F4 and see which gives you approximately the same voltage at the right polarity and, if you find a setting that matches, the base should be keying. Then, if it is other than the F1 function that works, it can probably be changed with switch or jumper settings so that the F1 function produces the right current.

The fact that the 3145 is an elaborate 4 frequency/multifunction unit makes the configutation more complicated than a normal one or two frequency remote.

RESCUE161 · Post by **RESCUE161** » Sun Feb 12, 2006 12:41 am

Well, I guess this remote is bad.

It's measuring 10.5 mV when I press the PTT and 1.8 when I let go.

I tried every setting on the dip switch to make it do 12.5 or 5.5, but nothing worked.

Any other suggestions before this thing goes to DRMO?

k2hz · Post by **k2hz** » Sun Feb 12, 2006 1:22 pm

How are your reading the 10.5mV DC, it that at the line terminals on the remote while it is connected to the control line?

The other day you said that you had 136V DC on PTT which I assume was across the line terminals into an open circuit? That would be a normal open circuit voltage for that unit and would usually mean it would be working normally.

The definitive way to check a DC remote is with a milliammeter in series with one side of the line. But, if you can not do that, I would try wavetar's suggestion with the 1K resistor. Disconnect the remote from the line. Repeat what you did before and see if you still get 136V DC open circuit across the 3145 line terminals on PTT. If the PTT voltage is less than about 120V, the remote is probably bad. If you still get approximately 136V into an open circuit, then connect a 1K resistor across the 3145 line terminals and measure the voltage across the resistor when you press PTT. You should see about 5 V if it is set for 5.5ma or 12 V if it is 12.5ma. If the voltage drops to near zero on PTT with the resistor connected, then the remote probably is bad.

If the voltages check OK with the 1 K resistor, I would suspect you may have a bad connection between the 3145 and your control line. I have seen cases with a bad phone jack or bad cord between the remote and the jack where the audio still seems to work OK with a high resistance connection but it won't pass sufficient current to key the base.

RESCUE161 · Post by **RESCUE161** » Sun Feb 12, 2006 6:13 pm

This one, I connected the my mieter (set on millivolts A/C) in series with the good remote and got approximately 50mVAC when keying the remote and 2mVAC when not.

The 3145 only produces 10.5mVAC using the same procedure, but still has about 2mVAC when just receiving.

Unless there is something I can do to bring the 3145 up to speed, it's off to DRMO it goes.

k2hz · Post by **k2hz** » Sun Feb 12, 2006 6:34 pm

RESCUE161 wrote:This one, I connected the my mieter (set on millivolts A/C) in series with the good remote and got approximately 50mVAC when keying the remote and 2mVAC when not.

The 3145 only produces 10.5mVAC using the same procedure, but still has about 2mVAC when just receiving.

Unless there is something I can do to bring the 3145 up to speed, it's off to DRMO it goes.

The AC readings do not mean anything. This is a DC control system. You need to either measure DC current directly with a milliammeter or indirectly by reading DC voltage across a 1K Ohm load as wavetar suggested.

Post by **wavetar** » Mon Feb 13, 2006 6:36 am

As I suspected, I have no manual. However, the known good unit I have here in the shop has all switches set to the "off" position. This is how they come from the factory, and the unit should definitely work for the "F1" channel.

If it's set like that, and won't key the radio regardless of line polarity, then I'd have to say it's defective.

Todd

RESCUE161 · Post by **RESCUE161** » Mon Feb 13, 2006 6:51 am

Well, I finally was able to use a good meter (from work) and was able to test both the good and bad remotes.

The good remote did exactly as stated, but the bad remote did not put any milliamps out, well, 0.1 mA while receiving and the same while transmitting. This was done while the meter was in series with the remote and the leased line.

Guess that's why it was sitting on the shelf.

Thank you for the help anyway.