Rci 63ffc4 current draw

[StrykerLiker]

Hi :D

I recently got the afore mentioned radio from a pal that didn't want it anymore. Now I am wondering if there was a reason for that...

When I hook up my clamp Ammeter on the posative wire (red) on the back of the radio, it always gives a negative result, and the ground wire (blue) always give a posative result. This confuses me since all other things I have tested show pos as pos. Etc. Maybe CB radio is different?

The other confusion I have is,
Radio low power DK = 10 amp draw
Radio low power PEP = 13 amp draw

Radio high power DK = 33 amp draw
Radio high power PEP = 27 amp draw!

The radio dips in current draw when on high power and speaking into the mic... is this normal?

I have a 145 amp alternator. Radio wires 8awg straight to battery. No other accessories running.

I could understand lack of available power and the current draw staying at 33 amp when speaking into mic, but swinging backwards I do not understand.

Thank you for any replies


Edit :

I fixed the negative reading issue. Just had to turn the ammeter around so the current flow went through the "front" side of the meters clamp ring.

[1206FL]

What are the pep wattage readings. That is a 400 watt radio with 4 Toshiba 2879's. It can draw some amps, but shouldn't draw that much power on a dead key. Sounds like the radio may have been messed with. Also are you checking this while On a dummy load or an antenna? You need a dummy load to properly test it with. The paint bucket type that will hold 1kw is what you need if you aren't already using a different one. But in the end one is needed to properly check the radios output correctly.. JMO.

[Deleted User 14541]

Too much dead key on high or maybe it's been tuned improperly. The current draw drops because the average power is swinging backwards. A pep meter will still show forward swing.

If the amp clamp is showing negative just flip it over.

[MDYoungblood]

Haven't a clue why your ammeter is reading reversed. The low power DK draw is right but the PEP seems a little low. It looks like 1206FL is right and someone had there fingers inside causing the lower high power draw, probably overdriving and clipping. Time for a real tune up.

3's

Greg

[1206FL]

Or a real detune and alignment lol!!

[Deleted User 14541]

What he's describing isn't uncommon for export radios with built in amps. Usually the carrier is too high and having the modulation clipped or cranked wide open will make it even worse. There is still envelope growth so a pep meter still shows forward swing.

What I do is set them by the service manual or in some cases back the carrier down below spec to get rid if the avg back swing and the best looking waveform. Then set it for 100% mod at max power. By design the percentage of modulation will usually increase as the power is turned down. Some radios are worse than others.

Some techs "fix" this average back swing by volting the radio final and doing an NPC mod. The average power from the radio comes up and the amp draw will comes up. I don't recommend it but some people are into these wacky things.

[1206FL]

Well said 543!!

[Buzzweiser]

That particular amp. board they put in those doesn't like a high DK. The variable power knob on those radio's should be taken off and thrown away. Anything over a 100 watts on AM and they tend to saturate too much. On SSB those radios usually draw about 60 amps avg. on transmit. Some a little less and some a little more. The radio section alone draws about 7 or 8 on transmit plus then add a 4 pill amp to that. When the golden screwdrivers get in there and start tuning stuff all they are tuning is the radio section. There's nothing on the amps they do. They tend to crank up the dual final output of that section to drive the amp harder to get maximum watts. That's bad on both sections of the radio. A good modulation adjustment and alignment is the only thing that should be done to those radios. I'd find a good tech that will re-tune the radio by bypassing the amp section, dial the output of the radio down to 45 watts maximum pep and go thru it and find out what other 90 day wonders have been done to it. And do yourself a favor and add the slimline blower to the amp section as well. That's $50.00 now instead of 200plus later for new pills.

[StrykerLiker]

I took it to a shop but the guy didn't have the equipment to run the radio properly. Power supply issue, and a junky untuned meter. He did use a 1kw dummy load tho.

Radio low power, his meter showed

DK 100 . PEP 350

Radio highpower, his meter showed

DK 100 . PEP 350 lol

The radios meter was swinging backwards in his shop... The radios meter swings forward when in my truck, so I just assumed his power supply and meter were, as he said, not up to the task. I guess I need to just man up and buy my own test equipment.

The radio uses different power wires, which I spent the weekend perfecting installing etc. So I'm hoping to run the radio on 'light and limited duty' until I get to a shop, proably clays in San Antonio this week.

Unless someone can recommend a shop between Tucson and San Antonio on I-10.

I hoped there were radio current draw dynamics I didn't understand, but yous guys are all agreeing that it's been molested and needs a psychiatrist. So I shall follow your prescription.

Thank you for your time gentlemen.


Sent from my SM-N900V using Tapatalk

[StrykerLiker]

. And do yourself a favor and add the slimline blower to the amp section as well. That's $50.00 now instead of 200plus later for new pills.

Do you mean adding a fan on the outside of the radio on the bottom? Like a cpu fan?

Or is that slimline something specific to the radio that gets installed inside?

TY



Sent from my SM-N900V using Tapatalk

[StrykerLiker]

The current draw drops because the average power is swinging backwards. A pep meter will still show forward swing.
.

So will an RMS meter show reverse swing then?

Sent from my SM-N900V using Tapatalk

[Deleted User 14541]

The current draw drops because the average power is swinging backwards. A pep meter will still show forward swing.
.

So will an RMS meter show reverse swing then?

Sent from my SM-N900V using Tapatalk

If you are seeing the current fall with modulation an avg meter will probably swing backwards. Another thing to think about is the chance that RF may be interfering with the amp meter.

If you deadkey 100 watts and inject a 1k sine wave tone to achieve 100% modulation the avg meter will still read 100 watts and pep will be 400. This is under text book conditions and will not happen under operating conditions. When the human voice modulates a radio to 100% the avg meter will just wiggle a bit. Pep power will be 3-4 times the carrier while speaking.

This is proper AM but unfortunately most cb shops don't set up equipment this way. If they did most customers would be unhappy because the truck stop tech at the chrome shop can get 50 more watts out of it.

[StrykerLiker]

So, since the current doesn't fall off with radio on low power, is it safe to assume that I can run the radio on low power safely for the next few days to a week?

Sent from my SM-N900V using Tapatalk

[Buzzweiser]

It's a slimline blower that goes inside the amp section. Since you are in the southwest I highly suggest finding one. Heat is those radio's worst enemy. They are a bit noisey but well worth the money. I have one but I also run the SRA-198 mic and it doesn't pick it up. Here's what it looks like installed. A switch can be added to turn it off and on.

[Deleted User 14541]

So, since the current doesn't fall off with radio on low power, is it safe to assume that I can run the radio on low power safely for the next few days to a week?

Sent from my SM-N900V using Tapatalk

It will be fine as long as the swr is low and you don't let it overheat. Reach up and touch the heatsink every few minutes if you get in a long conversation. If it starts getting too hot take a break. Even when they are set up properly you need to keep an eye on the temp.

[StrykerLiker]

Thanks guys. I appreciate the advice.

I am 110% interested in finding that blower to go inside the amp section.

I will make it happen ASAP!

And also get the thing set up properly.

[1206FL]

If you can't find the blower get a fan at least. Get some air flowing across the heat sink. Whatever you can get for now. Order the blower and install it when you get time. For now if you can't find one get a good fan and put it on. JMO. And be careful as you are already pushing the radio to its limit on low power!! Turn mic gain back some and use a good noise canceling mic like suggested by Buzzweiser. And don't stop at any more truck stop radio shops!! Send that radio to a real tech and get it fixed properly. The test equipment needed isn't cheap. Not talking dosy meters here. Real test equipment. 543 may know someone near where you are. IDK. But I would send it to a good tech like DTB radio or someone like him. Again JMHO. You can't buy Toshiba transistors anymore and if that one has 4 of them I would make sure they are working how they are supposed to be. Good luck and be safe.

[StrykerLiker]

It is difficult for me to ship stuff out to good radio techs as I'm an OTR driver, and I don't actually have a home. I live in my truck full time.

I did stop at a shop I felt like I could trust, in Eloy AZ. He's been in the same spot for 30 years or whatever. I bought my first radio from him in the 90s.

He fixed the problem with the reverse swing on the current draw. For some reason he refused to use a watt meter and only used a scope. He also thought a fan was unnecessary, and I finally gave up trying to convince him that I wanted one. Lulz.

On high power, the signal was all carrier with almost no modulation.

Now the current draw is.

Low power DK=4 Modulation=6

HighPower DK=20 Modulation=22

I still feel like the radio isn't right, so I chose to take it out until I am able to get it to a professinal and get a fan installed etc...


After running it for a week, I'm not that big on the radio anyways. The blue light is to bright at night, even on low (like the Stryker 490). The sound of the external speaker is very bassy, and the side mount mic is also a bit annoying for my install.

Thanks for all your helps!