2970N4, Less than 2 months and its gone tits up

[Limeybastard]

In conjunction with doing basic mathematics volts X amps and this new to me Swan WM2000A meter I noticed I am down a transistor perhaps. On full wide open unit is drawing 26A tops @ 13.8V minus loss.

The meter wont go past 300 or so W when modulating in PEP mode. The meter still shows low dead key 10W and high dead key 100W similar to before but in PEP mode wont swing past 300W wide open. Last week I thought the Workman 201s meter took a dump, but the Swan meter shows similar figures, what threw me was that the needle was sticking on the workman. But I should have paid attention to the PSU which shows current draw, which gives one a rough idea on something being a miss. The PSU is rated at 75A with 110V input , and shows current draw also, connected to radio via 8 AWG welding cables, approx 5ft in length.

Maybe Im down a "pill"? Whatever the case, I guess I will have to try and send it in for repair. Issue is, no one at RCI or their authorized radioshop supply center ever gets back to you, I had already sent them 2 emails via tech support in respect to when I first bought this and it was deadkeying on wide open at 250W, not a response back. The SWR on CH1 is hardly moving needle wise. Im hoping its something else.

 

[Yeti Communications Ltd]

jessica(at)radioshopsupply.com
..forget the tech support thing it goes no where use the email addy i supplied i get answers with in hours (bear in mind working hours) ...was talking to her only yesterday a few times

good meter also i use one myself ...use mine every day

 

[Limeybastard]

jessica(at)radioshopsupply.com
..forget the tech support thing it goes no where use the email addy i supplied i get answers with in hours (bear in mind working hours) ...was talking to her only yesterday a few times

good meter also i use one myself ...use mine every day

You must have read my mind, I sent the email of to her just a few moments ago.

Yes, the meter seems really nice. although I must confess cosmetically it looks like new but there is slight variances in the readings between 200,1k and 2kw scales. Heres my values( dk) RMS setting, full RF dial fully wide open:
CH1 Swr 1.1 AM,
200W reading 85W
1Kw reading 80W
2Kw reading 99W


The meter light , any ideas on how to change it? It flickered when I first powered it on I think .

 

[vkrules]

Good luck with the radio. That sort of variance is normal for meters ,they are rated at FSD (full scale deflection) so 85 watts on the 200 scale will be the most accurate

 

[Limeybastard]

Good luck with the radio. That sort of variance is normal for meters ,they are rated at FSD (full scale deflection) so 85 watts on the 200 scale will be the most accurate

Cheers mate, appreciate it.It feels so nice , I must be getting well old, when meters get my juices ( whats left of them ) flowing. LOL
I was reading the service manual for this meter and it said to properly calibrate it needs a 2kw amp. I also noticed the Yeasu service manual was identical except it was more readable. Just need a light bulb, but I think its gonna be hard to change?

 

[vkrules]

No worries. Might pay to go back and check all your leads fuses etc.Check the voltage at the radio ,doesn't take much loss to drop the power at those levels.Dirty fuse holder or dry solder joint can easily account for it.Also check the PSU, is there much voltage drop on TX.?

 

[Captain Kilowatt]

Once again I must remind people to FACTOR IN THE EFFICIENCY OF THE FINALS. 26 amps times 13.8 volts is 358.8 watts INPUT TO THE FINALS. Factor in the efficiency and you will get no where near that out. The rest is generated as heat. Sounds to me like you are in fact getting more out of it than you realistically should expect. Nothing wrong with the radio only in your understanding. That Workman meter is likely reading a bit high to begin with too.

 

[fourstringburn]

In conjunction with doing basic mathematics volts X amps and this new to me Swan WM2000A meter I noticed I am down a transistor perhaps. On full wide open unit is drawing 26A tops @ 13.8V minus loss.

The meter wont go past 300 or so W when modulating in PEP mode. The meter still shows low dead key 10W and high dead key 100W similar to before but in PEP mode wont swing past 300W wide open. Last week I thought the Workman 201s meter took a dump, but the Swan meter shows similar figures, what threw me was that the needle was sticking on the workman. But I should have paid attention to the PSU which shows current draw, which gives one a rough idea on something being a miss. The PSU is rated at 75A with 110V input , and shows current draw also, connected to radio via 8 AWG welding cables, approx 5ft in length.

Maybe Im down a "pill"? Whatever the case, I guess I will have to try and send it in for repair. Issue is, no one at RCI or their authorized radioshop supply center ever gets back to you, I had already sent them 2 emails via tech support in respect to when I first bought this and it was deadkeying on wide open at 250W, not a response back. The SWR on CH1 is hardly moving needle wise. Im hoping its something else.

What CK said is correct. As I told you on another thread, my N2 draws a good 16 amps on peak modulation and my meter will show peaking just over 200w to about 225w. I have an Astron 70 amp regulated PSU and is a stable 13.8v. Doing the math and subtracting some efficiency and it's about correct what my radio should do.

Having said that, I would start looking at your PSU and also see if your homes voltage is at least 115v or more.

Have you checked this radio in your truck to see if your results are similar?

 

[Limeybastard]

Once again I must remind people to FACTOR IN THE EFFICIENCY OF THE FINALS. 26 amps times 13.8 volts is 358.8 watts INPUT TO THE FINALS. Factor in the efficiency and you will get no where near that out. The rest is generated as heat. Sounds to me like you are in fact getting more out of it than you realistically should expect. Nothing wrong with the radio only in your understanding. That Workman meter is likely reading a bit high to begin with too.

The radio on wide open would sweep past the 400W range on the meter before, and also show a greater current draw. The math was my attempt to show the mathematics that I have learned from here a well as hazard a guess after loss that 358W ( 26X13.8) would be 298W probably. Which the meter is showing.
My concerns was raised after seeing lower current figures on keydown on the PSU display as well as lower wattage readings on the meter.

 

[Limeybastard]

Changed the power cord , used original wall outlet to the PSU no change. The voltage drop on the PSU is stable 13.8Vdc , now that the radio has "lost" power I dont think the PSU even drops to 13.7Vdc output. Stays on 13.8, before on wide open the voltage would drop to 13.7 not anymore.

I guess the only other thing left to do , is to run in the truck and see?

 

[Big Kahuna]

I know with the mosfets in some of the other radios with internal amp system I've tested that as the radios heats up the wattage will drop slightly. This wouldn't account for a 100 watt drop but I've seen radios experience a 10% drop once they heat up.

 

[camaro1]

are you testing into a dummy load or your antenna?

 

[Limeybastard]

Sending it back via RA number for repair. Like I said, if the radio was presented to me with a DEAD KEY of 250W , dummy load or no dummy load then there is probabilty wouldnt you say that other areas of the radio are also out of whack?

 

[Captain Kilowatt]

If you were showing more than 400 watts in the past and were drawing more current before than now then perhaps you did blow a final. If you did then it was because you were running the piss out of the radio and it was either operator error or the person that messed with it and called it a tune screwed up. Plain and simple that radio had the piss run out of it and maybe blew a final because if it.

 

[camaro1]

just saying if your testing into an antenna that isn't a perfect 1.1:1 50ohm then the meter results can be way off