Something Fried My Rig

[Harlock]

All - hoping someone can help identify what fried my rig this past weekend.

Equipment:

Yaesu 3100r 2m being used as a base station with a Pyramid 20 Amp power supply. The 3100r only needs a max of 15 Amps for its highest TX power of 65w, so the power supply should have been more than suitable for the task.

What Happened:

The radio had been powered up for a couple of hours, mostly for RX. I was on a net, and after my comments, I unkeyed, and my radio suddenly shut down, and the power supply protection circuit light came on.

Current Status & Tests:

The 3100r doesn't power up with my backup 5 Amp power supply, which it would normally work with for RX, and 5w TX. Opening up the radio, it appears that the capacitor is scorched, and smells as such.

As for the power supply, I tried hooking up a Cobra Classic mobile CB to the terminals, and upon turning the radio on, the protection circuit on the power supply comes on. Luckily, it didn't seem to fry my CB, but I was willing to take a chance with it.

When hooking a marine battery to the power supply, the protection circuit doesn't come on, but the amp meter doesn't budge either.

When this all happened, there were no noticeable power surges in the house, and I even had two other electronic devices hooked up to the power strip the radio and power supply were on. My shortwave radio was on that power strip, plugged in, but not on, and it is fine. I also had a single-bulb lamp plugged into the power strip, which was on, and it works fine, and didn't even flicker when the above happened.

This leads me to think that this was a power supply issue, and as unfortunate as it is, my 3100r suffered its wrath. Any ideas as to the cause, or what may have happened to the power supply &/or radio would be appreciated.

I've ordered another power supply (a switching 50 Amp unit that is getting great reviews), and my new Yaesu 857 (since I'm working toward my General), but am nervous about hooking anything up at this point, especially since the new gear costs 6x the amount of the above setup.

 

[prcguy]

This is not an unusual story from a Pyramid power supply owner. I suspect the power supply went unregulated due to the pass transistor(s) shorting, or from reacting to a high RF level near the power supply leads. When this happens the power supply can put out the max unregulated voltage, which can be around 19 to 22 volts and stuff inside the radio breaks.

Measure the output voltage and see what it is, you will probably find something scary. Otherwise, sorry to hear about another nice radio blown up by a Pyramid power supply.
prcguy

 

[Harlock]

Thanks for the feedback, PRCGuy. There wouldn't have been any high RF near the power supply, but I suspect the power supply was tweaky out of the box. There were signs from the beginning, but I rolled with it since everything appeared to be working well. I don't have the proper test equipment, but have friends that do, so we're going to see what's up. Even if I DO get the Pyramid fixed, I don't think I'm going to ever use it again; kind of like touching a hot stove burner again and again, you know?

 

[Harlock]

One of my friends seems to think that this may have been caused by a mis-matched antenna, causing strong SWR, which fried the radio first, and then tripped the power supply. It's an aluminum 2m/70cm j-pole that I picked up at our local hamfest last Summer.

Since the Yaesu 3100r only performs on 2m, I've only been using 2m TX on the antenna. I don't have an antenna analyzer, so I'm not sure what the SWR would be. Plot thickens.

 

[jonwienke]

High SWR would blow RF transistors, not a capacitor.

The power supply is the most likely culprit.

 

[N4KVE]

Considering the quality [or lack of] on the Pyramid supplies, I'd bet that's what fried your radio. Check the output voltage, & throw the supply in the dumpster.

 

[TheSpaceMann]

Power supply failed, sent surge into radio, and the Yaesu protection circuit kicked in and shut the radio down. Happened to me once with a Pyramid and a Yaesu 2m rig. My solution was to send radio to Yaesu for repair, and buy new supply.

 

[KC4RAF]

I as well as a couple of radio buddies stay away from the Pyramid power supplies, (as well as anything built by Pyramid). We have had those supplies fail and take out some of our equipment. Fortunately only the diodes or fuses blew. When you suspect something isn't right with a piece of equipment, STOP using it and check things out. There's good advice about in the previous posts.

 

[cmdrwill]

And, you had the correct size and type fuse in the radio's power cable???????

 

[Rred]

Time to take out a DMM and actually verify the power supply. Having no experience with Pyramid I can't comment on the quality, but the old LM317 and other voltage regulator IC's were all built with "heroic failure" modes, meaning, if they failed they'd shut down. The conservative rule of thumb is that your power supply SHOULD have "crowbar power protection" in it, and you can add that yourself to any rig. From the power supply, you take two leads. Fuse one or both, at a rating that will just support your equipment--not at the max rating for the supply or cable. This is to help them blow as quickly as possible, while still allowing the equipment to work. Then, in between the fuse(s) and the equipment, you add a component like a 15v zener diode. If the voltage coming out of the supply exceeds 15v, the diode makes a short circuit (the "crowbar" across the output) and promptly blows the fuse. Choosing a component, or a diode string, whatever, that will conduct and blow at, say 14 volts instead? All the better, presuming you are running 13.8 to the equipment.

Protection should be built in, yes. But protection circuits are cheap insurance to add.

You might also check the capacitor that blew. Many folks are unaware that Icom had to deal with threats of a class action lawsuit because they used 15-vot rated caps in the IC-706 series, and a 15V rated cap is simply not suitable for "12" volt (14.4) circuits, according to all the folks who make them. (A normal 15V electrolytic has a 10% tolerance, so 15-1.5=13.5 volts being the maximum working voltage they should ever be used with. Which is less than normal car voltage.)

 

[wrath]

Linear Astron supplies has never done me wrong, as for the new switching supply for your radios be aware that switching supplies although smaller and cheaper do throw a lot of garbage hash.

Sent from my SM-T810 using Tapatalk

 

[Harlock]

Thanks for all the input, gang - really helpful. I'll check with Yaesu about getting the radio repaired, but I'm not sure it's going to be worth shipping to CA, paying for repair, and shipping back for a $140 radio.

Really good to know about the SWR. The seller at the hamfest seemed pretty legit, and I can't imagine that the antenna was so far off as to blow up a radio transmitting at 65w, but I'll be testing the antenna tomorrow night.

 

[Harlock]

WRATH - yes, I thought I'd never purchase a switching PS, but this one got really good reviews.

The model is the QJE PS50SW III You can find it on Amazon for $159. Lots of good reviews, but there are a couple of duds out there too it seems.

 

[TheSpaceMann]

I've had good luck with Jetstream switchers. About $90 for a 25 amp unit.

 

[RFI-EMI-GUY]

Astron SS30M'S are good 30 amp switchers. I have no complaints except that the power terminals require retorquing from time to time. In my experience linear power supplies with pass transistors can suffer an overvoltage failure. Unless they have a good crowbar circuit, your radio will get zapped. You may have dodged a bullet if only the capacitors failed. Much better than had reverse polarity been applied. Start by replacing the fried capacitors with ones having higher voltage and temp rating.

Sent from my SM-T350 using Tapatalk

 

[wrath]

If you bought it used I would say use it as a parts radio and just buy another one ,the cost of a new radio would probably be an even swap or cost less than having it fixed by the company, if you don't have the ability to do it yourself ask your Elmer or somebody from the local club who in your area does.

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[N4KVE]

Linear Astron supplies has never done me wrong, as for the new switching supply for your radios be aware that switching supplies although smaller and cheaper do throw a lot of garbage hash.

Sent from my SM-T810 using Tapatalk

Only on HF. No problem on VHF/UHF.

 

[wrath]

Only on HF. No problem on VHF/UHF.

Yeah but since the op mentioned buying an 857 I figured the "Miranda" warning should apply regarding switchers .

Sent from my SM-T810 using Tapatalk

 

[buddrousa]

I have only used ASTRON POWER SUPPLIES. Also a word of thought put a VOLT METER ON YOUR RADIO DESK ALONG WITH A AMP GAUGE where you can keep a watchful eye on VOLTAGE AND CURRENT.

 

[prcguy]

I also highly recommend the Astron SS series switchers. I have an SS30M, SS30, SS25M, SS18 and have abused them for many years and they always work. I also power lots of HF equipment, sometimes with antennas near the power supply and never experience any RFI problems from the Astron switchers.

If a switching power supply fails, its normal failure mode would be no output, I have never seen a switching power supply of any kind fail and put out more than rated voltage.
prcguy

Astron SS30M'S are good 30 amp switchers. I have no complaints except that the power terminals require retorquing from time to time. In my experience linear power supplies with pass transistors can suffer an overvoltage failure. Unless they have a good crowbar circuit, your radio will get zapped. You may have dodged a bullet if only the capacitors failed. Much better than had reverse polarity been applied. Start by replacing the fried capacitors with ones having higher voltage and temp rating.

Sent from my SM-T350 using Tapatalk