Dead PSR-600 due to reverse 12v polarity

[blantonl]

Yup, I reversed the polarity on accident while feeding 12V into the radio, and it is now dead. Turing it on just results in a flash on the screen and thats it.

Any ideas on how to possibly repair myself? Or, what is the official repair process with GRE?

 

[gewecke]

Wow, that sucks! No inline fuse either? LINDSAY...really?
Ok, in all seriousness there might be a reverse polarity diode, but I've never known anyone to do this with one of those.
Have you called GRECOM yet?


73,
n9zas

 

[tonyclark]

Crack open the case see if anything is burnt. I hope the radio isn't toast.

 

[Ensnared]

Radio Shack Advice, C-Adapter

I suppose I was a lucky customer when I followed the advice of a RS employee. When I bought a replacement DC power source for my GRE PSR 500 at RS, I asked how to tell if the C adapter was installed with the correct polarity. He said, "if it does not work, reverse it." That was pretty simple advice; however, I never realized that this could result in a fried radio. Yes, I do have an in line fuse for this adapter. After I observed that the radio was working, I retrieved my trusty 3M 33+ electrical tape & secured the C adapter.

I hope your radio is not fried.

 

[gewecke]

Lindsay, if it's out of warranty you could open the cover and see if there's at least a 1 amp diode somewhere near where the pos lead goes into the pc board?

73,
n9zas

 

[RadioDaze]

This is what happens when folks who know absolutely nothing about radios try to play around with them

Seriously, though, my condolences. But I couldn't let the incredible irony pass by.

 

[Ensnared]

Test Light Before Pluggin It In

In the future, if I am unsure about the polarity of a unit, I will certainly look it up. Since I am unfamiliar with symbols meant for electrical circuits, I will also do some research in this area. Then, when I hook up the adapter, I can then use a test light on it before plugging it into my radio.

I used to use a 12-volt test light to find dead fuses & live wires in my car. I might add that most of the ones I attempted to buy in the recent past were flimsy pieces of crap. The lead wire was very thin. Also, the alligator clip was small and cheaply made.

My advice is to avoid the major automotive stores if you want a decent test light.

I found a decent version with larger gauge wire at Wal-Mart. It had a 3M logo on it.

So, I am sorry that Lindsay might have ruined his radio. But, I am certainly going to learn from this bit of bad luck. Still, I hope his unit is not fried.

 

[mmckenna]

I suppose I was a lucky customer when I followed the advice of a RS employee. When I bought a replacement DC power source for my GRE PSR 500 at RS, I asked how to tell if the C adapter was installed with the correct polarity. He said, "if it does not work, reverse it." That was pretty simple advice; however, I never realized that this could result in a fried radio. Yes, I do have an in line fuse for this adapter. After I observed that the radio was working, I retrieved my trusty 3M 33+ electrical tape & secured the C adapter.

I hope your radio is not fried.

Used to be you could trust what the guys at Radio Shack were telling you. Those days are long gone.

While fuses are a must, unless the radio has the reverse polarity diode, it wouldn't have saved this radio. The fuse would pop when it saw the dead short presented by the diode. If there is no diode, there might not be enough current flow to open the fuse, but enough to cook the radio.

As for test lights, they are OK for some applications, like telling you if a circuit is energized, but they won't necessarily tell you the correct polarity. This is where a multmeter and the skills to use it can come in handy. Learning to use one can take some time and practice, but once you know, it can really do a lot. I love my meter, and it's one of my favorite tools. Usually the first thing I grab out of the truck at work when I'm going to repair something.

 

[Ensnared]

Symbols Beside Plug?

Used to be you could trust what the guys at Radio Shack were telling you. Those days are long gone.

While fuses are a must, unless the radio has the reverse polarity diode, it wouldn't have saved this radio. The fuse would pop when it saw the dead short presented by the diode. If there is no diode, there might not be enough current flow to open the fuse, but enough to cook the radio.

As for test lights, they are OK for some applications, like telling you if a circuit is energized, but they won't necessarily tell you the correct polarity. This is where a multmeter and the skills to use it can come in handy. Learning to use one can take some time and practice, but once you know, it can really do a lot. I love my meter, and it's one of my favorite tools. Usually the first thing I grab out of the truck at work when I'm going to repair something.

Here is my question for those of you knowledgeable about electrical symbols. On my PSR 500, I see the following beside the power plug-in: diamond shape with negative sign in middle-O-diamond shape with + sign in the middle. So, does this mean the power is on the inside jacket of the plug-in or vice versa?

 

[Swipesy]

Any ideas on how to possibly repair myself? Or, what is the official repair process with GRE?

Lindsay
Here is the GRE procedure. I am awaiting the return of my PSR500 this week after being repaired from my dropping on floor and the scanner would not turn on.

1. Call GRE at 650-591-1400 and explain the problem.
2. GRE will e-mail you a RMA form that you fill out with personal information and credit card #
3. Send radio to GRE 425 Harbor Blvd Suite B, Belmont, Ca 94002.
4. Minimum charge $60.00 +$12.00 shipping. $60 gets applied to any repair cost. If repair less than $60.00 you still pay $60.00 +$12.00.

Turn around time is generally 1 - 2 weeks.

Good luck. My repair set me back $160.00 + my shipping and insurance cost (broken board).

John

 

[Ensnared]

Think I've Found Myster Symbols

If my information source is correct, the PSR 500 uses a plug with a positive center based on this information:

Polarity symbols - Wikipedia, the free encyclopedia

Please, correct me if I'm wrong. Now, I am going to do more looking in my PSR 500 manual to see if they spell this out for the user.

 

[wireless]

It is fairly rare (but not unheard of) to find a device in these modern times with a Tip Center that is Negative. Most all Center Conducters (the tips) are Positive. The GRE Devices I have seen, and all of my Radio Shack Scanners over the years, my current Pro 106 and the PRO 97 that I have in front of me, both of which are Tip Positive.

The image below depicts the more or less standard diagrams found on devices to indicate plus or minus tips.

 

[Violation]

I once did this, too on a icom IC-229H. I consulted a Kenwood dealer-friend of mine, who advised me of a protection diode in the power supply area of the radio. I unsoldered one end of this diode, and sure enough it was shorted reading it both ways with an ohm meter. Replaced the diode and it worked fine. I don't know if the scanners now days have this protection or not, or if it is something to small for the average "Joe" to even fix. Good Luck.....PW

 

[Ensnared]

Shorting Out

It is fairly rare (but not unheard of) to find a device in these modern times with a Tip Center that is Negative. Most all Center Conducters (the tips) are Positive. The GRE Devices I have seen, and all of my Radio Shack Scanners over the years, my current Pro 106 and the PRO 97 that I have in front of me, both of which are Tip Positive.

The image below depicts the more or less standard diagrams found on devices to indicate plus or minus tips.

I've owned quite a few scanners, CB's, & radar detectors over the years. One of these devices, I don't know which one, had the positive on the outside jacket. Hence, I was constantly changing fuses when I would frequently drop the wire on a grounded object. I think this power cord went to a Whistler Radar Detector, one without KA band or the Regency HX 1500.

Thanks for the information concerning polarity symbols.

 

[pro92b]

Here is the circuit if you want to do a few measurements.

 

[SCPD]

At the time reverse power was applied, was the radio connected to a computer via PC I/F cable or a headphone cable or discriminator tap?

 

[blantonl]

Thanks for all the feedback guys. I was attempting to connect the radio to my Rigrunner, and inadvertently reversed the polarity. I'll do some tests to see where we aren't getting proper power to the radio and keep you advised. Thanks!

 

[ScannerSK]

The most likely culprit is Diode 41 which is listed as a RL1N4002-F or S5566B(Q) or RL1N4002 or S5566B.

Next likely are the following:
D39, D40 (same specs as D41)
IC12 LM317BT Voltage Regulator or LM317T or LM317T-E
IC13 KIA7808AP Voltage Regulator Bipolar or KIA7808API or KA7808

Shorting D41 (while supplying correct voltage and polarity) will power on the radio if D41 is the culprit.

 

[jackj]

In the future, if I am unsure about the polarity of a unit, I will certainly look it up. Since I am unfamiliar with symbols meant for electrical circuits, I will also do some research in this area. Then, when I hook up the adapter, I can then use a test light on it before plugging it into my radio

How will a test light show if you have the proper polarity? The light will light regardless of the polarity of the voltage applied to it. What you need is a multimeter or VOM (Volt/Ohm meter) that will show you the polarity as well as the voltage. You can get cheap ones for about the same price as a good test light.

 

[MattSR]

At the time reverse power was applied, was the radio connected to a computer via PC I/F cable or a headphone cable or discriminator tap?

A very good point - this can create alternate earth/ground paths...