Spectra Power Supply

[nick1427d]

I found an older spectra that I had years ago and had hooked up in vehicle. I'm looking to run it in my office as a Ham radio. I'm wondering how I get power to it from wall outlet.

Model #
DA5KM+067W

[kb0uxv]

I have had good luck with Samlex power supplies. Affordable and well built. The 30 amp one will run a trunk mount 110watt unit with no trouble. $100 for the 23a and $120 for the 30 amp at AES:

AES Price list

[MTS2000des]

One word of caution about those switching power supplies, make SURE you use a PROPERLY GROUNDED outside antenna, not some mag mount on top of your cabinet near the radio. Switching supplies are very sensitive to RF, unlike conventional power supplies, and you can even blow them. Seen many of those slim line Samlex's in a junk pile at my old radio shop.

I prefer Astron transformer power supplies. Sure, their big, heavy- but they last FOREVER, can put out much greater surge capacity, and can tolerate RF (and generate way less RFI hash unlike switching supplies which can be noisy, especially on HF). They're also very serviceable. Not much to break: caps usually need replacing in 10-15 years but they're cheap and it's a 15 minute fix. If the rectifier gets shot, again, a simple 10 minute fix. Transformers rarely go bad unless they're constantly overloaded, overvoltage or physically abused (moisture, etc).

FWIW, I have an RS-35 circa 1991. Been in constant service for over 20 years, runs three radios now (only one on TX at a time!), a high power CM300, Kenwood TM-V71A, and high power Astro Spectra W7 800. Never failed yet.

Sure Astron is expensive, but you get what you pay for. You'll only ever buy one, because it will last forever.

[kb0nly]

Iota... Thats the brand i use now. I use a DLS-55 for the shack and the workbench, 55a continuous rated. Not like an Astron which is sold based on their Intermittent Rating!

Don't get me wrong Astron power supplies are good, but i have dealt with just as many dead Astron's, failed regulators and transistors that usually end up frying the connected equipment do to an overvoltage condition, as well as newer ones with separated transformer laminations causing hum and vibrations. I have spent my fair share of time fixing Astron supplies.

I had a Samlex 23a unit for years, was a great quiet power supply that never gave me problems or interference issues. I never had that grounded other than the power cord either so can't say i share the same experience. Never had any RFI problems with them or my current Iota supplies either, on HF or otherwise. So again i can't say i have had that problem.

If you got a bunch of dead Samlex units i will pay you to box them up and send them my way, i will fix them and resell them!! LOL

[nick1427d]

I've looked online and can't find much on this radio as far as specs go. It's been so long I don't even know what wattage it is. Are the above power supplies correct?

Model #: DA5KM+067W
ID #: D43KMA7JA5BK

I've decided to only use it for receive as it's programmed for local public safety and I can't program it

[cmdrwill]

Originally Posted by nick1427d

I've looked online and can't find much on this radio as far as specs go. It's been so long I don't even know what wattage it is. Are the above power supplies correct?

Model #: DA5KM+067W
ID #: D43KMA7JA5BK

I've decided to only use it for receive as it's programmed for local public safety and I can't program it

VHF 146 -174mHz, 50 watts TX. 128 channel conventional.
The radio draws up to 2 amps on receive with full audio output, less than 15 amps transmit.

You do not heed those above mentioned heavier power supplies for your application
So even a one amp wall wort would power the Spectra for receive in your office.

BE SURE that the little red lead going to the 15 pin DB connector is fused at 2 amps, that is the control 12 volts. The two pin cable is fused at 15 amps. For your application you can use a 5 amp there.

[nick1427d]

Do you have a link for the 1 amp power supply you mentioned?

I appreciate all the help

[cabletech]

I have a couple of standard Motorola power supplys that work just fine for that radio. Send me PM and we will talk.

[cmdrwill]

Look in your junk box, there is probably one from an old DSL modem or router that is 12 volts at 1 amp.

[nick1427d]

Reviving this older thread. Found an old 1 amp 12 VDC power supply but of course the end plug isn't going to work. I cut it off so how do I know which is positive and which is negative, volt meter? Do I just splice the power supply with the two pin plug? Where does the fused lead wire go?

[mmckenna]

Nick,
That wall wart transformer would only work for RX, but not transmitting. The radio will "bonk" if you try. Worst case would be that you would fry the wall wart and it would stop working. Ideally you want something a little bigger than what you need. Be careful about what type of wall wart you use, you need to have something that has a regulated output.

A volt meter would be the easiest way to check for polarity.

Put the fuse on the positive wire as close to the source as you can. Splicing into an old Motorola power cable would work fine.

[cmdrwill]

Fuse in the + side. + goes to the un insulated pin of the 'trailer connector' power jack. Ground, - lead to any screw on the chassis..easy. Or the insulated/shrouded pin of the 'trailer connector' power ground.

The 15 pin connector will need + 12 volts on it's red lead, it can go to the main + power pin in this case. That way both power feeds are fused by the one fuse.

[nick1427d]

Well like I mentioned earlier this is strictly receiving. I hooked it up to an old wall wart for a boombox. I connected it per the instructions you guys mentioned and I'm getting nothing. I reinstalled it in my vehicle (hooked) to battery and nothing. I'm wondering if I messed up the radio using that old wall wart. It was a 1.8A and 12 VDC. The ignition lead wire is temporarily spliced into the red power cable between source and radio. On that lead is my fuse (2 amp). Fuse is intact.

Radio was working when Installed in vehicle.

Any thoughts?

[mmckenna]

I'd suggest double checking your polarity, but there is a diode on most Motorola radios that will cause a direct short when the polarity is hooked up backwards. The fact it works in your vehicle says that didn't happen.

I still think the wall wart isn't going to provide enough power, and if it isn't a regulated supply, it could be causing any number of reasons that it would fail to power up. You really need to look for a higher current regulated power supply. Powering up a radio can sometimes take more power than the idle current you see when it's just sitting there.

One thing you could do is hook up your volt meter to the power supply and see what happens when you plug it in. If it suddenly drops the voltage when you plug it in, then you are overloading the wall wart.