Pyramid PS 36 KX power supply hooked to a cb was TXing for about 25 seconds when warning light and beeper came on. No output voltage or amps or blown fuse.Any help is appreciated. Thanks.

OK... LOOKS like this is a 'vintage' CB Radio??

Some recommend just a 3 AMP 12 volt supply BUT PLEASE don't settle for that! I will highly recommend THESE BETTER SUPPLIES instead!

Pyramid PS8KK and/or PS9KK Power Supply! (sorry about the CAPS)

Because EACH TIME YOU TRANSMIT ~ there is a 'instant' current DEMAND of FIVE AMPS! A THREE AMP supply will "sag" in output voltage and AMPS under that load.

So each time you transmit your supply stressesfrom that 'hit' of 5 AMP demand... not good for a 3 amp supply.

And as your supply tries to recover, THAT could cause a voltage "spike" that can be quite destructive.

With CB radios and other items, it's best to have that extra cushion (if you will) of 'reserve' amps available!

Also note the cigarette power jack? THAT can be quite handy too for other items ~ OR you can add the MALE jack to your radio power wires for quick disconnect!

Now this 6 amp supply will cost slightly more than the 3 amp versions... but it will be SO worth it in the long run ~ BECAUSE your supply will run cooler and it's ready to give you the FULL POWER when you need it most.



https://www.rakuten.com/search/Pyramid%20PS8KX

Pyramid 6 Amp Power Supply PS8KX eBay

ANTHONY

Sounds as though the regulator transistor/s have gone bad. Check these parts by taking them out of line(disconnect them from any wiring) and check for shotrs or opens with a transistor checker or VOM.
If I can be of any more help, please email me at [email protected]. "Original Radio Man" Ed

Usually, this indicates an overload condition. I have a Pyramid 35 amp supply that has no green light but uit does have a red light and an irritating little beeper that the instruction book says is activiated when power draw approaches 90% of rated output. (Why not call it a 30 amp supply if you can't use the full 35???) Enough editorializing. You don't say if the supply actually works, just that the light changes color. If it doesn't work at all, I would start with checking the diode bridge for a blown or leaking diode. If one is bad, it can output enough to drive an LED but fail anything else. If these are good, check the filter capacitor. If this is bad, the hum could concievably confuse the regulator circuit. Next, I would check what ever voltage regulator it has in it. I can't comment on specifics as there are many schemes that can be used. My unit, for example, is like a mouse driving an elephant. It has a small 723 regulator IC, (Aprox. 100ma output), controling 4 large TO-3 pass transistors driven by a 36 volt 40 amp transformer to boil it all down to an adjustable 12 to 15 volts.
The bottom line is without knowing if the unit is puting out or not and not having it in my hand to look at, this is the best I can do. I hope it helps.
Good luck.
Jeff

This is normal for the LXLE's. The new circuitry power the new face plate uses a small high voltage transformer and if power is applied to the receptacle on the radio it is drawing some current. When the power supply is turned off or on with the on/off switch on the LXLE turned off there is still a spike of current going through the radio. Not to worry, it will hurt nothing. If this is truly a problem, someone could probably design a little diode circuit to stop this issue. I would if I could but am not that smart.

Might want to read this

http://www.eham.net/reviews/detail/3442

Hi! I saw your question, and maybe this will help. I also have a Texas Star 100w amp, and this same power supply. Even though the nominal draw for your equipment is way below the rated amp flow of the power supply, when you key up, and the output on the amp is at max, you are drawing the limit of your power supply! Try running this setup at a lower linear output. You don't need the full 100 watts to get out! 60-80 watts is aplenty! You should start at a low output, and slowly increase the output(while keyed up), untill the power supply starts to complain.(buzzer/light). This is what your limit will be. The only other cure, is a MUCH bigger power supply. Unfortunately, I cannot afford a 60-90 amp supply, so this is what I am forced to do to use the one we have. Also,keep your cb's output very low when using the linear amp. These amps are supposed to get a low signal from your radio, or the linear amp is overdriven. (noisy and unstable. Hope this helps you! 73's to you! jimsjinx

you need to get the voltage regulator circuit checked in your ps-21k

Use specified power supply by the computer.

The problem I have had with a PS-20 is a blown capacitor. Hooked to a radio, would allow radio to receive fine, but when trying to transmit, amperage would bottom out. Behind the transformer is a large circuit board. UNPLUG POWER SUPPLY, remove cover, Undo the two nuts, flip board over, and gently rock the 4700uf capacitors side to side. If they move more than 1/16th of an inch, chances are they are blown. Remove/replace and should be good to go...

Most of Pyramid's supplies are based on the LM723 voltage regulator. The DATASHEET should tell you most of what you'll need to know to repair it. THIS is the schematic diagram.

If the output voltage drives the voltmeter to the end of the scale, it likely has one or more shorted power transistors.