Transmission1

Easy enough if your ok with tools and some light soldering, i like the pic above, ive modded about a dozen atx's room inside is usally tight, i was toying with the idea of an extended case using a small project box, it dont add much bulk and the extra room means extras, good idea.

Great for making bench psu's here's one i am on with at the moment.
Universal laptop psu's are great for a 0-30v psu i used one in this psu (0-30v @10A) along with an atx psu.
You don't need to use a load resistor if you put 5v into load detect pin on smps ic pin.

Yes sorry not seen this post until tonight, got me wires crossed with the other ATX post, the one where the OP got ripped off on ebay by that fool selling as ham CB supply's.

Nice to see a fellow enthusiast at a project, wish people could see the wood through the tree's, SMP's don't have to be noisy, all the top retail units are SMP, ok get a rubbish ATX supply and it will fail with gross output electrical noise, those better makes are more than clean enough for radio use, good luck with the modding.

Can this be done with any new pc psu?

Yes it can, as mad as it sounds the one i use daily was purchased new from maplins, it been in use a very long time daily almost 24/7 you can follow one of the on line tutorials its easy enough. The two in the link below are the best for a beginner.

http://jumperone.com/2011/06/atx-power-supply-tutorial/

http://web2.murraystate.edu/andy.batts/ ... supply.htm

For others that read this the nut case bought a new atx power supply to convert it for CB Radio.

The dreaded atx psu threads.

Radio power pic A , Tuner in my back room and a micro atx, old one not new.

And the radios its powering. Only two pic's per post, below sorry naff pic's.

The radios powered from the one in the electric meter cupboard .

I have a new coolermaster psu cost me bout £90 bout 9 months ago but ive never used it lol . Its still boxed lol , So thinking for another project ill convert that...... Thanks for the links

No problem, mine in that cupboard is 370 watts cost £ 25 yours sounds like a real good quality unit, cant you try a more modest priced one first, you might need that quality one for a PC etc, but if its knocking round doing nothing it will work fine on that as well, best results are the load resistor of 4.7 ohms 10 watts this draws just over 1 amp on the 5 volt rail, you need it for a stable output, the rest is how little or much you want to do, add on's etc, good luck if you give it a go.

yea it just kicking around doing nothing..... the supply is a 600watt 22amp on the 3.3v, 25amp on the 5v and 48amp on the 12v pics inside below

That current output is odd, normally its the lower voltages with the greatest current, maybe it was high current on the 12 volt rail for a punchy CPU.

Any way its a good thing more power on the 12 volt rail just follow the tutorial and use 4.7 ohm 10 watt ceramic resistor, do a temporary set up put the resistor on one black one red first so that's +5 volts and ground, get a multi meter if you can read the 12 volts from the yellow and black +12 volts and ground, then turn off and put the resistor across the +12 volt rail, another resistor for this 20 or 25 watts and 10 ohms again ceramic or aluminum clad type, which ever rail with the resistors on gives you the highest voltage on the 12 volts rail yellow and black, oh if two wires on the 24 pin connector share the same pins IE two wires together you must keep them together its a sense wire for feedback with out them connected together the supply will be unstable, your power resistor can go inside the case or on the outside, be very careful if you power up with the lid off, there is very high voltage where the two or more largest capacitors are, ive had a knock from the high side really only power up with the lid on.

Just another quick thing those two or more high voltage capacitors can hold a charge for a while even after powers off. avoid touching anything for 15 20 minutes, depend if discharge resistors are in the circuit, or put a load resistor across the 12 volt rail until the meter reads 0 volts.

Really just follow the tutorial and you cant go wrong.

Yeah the big current was to to with bigger processors i.e 6/8 core processors and big hefty graphics cards wanting more juice lol, ok thankyou for your help ...... Again lol

sureshot wrote:Any way its a good thing more power on the 12 volt rail just follow the tutorial and use 4.7 ohm 10 watt ceramic resistor, do a temporary set up put the resistor on one black one red first so that's +5 volts and ground, get a multi meter if you can read the 12 volts from the yellow and black +12 volts and ground, then turn off and put the resistor across the +12 volt rail, another resistor for this 20 or 25 watts and 10 ohms again ceramic or aluminum clad type, which ever rail with the resistors on gives you the highest voltage on the 12 volts rail yellow and black

do i need both 4.7 ohm 10watt and a 10 ohm 20/25 watt power resistor for this or was the 10ohm power resistor just an alternative?

i just put the 4.7 ohm power resistor between red (+5v) and ground? then try it in the +12v and see what the biggest voltage is on the 12v line

good thread

hdjmings1 wrote:

sureshot wrote:Any way its a good thing more power on the 12 volt rail just follow the tutorial and use 4.7 ohm 10 watt ceramic resistor, do a temporary set up put the resistor on one black one red first so that's +5 volts and ground, get a multi meter if you can read the 12 volts from the yellow and black +12 volts and ground, then turn off and put the resistor across the +12 volt rail, another resistor for this 20 or 25 watts and 10 ohms again ceramic or aluminum clad type, which ever rail with the resistors on gives you the highest voltage on the 12 volts rail yellow and black

do i need both 4.7 ohm 10watt and a 10 ohm 20/25 watt power resistor for this or was the 10ohm power resistor just an alternative?

i just put the 4.7 ohm power resistor between red (+5v) and ground? then try it in the +12v and see what the biggest voltage is on the 12v line

i have 2x 3.3 ohm 5 watt.........can they be used? or would it need to be the 4.7 ohm?

right need help please..... i cant find where the +5v goes to the voltage regulation? ive added a few pics