| Author |
Message |
    
Dx431
| | Posted on Monday, January 12, 2004 - 1:19 pm: | 
|
I have an old Pyramid Gold Series PS-36K running a Lincoln and Palomar 225 mobile amp. Here's the problem:
I connected the amp to the power supply, checked all connections, adjusted my carrier, and it all seemed to work fine, but, now when I key up,whether it be am or ssb the power supply's protection curcuit shuts everything down. It has the voltage adjustment on the front and I have it set for 13.8 volts.
I called a tech friend of mine and he said that it is shutting down to early, which is what I thought, because the radio and amp are not drawing that many amps to shut it down. So, what i need is the proper pot to adjust so I can get this working.
He didn't have the schematic for the power supply so he couldn't tell me which one to adjust.
Could someone help me out here?.
Thanx
431 |
Stitches
| | Posted on Monday, January 12, 2004 - 11:46 pm: |
|
My Pyramid PS-52KS is doing the same thing too! I've got it set at 13.99v. but it only shuts down when the radio and amp is in ssb mode, what's wrong with my power supply? |
Dx431
| | Posted on Tuesday, January 13, 2004 - 1:59 am: |
|
What type of radio and amp combo are you running?
I found out that the Lincoln is to much radio for the 225 and blew one of the finals.  |
Bigbob
| | Posted on Tuesday, January 13, 2004 - 6:37 am: |
|
It may be you're drawing twice as much power as in AM. |
Stitches
| | Posted on Tuesday, January 13, 2004 - 9:49 am: |
|
Dx431:
I'm running a Cobra 2000 gtl and a Texas Star DX400V with a Yeasu #YS-60 swr/power meter. The amp and meter are the only two items that are hooked up to the power supply. |
Bigbob
| | Posted on Tuesday, January 13, 2004 - 6:31 pm: |
|
Dx431,my opinion,when running a low drive amp that has an adjustable power switch with a dual final radio set it on low,that will bleed off some of the extra rf energy from the radio and protect the amp transistors,Stitches,my opinion,the 400v may be drawing more power than your supply is capable of when on ssb with variable all the way up.Is your supply capable of 40 amps continuous?I have a boomer 400 it draws 40 amps,driven by a dx2517 and the boomer is avg. 445 watts,my supply is set at 14 volts,and has 9 150 watt,15 amp pass transistors and is just adequate,three more would have given me a little more insurance but I ran out of heat sink,so I built a ten amp supply I will run in tandem with it,you would have been better served by a ts 350v or a 70 amp supply,a friend and ham ran a ts 350v and he had to use a tripplite PR60 minimum to keep the amp from clipping,he tried a PR50 but the amp was to much for it,always check the duty cycle of the supply,most are only 50%,when buying a supply make sure it will supply 50% more than you need continuous,then it will be happy,you will be happy,and all will be well.Bigbob |
Stitches
| | Posted on Wednesday, January 14, 2004 - 9:45 am: |
|
Bigbob:
Thanks for the information, my ps just has the wording "12-15vdc 52A
on the front. I've sent away for a manual for this thing and I'm in hopes it'll tell me more about it. I sure thought the ps would have had enough power to run that TS.
However, I did notice when keying up on ssb the meter on the ps would peg at 40A., so I guess it did work the ps pretty good. |
Bigbob
| | Posted on Wednesday, January 14, 2004 - 6:30 pm: |
|
The tripplite 50 is rated at 40 continuous amps,go 1/10th amp over this and bingo the overload protector shuts it down,you may just have to tandem a smaller one or get the next larger one,or there may be an adjustment to the current limitter.Bigbob |
Mr_Rf
| | Posted on Wednesday, January 14, 2004 - 11:40 pm: |
|
Gut feeling guys is that the power suplies are performing properly. I suspect the protection circuits are very sensitive to the fast current PEAKS... and while the ratings or meter readings don't rate or show you near the supplies upper limit, the actual fast peaks of the current you're drawing while in SSB mode is hitting the limit and tripping the supply off. |
Viking
| | Posted on Thursday, January 15, 2004 - 10:48 am: |
|
I had the problem that Mr. RF described with my 'homemade' 15V power supply. (3 computer power supplies with the 5V leads ran in series). The fix was adding a .25 farad capacitor in line. I used the .25 because that's what I had lying around. |
Bigbob
| | Posted on Thursday, January 15, 2004 - 7:34 pm: |
|
WEll,go to your car audio store and get a 1-farad cap,about 129$,I have one on the output,don't know if I need it but it looks really COOL,all chrome and has a built in digital volt-meter,STINGER brand. |
Kc0gxz
| | Posted on Friday, January 16, 2004 - 7:00 pm: |
|
Dx431
It's NEVER been good practice to run both radio and amplifier on the same power supply. And I don't care how strong the power supply is.
Try running your President on a separate 10-12 amp power supply and let your linear have the 36 amp Pyramid to itself. You'll end up with more "breathing room" for the Pyramid. However, if the same problem persists, power supply Voltage-Regulator comes to mind OR you're over-taxing the Pyramid in some way like the Democrats love to do with us. And by the way, what ever you do, DO NOT trust those two PS meters to be accurate. As much as I love these Pyramid supplys, I have yet to EVER see their meters to be right on the money.
Another reason why this can happen is if the power supply is getting any RF into it via the DC power leads from either the radio or from the amplifier. Believe it or not, power leads CAN AND WILL carry RF right to the power supply if they are too long. They have the tendency to act as an antenna if too long especially when using a linear. All kinds of weird things can happen in and around your shack when using long leads that aren't wrapped up. Also, make real sure you are using a good shielded coax jumper between the radio and amp. DO NOT USE CHEAP RADIOSHACK JUNK. Copper has and sells some of the best coax on the market.
Again, start with running a separate PS for your radio and see if that doesn't cure the problem. Bundle up any excessive radio and amplifier power leads to keep them as short as possible.
Good luck. I hope this gibberish may have been some help to you.
Jeff, kc0gxz. |
|
