Might check to see if the input coupling cap hasn't popped from too much input power. Not likely; but possible . . .
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RM Italy KL203 troubleshooting
- Thread starter arinkuddy
- Start date
Are you referring to capacitor C1 in the relay circuit? That is good as the relay does close with RF applied and I did test the relay contacts to be good.
No.
There is a coupling disc cap right at the input.
I haven't worked on a lot of amps; just a few.
Simpler than an SSB or export radio by far.
I worked on a dual 1446 pill amp a couple of years ago. The problem? Someone tried to push 100+ watts into the input. Checked the pills; no problem. Happened to glance at the input cap, and I saw a burn hole thru the side. Replaced it and it worked fine. Not a common fault; or maybe it is. Any time someone wants to put more power into the amp than it was designed for and something will snap. Glad it was a $1 part and not $50 worth of parts. Good thing it was a silver mica cap and not a ceramic disc cap. But it wouldn't surprise me if a ceramic will puke its guts if too much power is supplied. Lack of experience on my part; but think it can too . . .
There is a coupling disc cap right at the input.
I haven't worked on a lot of amps; just a few.
Simpler than an SSB or export radio by far.
I worked on a dual 1446 pill amp a couple of years ago. The problem? Someone tried to push 100+ watts into the input. Checked the pills; no problem. Happened to glance at the input cap, and I saw a burn hole thru the side. Replaced it and it worked fine. Not a common fault; or maybe it is. Any time someone wants to put more power into the amp than it was designed for and something will snap. Glad it was a $1 part and not $50 worth of parts. Good thing it was a silver mica cap and not a ceramic disc cap. But it wouldn't surprise me if a ceramic will puke its guts if too much power is supplied. Lack of experience on my part; but think it can too . . .
Thanks for the suggestion, the only cap on the input of this amp is across the input transformer primary and appears to be physically intact.
Perhaps a diagram will explain my point. In the red circle at the amp input is a coupling cap. That can pop. Without continuity, no workee. Been there; seen that . . .
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Heeey I fixed it, and guess what it was. The freaking relay. I bought another one off digikey just in case because I saw another thread with the top blown off the relay. I replaced that first and i got 60 watts out (before was <2 watts). The funny thing is the relay ohmed out fine, the relay coil was even about the same resistance as the new one. For $3 i cant complain. Relay PN V23105A5303A201
But I bought 10 IRF520N's so I decided to put them in and well now I'm down to like 25 watts..soo. Do I put the old fets back?
But I bought 10 IRF520N's so I decided to put them in and well now I'm down to like 25 watts..soo. Do I put the old fets back?
Get some ERF2030 fets or try to boost the bias a little bit. The old fet's were weak and I don't think heating them up helped.
It looks to me that R2=10k and R3=3.3k are a voltage divider for the bias circuit and the output is set to about 1.86 Volts... The threshold voltage for the IRF520N is 2-4 volts. So im thinking that I can put a 10k pot in there and tweak it until I regain the power lost. What do you think?
Its only at 25W on the meter now so thats low.
If you mean the bias voltage then I don't know, I'll have to check.