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2995dx

my2995dx

my2995dx

Active Member
Apr 2, 2005
296
74
38
lancaster pa
Question picked up a 2995dx with the MOSFETs in it what is pep on these I'm getting about 50w Am and 20w sideband came with a UTB board in it but doesn't work might take that out I had one years back it had the 2 pills in it and that did about 190w pep.
 

A factory 2995DX would average around 150 watts PEP. As always the problem will be that someone messed with it. I would start with an alignment to see what it could do. 20 watts on LSB almost sounds like the radio is not triggering the built-in amp.
 
Lkaskel said:
A factory 2995DX would average around 150 watts PEP. As always the problem will be that someone messed with it. I would start with an alignment to see what it could do. 20 watts on LSB almost sounds like the radio is not triggering the built-in amp.
Click to expand...
That's what I'm leaning towards amp not being keyed just got to find out why
 
A tweaked radio can cause this, if the wrong tuning slugs on the main circuit board got molested.

I would apply the cheapest and best tool on hand, the calibrated eyeball. Pull the heat sink off the back and then unbolt the tin shield cover from the linear. When things go wrong in that amplifier, something nearly always gets scorched badly enough to spot easily.

That amplifier will tolerate almost no SWR at all. If someone has mistreated it, the evidence will be visible.

It's possible to pull a plug and put the amplifier on standby. This would tell you how much power the radio has to drive the amplifier. A weak radio circuit board will hold back power even if the linear is perfect.

So far you have a chicken-and-egg puzzle to solve first, deciding whether to blame the amplifier, or the barefoot radio's performance.

Thought I had a picture of the plug you pull to disable the amplifier and make the radio barefoot. I'll keep looking.

73
 
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nomadradio said:
A tweaked radio can cause this, if the wrong tuning slugs on the main circuit board got molested.

I would apply the cheapest and best tool on hand, the calibrated eyeball. Pull the heat sink off the back and then unbolt the tin shield cover from the linear. When things go wrong in that amplifier, something nearly always gets scorched badly enough to spot easily.

That amplifier will tolerate almost no SWR at all. If someone has mistreated it, the evidence will be visible.

It's possible to pull a plug and put the amplifier on standby. This would tell you how much power the radio has to drive the amplifier. A weak radio circuit board will hold back power even if the linear is perfect.

So far you have a chicken-and-egg puzzle to solve first, deciding whether to blame the amplifier, or the barefoot radio's performance.

Thought I had a picture of the plug you pull to disable the amplifier and make the radio barefoot. I'll keep looking.

73
Click to expand...
Ah ok going to get cracking on it Saturday to see what's going on with it
 
Whenever we convert one of these I warn the customer how delicate the MOSFET linear is. I tell them that ANY SWR at all tends to be fatal for the amplifier. Of course they decide that I'm exaggerating, but that's okay. My consciense is clean at least.

One customer came back with a blown 2995DX linear and a curious tale. He had unhooked the coax from the radio with the power still on. Then he knocked the hand mike off the top of the radio. Murphy made sure it landed on the PTT button. It was clear the radio could not have been keyed for a 20th of a second, probably less.

Blew it out.

But the guy was cool about it, did mention I had warned him.

Like I said, start with the plug that activates the linear, and the calibrated eyeball. These will likely dictate your next move.

73
 
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nomadradio said:
Whenever we convert one of these I warn the customer how delicate the MOSFET linear is. I tell them that ANY SWR at all tends to be fatal for the amplifier. Of course they decide that I'm exaggerating, but that's okay. My consciense is clean at least.

One customer came back with a blown 2995DX linear and a curious tale. He had unhooked the coax from the radio with the power still on. Then he knocked the hand mike off the top of the radio. Murphy made sure it landed on the PTT button. It was clear the radio could not have been keyed for a 20th of a second, probably less.

Blew it out.

But the guy was cool about it, did mention I had warned him.

Like I said, start with the plug that activates the linear, and the calibrated eyeball. These will likely dictate your next move.

73
Click to expand...
Will do
 
Amp seems to look ok but I do see a meanwell sp-320-12 power supply in here voltage test on that is 13.6 and.that is turned all the way up I don't see anything burnt on board got 4 irf520 in it
 

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It's always a good thing when nothing is visibly burned up.

I'm pretty sure the 2-pin plug on the amplifier board with the green and yellow wire is what activates it when you key the mike. Pull that plug and this should tell you how much power the radio alone is driving into the amplifier.

73
 
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nomadradio said:
It's always a good thing when nothing is visibly burned up.

I'm pretty sure the 2-pin plug on the amplifier board with the green and yellow wire is what activates it when you key the mike. Pull that plug and this should tell you how much power the radio alone is driving into the amplifier.

73
Click to expand...
Will do
 
nomadradio said:
It's always a good thing when nothing is visibly burned up.

I'm pretty sure the 2-pin plug on the amplifier board with the green and yellow wire is what activates it when you key the mike. Pull that plug and this should tell you how much power the radio alone is driving into the amplifier.

73
Click to expand...
With the plug disconnect radio still does 50w pep so is that saying the amp MOSFETs are bad.
 
Does say that activating the amplifier isn't boosting the wattage. Next thing I wonder about is whether or not a faint "click" can be heard from the amplifier's relay when you key the mike. Gotta put the plug back in to check for this. If the relay never activates, then pulling that plug didn't change the way it's behaving.

And if you CAN here the "click" from the relay I would agree the amplifier has failed halfway or two-thirds way.

73
 
nomadradio said:
Does say that activating the amplifier isn't boosting the wattage. Next thing I wonder about is whether or not a faint "click" can be heard from the amplifier's relay when you key the mike. Gotta put the plug back in to check for this. If the relay never activates, then pulling that plug didn't change the way it's behaving.

And if you CAN here the "click" from the relay I would agree the amplifier has failed halfway or two-thirds way.

73
Click to expand...
Ok I do hear a click with amp hooked up but my mistake radio with amp unhooked does 3 watts I said 50 but I forgot I put the meter on 20w scale
 

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