RM Italy KL 7405V 10 meter Linear Amplifier With Fan

[Mudfoot]

I don't keep a meter inline. I believe it was dead keying around 40 watts with a little over one watt. I snipped the leg off an old burnt transistor and soldered it in as a jumper on the underside of the board. I pulled the front panel down.

I have an HLA-150, KL-203 and this 7405. I have had several other over the years. I've never had any of them go poof. I never push 'em hard. Always get good reports with them. They are what they are. Get stupid with them and they'll poof.

 

[Tallman]

I don't keep a meter inline. I believe it was dead keying around 40 watts with a little over one watt. I snipped the leg off an old burnt transistor and soldered it in as a jumper on the underside of the board. I pulled the front panel down.

I have an HLA-150, KL-203 and this 7405. I have had several other over the years. I've never had any of them go poof. I never push 'em hard. Always get good reports with them. They are what they are. Get stupid with them and they'll poof.

Meters belong on the test bench and not in line on a mobile.

 

[Shadetree Mechanic]

I keep an SWR meter inline on all my radios. I like my radios that much.

 

[Tallman]

I keep an SWR meter inline on all my radios. I like my radios that much.

Most of my radios will not transmit into a bad antenna or cable problem. Some times the meters cause the same problems you look out for.

 

[CB590]

Most of my radios will not transmit into a bad antenna or cable problem. Some times the meters cause the same problems you look out for.

True unless your radio has an inaccurate TSR setting by default like my Lincoln 2+ did.. I had a NGP antenna and the swr went South and the radio didn't pick it up.. Even President in France couldn't explain it and the dealer did a full refund..

I check my truck radio every few months with a inline meter just to be sure.. then run without one inline.

 

[Mudfoot]

I've been working this amp out lately. The overheat temp needs to be set higher before it trips, or a faster fan speed. When I get windy, it shuts down. It gets warm, but not as warm as you'd think. Seems pretty sensitive. I need to get another one of the temperature gun thingies to see how hot it gets. Only trips on AM/FM, SSB has yet to trip on high power. I still like it, though.

 

[Tallman]

I've been working this amp out lately. The overheat temp needs to be set higher before it trips, or a faster fan speed. When I get windy, it shuts down. It gets warm, but not as warm as you'd think. Seems pretty sensitive. I need to get another one of the temperature gun thingies to see how hot it gets. Only trips on AM/FM, SSB has yet to trip on high power. I still like it, though.

It is better for it to shut down rather than it going up in smoke yes?

 

[Mudfoot]

True, but it's not really even warm.

 

[CB590]

I've been working this amp out lately. The overheat temp needs to be set higher before it trips, or a faster fan speed. When I get windy, it shuts down. It gets warm, but not as warm as you'd think. Seems pretty sensitive. I need to get another one of the temperature gun thingies to see how hot it gets. Only trips on AM/FM, SSB has yet to trip on high power. I still like it, though.

Maybe try and find the thermistor inside that hooks to the fan switch and power source. Disconnect thermistor and run fan just straight on all the time thru a different source (if it is the same).

How long is long winded? Or is it back to back qso?

 

[Mudfoot]

Mostly back and forth. Fan stays on, but speeds up when keying. If it ran faster, it would probably be OK.

 

[Tallman]

You could just rewire the fan to come on when the power switch is turned on,

 

[Mudfoot]

Thinking of taking it off and putting one of my USB fans on it. It's larger, near silent and moves more air. The stock unit is a little noisy.

 

[Tallman]

Are you talking about one powered by the USB port? Well those are nice looking fans. Do you have a usb port available to plug in to?

 

[Mudfoot]

Yes

 

[magnuman]

Open it up and make sure they put thermal paste on the transistors. In some of the similar units they forgot. Transistors getting hot but they wasn't being cooled. And remember the ratings for those mosfets was never very good in continuous mode. FM really hurts them. Divide the SSB rating by 5. Another option is to add a fan inside.
I have been using the RM amp with 16 of those things and it is a monster. It does not get anywhere near warm. Good luck and keep us informed of how you get on.