FL2100B cloudy tubes?

[357]

After a few hours idling on HV the glow is gone.

 

[357]

Well it seems to be ok, about 500w with 60w in on "10".
Sure got hot in here....

The 756 seems to really suck for rf getting into the audio though.
The icom doesnt really like it at all, the pass though swr is 1.8 and it wont go over 60 on rtty in that state.
I think I might just sell it.

 

[Sonar]

Those tubes were most likely made by RCA or Sylvania....
Hard to replace, so treat them nice!
Run them about 500w PEP and you'll have a good working amp for a long time.
Amp looks very clean...well taken care of, by the interior pics.
Do your self a favor...Don't use it on AM...
All the Best
Gary

I've read not to use (most) amplifiers made for HF application should be used in the AM. mode.
I have no doubt that this is true.
My question is, why?
Thanks. 73

 

[Sonar]

I picked this up yesterday and it looks pretty mint.
Nothing overheated or charred, no mods, looks barely used.

I unhooked the HV and let the tubes burn over night.
I wanted to inspect the tubes further and noticed some clouding on the glass and was curious if I have a problem.
Pictures look worse than it is but still...

View attachment 21938 View attachment 21939 View attachment 21940 View attachment 21941 View attachment 21942 View attachment 21943

Yaesu must have sold so many of these amplifiers. I see 5 through 20 listed every week on eBay. They must be very robust. I also suspect that the price at the time they were being produced and sold was fair compared to some if not most of the other HF amplifiers being offered. I'm seeing many photos of them sitting next to the 101 series and they certainly look like they belong together. Terrific looking find.

 

[357]

I've read not to use (most) amplifiers made for HF application should be used in the AM. mode.
I have no doubt that this is true.
My question is, why?
Thanks. 73

I think its the glass...they dont like carriers.
I think he is imagining I'm going straight to ch6 and gonna tune it for max smoke.
I cant do that if the neighbors recognize my voice coming out of the toaster, I'll get complaints.
SSB is harder to decode without a blender on to insert some carrier.

 

[Sonar]

I think its the glass...they dont like carriers.
I think he is imagining I'm going straight to ch6 and gonna tune it for max smoke.
I cant do that if the neighbors recognize my voice coming out of the toaster, I'll get complaints.
SSB is harder to decode without a blender on to insert some carrier.

I guess I should have asked, what makes some amplifiers okay for AM use and others not (besides their class rating?)
I don't think that members thought you would or might use it on am. I think he was just sharing some knowledge.
When I read a post like yours, where somebody actually takes the time to burn in tubes, and wait for a variac before plugging it in (after it sat for who-knows-how-long) and throwing the switch, i e mediately think, that person knows exactly how to use this amplifier.
It surprises me a bit that this amplifier isn't recommended for am use. Those 101's sure sounds nice on AM.
I always assumed those 2100 and 2100b's were produced and advertise towards owners of the 101 series.
Either way it looks like a very nice amplifier, and I'm assuming you won't let anyone know how how much you paid for it. LOL I have a feeling that you got a great deal on it. I can't imagine 3 5 7 paying that much for a 30 to 40 year old amplifier. No matter how nice it looks. 73

 

[Captain Kilowatt]

I've read not to use (most) amplifiers made for HF application should be used in the AM. mode.
I have no doubt that this is true.
My question is, why?
Thanks. 73

Usually it is in regards to the power supply limitations or in some cases plate dissapation of the tubes. No other reasons really. Most amps are designed with SSB ratings in mind and certainly can be run on AM but with reduced output. The carrier is hard on tube dissapation and puts a lot of extra strain on the power supply as it does not get a rest between words like it would on SSB.

 

[Sonar]

Usually it is in regards to the power supply limitations or in some cases plate dissapation of the tubes. No other reasons really. Most amps are designed with SSB ratings in mind and certainly can be run on AM but with reduced output. The carrier is hard on tube dissapation and puts a lot of extra strain on the power supply as it does not get a rest between syllables like it would on SSB.

Lesson learned. I wish everything else was as easy as that to understand. 73

 

[Captain Kilowatt]

It gets rather interesting to see an amp or transmitter properly designed for full-bore AM operation as compared to SSB operation. The Gates 1 Kw AM transmitters I used to service weighed in at about 1000-1200 pounds and the plate transformer alone weighed about 85 pounds. Most 1 Kw pep SSB amps weigh less than the plate transformer weighed. LOL

 

[Sonar]

Usually it is in regards to the power supply limitations or in some cases plate dissapation of the tubes. No other reasons really. Most amps are designed with SSB ratings in mind and certainly can be run on AM but with reduced output. The carrier is hard on tube dissapation and puts a lot of extra strain on the power supply as it does not get a rest between words like it would on SSB.

Okay. Here's the dumb question.
Most HF amplifiers (if not all) have 2 mode choices, CW, and SSB.
I've no experience or knowledge of CW. When one is going to use a amplifier on AM but the amplifiers mode choices are CW, and SSB, I'm assuming that CW would be the mode to use on AM.
When an (HF) amplifier is in the CW mode, is there a steady carrier?
Are the dots and dashes inserted into a study carrier? I was just wondering how that works.

 

[Captain Kilowatt]

Okay. Here's the dumb question.
Most HF amplifiers (if not all) have 2 mode choices, CW, and SSB.
I've no experience or knowledge of CW. When one is going to use a amplifier on AM but the amplifiers mode choices are CW, and SSB, I'm assuming that CW would be the mode to use on AM.
When an (HF) amplifier is in the CW mode, is there a steady carrier?
Are the dots and dashes inserted into a study carrier? I was just wondering how that works.

The CW position usually just changes a tap on the high voltage transformer to a bit lower value. This allows the tubes to run a bit easier in carrier modes. The amp only has output when driven by the radio. CW mode is simply a carrier swtched on and off.

 

[2RT307]

I think its the glass...they dont like carriers.
I think he is imagining I'm going straight to ch6 and gonna tune it for max smoke.
I cant do that if the neighbors recognize my voice coming out of the toaster, I'll get complaints.
SSB is harder to decode without a blender on to insert some carrier.

Now that made me laugh! I had a 2100B with Cetrons, and it ran really well. Never on AM with it, though.

73,
Brett

 

[357]

I got bored.
Hopefully these safety caps will be ok.
I got 1 across the line and 1 on each side to ground.



R46KR410000M1K
R413I21004000M x2

 

[Sonar]

The CW position usually just changes a tap on the high voltage transformer to a bit lower value. This allows the tubes to run a bit easier in carrier modes. The amp only has output when driven by the radio. CW mode is simply a carrier swtched on and off.

I hate asking stupid questions. But here goes another one.
If one is going to use an HF amp that only has 2 modes, CW and SSB will that person be using the amp in the SSB mode when their transmitting on AM? By your description I'm guessing yes, but I'm asking because I don't know for sure.
The question is based purely on curiosity as I have no intentions of ever owning such an amp. I own too many of the CB craze era amplifiers to ever have the need to spend money on a FCC approved amplifier when I'm not a licensed amateur radio operator. I only operate on 11 meters. I know the amplifiers I use are subpar, (understatement) but In all honesty they work fine for me.

 

[357]

I got my new cap kit today.
What a great deal.
I tested all 6 caps, esr was excellent and all the caps were within 2% uf of each other.

https://www.ebay.com/itm/6PCS-180uf...237264?hash=item2a5268f790:g:-agAAOSwR0JUM49J