I think he and the amp are long gone.....
Good advice. From what you described I would be inclined to measure the R of the parasitic suppressors to eliminate that possibility.
In the future, it is a good practice to never replace a fuse or reset a circuit breaker more than once without stopping operating and troubleshooting the problem.
Does this amplifier have a glitch-R in the HV+ ? If so pse describe. tnx
In this case you turned a simple symptom of a blowing (but really a Warning of a problem) into a catastrophe.
Something doesn't smell right about this whole story. This OM also gave the 8410 a ZERO rating in the amplifier section of Eham.net. 63 previous owners had given the amp a perfect 5.0 rating. His zero rating knocked the overall rating down to 4.9. I just happened to be following the Eham.net 8410 rating so I am familiar with this story. As a matter of fact, I had my control board go after about two months (I bought the 8410 new via HRO). I called Alpha the next day and they diagnosed the problem over the telephone. They sent me a new control board the very same day and I installed it in half an hour (just 1 solder connection). I really did not want to box the amplifier up and send it back to CO, so when the technician said I could swap the control board rather easily, I jumped at the offer. Actually, my LED wattmeter was dead, just like his, so he probably had his control board blow on him. God only knows what further damage he caused by replacing fuse after fuse. That is just dumb!
Alpha is a top notch company with super service, and they give a 4 year warranty on their amps which is the longest warranty offered by any amplifier manufacturer. The 4 year Alpha warranty is one of the reasons I bought my Alpha 8410 (I also get a fifth year of warranty coverage because I used my American Express card. They offer that as an inducement to use their card). Ameritron offers a 1 year warranty, for example, and Acom offers a 2 year warranty.
I installed my 8410's transformer and it uses three different Molex connectors. It's impossible to screw up.
Any piece of Amateur gear can have a failure. That's why the warranty and the reputation of the company are so important. This was an opportunity to let Alpha show what kind of customer service they provide when something does go wrong, and in my case it is a major reason I gave them a prefect 5.0 rating on Eham for their product.
W3XAF should have been on the phone with Alpha as soon as the first fuse blew instead of crying in multiple forums. How come he never answers when people ask what happened when he called Alpha? This story doesn't hold together. Facts really are stubborn things!
Last edited by NU1O; 04-12-2012 at 07:48 PM.
That may all be correct. It doesnt change the fact that his 3 week old amplifier developed a problem. I would downrate a product for that reason as well. Especially with the price tag of that amp.
RE: Alpha (Dick Erhorn's) amplifiers:
Originally Posted by NU1O
1. used an oil-filled HV filter capacitor that was not designed to handle ripple current. so it heated. expanded, broke the seam and leaked.
2. used ceramic doorknob caps that were intended for coupling and bypass apps as low band padders in tank circuits. This resulted in excessive drift from capacitor dielectric heating.
3. failed to realize, along with Tom Rauch. that C-feedback can not be safely ignored in UHF-rated triodes.
Erhorn once complained to me that the had c. 150 bad 3CX800A7s in his shop that had a "Eimac manufacturing defect" - which turned out to be leakage from gold-sputtering from the grid -- which is a problem caused by inadequate amplifier engineering - not the tube mfg.
Isn't that the same letter that Eimac retracted?
Besides, dragging out a 26 year old third party letter about a technical issue is hardly convincing that Alpha is not a top notch company in 2012.
Your anecdote of a confidence from Dick Erhorn clearly shows that he was standing behind his product and supporting his customers by replacing bad tubes.
Last edited by KB4QAA; 04-13-2012 at 01:07 PM.
"Lossy Traps, Oh my!"
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Anybody note that the letter states they were 8875 tubes and not 8877's?
Noticed that and had a particularly snarky reply all typed up along the lines of "when can we expect the AG6K "perfect" amplifier to hit the market"?, and thought better of it.
Originally Posted by KM1H
Pretty easy to sit back and criticize a manufacturer when you don't have any blood or treasure in the game.
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8875s are a smaller version of the 8877. Both have high-Mu, oxide cathodes and gold-plated grids. Both can suffer from gold-sputtering in HF amplifiers. For photos see "Parasitics Revisited", September-October, 1990 QST Magazine.
Originally Posted by AC0H
Those who have no blood or treasure invested in an issue are somewhat less likely to deny reality.
The info in the Foote letter originated with Eimac's 8877 development team, not a third party. Due to its high boiling point, I did not believe that gold evaporation was possible until I autopsied a kaput 8873 and looked at the cathode with a microscope. After "The Nearly Perfect Amplifier was published in QST, Eimac's Reid Brandon told QST's Paul Pagel that Bill Foote was not authorized to tell me about the gold sputtering phenomenon that Eimac's 8877 development team encountered. .
Originally Posted by KB4QAA
Bad tubes are replaced by Eimac if they are less than 12 months old.
Last edited by AG6K; 04-15-2012 at 04:52 PM.