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Author Topic: VL-1000 Amplifier Work  (Read 718 times)
W8DMC
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« on: March 20, 2008, 10:35:02 PM »

Has anyone in the Michigan area come across someone that is qualified in with doing work on the Yaesu VL-1000 Amplifier? Within 200 miles of Detroit, Michigan. Thank you.
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K6AER
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« Reply #1 on: March 21, 2008, 09:30:08 AM »

There are those who would argue that Yaesu is not qualifier to work on their own amplifiers but that is for another posting. Solid state amplifiers are a financial time bomb when the output devices fail. Several things can cause an amplifier to fail.

•   Power supplies are typically not regulated and surges are passed through to the amplifier final stage.

•   Solid state amplifiers are sensitive to intermittent VSWR loads.

•   With time the transistor heat sink compound can dry up and the thermal coefficient of the devices is compromised.

•   On less sophisticated units they can be overdriven.

•   Duty cycle and heating is at best a compromise in the specifications. Even the Tokyo High Power’s 1.5 KW output amplifier (2.5 model) is capable of only 1800 watts key down and has almost no head room. Many of these amplifiers have failed under contest conditions and have been returned with the owners buying replacement tube amplifiers.

The biggest problem with independent amplifier repair is, as I said, there is a finical time bomb waiting to happen for the repair center. A tube manufactures carries a warranty but a solid state device manufacture will not. Bottom line is the repair center will be unwilling to pick up the cost of warranty devices especially when the owner could be the cause of the amplifier failure. Also when device fails the PCB can burn or will be destroyed in the repair process. You can design solid state amplifiers with all the protection circuitry necessary but now you have a very expensive watt per dollar amplifier. The ham radio market has been unwilling to support such a unit and hence I expect tube amplifiers to be here as long and there are at least two hams on the air.

Getting back to your original question, good luck and you might try  Burghardt Amateur Center
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W4VR
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« Reply #2 on: March 21, 2008, 01:47:43 PM »

K6AER is correct for the most part.  However, lets not forget that some of the tube amplifiers...especially the heavy duty amps...use tubes that are very expensive.  Although you normally don't have to ship the amplifier for repair if it's only a tube problem, you're looking at 500 to 1000 dollars to replace that tube.  Most people that have sent their solid state amplfiers out for repair due to bad finals generally spend as much money.  There are exceptions to this; for example, the Icom PW1 has a switching power supply that may fail if exposed to power line surges; Icom normally will not repair the power supply...they replace the entire unit for a couple thousand dollars.  The VL-1000 has a non-switching power supply and would be somewhat more immune to power line surges.
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W9DKC
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« Reply #3 on: February 17, 2013, 07:31:56 AM »

"The VL-1000 has a non-switching power supply"

HUH?
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W9GB
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« Reply #4 on: February 17, 2013, 10:06:01 PM »

Quote from: W8DMC
Has anyone in the Michigan area come across someone that is qualified in with doing work on the Yaesu VL-1000 Amplifier? Within 200 miles of Detroit, Michigan.
Have you called SAR Technical Services, Inc. ??

SAR Technical Services, Inc.
1792 Nash Dr.
St. Joseph, MI 49085
269-429-2334
http://www.sarts1.com/

The Vertex Standard Yaesu VL-1000 is the QUADRA HF amplifier.
http://www.ab4oj.com/quadra/main.html

The PA stage consists of four push-pull modules, each comprising a pair of Motorola MRF150 MOSFET devices. Each MRF150 is rated at Po = 150W.  The amplifier thus has a 20% safety factor, but is operated somewhat conservatively at 1 kW P.E.P (1.8 to 30 MHz) to maintain optimum IMD3 (< -30 dB relative to peak 2-tone).
The PA is de-rated to 500W P.E.P. output on HF RTTY/FM (1 hr. transmit time at 100% duty cycle), and on 6 meters.

The VP-1000 Power Supply is a 2.5 kVA switching power supply, cooled by two large muffin fans.
These are visible at the rear. The mains circuit breaker is to the left of the fans.
The VP-1000 delivers 48V DC at 50A when operated on 220V mains (reduced to 35V when the LOW key is pressed for 500W output.)  The acceptable mains voltage range is 100 to 235V, 50/60 Hz. RF power output is derated to 500W P.E.P. with 120V mains.
===
Bill, N4ATS has worked on / repaired the Yaesu Quadra VL-1000 amplifier.
http://www.n4ats.com/

Yaesu Quadra VL-1000 Repair by N8NN
How to replace resistors R2A, R2B and R2C -- 5.6 Ohm 5 W ceramic Yaesu part number J31379004 -- located on power supply board 1. These resistors act as a fuse to protect from surges when turning on the power supply.
http://www.ab4oj.com/quadra/vp1000_repair.pdf
« Last Edit: February 17, 2013, 10:18:30 PM by W9GB » Logged
W4VR
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« Reply #5 on: February 20, 2013, 01:39:15 PM »

The original post is almost 5 years old.  I'm sure that by now he's figured out what to do.
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