Posts Tagged With: amplifier

POWER SUPPLY FOLLOW UP

Well, the HV power supply seems to be humming along nicely.  The meter on the control head displays 2500 VDC which is probably about right considering my line voltage in the shack (248 VAC).  As promised, I measured all the resistors that were removed from the supply and noted their values.  I also noted their specified range based on the five percent tolerance value.  As expected, not a one was in spec.  I’m not sure that this really makes much difference as the power supply isn’t exactly a calibrated circuit, but it would be silly not to replace them while refurbing the supply.  They’re inexpensive and easy to replace.  I substituted metal film resistors of the same value and power rating rather than the original carbon composition.

I haven’t had a single issue at all with breakers tripping on the amp or sub panel since making the repairs.  I’ll conclude that it was definitely a faulty filter cap (or maybe several).   It uses six 240 uF 450V computer grade electrolytics in series for a total of 40 uF DC filtering goodness.  I don’t have a way to test them at this time to determine their values.   Actually, I don’t even have them anymore.  The neighbor kid (Jacob KC9ZYV) wanted them (and also the caps from the Amp Supply LK-500 NT power supply I refurbed last year).  He mentioned something about a rail gun…future mad scientist at work!

I recorded the values for everyone on a pad of genuine Purdue green engineering graph paper.  I still have nearly a full pad of this stuff after nearly 20 years.  I wasn’t an engineering student!  I hope you all find the info interesting.  The next order of business for the amp is to synch the DC drive system with the Tune and Load air variable caps in the RF deck.  Then I can calibrate them all for roughly every 100 KHz of each band and let the amp auto tune itself!

Check out how far some of the resistor values have changed.

Check out how far some of the resistor values have changed.

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ARD MODEL 230A POWER SUPPLY


Another phase in the amplifier rebuild is now complete.  Thanks to the large chassis I was able to remove the transformer and HV power supply with little effort.  It’s a lot lighter with that monster Peter Dahl hypersil removed.  Only a moderate amount of contortion was required to extricate the power supply assembly through the bottom opening.  The rebuild went pretty straight forward.  Fortunately, power supplies are not incredibly complicated beasts.  The main issue I had was a couple traces came loose from the circuit board as I was de-soldering.  Thankfully, I was able to get them all back down into position when the new components were installed.  The solder is holding them in place.

Grungy bits removed from circuit board.

Grungy bits removed from circuit board.

Components removed were: six 240 uF computer grade electrolytics, twelve 150K 2W resistors, one 1M 2W resistor, and five .01 uF disk caps.  The other components looked to be in pretty good shape.  The board was pretty grungy so I took some time to wipe it all down with alcohol before soldering it back together.  I made only one component substitution.  The original carbon composition resistors were replaced with metal film resistors of the same value and power rating.

The HV power supply is designed to provide 2300 VDC at 1.0 A.  There is a total of 40 uF of capacitance for filtering the DC.  My original problem was the circuit breaker on the chassis and/or the circuit breaker in the sub panel would trip when I powered up the amp.  This would happen either right after the power switch was flipped or as the step-start circuit dropped out.  On occasional times when it didn’t trip, it would run for some time and then trip suddenly.  This was especially annoying!

I’m pleased to report I’ve successfully tested the supply several times now and it seems to be working great.  The meter on the control head shows a steady 2500 VDC.  Initial load testing with low drive (up to 35 W) has provided up to 700 W out into the dummy load.  If everything proves to be linear, as it should be, then I should easily see legal limit with under 100 W drive from the exciter (in this case a Flex-5000A).  This is also without getting Plate and Load caps fully peaked in manual tune mode.

The gear motor drives are not properly synced right now.  They should be turning from 0-180 degrees as shown on the control head indicator.  Right now one is and the other just moves from roughly half-meshed to half-meshed on the other side, never getting fully meshed.  Getting them properly adjusted will be my next project.  This portion will switch from electrical to mechanical technique.  Good thing I do this kind of stuff in the real world!

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ARD MODEL 230A BACK STORY

ICOM ARD BrochureThrough the magic of the internet, namely Google, I’ve been able to learn a little more about the Advanced Radio Devices Model 230A.  I’ve been in contact via email with the ham that owned ARD and he’s been kind enough to share with me many details about the company.  So now I’ll be able to share the info with the rest of the ham community.

Advanced Radio Devices was owned by Bob Sullivan W0YVA.  It grew out of a previous company, Technical Services and Manufacturing.  Originally they provided product design and manufacturing services.  The lead engineer was Chuck White.  I don’t know if he was a ham or not.  They later changed the name after investigating HF amplifier design and production.  The company was in business from the 1980’s into the mid 1990’s.ARD dealer listing

Various models of amplifier were produced by ARD.  Models 230A, 230AX, 230C, 230CX were sold both stateside and export, as well as government contract sales.  The two models of chief interest to amateurs would be the 230A with two 3CX800 tubes for 1500 watts continuous output and the 230C with three 3CX800’s for 2250 watts continuous output.  There aren’t any specific sales records, but Bob believes they sold about 100 230A’s and maybe only 25 230C’s!

By 1989 they had established a world wide dealer network for the amp.  Many of these are big name companies still in business.

Dayton AdvertThey also had a booth at the Dayton Hamvention that same year.  With the exception of military equipment, this was the only truly automatic linear amp on the market.  This was an opportunity to present the revolutionary new amplifier to the ham community.  So much so, that it even attracted the attention of ICOM!  There were several months of company negotiations which were to culminate in the production of a genuine ICOM badged super amp.  In the end, ICOM backed out which probably led to the eventual demise of ARD, being it was a pretty small company.

Dayton Hamvention Booth 1989

Dayton Hamvention Booth 1989

I’m happy to report that Bob Sullivan is still an active ham.  His QRZ.com bio page is quite nice and informative.  You can view it here.  He also has a personal webpage which showcases his love of ham radio as well as other interesting hobbies.  Click here for Bob’s personal page.  A lot of good information here for the ham enthusiast.  You can view his rundown on the ARD-230 from here.  Next step for me is to order parts and get busy with the soldering iron.  All for now.

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ARD MODEL 230 VIDEO OVERVIEW

I just finished making a video that shows the ARD 230A on the bench.  I go over some of the basics about the amp and a little history.  I’m still doing research and will eventually devote a whole page here on the blog site to this rare beast of QRO proportions.  Next step is to start the tear down and order parts.  Hope you all find this informative.

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ADVANCED RADIO DEVICES ARD-230A AMPLIFIER

 

OLYMPUS DIGITAL CAMERAOLYMPUS DIGITAL CAMERA

Several years ago in the Dayton Hamvention fleamarket this beast of an amplifier revealed itself.  I’d only ever seen one other example of this technical marvels of the 1980’s; and oddly enough, it resides in my own county.  Neighboring ham and fellow ARD-230A owner Steve W9RO nicknamed the beast “R2D2” because of it’s unique commercial design features.  Alas, the siren song could not be overcome.  Hamfest buddy Nick N9SJA and I each pooled our funds and gambled $1000 on this mysterious amp.  Click below to see a neat, period advertisement from the February 1988 issue of 73 Magazine.

ARD 230 amp-Feb1988-page102-73magazine

 

OLYMPUS DIGITAL CAMERA

So here’s a quick rundown on the basic specs of the ARD-230.  It’s a remotely operated linear amplifier capable of operation on any band from 160m through 10m.  The RF deck is integral to the power supply and contains a pair of Eimec 3CX800 metal ceramic tubes.  The power supply provides 2300V DC at around 1.5A max.  This combination will make 1500W at full duty cycle continuous operation with around 60W drive from the exciter.  It’s operated by the remote control head that can be located up to twenty feet away.  You can choose from fullyOLYMPUS DIGITAL CAMERA automatic operation, semi automatic operation or manual operation modes.  It’s capable of sensing the frequency of operation and changing bands automatically, while adjusting the Tune and Load capacitors for ideal settings.  During operation it can also sense various abnormalities such as excessive plate or grid currents, or low air flow, and alert the operator or entirely lock out the amplifier for protection.

OLYMPUS DIGITAL CAMERAMuch to our dismay the amp proved to be in ill health.  Initial testing rewarded us with many tripped breakers.  Further inspection found some damage to the undercarriage.  Possibly the result of a drop?  After some weeks of gentle coaxing I was able to fire it up without tripping breakers.  Perhaps the HV power supply caps were re-forming?  Now I could apply some low drive and see if it would truly amplify.  Fully and semi auto modes proved unsuccessful.  Manual mode was slightly better but more discoveries were to come.  Further inspection revealed the proverbial golden screwdriver had been used quite liberally on this device.  The motor driven air variable caps where totally out of synch, and didn’t even come close to indexing with the 0-180 degree indicators on the display.  The shaft couplers from motor to drive, and drive OLYMPUS DIGITAL CAMERAto cap were a mess.  The only redeeming values so far have been the beefy power supply with a massive Peter Dahl transformer at its heart and a very clean RF deck.  The 3CX800 triodes were still in good shape, too.  This is an instance in which the sum of the parts is actually more valuable than the whole.  It’s worth more money in pieces!  But what a shame to hack the beast…a very unique and capable amp that seems to be fairly rare and something of an enigma for hams.  And so it’s lived for several years now–cast away in a dark corner of the ham shack and awaiting its turn on the workbench.

OLYMPUS DIGITAL CAMERA

While I haven’t been working on the amp too much, I have had a pretty good opportunity to research it.  It’s not without flaws, but they’re few in number.  The components are of high quality and it’s even capable of QSK CW operation due the the vacuum relays, for the so inclined.  As I understand it, ARD was supposed to produce this amp and badge it for Icom, as a part of their product lineup.  In the end, Icom backed out of the deal.  What a difference that might have made!

Google searches have turned up tiny bits of information but a lot of it is dated material from old listserv sites and such.  I’d be curious to the know the total number produced by ARD.  I’d be even more curious to know how many are still in operation.  My goal is to refurbish this amp and enjoy a little unashamed QRO operation.  This amp is just plain hamsexy!  It’s capable of mondo power output if desired.  I don’t think it’ll win a key down contest with a Henry 4K Ultra, but we only get 1500W PEP, right?  An ARRL search turned up a couple documents from 1988, ’89.  I’ve included them below if you’re interested.  The first is a product announcement for the amp and the second is their product review.  They found it quite capable and were very impressed.  Keep in mind that this was a time when a powerful computer of the day had less performance than my smart phone!  A little Z80 processor was the brains of the machine.  Only a serious ham would’ve had the cash to own one of these.  Suggested list price was anywhere from $3500-5500!  I think this blog will become a series as I go through the necessary repairs to return R2D2 back to its former glory.  Perhaps I’ll even post some videos on my Youtube channel.  Hope you enjoy.

QST_Apr_1988_p25 ARD230

QST_May_1989_p43-46 ARD230

Categories: Amateur Radio, Projects | Tags: , , , , , , | 3 Comments

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