Added again:

    I started the above posts before you had the pix available.  Looks correct, and it appears you are using the original Hy-Gain provided balun.  Like Steve said, the Beta match hairpin is bent a bit differently, but that shouldn't matter if it's still the same length.  Could the balun coax (or even feedline)be bad?  (Check for short to ground or contimuity between center conductor on each driven element arm...)
    Can you borrow an antenna analyzer from another ham to check if there is resonance above or below 146 MHz?

Added:

    I know Steve (WIK) gave slightly different recommmendations for the balun lengths.  I took the measurements just now from one of my own baluns.  (Same part # as for your antenna) and measured to the nearest 1/16", so that's what Hy-Gain provides, and how they dress the ends for connection to the antenna.  I suspect using solid poly insulated RG-213/U with the suggested lengths will get you real close to optimum performance.  Although Hy-Gain supplies Belden RG-58A/U for the balun, it's really a poor choice for 2 Meters because of loss.
Keep us informed.

Just a thought:  (Sorry if it sounds too simplistic) but you ARE using the "balun," aren't you?  The balun ia a half electrical wavelength.  Since the antenna is designed for the FM portion of the band, it probably uses a design point of 146 MHz like the other Hy-Gain antennas.

A half wave at 146 MHz is 1.027 Meters, or approximately 40.5 inches.  To get an electrical half wave, you have to know the velocity factor (Vf)of the coax used.  (HY-Gain usually provides RG-58/U for baluns, not the best choice, especially for 2 Meters.)  RG-123/U will have a Vf of 0.66, RG-8X should have a Vf of about 0.82  So you would want a piece of coax that's 33.2 inches long if it's RG-8X, or 26.5" if it's RG-213/U.  According to Hy-Gain directions, cut a piece of RG-213/U coax 30.5" long and bare 2" on each end.  Seperate the shield from the center conductor and remove the insulation from the center conductor about 3/4".  make your connections with thses stripped ends; the shield of both ends of the coax AND the feedline all connect together through the bolt affixing the driven element insulator to the boom.  (Small ring or spade connectors on the ends of the balun and feedline make connections easier...)

    Check the balun you have (if you have it;)it may not be the proper length.  RG-58 cable should have a Vf of 0.66, so it's length would be the same as for RG-213/U.

    Since you bought this at a hamfest, it's presumably used, so it may be missing parts.
    Did you also make sure to polish or burnish the parts of the driven element and boom where electrical contact is made?  You should use steel wool or very fine sandpaper to ensure you have good electrical contact between your feedline conductors and the connection to the elements.  Also, replace any rusty screws, nots, or washers used to make connection to the feedline or driven element.

    Then keep us informed with your progress.  Good luck!

Added:  

    I believe you said you used foam insulated RG-8 type coax for the balun?  That's the problem!  The coax is probably OK, but the length may be wrong.
    The dimensions above are for RG-213/U coax, which has a Vf of 0.66.  YOUR foam insulated coax has a different Vf, but probably somewhere around 0.82.  So your balun electrical length would have to be .82/.66, or 1.24 times as long as for RG-213/U.  The shield-to-shiled length would be about 32.9" long, with an additional 2" on each end bared to provide for connections.

Look at it this way:

    What IS the current rating on the amp for 120 VAC?  Ameritron says 10 Amperes.  Regardless of the capacity of your dedicated line, typical residential wiring is 15 Amperes; on such a line, a 10 Ampere draw will cause lights to dim, and is already using 2/3 of the total capacity of the AC circuit.  But the same occurs inside the amp:  the current draw WILL cause the voltages inside to sag also, so plate voltage will drop somewhat.
    The effect on the amp and other items in the shack will be less if the amp is run off 240 Volts.  And as pointed out, if you are paying an electricial to run a dedicated line, it shouldn't cost significantly more to run 240 V vs. 120 Volts, and your shack WILL be equipped for any other equipment you may wish to add, even a larger amp.  Just have the electrician install more than one 240 V. outlet, in case you ever rearrange your operating position.  (It's happened to the best of us.)

Three thoughts:

1.  If you are paying an electrician to run a dedicated line for the amp, I'd recommend it be a 240 Volt line.  The amp will appreciate it.

2.  While dummy loads such as the MJF oil-filled, or the Heath "Cantenna" can handle a kilowatt of power, that is not a continuous rating; that's for intermittent use at that level.  I believe it's a 10% duty cycle fro the Cantenna; that means if you run it for 1 minute, it needs nine additional minutes to cool down.  Overheating such a dummy load can cause a permanent change in resistance, making it useless as an accurate load of known impedance.

3.  DO NOT use the amp as a a "routine" accessory.  It is NOT always necessary for DX, and FCC rules (as well as "Good Amateur Practice") specify that you use no more power than necessary to make a contact.  If the other station already hears you "5x9," there's no justification for turning on an amp just to be heard "10 or 20 over."  Your neighbors on the band will appreciate it, also.
    If you NEED the amp, use it.  But don't routinely use it every time you hit the PTT button or close the key.

If the amp had presumably normal HV in standby for a 24 Hour period, it's unlikely the capacitors needed "reforming;" if one or more were going to fail, they would most likely have failed early in the resuscitation.
    Obviously, something arced and shorted, and it appears it was related to attempting to bring the amp up to full power.

    First off (sorry if this sounds TOO elementary) unplug the amp, and short the HV caps with clip leads, and leave them shorted while you have dinner, or whatever.  You want to be SURE the HV is completely gone before touching ANYTHING.  Also, do the same for any other electrolytic caps.

    Inspect the filter caps and their circuit board; and test the rectifiers with an ohmmeter.  Then progress to areas that have HV.  Look for a short (dust, deceased insect) in the tuning capacitor(s) or signs of arcing.  
    Are you sure the SWR on your load (hopefully a dummy load) was sufficiently low and your coax cable was intact?  A shorted or open on the coax might explain arcing; once the arc occurs, damage may continue whenever power is applied.

    That's all that instantly comes to mind.  Something arced, and you have to determine where the arc occurred before you can fix the problem.  Good luck, and keep us informed.

Oh, GOOD GRIEF!

    Fuses actually have TWO ratings.  Voltage AND current.

1.  You may use a higher voltage rated fuse anywhere a lower voltage fuse is used, as long as the current rating is the same.  THUS, the Handbook statement that you can use a 1 Amp. 250 Volt fuse in a low voltage (e.g. 12 Volt) circuit in place of a 1 Amp. 32 volt fuse.  You MAY NOT safely use a 1 Amp. 32 Volt fuse in place of a 1 Amp. 250 Volt fuse!

2.  The voltage rating DOES matter.  The fuses are designed to ensure that when a fuse blows, the result will not lead to an arc inside the fuse body.  (600 Volt rated fuses are usually ceramic insulated to withstand the additional heat and stress from the possible higher voltage.

3.  The current rating of a fuse is for AC OR DC.  It does NOT matter.  The "appearance" of a blown fuse tells you nothing about the type of current (AC or DC) going through the fuse, just the AMOUNT OF CURRENT flowing through the fuse when it failed.  A large surge will "vaporize" the fuse element, whether it's AC or DC.  A small amount of overload will often leave much of the element still visible, whether the current was AC or DC.

4.  The fusible element width, etc. is NOT determined by the voltage rating, but by the current rating.  10 Amp fuses will appear similar, whether they are 32 Volt or 250 Volt units.  Low voltage (e.g., 32 volt types used in Automotive applications) will often have thicker or wider, or physically "larger" fusible elements because they typically carry larger CURRENT than 250 volt rated fuses.  Auto (cylindrical type) fuses often go up to 20 or 25 Amps, values not often seen in the 250 Volt variety.  (Think about it:  20 Amperes from the AC line in the U.S. would be protecting 2400 Watts- a rating that meets or exceeds the main circuit breaker of many residential lines. (Usually 15 or 20 Ampere service.)  Yet, 20 Ampere fuses are common in automotive lighting systems, Air conditioning systems, etc.)  

Pure and Simple, lets look at the "Public Notice:"


QUOTE:
"PUBLIC NOTICE

FEDERAL COMMUNICATIONS COMMISSION

1919 M STREET NW

WASHINGTON, D.C. 20554

62882

May 13, 1996


Extended Coverage High Frequency Transceivers

The purpose of this Public Notice is to clarify the commission's Rules regarding equipment that is intended to operate in various radio services in the high frequency radio spectrum, including "10-Meter" Amateur Radio Service (ARS) equipment.

The Commission has noted that a number of transceivers imported as ARS equipment are also capable of transmitting and are being operated in nearby frequency bands allocated to other radio services such as the Private Land Mobile Radio Service, Maritime Services, Auxiliary Broadcast Services, International Broadcasting Services, the Citizens Band Radio Service, and the U.S. Government.
=========

    OK.  Operation of Amateur Radio equipment is NOT permitted to be USED in other services.  No disagrrment there.
=========
QUOTE: "Operation of this equipment causes interference to the authorized users of these frequencies. Some of these transceivers are capable of using output powers or emission types which are not permitted for the radio services listed above and some are capable of transmitting in the radio astronomy band where no two-way radiocommunication is permitted. Some manufacturers are promoting the sale of conversion kits, or have designed their transceivers such that they can easily be modified by the users, to extend the operating frequency range into the frequency bands listed above. In addition, so called "export" radios which are deliberately designed to facilitate this capability are also being imported and marketed.
========

OK, use outside Amateur frequencies is not permitted.  STILL no arguement.
========

QUOTE: "Manufacturers, importer, vendors and users of these transceivers are reminded that transmitters intended for operation on frequencies allocated to any of the FCC authorized radio services listed above, except the ARS, must be type accepted by the Commission for the particular radio service(s) in which they are intended to operate prior to their importation, marketing or use.
===========

OK, the FCC says that (basically) other than Amateur Radios, equipment for other services must be certified before marketing or use IN THOSE SERVICES for which they are intended.  STILL no argument.
============
QUOTE: "The Commission considers that the transceivers discussed above are intended to be operated on frequencies where the use of type accepted equipment is required, because of the simplicity of modifying them to extend their operating frequency range. Transmitters designed and intended for use only in the ARS must comply with the applicable technical standards contained in part 97 of the Commission's Rules but are not required to be type accepted.
============
OK, the FCC considers the radios as requiring certification because they can be easily modified to operate on frequencies where cert. is required.  Amateur equipment doesn't need certification.
===========
Quote: "It is a violation of the Commission's regulations to: (1) import or market a transmitter that is designed or intended to operation frequencies outside of the ARS bands, if it has not be issued a grant of equipment authorization for the radio service(s) in which the transmitter is capable of operating; (2) import, market or operate a transmitter that requires a grant of equipment authorization but for which no grant has been issued; or, (3) transmit on a frequency allocated to a licensed radio service without the appropriate Commission-issued station license.
========
OK, 1.  It's a violation to import or market a radio if it's capable of transmitting outside the Amateur bands and doesn't have certification.
2.  You can't import, market, or operate a transmitter that requires a cert but doesn't have it.  Amateur equipment doesn't require certification!
3.  You can't operate without a license where a license is required, (regardless of equipment used;)   DUH!  Unlicensed operation shouldn't have to be mentioned.
===============
Quote: "Violation of the Commission's regulations will subject manufacturers, importers, vendors and users of this equipment to appropriate criminal penalties as provided for by federal law(s), including fines and/or imprisonment. In addition, the equipment described above can be seized by, and forfeited to, the government.
=================
    That's nothing new.Those that market non-certified radios are in violation of rules.  And it's ALWAYS been a violation to USE non-certified equipment where certified equipment is required.  That means a CB'er using a non-certified radio is in violation and can be subject to fines and equipment seizure.  So would anyone using (transmitting) with even YaeComWood Amateur gear modified to operate outside the Amateur bands.
=================

Quote: "For further information concerning this Public Notice, contact Gary Hendrickson at the FCC Laboratory, 7435 Oakland Mills Road, Columbia, Md. 21046, (301) 362-3043, or E-mail: ghendric@fcc.gov
 ================

    NOw, where does it say it's illegal to use such equipment on Amateur frequencies by a licensed Amateur?
==========
    Here's a quote from another site, with a case reference to the FCC:

"...an Amateur is allowed to use the Amateur portion of an export radio. So that settles the question for good with me.
If anyone would like to verify the answer you can call Diane at 877-480-3201 option #2. The case# for my question is #776635"

JFJ:

    Pure and simple:

    The FCC has decided that certain radios fall under THEIR definition of "CB radio." regardless of how they are described or advertised.  THEIR definition included radios that appear to be Class D CB radios and some that are advertised as "10 Meter" radios.  The FCC's OET (Office of Engineering Technology) has determined that some of the radios, because of ease of modification to cover CB frequencies, fall into a category that the FCC defines as CB radios.
    In order for CB equipment to be MARKETED (sold, leased, advertised for sale or lease, or imported for the purpose of sale or lease) in the U.S., it must have FCC certification (formerly "type acceptance.")
    The FCC has ststed it will NOT grant certification to radios that either exceed CB power limits, or are capable of operating (transmitting) on ANY frequency other than the discrete 40 CB channels.  Since some of the radios can be easily modified to allow more than the CB channels, or the "10 Meter" models can easily be modified to include CB frequencies, they are all lumped into the "CB" definition by the FCC, and will not be certified.  Thus, they can't be marketed in the U.S. by U.S. dealers, whether they are indivuduals in business, or large corporations with multiple sales outlets.  The illegality concerning the radios is in the SALE, not posession or use by Amateurs on Amateur frequencies!

    The FCC has no quarrel with the equipment on a technical standpoint, and indeed, may be perfectly legal for commerce in other countries.  The SOLE REASON for the citations and NAL's involving these radios is for the SALE of such equipment, and to keep such equipment from being used illegally on CB,and Freeband frequencies.

    The FCC has even clarified the matter with letters stating that posession, ownership or use of such radios, by a licensed Amateur ON AMATEUR FREQUENCIES is perfectly LEGAL.  Only on Amateur frequencies.
    If a CB or any radio can be modified to operate on Amateur frequencies, it is legal for an Amateur to use.

   

 KC8VWM on May 29, 2007     ...Honest, down to earth, no BS recommendation?

Loose the export radio equipment from your station.

Nothing impresses an FCC inspector more than the idea of them showing up at your door and seeing an illegal President HR 2510 etc. export radio setup in your ham shack right next to your Yaesu.
=================

    No offense, but that is NOT accurate.
    There is no such thing as an "illegal HR-2510."

    The radios are banned from maeketing (sale, lease, advertising, or importing for the purpose of selling or leasing) to keep them from the illegal "CB" and freeband market.  It is the act of selling, leasing, or otherwise marketing the radios that is illegal, NOT the posession or use on Amateur frequencies.
It is perfectly legal for an Amateur to own and use such a radio ON AMATEUR frequencies, ONLY, but may NOT use the radio on CB frequencies.
    Amateurs may use ANY equipment they wish on Amateur frequencies for which they hold the appropriate class license.  They may MODIFY any equipment to operate on Amateur frequencies.  And that applies to CB radios, whether they are 40 days old, or 40 years old, as well as mil. surplus, and any other type of equipment they may choose.  The ONLY requirements are operation only on Amateur frequencies, and abiding by the Technical standards for spectral purity and harmonic suppression.

    Please don't spread misinformation...

Many current model H-T's have "wide-band" receive, and while they are limited to transmitting on the Amateur frequencies as supplied from the factory, they may very well receive the "CB" frequencies you wish.  You WOULD be able to program non-Amateur frequencies into memory; it's just that the radio wouldn't transmit on those non-Amateur frequencies.  If THAT is what you want, no mod should be required.
    If you want to also transmit outside the Amateur frequency allocation, that would most likely be illegal in your country, even if the frequencies you want to use are for unlicensed operation.
    You WILL have to check closly with the regulations of your own government agency with authority over Telecommunications; the equivalent of our FCC.

No offense, but CB radios aren't Amateur Radios, and your license doesn't cover operation on CB.  (In fact, no license is required for CB.)
     However, if the radio lacks an FCC certification label, it is illegal to operate on the CB channels.
    The amplifier is illegal to use on CB frequencies under ANY circumstances.

    It MAY be possible to modify the radio for operation on the Amateur 10 Meter band, where (as a Tech) you can operate CW and data modes between 28.000 and 28.300 MHz; you may also operate CW or SSB between 28.300 MHz and 28.500 MHz.  Power for Techs (and Novices) on 10 Meters is limited to 200 Watts PEP, and NO other modes or frequencies on 10 Meters are authorized.  Convention is UPPER Sideband on 10 Meters.

Regardless of whether the amp (or any piece of equipment) is used in a moblie or home installation, the correct place for the fuse(s) is as close to the power source as possible.
    Remember (contrary to popular belief) the purpose of fuses is to reduce the possibility of fire in the event of a short circuit.  Protection of equipment (other than by fire) is secondary.

 Unless you are a licensed Amateur, it is illegal to transmit on the Amateur frequencies OR the "CB" frequencies in your country.
=========
    Clarification:  I worded that poorly.

    Unless you are a licensed Amateur, it is illegal to transmit on Amateur frequencies; and more than likely illegal (Amateur license or not) to use modified Amateur equipment on your "CB" frequencies.  An Amateur license (at least in most countries) has no authority over "CB" frequencies.

Homebrew or commercial product?

    The ARRL HB has dimensions only for the 22 and 33 element models.

22 el.:  (on a 1" diameter boom section)

D10=288 mm
D11=286 mm
D12=285 mm
D13=284 mm
D14=283 mm

33 El.  (1 1/8" dia boom section)

D10=290 mm
D11=288 mm
D12=287 mm
D13=286 mm
D14=285 mm

    Yagis shorter that the 22 el. design will require slightly different lengths than those given above; typically 2 mm shorter than the free space values.  
   
     I'd interpolate a value from the lengths you already have; D12 is about 1 mm longer than D13, and 1 mm shorter than D11.  At 70 cm, even a "silly millimeter longer" can make a difference!
    In the K1FO designs, each specific boom length/element number Yagi was optimized, and the lengths of specific elements vary with the number of elements and total boom length (as well as boom diameter.)

Good luck.