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136
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eHam Forums / Misc / RE: Radio repair
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on: March 24, 2013, 07:23:47 AM
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By DOA you mean completely dead as if power is missing? YES, Dead On Arrival (DOA). For those eBay, Craigslist and Internet Swap purchases, I also include No Transmit/Receive and when radio is sold as a parts radio (previously badly hacked). == FLIPPING and STRIPPING is a new aspect -- that has more in common with Automotive & Truck Chop Shops. |
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137
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eHam Forums / Elmers / RE: Speaker for hf use
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on: March 24, 2013, 07:06:37 AM
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Some time ago it was a ham operator who was using an outdoor speaker and
said that was amazing for the sound that produce in ssb and cw and the best of all
the price was real cheap.i can recall his call letters but if anyone could tell me about The Motorola Motrac metal speakers for mobile installs are excellent for communications. I routinely find "beat up" ones at hamfests or $5. Clean-up, a new cord, and some fresh paint make them presentable in the radio shack. I have one hung on my workbench, for speaker connections to radios on the workbench. |
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138
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eHam Forums / Mods And Repairs / RE: Kenwood TR-7400A Power Cord
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on: March 24, 2013, 06:36:56 AM
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If you end up getting more involved in the hobby I would recommend buying something newer with memories and built in PL. Mark, Ironically, many of the new dual-band FM transceivers have POOR selectivity in The INTERMOD ALLEYS of city and urban areas. Most new ones do not handle skyscraper alleys, interstate RF around weight stations and some toll-road transponder systems.The Kenwood TR-7400 as well as Icom radios from this 1970s era are very well built (more like LMR units). w9gb |
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140
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eHam Forums / Misc / RE: Radio repair
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on: March 22, 2013, 10:28:08 PM
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I have a yaesu FT-7100 that i picked up off a fellow ham. It was DOA. The seller made it clear in the listing an took the gamble and bought it, figuring it would be a simple fix. Lee -- You need to adjust your $$ betting methods on newer DOA radios. 1. Easy fixes for modern radios designed/manufactured over past 15 to 20 years are becoming rare. Almost all use SMT components and with low failure rates. Just no longer a good bet for buyer.2. Component level repair by Major retailers and mfg. stopped at end of 20th century (1999/2000). I watched whole shops of test equipment sold as surplus and techs retired or laid off. 3. Parts obsolescence is a growing problem, especially with Asian mfg. This is why End of Service occurs as soon after end of production, as permitted by consumer protection laws of that country. 4. LOOK at eBay in the past 2 years, with their buyer protection. Sellers are now stripping broken radios down to parts/modules, trying to sell parts for more $$. I would suggest Yaesu service first. Check with the eHam.net reviews of 134 repair technicians/service centers. Some only specialize in specific mfg. or models -- often due to parts availability or their mfg. training. http://www.eham.net/reviews/products/26 |
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142
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eHam Forums / Mods And Repairs / RE: ICOM IC-28H PANEL LIGHTS
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on: March 22, 2013, 12:59:59 PM
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I can't quite get a handle if you work for ICOM, or are just knowledgeable on this subject...Have you ever done the replacement yourself. Bob, I have worked on (repair, refurbishment, rebuilds, DIY homebrew) countless radios since 1970 -- when I started high school. After awhile, you can see design patterns (like architecture) by manufacturers (Icom, Yaesu, Kenwood). Just passing on my knowledge -- so you avoid dead-end pursuits. I have probably replaced the bulbs or lithium battery on this model at one time in past (not in past couple of years).== Disassembly of the front panel should be performed when you have time (not a rush job). The lamps and battery were NOT designed for end-user (non-tech) replacement. The Icom IC-28H Service Manual is not clear where the DS2 and DS3 are actually mounted. Page 8-2 (schematic) show both lamps (DS2, DS3) adjacent to the LCD and R3 (photo-resistor for dimming). These two lamps Backlight the LCD screen. They are not shown on page 2-3 (Figure 2-5). On page 5-1, the lower disassembly diagram, do you see the TWO cylinders on the EF Unit PCB, B-1138B ? They are not identified, but likely represent the DS2 and DS3 locations. They are in right location to serve as LCD back lighting. Look at the EH Unit - Board Layout on page 7-1. You will see the large surface mount IC in the center of the EH board. The lamps should be located behind the LCD (for backlighting) mounted on the other side of that EH Unit. Icom only shows one-side of that double-sided EH Unit board on pages 2-3 and 7-1 !== Everything about incandescent lamps. http://lamptronix.thomasnet.com/Asset/Lamptronix-2-8.pdfBTW --- If you have this open, you might as well replace the (BT1) lithium cell: BR-2032/1T2 Icom and Digi-Key stock those replacements. w9gb |
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143
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eHam Forums / Elmers / RE: Intimidated
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on: March 22, 2013, 12:40:42 PM
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There seems to be a disdain for new Hams among those who have many years of experience. My fear is I will offend someone out there while I get into the HF learning curve. How do I get going without upsetting folks on the air? Tim -- Just be truthful, to yourself and representations of what you know -- and what you don't know. After 40 years in amateur radio, this is not new (despite what you may read). When I started in late 1960s, there were some retired (65+) amateurs who started as teenagers when radio was NEW after World War I. They were a rare breed -- they DIY built everything.Some were a bit grumpy with those in the Baby Boom generation that said "Just Tell Me The Answer!". That attitude still exits today with new and experienced amateurs. I would argue that is the normal operating mode. One characteristic that is "new" (my observations) -- is an anger (almost violent reaction), in being corrected for an incorrect understand (or wrong conclusion), even when the industry standards are presented. This is how learning, teaching, and continuing education occurs. In many instances, it is an issue or point of Personal Safety (HV, electrical wiring, tower erection/climbing).IF you wanted to LEARN, as an Old World Apprentice to a Master -- the WW1 generation loved to teach and a sharp student learned volumes. |
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145
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eHam Forums / Misc / RE: News Flash: comment on recent events
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on: March 22, 2013, 08:13:02 AM
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I believe that Vatican City is on the DXCC roll. Prefix is HV and it is on the dxcc most wanted list at 113. Yes. I heard them a couple of years ago on 15 meters (nice signal), but the Pile-Up happened quickly and I never made a QSO before 15 meter propagation changed. Still on my list to work. |
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147
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eHam Forums / Mods And Repairs / RE: ICOM IC-28H PANEL LIGHTS
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on: March 21, 2013, 07:35:42 PM
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Bob - Turn to Page 11-2 (Parts List) : , 2 lamps (DS2, DS3) Disassembly of Front Panel, Page 5-1. Lamps on EF Unit. Icom IC-28H Service Manual (PDF) http://www.ko4bb.com/Manuals/ICOM/IC-28A_E_H_Service_Manual.pdfEF Unit (Front Panel) DS1 - LCD - LP234A DS2 - Lamp - HRS-7219A-G40 DS3 - Lamp - HRS-7219A-G40 DS4 - LED - GL9ND2 In the Icom IC-28H these 12 V lamps are powered from a regulated 11.5 V rail.
This radio also features a photo-resistor for lamp intensity adjustment.Icom loved to use the HRS-7219A lamp, which is widely available in Eastern Asia. http://radionut53.tripod.com/id375.htmlSpecifications: T-3.0mm (T-1) 12 Volt, 60 mA bulb (HRS-7219A) Design life is 5,000 hours (DC); 10,000 hours (AC) A suitable Grain of Wheat bulb (hobby shops) can be used. BTW, HRS-3110A is the 14 Volt version if this lamp. JAN SONS ELECTRONIC INDUSTRIAL, CO. LTD. Address：No.23, Puding Rd., East Dist., Hsinchu City 300, Taiwan (R.O.C.) Tel：03-5772197 Fax：03-5778525、 03-5786230 E-MAIL：js_sales@jansons.com.tw E-MAIL：al_sales@ally-opto.com.tw JAN SONS Miniature & Sub-Miniature Lamps http://www.jansons.com.tw/product.php?type=11=== The Parts Department provides pricing, availability and sales information on Icom America product parts. Parts and Manuals Replacement parts, service manuals, and instruction manuals may be ordered from your local authorized Icom America dealer or from Icom America's Parts Department. Icom America Parts Department 2380 116th Ave NE Bellevue, WA 98004 (800) 346-0495 Monday - Friday, 8:00 AM-5:00 PM Pacific Time Contact Us Via Email You may contact the Parts department using our online email form. http://www.icomamerica.com/en/contac...ContactType=PA |
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148
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eHam Forums / HomeBrew / RE: Hand winding coils for L-match
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on: March 21, 2013, 02:29:35 PM
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Homebrew Your Own Inductors! Can’t find the inductors you need for an antenna, a tuner or amplifier? Build your own—it’s easy! By Robert H. Johns, W3JIP, QST, Aug 1997, p 35. http://www.arrl.org/files/file/Technology/tis/info/pdf/9708033.pdfhttp://www.learningace.com/doc/1355405/7d1e13a1ceed01534f0619ac6aa6d991/windinductorsRobert H. Johns, W3JIP, “Coaxial Cable Antenna Traps,” QST, May 1981, pp 15-17. Robert H. Johns, W3JIP, “Dual-Frequency Antenna Traps,” QST, Nov 1983, pp 27-30. Robert H. Johns, W3JIP, “Home-Brewing Large Antenna Coils,” QST, Oct 1992, pp 45-49. == SINGLE LAYER AIR COIL WINDING FORMULA AND Q FACTOR (CWS Bytemark) http://s.eeweb.com/members/earl_albin/answers/1352787787-Air-Coil-Inductors-1.pdf |
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150
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eHam Forums / Mods And Repairs / RE: Kenwood TR-7400A Power Cord
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on: March 20, 2013, 06:35:30 PM
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Second Note: Does this TR-7400A have a CTCSS encoder installed for FM repeater usage? http://www.universal-radio.com/catalog/fm_txvrs/tr7400a.htmlComSpec SS-64 is an after-market add-on. ComSpec has been offering these add-on for the commercial land-mobile,
government/military, and amateur users since 1970.The CTCSS boards from ComSpec are very inexpensive ($28.95 USD) and I routinely see these used at hamfests/flea markets for a few almost same as new! http://www.com-spec.com/ss64.htmCOM-SPEC Detailed Directions for SS-64 installation in the Kenwood TR-7400A http://www.com-spec.com/insheet/tr7400a.pdfThe most common place to connect the SS-64 output is just prior to the modulation stage of the FM transmitter.
Typical connection would be to the connections would be to the center of the deviation pot. to the varactor diode in the modulator circuit, or to the manufacturer’s suggested connection point.
This connection point can vary from radio to radio.
DO NOT connect the SS-64 CTCSS Output to the Microphone Input as the microphone audio stages will distort and attenuate (filter out) the CTCSS signal. |
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