Original 3-500Z tubes are very hard to find today and may be risky due to their age. These capacitors were less than $3 each, but tax and shipping added some cost. The HV supply showed about 600 VDC on the meter. There was evidence of arcing on the side of at least one of these resistors. Restoration spanned several months and probably 25 to 30 hours of work and included a thorough cleaning, rebuilding the HV capacitor bank, replacing 1 tube, and adding Soft-Start and Soft-Key upgrade kits. Brilliant applies to both the overhaul, and the documentation I just read. This took several hours of careful mechanical and solder work. After the cost of the amplifier, the Harbach kits, and several orders from Mouser, I believe I am in to the project for just under $1,000. This is the manuals page for Heathkit. I put amp on the shelf for a few months and was in complete denial trying to justify that it was just an old electrolytic gone west. Testing showed that the HV diodes and the capacitor bank bleeder resistors appeared OK, but the HV capacitors appeared damaged with small cracks in the base, and the three 4.7 Mohm resistors in series in the HV measurement circuit were very badly out of spec. It was the first, reasonably priced, intelligently designed, SSB-CW, HF-amplifier that was sold to the amateur radio community. To build the largest and most complete Amateur Radio community site on the Internet - a "portal" that hams think of as the first place to go for information, to exchange ideas, and be part of whats happening with ham radio on the Internet. All in all a very satisfying project and well worth while. Let us know what you traded it for and help other ham operators! Then I spent 15 minutes pondering before hitting the switch. But inrush current can also negatively affect hard to find (and expensive) components such as Heathkit on/off and band switches, so its well worth the $35 to install this board. Not with teh 220. This page is a collection of Copyright 1988, 2014 by James W. Hebert. 6) I removed the metal rod between the HV feedthrough insulator and the RFC feeding the main RF choke and substituted a junkbox surplus steatite insulator and placed a couple of fuse clips across it which allowed me to insert a 1A fuse in the B+ supply to the plates. The next steps were to install the Soft-Start and Soft-Key upgrade kits by Harbach for the SB-220. I measured the dimensions of the board and location of its mounting holes, designed a 1mm thick platform in Tinkercad, and 3d printed it using PETG. I also could have added a toggle switch to the faceplate of the amplifier, but I wasnt comfortable drilling new holes in what is a nice original faceplate. There was a uniform amount of dust on all components, but this just meant that the amplifier hadnt been messed with much lately. The RM-220 rectifier/meter board replaces the stock power board and is an improved design that also includes meter protection. Only run it 4200 on the plates and can get full 2200 out but I dont run it anywhere near that ! It was time to start putting the amplifier back together. Not a single component lead had been clipped after soldering. SB-220 Schematic.zip: 354 Kbytes: SB-221 Addendum part 1 and 2.zip: 1.750 Kbytes: SB-230 Manual.zip: 24.575 Kbytes: SB-230 Schematic.zip: 338 Kbytes: SB-240 Schematic . The next step was to actually apply RF drive and test the SB-220 under normal operating conditions. I had the bones of an Amp Supply LK-500 that I bought years ago with the intention of building (another) 6M amp. The model 2kW Linear Amplifier is part of the collections of the following members. . By gently rocking the wrench back and forth the glue was broken without damage to the slug, and then I rotated it +- about 3 turns to clean out the glue. The SB-220 is one of the classic amps. The load is switched out of the circuit by the relays a few milliseconds later.. by Paul B. Peters, Little did I know that I was signing myself up for an entire day of work for this part of the job. The guts of the SB-220 appeared fine at first. 73s. In fact, they did such a good job that I used almost an entire spool of solder wick getting the grid circuitry removed from the terminals and ground lugs. Other solid-state transceivers likely use relays or open collector transistors of similar ratings for amplifier control. Because of this, special care is needed if the SB-220 is to be used with solid-state transceivers. I used the same 18 gauge solid copper wire for grounding that I used to build the new parasitic suppressors for the tubes.
And finally, if you find an old beat up tube amplifier for a good price, take it home and restore it before somebody else does. Click on the schematic thumbnail to request the schematic as a free document. Last modified I mounted the box to the side of the SB-220 with a strip of velcro, so there is no permanent defacement of the amp or enclosure. Technical Specifications Number of Tubes 2 Valves / Tubes 3-500Z 3-500Z Main principle Radio Frequency Amplification only Wave bands Wave Bands given in the notes. HP-23, SB-401: Power transformer (single primary)-54-144: HP-13: Inverter transformer-54-149: GR-180: Power transformer-54-151: SB-200, SB-201: Power transformer-54-168: SB-610: Power transformer-54-177: IM-25: Power transformer-54-179: HW-16, SB-400, SB-401: Power transformer-54-181: AR-15: Power transformer-54-182: SB-610, SB-620: Power . ), Some of the other circuitry improvements have been to get rid of all the garbage grid circuitry and ground them direct, Vacuum relay antenna switching for QSK, Step start power up (using the old antenna relay!)
Heathkit Ham Radio Amplifier 2kw SB-221 SB-220 - Shoppok The SB-230 was sold in kit form by Heathkit from 1974 to 1978. Some folks who don't know amps say, this amp is old, prefer something newer, blah blah blah. SB-220: 2KW Linear Amplifier Complete manual : 61.5 MB: SB-221 . Code = Picture = Specifications - = No data: Model Number . I read the whole thing tonight.
Heathkit Schematic and Manual Archive | Vintage Radio Info I shipped the amp to Cal at hamradiorepair.com in Carrollton, TX, who did all the current Harbach mods, installed new finals from RF Parts, new parasitic suppressors (available on eBay from a ham in France), and a standby switch which is something Heathkit omitted from amps of that vintage.
Heathkit SB-220 - KA2C Includes step-by-step instructions and a list of necessary tools and parts. Power type and voltage Alternating Current supply (AC) / 120; 240 Volt Loudspeaker - - No sound reproduction output. While the Harbach soft key board came with a lug to mount the board to the amplifier chassis, the Harbach soft start board did not, and I didnt have anything similar to mount it. This was a simple job, but I did not realize that I would be removing that diode during the install of the Harbach soft key board in the near future anyway. A cousin, who hadn't been active on the ham bands for a long time, recently gave me his factory made SB-220 which had been wrapped up under his desk for many years. I can easily produce 1100+ on 120v with about 80 watts of drive. Using the SB-101 for RF input, I slowly brought up the RF input to the SB-220, tuning both units at 25 to 50% RF power levels before going to full power. the ensuing years, the SB-220, which has some excellent design features, has SB-301 Partial Manual with schematic.
Heathkit Sb 220 for sale | eBay Basically you don't need a "big bang" in the middle of a ferocious run on 20M. Then the three 4.7 Mohm resistors on the HV diode PCB were replaced with units obtained on Ebay. Two diodes were wired in series on the transmit relay at this point as well. Product is not in production. write to the Forums Manager. I bought an SB220 about 3 years ago after being impressed at how good they sounded on the air. Unfortunately one of the tubes showed that gas had leaked into the tube, and it clearly would not work and would short the HV if attempted, but one tube appeared fine.
Heathkit SB 230 - eHam.net IG-18 Modifications Copyright 1970 by Edward T. Dell Jr. Tube Data for IT-17, IT-21 and IT-3117 Tube Testers, Low-Input Stereo Hi-Fi Booster (Preamplifier). 3) When it is Zero, check with a screwdriver across the chassis to the plate caps. The next step was to trigger the TX/RX relay after returning the CW/Tune mode, and the plate current showed about 60 ma as expected which suggested the tube was good. I got a SB-220 years ago from a friend. to a product via email. Regardless, their age could not be confirmed so they would be replaced. Purchased an SB220 off of Ebay from a reputable seller. Lethal voltages exist in the SB-220.) But heck, plays great all the time. The HV transformer has a Hypersil core. Only after removing the rotating blades from the capacitor did the extent of damage become apparent. As proof, I found the word deformed where, I believe, you meant reformed. You might notice that this is wired improperly in the photo. It was designed in an era when most amateur equipment was based on vacuum-tube technology. Understand SB101 complete assembly manual. intelligently designed, SSB-CW, HF-amplifier that was sold to the amateur radio First, I had to get the boards mounted in place. . Digging in, a few things jumped out at me. I have had to go back to ACOM technical repeatedly over nit issues with what could have been a great amp for me. It appears RF-Parts is about the only USA source of Chinese manufactured 3-500Z tubes, and they are priced at over $200 each. It has been reassembled from my copy (saved when the site was live) together with files retrieved from http://web.archive.org and other resources. I got the SB-220 back today and am extremely pleased with both its on air performance and Cal's fine rehab work. Heathkit Ham Equipment Matrix. I also installed a 150 ohm 25w glitch resistor on the HV connection to the tubes, which is an additional protection in case of filament to grid shorts. The finals were gassy and arced internally about 5 seconds after we took it out of retirement, which of course smoked a few components. (65 pages) Amplifier Heathkit Heathkit SP-2 Schematic Diagram. Both transformers also appeared original and in good shape. After returning the slug to its original position, I tested 40 meter power again, and then powered the unit off (and unplugged it) several times while moving the slug 1/2 to 1 turn per cycle to safely optimize the circuit. SOUNDS BROKEN. This resistor must be changed due to a change in coil resistance of the . Replaces SB-200 - no 10 meter---78: 83: SB-220: Amplifier: 80-10 2KW PEP 1KW CW--BAMA: 70: 78: SB-221: Amplifier: 80-15 2KW PEP 1KW CW--BAMA: 78: 83: SB-230: Amplifier: 80-15 1200 PEP 600 CW . Antique Radio Restoration RCA Victor Model 3-X-521, Heathkit SB-220 Restoration and Modification. A note on disassembly of the SB220: It is time consuming. This project involves a management team of volunteers who each take a topic of interest and manage it with passion. At first glance, or to the untrained eye, everything looks fine in the tube chamber. It wasnt. Material Metal case from Radiomuseum.org Quoting Harbach Electronics: The SS-221 limits inrush current during amplifier start-up by placing a small resistive load in series with the AC mains. I finally grew a pair and hit the switch, and much to my surprise, the fan spun up, the meters lit, and the HV meter shot up to 3100v. The fan was frozen.
Heathkit SB-220 & SB-221 | Product categories - Harbach Electronics These would not be installed until the tubes were back in their sockets, so I set them aside. Two of the relays are Jennings RJ series available from Maxgain systems and the third small reed relay switches the 120VDC bias to the filament/cathode on standby. Once the chassis is removed from this outer shell, the high voltage area of the amp is still sealed behind a panel with at least 12 screws. The leads of the resistor were just wrapped around the bent wire, free to slide around. The meter's plastic case inside the chassis was partially melted and deformed . or Best Offer.
Heathkit Ham Equipment Matrix - Nostalgic Kits Central Pads are provided for voltage doubler or conventional rectifier use. My next step was to flip the amplifier over and begin removing the stock grid circuitry on the tube sockets. Since the amp has been extensively reworked with vacuum relay switching etc, I had nothing to lose and decided to take my 4 grinder and mount the big 20 lb toroid into the chassis with a bit sticking out the back which will be covered with a safety cover plate. 700 files available. The individual who assembled this did a fantastic job. Show contact information Figure 1B shows my solution to this problem. If you have comments, questions, or problems with this procedure please After obtaining the new tube, and testing the filament, I connected the HV to the plate, and it appeared OK. . This is the end, right? You can't compare amps like that. Regrettably, the amplifier kit is no longer being manufactured. Testing TX mode with the TX/RX relay showed a total plate current of about 120 ma as expected, and that in spite of using non-matched tubes from different manufacturers, the idle plate currents of the 2 tubes were reasonably matched.
This also foreshadows the re-assembly of the SB-220. This is brilliant work. The Heathkit SB-200 is an iconic amateur radio linear amplifier first introduced in 1964 with the last unit delivered in 1983 as the SB-201 (minus 10M) - a phenomenal 19 year production run. Dimensions (WHD) 15 x 6.75 x 14 inch / 381 x 171 x 356 mm. SB220, money well spent. And the cost was $99.00 about one third the price of a Dahl replacement. A little history, condensed: This switch is a throwback to the days when the FCC required 1KW max input power on radio amplifiers for some reason (this was before my time so Im murky on the details). It is durable, tubes are reasonably inexpensive and available, and it performs for decades. Heathkit Brand, 2kW Linear Amplifier SB-220 (3), Heathkit Brand, 2kW Linear Amplifier SB-220 (2), Heathkit Brand, 2kW Linear Amplifier SB-220 (1). Model page created by a member from D. See "Data change" for further contributors. Also, these feet were a little high and I was concerned about the amp fitting into my radio rack with enough room for my tuner above it.
Heathkit SB-220 Restoration and Modification - KN3B.com Would recommend. A total of 8 capacitors are needed. I replaced the original diodes with 1N5408 3A diodes. Lots of big words were uttered. The entire chassis lives within a single piece outer shell, and removing the chassis requires orienting the amplifier in several different positions. If there is a flash and a bang, count yourself lucky to be alive and go back to step 1 and 2!!!!!!!!! Couldn't be more pleased. Heathkit SB-220 Restored SB-220 RF amplifier with SB-101 transceiver - The SB-220 appeared in good physical condition when initially obtained, but had not been used in about 20 years and was a bit dirty, so significant restoration would be needed.
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