Heathkit I0-1128 Users Manual Pdf

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  1. Heathkit I0-1128 Users Manual Pdf Download
  2. Heathkit Io-12 Manual
N0GVRating: 2021-03-02
Best Amp out there - some may be as good, but none better!Time Owned: more than 12 months.
The SB-220 is one of the classic amps. It is durable, tubes are reasonably inexpensive and available, and it performs for decades.
I have had mine, bought used about 20 years ago, in service with the same tubes for that entire time. When I bought it, it was already over 20 years old. It will be 50 years old this year as near as I can tell. It still works, breaks pile ups with the best of them and gives the room a soft warm glow.
If you haven't used it for a few years use the exhaust of a shop vac to spin up the fan for a few minutes before powering it up. That will get the fan turning and when you fire it up it will continue to turn nicely. Let it idle for a couple of hours to reform the capacitors and it will be ready to chug along for another decade or three.
Great amp and well worth three times the price! If 1200 Watts doesn't get the job done, trust me, 1500 Watts won't do it either!
KB9FMVRating: 2021-02-14
BEST AMP FOR THE MONEY 10 STARSTime Owned: more than 12 months.
Own the Heathkit SB 221 did the harbach mods and now run out board transformer with 4500 volts on the plates! Only run it 4200 on the plates and can get full 2200 out but I dont run it anywhere near that ! This is one of 6 I have owned in a number of years and have to say for the money these amps go for well worth it for a pair of 3-500z's Grab one if you can worth the rebuild ! GREAT AMP!
W0BKRRating: 2021-02-02
Great Amp, yes, even todayTime Owned: more than 12 months.
Had a couple of these 220's over time and still have one. Never fails, very reliable. Some folks who don't know amps say, this amp is old, prefer something newer, blah blah blah. I have an ACOM that I have frequent issues with. Not with teh 220. You can't compare amps like that. The build on mine is great and even if it wasn't you can easily rectify it without great skills. I have had to go back to ACOM technical repeatedly over nit issues with what could have been a great amp for me. SB220, money well spent. Will likely outlive me. A really good amp and just wish it had either 160 meters on it or 6 meters. But heck, plays great all the time.
W5ZYXRating: 2019-05-16
An even better amp with the Harbach modsTime Owned: 0 to 3 months.
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. The finals were gassy and arced internally about 5 seconds after we took it out of retirement, which of course smoked a few components. 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. I got the SB-220 back today and am extremely pleased with both its on air performance and Cal's fine rehab work. I've decided to only load it up to 1 kw out, which should help ensure that the beast keeps on performing for many years to come. My cousin never had a minute's problem with the SB-220 during his several years of use and neither of us were aware of the reputation of the 3-500's to get gassy and spectacularly fail if sitting for a long time without high voltage applied to getter the internal gas build up.
KE5GGYRating: 2018-08-12
So Good I Bought a Second One!Time Owned: more than 12 months.
I bought an SB220 about 3 years ago after being impressed at how good they sounded on the air. I bought the amp from its second owner, who said that the original owner was an engineer who was meticulous about detail when he built the amp from a kit as well as taking care of this amp. The amp was very clean with almost no wear at any place, including the front panel.
I've been using this amp for almost 2 years on the 3.916 nets on 80 meters, where I regularly participate. It puts out around 1,100 watts with around 90 watts of drive and does this all night long.
I really like the small footprint of the SB220 and 221, relative to other amps. I also like the fact that the 3-500Z tubes are readily available at a reasonable cost. And, there are plenty of people around that can work on the amp. I was so impressed with the amp that I bought a second one as a back up. It was also very clean and was a Heathkit 'store built' amp, based on a certification on the back of the amplifier.
If you can find one that's clean, I recommend buying it. If it hasn't had some of the more common and needed updates/mods completed, you'll want to adjust your offer down to account for the upgrade costs. The more common Harbach mods can really make this amp work well for years.
If you have further questions, join us on 3.916 MHz any night between 7-10P Central or email me at ke5ggy at gmail.
N4UERating: 2018-03-22
Fun to 're-do'Time Owned: more than 12 months.
Last year I was in the process of up grading my 6M position. I had the bones of an Amp Supply LK-500 that I bought years ago with the intention of building (another) 6M amp.
I did a WTB ad here and purchased a very nice SB-220 from a local chap for cheap, minus the tubes.
The amp was in very nice shape and I was going to modify it for just 50 MHz. The front panel, knobs were perfect. And NO shipping!!!!
However, after checking the transformer, etc, I decided to do a full rebuild. I disassembled the amp down to every screw and nut. I'm retired and this was a great project. I had a copy of the Manual and started from Page 1. Polished all the aluminum sheet metal (with flat black paint in the RF area!). All the hardware was replaced with SS.
As I rebuilt it, I added the Harbach mods with my own caps. I even added a fan shroud below deck to cool the tube pins. Directly grounded the grids, etc. Added the Harbach HV fuse (no cost), new cover paint, just a fun project.
I had several spare 'older' 3-500Zs from another amp. Even a few 3-400Zs.
Results, a beautiful, classic amp that works perfectly and produces excellent power as indicated by my LP-100.
Great, older boatanchor.
I just shelved it and did the LK-500 amp which with the Peter Dahl transformer and new 3-500Zgs produces GREAT power.
ron
N4UE
HK3PJRating: 2017-05-20
EXCELLENT AMPLIFIERTime Owned: more than 12 months.
20 years ago, I bought a SB 220 used, built in 1980's. I made all the modifications available in Harbach Electronics. 1200 Watts with the original tubes.
No problem at all, low Price, and it is nice.
Now I have an ACOM 2100. I am keeping as a back up.
VK2LCRating: 2017-05-02
built like a tankTime Owned: more than 12 months.
I bought a used SB-220 and it had an interesting history, it spent 12 months on an Antarctic station by an Australian Amateur.
It had most of the mods done, I replaced the tubes with new 3-500zg's replaced the caps and rectifier boards and fitted upgrade suppressors. It had a non genuine plate voltage meter but I found a pair on Ebay so it is now original in looks. It idles along at 750W with 50W in so I don't drive it hard as the Australian maximum is 400W.
I replaced the caps because I figured 40 years for high voltage caps is long enough and Harbach Electronics make an excellent kit for caps and diodes.
Machlett Tubes from Ebay are quite reasonably priced and mine had original Eimac tubes which were getting a bit on and not quite up to the power. I recommend doing Harbach upgrades as it gives it a new lease on life especially the soft keying so it runs with new transceivers.
If you can find a good one, grab it. Might be 40 years old but a set of caps, diodes and tubes with a couple of mods and you have an amp that is well made and performs like the best
W1UFLRating: 2016-07-11
Built like a tankTime Owned: 3 to 6 months.
Purchased an SB220 off of Ebay from a reputable seller. They produced a video showing all bands into a dummy load which allowed me to watch the tune process and the grid and plate's on the various bands. It had the original Eimac tubes. I replaced both with 3yr warranty RF Parts 3-500zg's. I will cycle the Eimac's in occasionally to help prevent gassing. I can easily produce 1100+ on 120v with about 80 watts of drive. I usually run about 70-75 in and easily cruise at 1100w. It has a few upgrades, new caps, soft start, soft key, parasitic suppressors. Couldn't be more pleased. I owned one back in the early 2000's and when I saw the opportunity at the price I was comfortable with, I grabbed it. The individual who assembled this did a fantastic job. You can't go wrong with an SB220. For efficiency I still think the best bang for the buck is a single 3-500 setup, such as my SB-1000, another masterpiece!
N8MUSRating: 2014-12-14
Original owner K8UATime Owned: more than 12 months.
I am proud 2nd owner of a beautiful SB-220 originally meticulously assembled by Norm Mendendorp K8UA. Norm is now SK and I wanted post this review of his amp.
I purchased this back in 2006 from Norm, he had not used it in some years. Still is was clean inside and out and looked like new. I did the usual start up procedure for an amp not used in a long time. Everything was working and output was at spec. Interior build quality was amazing. It looks factory built. Norm was an electrical engineer and his workmanship is outstanding.
Since the amp worked so well I saw no need to add mods to deviate from what Heath kit originally designed. Then the high voltage started to drop. So purchased new caps, bleeder resistors, rebuilt the filter board, and installed the soft key kit.
Amp is back to full output, I did not buy the expensive caps but caps rated equal to or better and by purchasing the board rebuild parts verses replacing it I saved on that too. (I read all the information I could find first. Both from Harbach as well as Rick Measures. Ended up deciding mostly toward what Rick suggested.)
Though I did not originally assemble the kit it is neat to have a part in keeping this big green machine up and operating as well as making the few small improvements. It makes getting those great reports somehow more satisfying.
I find the layout well done, easy to work on and easy to maintain. Support is available as well as parts are easy to obtain. Lots and lots of information out there on the internet too.
Highly recommend if you can find a decent example to start with.
73
Jon
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Page 65

4

3 ) Connect one end of a 23' length of white

APPROXIMATELY I2- @ IE ALL SUPPLIE®

HEATHKIT -˜9

Detail 17

hookup wire to terminal lug BX (5-2). Route
the wire down across the front opening of
the chassis, then up over the chassis (be-

ward the rear where it will be connected
later.

Cut both leads of a 100 (2 1/2 watt resistor

y L tween the circuit board and front end) to-
? )
I

I

I
A

v
w
I

I

A-. .; New... '_.___.:4.Ww. .

0'

(hrown-black-brown) to 5/ 8- in length. Con-
nectone lead to dial lamp terminal BS (S-l).
fonnect the other lead to ground lug ET
8- 1).

Heathkit

,

l

Ul-˜E: Use extreme caution to avoid applying
excessive amount of heat or tension to lugs
1 and BDZ when soldering, or damage to the

lsstic meter case will result.

) Connect the blue wire, previously installed,
to lug 2 of the meter ED (S-l).

Heathkit io-12 manual

( Ii), Connect one end of a 4' length of white
hookup wire to lug l oi! the meter ED (S-l).
Connect the other end oi this lead to lug 4

Heathkit

j of the AVG switch BC (8-1).

(

) Strip and tin both ends of an 18' length of
.Z-conductor line cord.

Heathkit I0-1128 Users Manual Pdf

) On one and connect one lead to lug 1 of the
VOLUME control switch AU (S-l). Connect
the other lead to lug 2 of the VOLUME
control switch AU (S-l). See Figure 23.
Form the other end of this pair over the
chassis between the front end assembly and

0/ circuit board, as shown in Figure 26.

)

Heathkit I0-1128 Users Manual Pdf Download

Prepare the length of shielded cable as
shown in Detail 1?. Tin the shield pigtails
and the center conductor.

) Refer to Figure 23 and place the end with
1-1/2' of outer insulation removed through
hole BE from the top of the circuit board.
Run the center conductor lead through lug 2
of the phone jack AF and pull the lead
through to the point where the end of the
outer cable insulation is flush with the
top of the board (but not under tension).
Make connection and solder lug 2 (5-1).
Connect the cable shield lead to lug l
of phone jack AF (S-l).

Connect one end of a 1-1/2' length of yel-
low hookup wire to lug 3 of the phone jack
°AF (S-l). Connect the other end of this
lead to the speaker terminal pin (S-l).
See Figure 23.

( ) onnect one end of a 2' length of blue wire
to the AF input terminal pin (S-l). Leave
the other end free for the present.

( ) Run the free end of the blue wire coming
from pin 3 of transistor socket X2 through
grommet A0 and connect to the IF input
transformer terminal on the circuit board
(8-1). See Figure 23.

aEll-54

STRIP ALL WIRES V4' BACK
AND TIN

Users

Detail 18

Heathkit Io-12 Manual

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