Heathkit Troubleshooting Tips

Last updated: Saturday, 2 April 2005
I've made some internal changes, but there's been no technical changes to the content since 29 March 1997.


Introduction

From 1973 to 1978, I worked as an electronics technician at the Heathkit Electronics Center (store #45) at 9207 Maple Street in Omaha, Nebraska. It was the first "mini-store" that Heath Company tried. A mini-store is a Heath store with three or less employees. A full-size Heath store usually had eight or more employees. People in those stores could be in sales or a specialized area of service.

In Heath's first mini-store, the three of us (that includes the manager) did both sales and service. Since I was more of a "techie" than the other two, I spent most of my time repairing the products. (The other employee, Vern, spent his time between TV repair and sales. The manager, Joe, managed.)

Because we didn't have enough people to specialize, I ended up working on a wide variety of Heath products. To help me keep track of the problems associated with each product, I kept notes in a little black notebook I purchased from Lefax®.

When I transferred to Michigan, I transcribed those notes to an H8 cassette and left a copy in Omaha for my successor. I was told that it came in handy several times. Over the years, the tape had gotten lost. However, I've managed to hang onto the original document and have laboriously transcribed it again--this time for the Web.

Some words of caution: It's been a long time since I've serviced Heath products and have forgotten a lot of the details of some of the circuits described here. Though I've cleaned up some of the grammer and spelling, I've left the original notes intact if I could no longer recall what the note was about. The original writing may make sense to an experienced technician still servicing electronics.
Some of the fixes listed in here weren't authorized by Heath Company and I doubt that they or anybody else will support them. They were fixes that got the unit back to working within specifications and back to the customer in a timely manner.

Also, many of these fixes are model number specific. What would work for an SB-104, for example, would not work for an SB-104A.

So here's the

Legal Copout

Don't attempt to use these service procedures unless you have a strong background in electronics and can analyze the circuitry. (I may have made some typographical errors when transcribing this information and missed them during proofreading.) A strong background in electronics would include attending a two-year technical school, three years training and experience with military digital electronics, a couple of mail-order courses in computer and RF communications engineering, a First Class Radiotelephone License with Ship's Radar Endorsement, and CET certification. (What, me brag?)

In other words, don't blame me if applying these troubleshooting tips gets you upset in some form.

With that bit of noise out of the way, here's the notes from my little black book. Have fun.

(By the way, I didn't single-handedly come up with all these ideas. Many were suggested or inspired by others—or are factory-authorized modifications. I just noted them down at the time. I'll try to give credit where credit is due if I can remember who the contributor is.)

--Bill


A


AA-Series Amplifiers

AA-22

AA-29

AD-Series Audio Equipment

AD-17, AD-19, AD-27, and Other Systems w/BSR-500 Changers

Picture of changer mechanism.

AD-17, AD-27

AD-27

AD-110

AJ-Series Tuners

AJ-15

AJ-29

AJ-33

AJ-43D

AM Through AP-Series Audio Equipment

AN-2016

AR-Series Receivers

AR-13

AR-15

AR-29

AR-1500

   Component       DC Volts        P-P RF (10.7 MHz)
   ---------       --------        -----------------
   IC201-3         1.5 V           0.1
   IC201-6         10.7            0.4
   R202                            0.2
   Q201 base       1.0             0.2
   Q201 collector  3.3             0.5
   IC202-1         2.2             0.5
   IC202-5         7.2             0.9
   R210                            0.3
   IC203-1         2.2             0.3
   IC203-5         7.0             2.5
   T201-3                          0.3 (audio)
   Component       DC Volts        P-P RF (10.7 MHz)
   ---------       --------        -----------------
   Q204 base       0.7             0.5
   Q204 collector  3.2             5.0
   Q205 collector  12.3            7.0
   R230, C228      -4.8            0
   D201, D203      0               6 VAC (P-P)
   D201, D202      0.8             0
   R225 to meter   0.14            0


C


C-Series Automotive

CI-1079

CO-1015

CO-2500


E


E-Series Educational Products

ET-3400


G


G-Series Digital Clocks

GB-1201

GC-1092

GC-1093

GD-Series Radio Control

Note: If I remember right, I got most of the following information from Bob Ellerton, who was a Heath Technical Consultant at the time and an RC enthusiast. Later, he was promoted to Factory Service Supervisor for the computer product line. Still later, he took over as Manager of the Heath User's Group.

General

GDA-19-4

GD-Series Small Items

GD-39

GD-48

GD-113

GD-348

GD-1112/GD-1162

GD-1150

GDA-1158-3/-4

GD-1185

    IC-1106-3: freq=1,733 kHz to 1750 kHz; pulse count=8 pulses
    IC-1111-4: freq=108 kHz to 110 kHz; pulse count=8 pulses
    IC-1111-6: same as IC-1111-4 except for a + or - 2 digit error
	       on the count.

GD-1187

General Audio

Differential Power Amps

Tape Dubbing Test

GR-Series SWL and Ham Receivers

GR-78

Schematic of Q301.

GR-110

GR-Series Television

GR-104

GR-300, 400, and 500

GR-900

GR-2000

GR-2001


H


H-Series Computers

H8

H8-1/3

	Data    Size
	----    ----
	057      4 K
	077      8 K
	117     12 K
	137     16 K
	157     20 K
	177     24 K
	217     28 K
	237     32 K
	257     36 K
	277     40 K
	317     44 K
	337     48 K
	357     52 K
	377     56 K
		64 K

H8-5

H8-16

H9

Schematic of P603.
Schematic of 20 mA current loop tester.

H10

H14

H17

H27

H-Series Ham Equipment

HD-1982 and HW-2036

HD-1982 and HWA-2021-3

HG-10B

HM-102, HM-103

HM-2102

HN-31

HR-10B

HR-1680

HW-8

HW-16

HW-32

HW-32A

HW-100

HW-101

A couple of these are my own, but most came from Engineering, Tech. Consultants, Heath technicians, and field technicians. The HW-101 was a great transceiver, but it was truly an art to repair one that was broken.

HW-2021

In March of 1979 I was promoted from Senior Technician to Service Technical Writer and was transferred from Omaha to St. Joseph, Michigan. The H19 terminal and H89 computer were being introduced, and I was required to write service manuals for them. (More accurately, I cowrote the H89 service manual with Don Gohr. I covered the CPU board, while he wrote up the peripheral boards: That is, the serial interface, floppy disk controller, and cassette tape interface boards.)

After I finished that project, my boss, Frank Kendrick, assigned me to write a manual on a new Heath 2-meter digital transceiver, the VF-7401. Frank advised me to use the HW-2021 service manual as a guide. I, with my vast experience of writing two service manuals, pointed out to him that while the HW-2021 manual was good, I found it lacking. I went on at great length describing in detail how I could write a better manual.

When I finally stopped to catch my breath, Frank quietly said "I wrote that manual."

Meanwhile, our typist/proofreader/illustrator, Fran Kendall, was doing her damnedest not to bust a gut.

At the time, I didn't realize that I was still new and that Frank had many more years of servicing, writing, and editing experience than I did.

Frank was okay, though. You begin to realize you have a good boss when you work for him for 13 years and even turn down job offers from other departments.

HW-2026

If I remember right, the HW-2026 caused some serious cross-talk problems in cities with repeaters that were close together. At the time, the Heath engineers could not solve the problem (short of totally redesigning the unit). So the Heath company contacted all their customers to recall the kit. The deal was this: If the kit wasn't built yet, Heath would refund the customer's money plus pay an extra $25. If the kit was already assembled, Heath would refund the money plus pay the customer $50 (big bucks in those days). If the customer chose not to return the kit, Heath would not provide service or any other support.

Amazingly, many customers chose to keep the radio.

HW-2036

HWA-2021-3

HX-20


I


IB-Series Counters

IB-1103

IG-Series Generators

IG-28

Schematic of IG-28 fix.

IG-42

IG-57A

IG-1271

Most of this information is based on information from an article written by Charles Gilmore (who was a Heath engineer at the time) in the May, 1976 issue of Radio Electronics.

IM-Series Meters

IM-17

IM-18

The IM-18 VTVM was one of my favorite tools. It was one of those basic designs that couldn't be improved upon. The circuitry was essentially the same since it was introduced (under a different model number) back in the '50s. The circuitry hadn't changed in the late '70s when it was later given a new paint job and the model number changed (Marketing moves in mysterious ways).

Anyway, it was a rugged tool. In the '70s, Heath came up with an upgrade (the IMA-18-1) that replaced the two vacuum tubes with solid-state equivalents so that it would be ready the instant you turned it on. I did a lot of warranty service on the modified units as they tended to blow up when brought near the high-voltage circuits in color TVs. I think most customers who bought the mod went back to the vacuum tubes.

IM-25

IM-48

IM-104

IM-1202, IM-1212

IM-1210

IM-1212

IM-2202

IM-4100

IM-5248

IM-5284

IMA-18-1

IO-Series Oscilloscopes

Oscilloscopes are cool. I could sit and watch waveforms all day.

IO-101

IO-104

IO-4510

IO-4530

IO-4540/IO-4560

IO-4540

IO-4550

IO-4555


M


M-Series Marine Equipment

MI-Series Depth Sounders

I think the following bullet came from either John D'Amore or Kent Barnes--both Field Service Managers at one time or another.

MI-29

MI-2900, MI-2901, MI-1030, and MI-1031

MI-1030, MI-1031

MP-10


P


Parts

    45-  80-00 heat sensitive
   417- 264-00 may sub for 417-818
   432-  72-00 subs 432-861

Probes

PKW-101

   Frequency         Xc
   ---------         -------------
   10.7 MHz          1293 ohms
   455 kHz           30.5 kilohms
   3.395 MHz         4 kilohms
   15.75 kHz         880 kilohms


S


SB-Series Ham Equipment

SB-100

SB-104

SB-303, SB-313

SB-634

SW-717


T


T-Series Equipment

TD-1080


Those are my notes.

I have no plans to adding to them (other than correcting errors I've missed). This is partly because I want to use the remaining space on this URL for other projects. If you have a collection of service hints for Heath products (or other Heath information) that you want to share, place them on your Web page, please email me and I will create a link to your page.

--Bill


Go to the Heath Company page.

Copyright © 1996, 1997, 2003—2005, William Albert Wilkinson. All rights reserved.

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