DZ HT-7 User manual

Page
DZKit
ASSEMBLY MANUAL
HT-7
40M AM HANDIE-TALKIE
Price: $10.00
DZ CompanY • LOVELAND, COLORADO

Page 2
DZ COMPANY CONTACT INFO
Orders, parts, phone assistance.....................................................................[phone]
Email orders............................................................................................... [email protected]
Email technical support .........................................................................[email protected]
Web site .......................................................................................................www.dzkit.com
Mail:
DZKit
710 Grove Ct.
Loveland, CO 80537
During your first ninety (90) days of ownership, DZ Company will replace or repair free of charge—as soon as
practical—any parts which are defective, either in materials or workmanship. You can obtain parts directly from
DZ Company by writing us, emailing us or telephoning us. And we’ll pay shipping charges to get those parts to
you—anywhere in the world.
We warrant that during the first ninety (90) days of ownership, our products, when correctly assembled,
calibrated, adjusted and used in accordance with our printed instructions, will meet published specifications.
You will receive free consultation (except for the cost of your long distance phone call) on any problem you may
encounter in the assembly or use of your DZKit product. Just drop us a line, email us, give us a call, or visit our
website and click on “Support”. That will give you access to free on-line support and a discussion group. Sorry,
we cannot accept collect calls.
Our warranty, both expressed and implied, does not cover damage caused by the use of corrosive solder,
defective tools, incorrect assembly, misuse, fire, customer-made modifications, floods or acts of God, nor does it
include reimbursement for customer assembly or setup time. The warranty covers only DZKit products and is
not extended to non-DZ allied equipment or components used in conjunction with our products or uses of our
products for purposes other than as advertised.
If you are ever dissatisfied with our service—warranty or otherwise– or our products, please write or email the
president, Brian Wood, W0DZ, and he will make certain your problems receive prompt, personal attention.
THE DZ COMPANY, LLC
LOVELAND, CO 80537
YOUR DZKIT 90-DAY FULLWARRANTY

Page 3
Assembly and Operation
Of the
HT-7 40M AM Handie-Talkie
DZ COMPANY
LOVELAND, COLORADO
Copyright © 2009
The DZ Company, LLC
All rights reserved
3-24-09 HT-7
TABLE OF CONTENTS
Introduction...................................... 4
Available Accessories....................... 5
General Assembly/Safety Notes....... 6
Parts List ........................................ 12
Step-by-step Assembly................... 14
Chassis Integration......................... 19
Adjustments and Tests.................... 22
Final Assembly............................... 23
Using Your HT-7 ............................ 27
Theory of Operation....................... 28
Specifications................................. 34
Schematics ..................................... 35
Troubleshooting.............................. 39
Component Locator........................ 40
Notes.............................................. 41

Page 4
Intheearlydaysofamateurra‐
dio,andcontinuingwellintothe
1960’s,amplitudemodulation(AM)
wasthemodeofchoiceforphone
communications.Itswideband‐
width(6kHz)andrichsoundmade
hamradiosoundlikebroadcast
stations.

Eventually,withcrowdedbands
andadesireforsmallerrigs,AM
gavewaytosingle‐sideband(SSB)
operation.Radioshadmoresensi‐
tivityonSSBthanwithAM,so
worldwidecontactsbecameeasier.
AMwasrelegatedto“callingfre‐
quencies”‐justsinglefrequen‐
ciesinthelargeamateurphone
bandswhereAMaficionadoscould
stillenjoythefunofthoseold‐
styleQSOs,whichweretypically
long‐winded,sinceVOXwasnot
usedandswitchingoverfrom
transmittoreceivetooklonger.

NowyoucanenjoythefunofAM
withoutspendinganarmandaleg
withyournewHT‐7Handie‐Talkie.
Notonlycanyouuseitasa
walkie‐talkie,withlimited
range,butyoucan,withanap‐
propriateoutsideantenna,talk
tothe“bigguns”onthe40MAM
callingfrequencyof7.290MHz.
SincetheoutputpoweroftheHT‐
7isjust2Watts,youmaywant
toaddanamplifier,butwhen
bandconditionsaregood,andthe
sunspotcyclecooperates,you
willbeamazedathowfar2Watts
willcarry!

ThanksfortrustinginDZKitto
providenotonlyuniqueelec‐
tronicproducts,buttogiveyou
hoursofbuildingfuntoo.
INTRODUCTION

Page 5
AVAILABLE ACCESSORIES
HTA‐3Tuner.Thisisthe
“DuckerI/L”madebyMiracle
AntennaofCanada.Addsabout
30dBofgaintoyourHT!
HTA‐257”ExtendableWhip.
AlsomadebyMiracleAntenna
ofCanada.Usewithorwith‐
outtheHTA‐2tuner.
HTA‐1BatteryPack.Includesbuilt‐inovercharge,overdischarge,
overdrain,short‐circuitandreversedpolarityprotection.Weight:
10.4oz(370g).Dimensions:2.6"(66mm)x2.1"(53mm)x
1.7"(43mm).MustberechargedusingLithiumIonchargeronly.Not
forusewithNiCdorNiMHchargers.Canbechargedinusebyconnec‐
tionofa12VDCpowersupply,orgotowww.batteryspace.comtoorder
aninexpensivechargermadeforthisbattery.

Page 6
1.Asyoutightenascrew,itis
veryimportantthatyoudo
notstripthethreads.All
screwsshouldfastensmoothly
withoutresistance.Ifa
screwappearstobehardto
fasten,somethingelseis
probablywrong—acablecould
beintheway,youaretrying
tousethewrongsizescrew
orsomethingelseiswrong.
DONOTFORCESCREWS!Instead,
inspecttheassemblycare‐
fullyandtrytoseewhyyou
arehavingdifficulty.Abbre‐
viations:PH=panhead.FH=
flathead.M/S=machine
screw.
2.Allreferencestoleftand
right,frontandbackare
withthechassisinanorien‐
tationsuchthatthespeaker
facesyouandthetextreads
correctlyfromlefttoright.
3.Eachcircuitparthasitsown
componentnumber(R1,L4,Q3,
etc.).R1ononeassembly
willnotbethesameasR1on
adifferentassembly,sobe
sureyouarelookingatthe
rightsetofpartswhencom‐
paringpartnumberswiththe
printedpartslist.Checkoff
eachpartatthebeginningof
eachsectiontomakesureall
thepartsarethere.Ifyou
findanymissing,giveusa
calloremailusandwewill
rushareplacementtoyou.
4.Mostelectronickitsthatare
returnedforservicehave
poorsolderingjobs.Please
takeamomenttofamiliarize
yourselfwithpropersolder‐
ingtechnique.Anddonot,
underANYcircumstances,use
corrosive(“acid‐core”)sol‐
der!Thatwillvoidyourwar‐
rantyandrenderyourkitin‐
operative.Alsobesureto
avoidtheuseofproducts
thatmaybecalledsolderbut
arereallyglue.Soldering
shouldonlybedoneinan
areawithgoodventilation
andwithaproperlyheated
solderingiron.
5.Capacitorsareidentifiedby
theirtype—disk,polysty‐
rene,polypropylene,electro‐
lytic,trimmer,etc.)andca‐
pacitancevaluesarein
microfarads(uF)orpico‐
Farads(pF,oftenpronounced
“puff”).Polarizedtypeshave
thepositivepinmarkedon
thesilkscreenandalsohave
asquarepad.
6.Inductorsarerepresentedei‐
therbytheirinductancein
nanoHenries(nH),microHen‐
ries(uH),milliHenries(mH)
orbythenumberofturnsin
thecoilifyouaredoingthe
winding.
7.Diodesaremarkedwithaband
onthecathodeend.ThePC
boardshaveabarsilk‐
screenedacrossonesideof
thecomponentoutlineanda
squarepadwhichidentifies
thecathode.
General Assembly Notes

Page 7
Mostkitbuildersfindithelpfultosepa‐
ratethepartsintocategoriesforquick
identification.Muffintinsandeggcar‐
tonsservethispurposeadmirably.
8.ICshaveanotch,beveledside
and/oradotrepresentingthe
sidecontainingpin1.When
youholdanICwiththenotch
pointinguporthebeveled
sidetoyourleft,pin1isin
theupperleftcorner.The
silkscreenedoutlinesonthe
boardallhavenotchesandpin
1alsohasasquarepad.

ItisCRITICALthatyoumountpo‐
larizedpartscorrectly!Double
checkyourworktobesurethat
allsuchpartsmatchthephotos.























IC—pin1(throughholepart)
Electrolyticcaps—negativeterminal
Diode
Cathode
Anode

Page 8
Thestepsinvolvedinbuildingakitarelistedbelow.Besuretofol‐
lowthemandyouwillhavealotoffunbuilding,aligning,testing
andusingyourkit.

1.Doapartsinventory.Checkoffeachpartinthepartslisttobe
sureyouarenotmissinganything.Ourmethodofbaggingpartsis
differentfromallotherkitvendorsandwillmakethetaskmuch
fasterandlesserrorprone.Butdespiteourvaliantefforts,mis‐
takescanhappen.Ifyouaremissinganyparts,calloremailus
andwe’llrushreplacementstoyouimmediately.
2.Donotremovepartsfromthebagsuntilcalledfor,toavoidmixing
partsup.
3.Payattentiontosolderingtechniques.Keepyoursolderingiron
cleanbyusingawetsponge,useappropriateheatandmaintainheat
longenoughtomakegoodsolderjoints.Solderproblemsarethe
numberonecauseofproblemswhenbuildingelectronicproducts(not
justkits!),sotryextrahardtodoitright.
4.Takeyourtime!Weknowyouwanttogetitdoneandstartusingit,
butdoingitwrongwillonlydelaythatmoment.Beforeyoustart,
setupaventilated,static‐freeworkareawithenoughroomto
buildthekit.Preparepartsbinsandgetthetoolsyouwillneed
(needle‐nosepliers,wire‐cutter,wirestripper,Phillipshead
screwdrivers,wrenches,solderingiron,solder,insulatedtool,
awlorothersharp‐endedtool,scissors,magnifyingglass,etc.)If
you’retired,takeabreak.Enjoybuildingyourkit!
5.Makesurethatyouareloadingthepartthat’scalledforinthe
rightholes.Onceloaded,itcanbehardtofindamisloadedpart.
Beespeciallycarefultoloadpolarizedparts(ICs,transistors,
diodes,electrolyticcapacitors)therightdirection.Ifyouare
notsureaboutanystep,call,writeoremailus!
6.Onceyou’vedoneastep,putacheckmarkinsidetheparentheses.
7.Afteryouhaveassembledacircuitboard,takeamoment(justone)
tomarvelatyourhandiwork,thenspendafewmoreminutescritiqu‐
ingit!Checkforsolderbridges,unsolderedorinsufficientlysol‐
deredconnections,solderblobs(especiallyoninsulatedmagnet
wireusedontoroids),loosescrewsandelectronicparts,reversed
polarizedcomponents,etc.Sometimesithelpstohaveafriend
checkyourwork.
KIT-BUILDING PROCEDURES

Page 9


Yoursafetyisofutmostimportancetous.Pleasereadthisinforma‐
tionbeforeyougetstarted,andremembertheserulesasyoucontinue
buildingandtestingyourkit.

1.Alwayshaveahealthyrespectforelectricity.Useapowersupply
withovercurrentfoldbackorcrowbarprotectionsothatincaseof
highcurrentsthesupplywillshutdown.Settheoutputcurrent
onlyashighasnecessaryforagivenstep.
2.Whenmeasuringvoltagesinsideelectronicequipment,itisgener‐
allyagoodideatouseonlyonehand,wearrubber‐soledshoesand
avoidareaswithstandingwater.However,rememberthatslightly
humidenvironmentscanpreventstaticelectricitythatcoulddamage
theelectronicparts!Useahumidifierindryclimates.
3.Donotworkonpoweredelectronicsbyyourselfifatallpossible.
Haveaparent,spouseorfriendnearby.Ifyoumustworkalone,
keepatelephonehandyintheeventyourunintoproblems.
4.Solderingironsarehot.Theycanburnyourskinandcausedamage
toworkbenchesandcarpets.Werecommendyouuseonewithanauto‐
maticshutoffincaseyouforgettoturnitoffwhenyouaredone.
5.Donotworkonelectronicprojectswhenyouaretired.Weknowyou
wanttofinishit,butaccidentsaremorelikelywhenyouare
tired.Takebreaks!Becareful!
6.Useproperventilationinyourworkarea.Soldercontainstinand
lead(ortinandsilver),andsolderfumesshouldnotbeallowedto
“hover”nearyourwork.Openadoororwindow,useafan,andbe
cognizantofthepotentialdangers.
7.Whenclippingleads,useeyeprotectionand/orbesuretodirect
theflyingleadsdownintoanearbytrashcan.Asyougainexperi‐
enceclippingcomponentleads,youwilllearnhowtoclipthemso
thattheyfallharmlesslyawayfromtheboard.
8.Becarefulnottocutyourselfwhenhandlingsharpobjectssuchas
connectorsandsheetmetal.Keepsometissues,bandagesandantibi‐
oticointmentnearbyintheeventofaninjury.
9.Thismaysoundobvious,butdonotinsertanypartsinanyportion
ofyourbody.
10.Usecommonsenseindealingwithunfamiliarthings.Ifyoudon’t
understandsomething,callusoraskafriendforhelp.
Safety First!

Page 10
SOLDERING INSTRUCTIONS

Poorsolderingaccountsforalmost90%ofallkitbuildingproblems.
Thephotographsbelowshowexamplesofthemostcommontypesofbad
solderconnectionsandagoodone.Ifyoulocateanyofthesebadsol‐
derconnectionsinyourkit,correctthemasdescribed.Studythis
sectioncarefullybeforeyoustartbuildingyourkit.
Useagoodquality,variabletem‐
peraturesolderingironwitha
conical,narrowtip,andsetthe
temperatureto750degreesF.Use
thin,non‐corrosive,rosincore
soldertoassembleyourkit.Keep
thespongedampandwipethetip
onthespongeaftereachsolder
step.
Solderblob.Inthisexample,
solderflowedontoalead,but
theheatwasnotmaintainedlong
enoughforittoflowontothe
circuitboardpad.Solution:re‐
heattheconnection,touchingthe
irontoboththecomponentlead
andthepadatthesametime.
Solderbridge.Solderthat
stretchesfromonetraceorpad
toanothercreatesashortcir‐
cuit.Solution:Holdtheboard
upsidedownandreheatthearea.
Theexcesssolderwillflowdown
thesolderingiron.Anotherso‐
lutionistousea“solder
sucker”orsolderwicktoremove
excesssolder.Soldersuckers
workwelloneortwotimesona
givenconnection.Ifusedtoo
much,theycanpullpadsand
tracesoffofPCboards.
Agoodsolderconnectionlooks
likethis.Solderflowsevenly
ontoboththepartandthePC
boardorchassiscomponent.Itis
shinyandeven,notlumpyand
dull.Thecomponentliesflaton
theboard.Leadsthatareprop‐
erlysolderedcannotbemovedin
thehole.Youcanfindbadsolder
connectionsbymeasuringthere‐
sistance,usinganohmmeter,be‐
tweenthecomponent’slead(where
itattachestothebodyofthe
part)andtheotherendofthe
trace.Ifitreadsinfinity(or
veryhigh)theconnectionis
open.