Heath SB-610 Monitor Scope Modifications - Nostalgic Kits Central

•clamp switch is pulled out, the SB-61O turnedon, and no rf signal is applied . In any event,the plate d issipation of the 6BN8 relay amplifiershould not exceed the maximum ratingof 1.7 watts. The total resistance of therelay coil plu s series resistor should be atleast 10 K. (If you use a junk b ox relay,measure th e voltage from cathode to plate.and the current through the tube when therelay is pulled) in. The product of the voltageand current- in amperes-sho uld notexceed 1.7.)This completes the wiring of the modification.Check the wiring against the schematicin Fig. 4. Carefully plug the SB-61Oin with it still out of the case and let itwarm up. Check to see if the relay operateswhen the "pull to clamp" switch is pulledout and the sweep switch is in any p osition.If the relay does not opera te, first recheckthe wiring to make sure it is correct. Ifthe wiring is correct and the relay will stillnot pull.in, reduce the value of the resistorfrom the relay coil to pin 7 of VI untilthe relay reliably pulls in. This will assurethat minimum plate dissipation occurs intube VI. \ Vhen this value is found, solder inthe resistor permanently.When the "pull to clamp" switch is pushedin, the relay should drop out. The tracewill then appear on the face of the SB-6 1Oand it should operate normally.Set the sweep switch to Inl. and applya small amount of transmitter rf to theconnector at the rear of the SIl-6IO whilethe "pull to clamp" switch is out , The relayshould release and the trace should appearto allow normal transmitted signal monitoring. If the trace does not appear and therelay drop out, increase the rf signal. Whenthe rf is removed by turning off the transmitter,the trace should di sappear after 1to 2 seconds. If the trace has not movedcompletely off the scope face, it may benecessary to decrease the value of the 33 Kresistor. If the sweep still continues whenthe trace is off screen, the grid of tubeV3A (pin 9) is not being shorted to groundthrough the relay.I have operated my SB-6IO 24 hours aday for days at a tim e and experiencedno difficulties. You must now remember totu rn off the power switch after operating,for you no longer sec the green trace onthe screen to remind you that the 5B-6IO ison.. .. K6S D E•,•-_.-.. ,• •THE BEST2 METERCONVERTERModel 407$34.95ppd.144·146 MHz In. 28·30 MHz o"tor 146-148 MHz with a second crystalA f u ll description of this fantastic con ver terwould fill t h is page, but you can take our wor dfor it (or those of h u nd r eds o f satisfied users)that it's t he best. The reason is s im ple--we usethree RCA dual Kate MOSFETs. one bipolar, and3 d iodes in the best circuit ever. Still n ot co n ­vinced ? Then sen d for o u r free catalog and g'et.the full description, plus photos and even thes chema t ic.Can't wait? Then se n d W I a postal money orderfor $3 4.95 a n d we' ll rush the 407 ou t to you.N OT E : T h e Mode l 407 is also ava ilable in anyfr-eque ncy combinatio n u p to 450 M H z (some athiR'h er p r ices ) na listed in our ca t a log.*New York City a nd State resid ents add local sa les ta...VANGUARD LABSDept. H , 196-23 Jamaica Ave. , Hollis, N.Y . 11423ARNOLD'S ENGRAVINGPersonalizedELECTRi CON·THE·AIRSIGNW ITH CAllW orks on110 VAC$12.95Metaltex Lapel 8ar - $1.50 Metaltex Tie Clip. $2 .25ENGRAVINGRldgewood. N.Y. 11227ARNOLD'S2041 Linden St.the permaflex key •• ""th .. t¥o;" I...., '" dn,ight 1..,,01 10.,.i" • pi..otl . .. 2 ,..ddl. d.lig".• gi , i"ot.. ,,~ choic. 01 ....tom..ticI.mi utom.tic'" ' blillht hl"d h yi"g.• UI. dir.ctly ""ith . "y b l".mitt• • 0.thrO"llh . " . I.ctron;c ...,.• •.• 8 . mp. gold diU,,".d ,il... . con tach.dj.." l rom O·.o bO· '" 5.50 gr.",' .• di.t incti... "t... ,..ddr., . r. of"'91led G.IO ""• •gl.... . poxy.• ca"in.t i. te g. ..g. poli,hocl chro"'.19 95 •••p,....It••I: 1.9 5 " .q. • 3 .75 " . ,..ddl.1. ort. "d 1.1.5", w.i,ht ..pp. I po" " d, ..... "..&can.• l ilicon. "'"" • • fo.t ~ . ot..bility. _ntl.ct-k or "'oO.• 100:( US ",..d. '" ll..... nt•..r 10. I y.. soItI..,. roMIlI onlyJames Research compan\1,dep'l: AR- K11 schermerhorn 51., broold n n. • 11201APRIL 1969 45