August 10, 1984 HW-9 Bulletin No: QRP CW Transceiver HW-9-1 Schematic Correction - RIT Circuit In manual [PN 595-3059], make the following schematic corrections: At the RIT control, R1, the jumper should be between lug 1 and 2 instead of 2 and 3. At the junction of R132 and C191 in the base circuit of Q103, P101-4 should read P101-2. -------------------------------------------------------------------------------------------------------------------- October 26, 1984 HW-9 Bulletin No: QRP CW Transceiver HW-9-2 Schmematic Correction - T/R Board In manual [PN 595-3059], make the following corrections to the T/R board schematic. Change: C330 from 100 pF to .001 uF C341 from 100 pF to .001 uF C452 to read C552 L405 from [PN 40-2070] to [PN 40-2071]. L411 from [PN 40-2072] to [PN 40-2076]. R354 from 15 megohm to 1.5 megohm R418 from 27 ohms to 2.7 ohms The yellow schematic in the HW-9 Blue Book is correct. ------------------------------------------------------------------------------------------------------------------- April 25, 1986 HW-9 Bulletin No: QRP CW Transceiver HW-9-3 Blue Book Schematic Correction Make the following corrections to the yellow schematics in your HW-9 Service Data Manual. T/R Board Schematic Change: C327 from .01 uF to .001 uF C332 from .01 uF to .1 uF C333 from 10 uF to 100 uF C351 from .01 uF to .1 uF Oscillator Board Schematic Change: C105 from 200 pF to 300 pF L122 and L123 part number from 40-625 to 45-625 ------------------------------------------------------------------------------------------------------------------- October 31, 1986 HW-9 Bulletin No: QRP CW Transceiver HW-9-4 Frequency Stability Specification Change The specification for the frequency stability is changed: From: "Less than 150 Hz per hour after 30-minute warmup." To: "Typically less than 500 Hz/hour after 30-minute warmup. Typically less than 150 Hz/half-hour after 90-minute warmup." Note this change in your shop Assembly Manual and Blue Book for future reference. ------------------------------------------------------------------------------------------------------------------ December 12, 1986 HW-9 Bulletin No: QRP CW Transceiver HW-9-5 Manual Correction - Transmitter Frequency Offset Spec On page 97 of [PN 595-3059] manual, the transmitter frequency offset specifications should read "700 Hz higher" instead of "700 Hz lower." -------------------------------------------------------------------------------------------------------------------- December 23, 1986 HW-9 Bulletin No: QRP CW Transceiver HW-9-6 Spurious Emissions On 10 And 12 Meters At Various CW Level Control Settings If excessive spurious emissions occur on 10 and 12 meters at certain CW Level control settings, change Q402 on the T/R board from a [PN 417-172] transistor to a [PN 417-293] transistor. Make this transistor change only if needed. -------------------------------------------------------------------------------------------------------------------- April 30, 1987 HW-9 Bulletin No: QRP CW Transceiver HW-9-7 VFO Drifts Use a heat gun to heat the VFO coil, L118, for about 3 minutes. This will bake the coil and reduce the inductance change caused by ambient temperature changes. -------------------------------------------------------------------------------------------------------------------- May 29, 1987 HW-9 Bulletin No: QRP CW Transceiver HW-9-8 VFO Dial Slips Or Binds Since the introduction of the HW-9 Transceiver, its had a history of VFO dial slipping or binding problems. These problems are caused by different parts of the VFO assembly. Here are some of the areas of the VFO assembly which cause the slipping or binding problems and some fixes to correct them. Also given is the new method of mounting the VFO capacitor. If all else fails, make the changes given in the "New VFO Capacitor Mounting Procedure." The vernier drive assembly [PN 100-1839] in the first production run of HW-9s didn't meet torque ration specs. This caused the dial to slip. To identify this vernier drive assembly, see if it uses #6 setscrews. If so, it's an earlier drive assembly. Replace it with a vernier drive assembly that has #4 setscrews installed. These drive assemblies meet torque ratio specs. The drive assembly with #4 setscrews are in second production and later HW-9s, and also in Heath Part Replacement stock. In some cases, the dial will slip or bind only after installing the VFO shield [PN 206-2692] over the drive bracket [PN 204-2692]. Engineering corrected this problem by changing the thickness of the drive bracket from .041" to .030." Because of the small change, it's difficult to tell which drive bracket is installed. If the dial slips only when you install the shield, move the lockwasher on the vernier drive from the inside of the drive bracket to the outside of the bracket. This will allow the VFO shield to slide easily over the drive bracket, removing tension on the drive. Misalignment of the shafts of the variable capacitor and the vernier drive assembly will also cause dial slippage. If the capacitor frame is not bent at a right angle at either corner , the shaft will be misaligned and the dial will slip. To correct this, install a #6 flat washer [PN 230-60] between the rear of the capacitor frame and the drive bracket at the two locations shown in Drawing 1. ((Drawing shows the 6-32 x 1/8 screw into the drive bracket, then the flat washer placed on the screw before it is attached to the capacitor frame)). New VFO Capacitor Mounting Procedure The following method is used to mount the VFO capacitor in the HW-9 transceiver to mininize dial slipage and binding. This change will be installed in the next production run of HW-9s. Parts Required: QTY Description Heath Part No ----- ---------------- ------------------- 1 Drive bracket 204-2909 1 4-40 x 15/16" screw 250-480 1 4-40 nut 252-2 1 #4 Lockwasher 254-9 1 Rubber grommet 73-53 Procedure Refer to Drawings 2 and 3 on the adjacent page as you perform the following steps. ((Instructions seem self-explainatory - but as soon as I get scanner connected I will pass appropriate drawings to the Webmaster of the Heathkit Web to be included there)) -- Install the rubber grommet at hole GA of the new drive bracket. -- Push the 4-40 x 15/16" screw through the grommet at GA. On the inside of the bracket, place the 4-40 nut and the #4 lockwasher on the screw. Turn the nut about 1/4" onto the screw. -- Set the capacitor/drive assembly into the bracket. Turn the 4-40 x 15/16" screw into the indicated hole of the variable capacitor until the screw end is flush with the inside edge of the capacitor frame. Tighten the 4-40 nut against the capacitor frame. -- Tighten the control nut and rotate the shaft to make sure it turns smoothly. -------------------------------------------------------------------------------------------------------------------- January 29, 1988 HW-9 Bulletin No: QRP CW Transceiver HW-9-9 Wrong Polarity Screen At C336 The polarity marks screened on the T/R board [PN 85-2957-1] at C336 are wrong. This causes the 2.2 uF electrolytic capacitor [PN 25-924] to be installed backwards, increasing receiver noise. Install a new capacitor with the positive lead toward R347. ------------------------------------------------------------------------------------------------------------------- February 29, 1988 HW-9 Bulletin No: QRP CW Transceiver HW-9-10 Low Power Out And Low Sensitivity - Low RF Level At TP101 On the oscillator board, check the position of the slug in L118 in the VFO. Two slug positions will peak the coil; at the top and near the middle. The correct peak is when the slug is near the middle of coil. -------------------------------------------------------------------------------------------------------------------- August 31, 1989 HW-9 Bulletin No: QRP CW Transceiver HW-9-11 Low Power Output - All Bands Lift one lead of D407. If normal power returns, replace the diode [PN 56-56]. -------------------------------------------------------------------------------------------------------------------- October 27, 1989 HW-9 Bulletin No: QRP CW Transceiver HW-9-12 VFO Range Too Wide If you adjust the trimmer on C1 all the way out and the VFO range is still too wide, change: C186 from an 18 pF capacitor to a 10 pF NPO capacitor [PN 21-3] This capacitor change allows the VFO to cover the proper range. Make sure the VFO meets the drift specs. Install this change only when needed. ----------------------------------------------------------------------------------------------------------------- Thats everything I hold up to 1989 that covers the HW-9. ------------------------------------------------------------------------------------------------------------------ Enjoy! 73 de Joe W7LPF/4 [NNN0KUU] QWCA - SOWP - NCVA - FISTS - RCC Gordonsville, Va 22942 [Orange Co]