August 10, 1973 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-1 Distorted Receiver Audio In the first run of HW-202's there exists a possibility of distorted audio due to C325 & C327. In the subsequent kit production, these have been eliminated. If C325 & C327 are installed, they should be removed. -------------------------------------------------------------------------------------------------------------------- August 14, 1973 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-2 L208 Does Not Peak Properly If L208 does not peak properly, one can try substituting C278 (18pf) disc with a 15pf disc. This coil normally peaks 3-4 turns up from bottom of coil, while L209 normally peaks very close to circuit board. RF voltage at point AC with 51 ohm load installed should be 3 1/2 to 4 volts for proper amplifier drive. This change will be incorporated into future production. -------------------------------------------------------------------------------------------------------------------- October 26, 1973 HW-202 Bulletin No: 2 Meter Fm Transceiver HW-202-3 Corrections For Low Output Power And and Spurious Radiation The following changes should be made to all HW-202 transceivers received for repair. A regular modification kit [HWM-202-1] will be available after the 14th of December but if you have parts available you can make the changes now. Complete sets of parts are not available at this time and parts orders should be for the MOD KIT ONLY. All current production is being changed and insert sheets are being included in the manuals. If you need insert sheets order No. 591-1296. Transmitter Board Changes Parts Needed Quantity Part No Description Schematic Location Value ----------- ---------- ---------------- ---------------------------- -------- 1 1-69 .5W Comp Res R-229 18K ohm 1 1-118 .5W Comp Res R-234 82 ohm 1 1-130 .5W Comp Res R-236 8.2 ohm 1 21-3 500V Cer Cap C-279 10 pF 1 Ft. 348-2 Magnet Wire RFC-205 4 turns 1 206-444 Coil Cover L-205 Refer to the transmitter board schematic for the following changes: 1. Remove the 100K resistor at R-229 and install [1] 18K ohm resistor. 2. Remove the 390 ohm resistor at R-234 and install [1] 82 ohm resistor. 3. Remove the 33 ohm resistor at R-236 and install [1] 8.2 ohm resistor. 4. Remove the 4.7 pF capacitor at C-279 and install [1] 10 pF capacitor. 5. Remove the RF choke at RFC-205. REmove the 2 turns of magnet wire. Rewind 4 turns of magnet wire on the ferrite bead as shown in the pictorial. Reinstall the RF choke at RFC-205. [ ] Cut a 6" length of magnet wire. Thread this wire through the large ferrite bead so there are four complete loops through the bead. Form the loops down against the bead as neatly as possible. Be careful not to damage the wire coating. [ ] Cut the leads to 1/2". Then scape 1/4" of the coating from the end of each lead. Use a knife blade. Discard the cutoff wire. 6. Install [1] coil cover at L-205 by cutting off one lug of the cover and either drill a hole in the circuit board at the ground foil near the edge of the circuit board or just wrap the lug over the edge of the circuit board and solder the lug to the ground foil. 7. Connect the bare wire jumpers to the foil pads indicated in the pictorial. NOTE: if you have any difficulty identifying the foils to which the bare wire should be soldered, refer to the foil-side view of the transmitter circuit board on Page 130 of the Manual. Interconnect C207, C209, C212, C214, C216 and C218. Make sure the bare wire does not touch the soldered connections of any other components. Power Amplifier Board Changes Parts Needed Quantity Part No Description Schematic Location Value ----------- ---------- ---------------- ---------------------------- -------- 2 45-38 RF Choke RFC 301 and 302 .295uH 4 475-10 Ferrite Beads RFC 301 and 302 1 21-154 Cap disc C-305 .0051uF 1 25-220 Cap Tantalum C-306 10uF 1 21-17 Cap Disc C-317 270pF Refer to power amplifier schematic for the following changes: 1. Remove the RF chokes at RFC 301 and RFC 302. 2. Install 2 ferrite beads on each new RF choke [PN 45-38] and install these chokes at RFC 301 and RFC 302. 3. Remove the 150pF cap at C-305 and install (1) .0051 uF cap. 4. Remove the 2.2 uF cap at C-306 and install (1) 10 uF tantalum. 5. Install a 270 pf cap at C-317 as shown in the pictorial. [ ] 270 pf disc capacitor. Cut both leads to 1/4" and install the capacitor as shown. Solder both leads to the foil on the COMPONENT side of the circuit board. Then bend the capacitor over as shown. ------------------------------------------------------------------------------------------------------------------- November 16, 1973 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-4 Service Hint On all units, check soldering of relay lugs to the power amplifier circuit board. NOTE that the punched holes may sever the foil strip. Therefore, it is important that each relay lug is soldered to the foil on both sides in order to avoid open circuits. The symptoms relating to this condition will vary depending upon which foil strip is open. The construction manual is being revised to avoid this problem in future kits. -------------------------------------------------------------------------------------------------------------------- March 28, 1974 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-5 Low Power Output L304 and L305 on PA board are being made by the Customer with "9" turns instead of the proper 8 turns. This can cause a loss of as much as 3 watts in total output power. These coils should be checked on every HW-202. -------------------------------------------------------------------------------------------------------------------- November 25, 1974 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-6 Simple Signal Injection For HW-202 Receiver Board A common complaint when doing the receiver alignment without instruments is "No 'S' meter reading after adjusting T-106 successfully and moving meter lead to point S." The possible areas of trouble are many and the customer without a signal generator is at a loss as to what to do. By assuming that the second oscillator Q104 is working, we can check many parts of the circuit with the following test. Using a piece of hookup wire and a .01 mF disc capacitor connected in series, connect this combination between G2 of Q103 and pin 1 of transformer T101. Turn the transceiver on. If the "S" Meter now goes up scale about 2 or 2 1/2 divisions, you have just proved that everything from the bandpass filters to the quad detector IC-102 is working. This will narrow down the possible cause of trouble to the first mixer stage (Q-102), amplifier stage (Q-118) or RF amplifier stage (Q-101) and from here, finding the cause of trouble should be easy. Also, if the audio circuits are working, this injected signal should quieten the white noise of the receiver. ------------------------------------------------------------------------------------------------------------------ December 12, 1974 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-7 Transmitter Oscillator Dead Or Sluggish When Keyed After checking crystals and Q201 for proper operation, check diodes D201 through D206. If they are banded backwards or shorted, any one may cause the problem. ------------------------------------------------------------------------------------------------------------------ December 26, 1974 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-8 HW-202 Preset Alignment Chart -Transmitter Circuit Board - All turns are started with slug at top of coil form. These are approximate settings and some will vary. Numbers in parenthesis are alignment sequence. Others are number of turns down from top of coil form. Coil Seq # Turns TP Approx Volts + ----- ----- ----------- --------- ------------------ L201 [1] 6 3/4 TP201 3.5 L202 [2] 11 TP201 3.5 L203 [3] 11 1/4 TP202 2.0 L205 [4] 13 TP203 2.5 L204 [5] 11 1/4 TP203 2.5 L206 [6] 10 TP204 1.5 L207 [7] 12 1/4 TP205 .6 L208 [8] 13 TP206 .9 L209 [9] 13 TP206 .9 ------------------------------------------------------------------------------------------------------------------- July 9, 1975 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-9 '73 Magazine Article and Hotline Report The information that was printed in these magazines was not released by the Heath Company. Heath Company has no knowledge of where the article came from and we do not have any selectivity modification information as the article implies. Setting HW-202 Deviation Equipment Needed: FM Signal Generator [Radiometer MS-27G] Oscilloscope [IO-103] Audio Sine Wave Generator [IG-18] Shop HW-202 [modified for fixed audio gain] Step 1 The shop HW-202 and oscilloscope are calibrated and set up to recognize a 5 kHz deviation signal. This adjustment is only made once. a] Connect an F.M. signal generator, adjusted to the shop HW-202 receive frequency, modulated 1 kHz at 5 kHz deviation, to the shop HW-202 antenna input. b] Connect the oscilloscope test leads (vertical input) across the receiver speaker (or 8 ohm resistive load). c] Turn the "Audio" control ful CCW (beyond the "click"). d] Note the P-P voltage reading on the oscilloscope. The "gain adjust" control in the shop HW-202 can be adjusted to an easily remembered level reference as seen on the oscilloscope. Step 2 A signal which deflects the oscilloscope to the reference P-P voltage indicates 5 kHz deviation. The signal generator is no longer needed except for periodic checking and recalibration. a] Connect the audio generator test leads across the microphone input (Pin 1) of the unit under test (UUT). Adjust the audio generator for 20 mV RMS, and depress the 600 ohm switch. This simulates the microphone voltage output. b] Key the UUT by shorting Pin 2 of the mic jack to ground. NOTE: For the two preceding steps, the microphone can be connected and the P.T.T. switch depressed. c] Adjust the deviation control for the reference P-P voltage noted previously. In place of A and B in step 2, key and speak into the microphone of the UUT. Adjust the deviation control for the P-P voltage noted previously. Modifying The HW-202 To Provide A Fixed Audio Gain This modification involves defeating the function of the ON-Off Switch on the HW-202. The power switch on the companion power supply (HWA-202-1) will then be used to turn the unit on and off. 1. Remove the ground from the bottom end of the volume control. 2. Remove the wires from the power switch connections on the volume control. Splice the two wires together. 3. Connect the bottom end of the volume control to one of the switch connections. 4. Connect the other switch connection to ground. 5. Connect the 15K control [PN 10-180] across the switch terminals of the On-Off control. 6. With the On-Off switch in the Off position, the "Gain Adjust" control is adjusted for a comfortable listening level. ------------------------------------------------------------------------------------------------------------------- July 24, 1975 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-10 Bulb Obsolescence The Part # 412-39 is no longer available. If replacement is necessary use Part # 412-58 and # 413-40. -------------------------------------------------------------------------------------------------------------------- January 26, 1976 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-11 Poor Sensitivity, T104 Will Not Tune A number of kits with series number 12551 have been supplied with T104 [PN 52-160] defective. The defective transformers have pins 1 and 3 reversed inside the transformer can, which reverses the turns ratio around the center tap of the coil. If installed, this transformer will cause poor sensitivity. T104 will not tune properly, and because of insufficient noise, there will be no squelch action. The transformer can be checked with an ohmmeter by measuring the resistance of pins 1 and 3 with respect to the center tap pin 3. Resistance readings should be as follows: Pin 1 - 11 Ohms Pin 2 - Common Pin 3 - 2 Ohms Some parts stock shipments may also have included the defective transformer, and parts stock should be checked as well. -------------------------------------------------------------------------------------------------------------------- March 25, 1976 HW-202 Bulletin No: 2 Meter Fm Transceiver HW-202-12 Part No. 417-93 Transistor Installation The 2N3646 transistor [PN 417-93] used at Q205, Q206 and Q207 are now being supplied in two different case styles. These transistors are to be installed as shown in the drawing below: -----------------Explaination below should explain what the drawing shows------------ Note the wide space between two of the leads line up this wide space with the outline of the flat on the circuit board or, in the case of the other style of transistor, poisiton the flat of the transistor AWAY from the flat on the circuit board. Then insert the leads into their correct B, C and E holes. ------------------------------------------------------------------------------------------------------------------ February 14, 1977 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-13 Part # 417-803 and # 417-804 Identification + + + + Information not available at this time + + + + ------------------------------------------------------------------------------------------------------------------ April 28, 1977 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-14 Power Drops Off When Installed in Case + + + + Information not available at this time + + + + ------------------------------------------------------------------------------------------------------------------- June 28, 1977 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-15 Knob Removal From Pushbutton Switches + + + + Information not available at this time + + + + ------------------------------------------------------------------------------------------------------------------- September 21, 1977 HW-202 Bulletin No: 2 Meter FM Transceiver HW-202-16 Unit Inoperative + + + + Information not available at this time + + + + ------------------------------------------------------------------------------------------------------------------- That's all that I show for the HW-202 (1966-89). Enjoy! 73 de Joe W7LPF/4 [NNN0KUU] QWCA - SOWP - NCVA - FISTS - RCC Gordonsville, Va 22942 [Orange Co]