- #ICOM SERIAL NUMBER CHECK CRACKED#
- #ICOM SERIAL NUMBER CHECK SERIAL NUMBER#
- #ICOM SERIAL NUMBER CHECK DRIVER#
If problem is intermittent, check for bad solder at the legs of Q6, or D2.
#ICOM SERIAL NUMBER CHECK DRIVER#
Measure voltages at bases of driver and PA transistors in TX SSB mode. No bias voltage to driver or PA transistors. Turning on the speech processor seems to help a little. Average power is low, even at higher mic gain levels. Check the DC voltages at D47.ĭistorted/raspy-sounding TX in SSB modes. There may be other problems on the RF unit. Problem is traced to no output at J8 on the RF unit. Less common: Poor solder at ground jumper at mic jack. This transistor is mounted to the aluminum heat sink and is easy to find.
#ICOM SERIAL NUMBER CHECK CRACKED#
Most common: Cracked solder at TX reg Q7 on main unit. When the SEND switch is flipped, the green RX LED stays lit and unit does not go in the transmit mode. Check the voltages at D47 on the RF unit. There are probably other problems on the RF unit if this capacitor is bad. Shorted DC-blocking capacitor C15 on the ANT SW unit. Inspection reveals 6 volt DC at the center conductor of the antenna jack. RX disappears when outer shield of coax is connected to the antenna. Banging on case or switching between RX & TX may temporarily restore sensitivity. If Q15 is leaky, there may be other problems on the RF unit. BC band RX sensitivity may be low or marginal. Call technical support for details on this update.ĭistorted RX on strong signals.
#ICOM SERIAL NUMBER CHECK SERIAL NUMBER#
If the serial number is between 0200, a diode installed in the update may have been installed incorrectly at the factory. If the serial number of the unit is below 01800, the unit probably needs a factory update to the main unit to prevent future failure of these components. Unit is not repaired until listed voltages at D47 are correct Replace these components on the RF unit: D42, D44, D45, D46, D47, Q15. Correct voltages are: Cathode side- RX: 8.5, TX: 13.8. Check DC voltages at D47 on RF unit to verify problem. The better-performing (but more expensive) FL-80 filter can be substituted for the FL-30.īad components on RF unit, probable result of RF overload or lack of necessary update. Some filters are better than others so some test selection may be needed to satisfactorily alleviate the problem. If these are OK, then the problem is most likely in the FL-30. Misadjustment of the BFO and/or IF shift oscillator, or a faulty crystal filter, probably FL-30 located on the main unit.Ĭheck adjustment of the BFO and IF shift oscillator. USB/LSB RX frequency response may be equalized, to a degree, by adjustment if the front panel IF Shift control. USB audio has too much bass while LSB audio has too much treble. Replace plastic trimmer capacitors C42, 45 and C307 (all 30pf) in main unit with ceramic equivalents.ĭrastic change in audio frequency response between USB and LSB, i.e. While you have the PLL unit lifted, it would be a good idea to inspect the solder beneath the shield in the LPL VCO section. This will allow you to properly adjust the HPL lock voltage for that band. We suggest using a 12pf trimmer for C29 instead of a 7pf as listed in the service manual. Remove excessive plastic wax from around replacement trimmers to prevent wax contamination. Replace plastic trimmer capacitors C11, C20, C29, and C37 with ceramic versions. Problem may be temperature related.īad trimmer capacitors on PLL unit, HPL VCO section. Distorted SSB audio sounds raspy and rough.
![icom serial number check icom serial number check](https://www.wimo.com/media/catalog/product/cache/632673b92197f26e621db4ceed94c711/A/H/AH_4_7dac.jpg)
No RX/TX or distorted RX/TX on one or more bands. LPL problem, probably C226 has drifted out of adjustment. No RX/TX when unit is first turned on, but will return if VFO knob is spun or if power is cycled on and off a few times. While you have the off you may wish to drill a small access hole in the cover to allow easier (and more accurate) adjustment of C226. On these units, you will have to unsolder and remove the shield cover to make adjustments.
![icom serial number check icom serial number check](https://www.libble.eu/bestanden1/8954/bg23.png)
On older units, there is no address hole in the LPL shield cover to facilitate adjustment of C226. When replacing C226, inspect solder in LPL VCO section and remove excessive wax from around replacement capacitor to prevent contamination of the new part. If C226 is difficult to adjust or won't hold its adjustment, it has probably become unstable and should be replaced. Dead spots may eventually get smaller then disappear as radio warms up.ĭDS LPL trimmer capacitor C226 on PLL unit has drifted out of adjustment. Pay particular attention to the joints around the regulators and inside beneath the LPL VCO shield.ĭead spots in the bottom 250 kHz (or so) range of each band when radio is cold. Check DC voltages at R6 and R201 to verify the PLL unlock condition.
![icom serial number check icom serial number check](https://www.rsmanuals.com/src-html/7/7c2m3axz03/bg15.jpg)
Usually this is caused by cracked/overheated solder on the PLL unit, particularly in the LPL VCXO. Display and controls all seem to work properly. Unit will not transmit or receive on all bands. The information on this page is subject to the terms and conditions set forth on the ICOM America Service FAQ Index page. Most Common Service Questions for the Icom IC-765