Re: [IC-7000] Hi I am new to this group I have problems with no ssb on tx
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Helen - I can't remember anyone else on this group with no TX only on SSB. In this group's Files section, look for '7K TX RF Levels.doc', which contains various signal levels that are useful in troubleshooting problems. ?The TX signal levels were taken in CW mode, but should be similar for SSB with full modulation. What are you using to measure the IF voltages? ?What is the signal level INTO the 1st IF and under what conditions (tone generator, loud AHHH into mic, etc.)? The last section of that document also has ALC voltages for FM and SSB. ?You reported that you have all ALC bars on but no ALC voltage. ?Where are you measuring ALC voltage? ?For SSB it should be 2.25 - 2.75 VDC at the point described in my notes. If the ALC meter has all bars on, that would reduce the 3rd & 2nd IF stage gain, which would of course reduce the 1st IF output. ?Recheck the ALC voltage per my notes. There isn't much in the hardware that is unique to SSB. ?The 3rd IF local oscillator frequencies are changed, per page 3-8 of the service manual. ?If you have a frequency counter, you could verify they are correct. ?The DDS IC is programmed via its serial data port, so there's no SSB mode signal that would account for your problem. Other than the 3rd LO, I haven't seen any hardware that is unique to SSB mode -- it's all in the firmware. Is RX in SSB mode also broken? I haven't seen any problems with solder joint quality in the 12+ 7K's I've worked on. Most had a thorough inspection under a 20-30X inspection scope with ring light, including applying pressure on some leads with a micro probe to make sure the bond was solid. ? As to recommendations for SMT rework equipment -- if you don't have it already, it's probably cheaper to send the radio to a Service Center, in my opinion. ?It costs about $500+ (USD) ?for basic equipment to properly change chip caps & resistors plus small IC's. ?You can try to do it for less, but at the risk of lifting traces on the PCB. If you still have connections with people that work at a company that does SMT assembly & rework, they may be a better option. Steve, W3AHL ---In ic7000@..., <helen_3ry@...> wrote: Hi Robert Thank you for your reply. Yes it does seem that it can't be the dac as it provides the other modes.? I also notice that this radio has those ribbons as well, they make me shudder as I have had some trouble with those in other equipment. I have retired out of? radio a few years ago and I have not worked much with SMD. Is there in techniques or tools that may be appropriate? Of course I have used an iron on SMD boards but not on any thing that I have overly worried about the outcome ! Regards Helen VK3RY On Monday, 25 November 2013 8:23 PM, BT Yahoo!?2013 <robert.farey@...> wrote: HI Helen ?????????????? many of these problems coming to light are as a result of the lead free solder used in the construction of these modern transceivers. so a dry joint is the most likely cause of a lot of problems with the Icom Ic7000. ???????????????????????????????????????????????????????????????????????? Best Regards Robert G6LLP From: "helen_3ry@..." <helen_3ry@...> To: ic7000@... Sent: Saturday, 23 November 2013, 11:30 Subject: [IC-7000] Hi I am new to this group I have problems with no ssb on tx
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Hi I am new to this group my name is Helen Vk3ry I have lost SSB upper and lower on my rig. I have been able to track the lack of TX down to the 1st IF? my thoughts it may be the processor, the rig is quite happy on am fm Rtty and good on ex. it implies the Dac is ok too,alc indicates very high alc although there is no alc voltage. I sure I am not the only one with this prob? ? ? ?? Any one with similar experience? KInd regards Helen VK3RY лл
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Steve W3AHL