Re: Fixing the unrepairable IC7000
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Theres caps smooth the 5V rail, and were rated at 16V, Icom replacements are now at least 25V, Tants. have a life! The low capacity would have caused switching noise on the BUK 12V line, but should have worked. I have had this fault over 20 times with these radios. ? KR ? Andrew ?
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From: [email protected] <[email protected]> On Behalf Of Craig- KB4RU via groups.io
Sent: 13 March 2025 15:46
To: [email protected]
Subject: Re: [ic7000] Fixing the unrepairable IC7000? Based on the appearance of the solder joints, it looked like they were changed after radio was sold. ?It didn’t look factory. ?The solder joints were not clean, caps looked like a different brand, and looks like the solder used was different. ?I think someone serviced that display at some point and used wrong caps is more likely. ?
On Mar 13, 2025, at 8:13?AM, Bob via groups.io <W4JFABob@...> wrote:
? Nice job! I wonder if someone changed those caps for a particular reason or if it was a factory?change that didn't make it to ? Caps were 47uF instead of the 100uf listed in the service manuals.? Which I suspect lead to them failing or cause issues ? ? What do you mean by "inappropriate value capacitors"? ? It’s been a while since I updated, but the repair has been a major challenge.? Finally have a major update.? The radio has been repaired without having to replace any boards.? I bought a new DDS, Logic, and Main, but by the time the new boards would come in, I would find and repair the original.? So, now I have spares.? Onto the results! Not Powering on: Dreaded Click-Click was traced to Display Board having inappropriate value capacitors and burned spot next to connector on Main Board.? Replaced capacitors in Display Board and rebuilt the area around the burned spot on main board.? There was a broken/burned trace under the connector.? After this section was done, it powered up. Logic board- NO AUDIO.? This was a PAIN.? Found burned inductor L551, replaced.? Still no audio.? Replaced several resistors and capacitors trying to rule out issues along the signal path, no luck.? Replaced IC551 due to a suspicious spot and was in the path of the burned inductor….still nothing.? I pulled my 7000 back out and mapped ALL the signals for the audio circuits I could with an oscilloscope and found NO CLOCK SIGNAL on the CLK circuit.? Traced back to the same connector that was affected on the main board.? R705 on Logic Board had over 10x the resistance it was supposed to.? Replaced it and she is singing again. DDS board- no idea.? Seems fine for now, but I will find out when I move onto the alignment.? It said no RX/TX, but it seems like it is receiving.? If I post on this again, then I found a problem.? If not, there was no problem with the DDS unit.
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Andrew Lenton