Video: Repair of a Yaesu FT-817 with a Tx problem on SSB, CW, and AM - Page 1
Forum section: electronics / repair

author: w2aew
author_rank: Super Contributor
timestamp: June 24, 2016, 12:49:31 pm
content: This video documents the troubleshooting process I went through to repair a Yaesu FT-817ND QRP all-mode HF/VHF/UHF transceiver. The problem was that the unit would not transmit on SSB, AM or CW modes of operation. Transmit on FM, Digital and Packet were fine on all bands, and receive functionality was fine on all bands and modes. The video documents the troubleshooting process, but does not show the bench work (scope and DMM measurements). This repair wouldn't have been possible without the great information from Clint, KA7OEI, and the fantastic information available on his FT-817 resource pages:http://www.ka7oei.com/ft817pg.shtml

author: bitseeker
author_rank: Super Contributor
timestamp: June 24, 2016, 07:12:44 pm
content: Alan, I'm enjoying your recent repair vids. Hope you'll be doing more. Great idea making those big prints of the schematics: easier to read, but also looks cool.

author: w2aew
author_rank: Super Contributor
timestamp: June 24, 2016, 09:05:19 pm
content: Quote from: bitseeker on June 24, 2016, 07:12:44 pmI know! Now the the repair is done - I'm a bit torn about folding up the big schematic, or hanging it on the wall! :-)

author: bitseeker
author_rank: Super Contributor
timestamp: June 24, 2016, 10:08:07 pm
content: Yes! I was thinking the same thing. Why not hang it on the wall? Adds to the lab atmosphere.

author: The_Penguin
author_rank: Regular Contributor
timestamp: June 25, 2016, 01:06:29 am
content: Another great repair video.Enjoyed it. Just curious, how long do you think it would have taken had you not heard about previous cases of open transformers?

author: w2aew
author_rank: Super Contributor
timestamp: June 25, 2016, 01:48:05 am
content: Quote from: The_Penguin on June 25, 2016, 01:06:29 amSeveral hours longer, or more, I'm sure.

author: nowlan
author_rank: Frequent Contributor
timestamp: June 25, 2016, 03:04:51 am
content: I was wondering why the transformer failed. Vibration?Unrelated, but I was wondering about automotive grade parts. I always assumed was heat or water, and epoxy was solution.

author: bitwelder
author_rank: Super Contributor
timestamp: June 25, 2016, 11:31:15 am
content: Teardown of the failed transformer? Still possible?As coils/transformers usually would not be on top of my list of suspects, I'd like to see how they may fail.

author: HighVoltage
author_rank: Super Contributor
timestamp: June 25, 2016, 11:33:47 am
content: What a great repair video.I always learn something from your explanations.Thank you!

author: w2aew
author_rank: Super Contributor
timestamp: June 26, 2016, 03:11:55 am
content: Not sure how or why the transformer failed. Unfortunately, I destroyed the part while removing it, so no post mortem is possible. There is some really fine wire in there (40AWG?).

author: bitseeker
author_rank: Super Contributor
timestamp: June 26, 2016, 03:52:18 am
content: The first three things that come to mind:1. Excessive vibration2. Circuit design flaw3. Manufacturing flawIs that component spec'd OK for its given operation?

author: w2aew
author_rank: Super Contributor
timestamp: June 26, 2016, 04:40:44 am
content: I suspect a manufacturing flaw of the part. There are about two dozen similar devices in this rig.

author: bitseeker
author_rank: Super Contributor
timestamp: June 26, 2016, 06:57:27 am
content: I concur. Since it happened to someone else, perhaps it was a bad batch. Hard to tell with a small sample of incidents. Of course, a service note or similar from the mfg. would've settled it.

author: w2aew
author_rank: Super Contributor
timestamp: June 26, 2016, 05:31:08 pm
content: Nice validation of the repair yesterday. I setup an impromptu station at a local park, using a end fed half wave antenna raised in a tree and a 12v LiPo battery, I made several contacts between 500 and 1000 miles away with the 5 watt output of the rig on the 20m (14MHz) band.

author: bitseeker
author_rank: Super Contributor
timestamp: June 26, 2016, 09:04:22 pm
content: QA in the park. Very good!

author: w2aew
author_rank: Super Contributor
timestamp: June 26, 2016, 10:11:43 pm
content: Quote from: bitseeker on June 26, 2016, 09:04:22 pmThe coolest part is that the park was the Guglielmo Marconi Memorial Park in Franklin Twp NJ, which was once part of the Marconi Wireless Co. transmitter site known as New Brunswick Station over 100 years ago:https://en.wikipedia.org/wiki/New_Brunswick_Marconi_StationKind of an appropriate QA location, don't ya think?

author: bitseeker
author_rank: Super Contributor
timestamp: June 26, 2016, 10:15:59 pm
content: Yes, quite! Sounds like a perfect subject for a short video (repair followup and tour/history).

author: Radio Tech
author_rank: Frequent Contributor
timestamp: June 26, 2016, 11:07:03 pm
content: Most likely a manufacturing flaw. As stated the wire inside these transformers are very fine. Does not take much to cause an internal failure. Unlike the IF cans in an old tube rig, which fail from capacitance issues when the formers shrink.Good repair Alan, enjoyed the process.

author: w2aew
author_rank: Super Contributor
timestamp: June 27, 2016, 04:18:41 am
content: Here is a short 3 minute video overview of my Ham Radio Field Day setup where I used this rig (as well as my Icom IC-703).

author: bitseeker
author_rank: Super Contributor
timestamp: June 27, 2016, 05:44:02 am
content: You're too good, Alan. Already recorded it all!

author: Radio Tech
author_rank: Frequent Contributor
timestamp: June 27, 2016, 11:32:10 am
content: Nice field day spot.Good job.

author: mrf245
author_rank: Regular Contributor
timestamp: June 28, 2016, 02:23:45 am
content: FT817ND is a good QRP portable radio. Nice job