Nice troubleshooting. Glad I found your video channel and am going back to view your other episodes. Look forward to seeing how the repair progresses! 73 - Dino KL0S
+rich keller Thanks! Any way to do some of the checks I did to narrow it down? There will be a follow-up video once my dad understands that it is OK to have more time in retirement than before... We are going for a replacement filter from Murata, model CFWLA450KEFA-B0. It is available from mouser, part no. 81-CFWLA450KEFA-B0 It is important to select a filter with the correct bandwidth.
Very nice tutorial, I noticed that there are circuit measurements taken with the components still on the board, I guess if you know what is happening with the circuit it ok to do this. I do like the layout of the TenTec radio, and if you got a broken one on sale it could be quite a learning experience to fix it.
+Joseph Nicholas I guess you are referring to measuring e.g. resistance in circuit? You are very correct in that one has to be careful about that in the sense that resistors might be in parallel with other resistors or other components, which can potentially influence the measurement. Hence, it makes most sense to consult the schematic and asking the question "What reading will I expect when taking the measurement" taking into account all components. I did that but maybe I did not point out my thinking process sufficiently well while doing so. Thank you for watching!
1st, nice video. 2nd, It seems TT has had a lot of filter issues such as described. You can search this. Some say it is because TT doesn't use a DC blocking cap that is required per the Filter Mfg. application notes. And there is also a post regarding these Ceramic filters having internal moisture issues. Can't wait for the next video. A friend of mine just had two of these replaced on his Omni VII. Parts were cheap, the repair and shipping wasn't.
+Bob Ograv Wow, in one single comment, you put more information that I was able to retrieve from the Internet when I researched possible issues. I probably constrained my search too strongly on the Argonaut V, I will check again for general TT filter issues. TT was not very helpful in sourcing the replacement parts; I will discuss this in the follow-up: I do however have the replacement, now just have to schedule an appointment with my dad. Thanks and stay tuned!
in the minute 13:40 you say that the amplitud is 1.5 vpp and the power is 45mw.i can see the oscilloscope vertical scale is 50mv per division,then 3 divisions are 150mvpp and this is 56uw.power=vpp^2/8z =0,15^2/400=56uw.anyway very nice video
Heh, very nice I did not expect anyone to notice the mistake, congrats. I realized this on my way home but at the time the videos had been recorded already. This is what happened: This is my dad's scope and I used it back when I did not have a better scope. I have not used it in a long time. My dad had this fixed 10x probe that I always used and with this instrument, you have to multiply the voltage by 10 to undo the action of the 10x probe. The scope does not do that for you, unlike more modern scopes, you have to think of it yourself and do it in your head. Now of course the special adapter that I'm using is not a 10x probe, but because I was so used to always multiplying by 10 when using this scope, I did it without thinking and this is how my voltages are off by a factor of 10. Nice catch!
I find it massively annoying when a company withholds service information. especially when it comes to equipment like this. I refuse to buy any electronics that I can't get a service manual for.
