Nice going, Damien - Yes, an arc of 220VAC to GND could result in some rather loud sounds. Obviously, it must have been the side that's on the supply side of the fuse, or else the fuse would have blown. Check your fuse to be sure that it's the correct value: the current rating should be half what it would be at 120 (I don't have the schematic in front of me at the moment).
Complete lack of function on one band suggests a bad crystal. I'd check all of your connections off the rotary switches, then try re-seating the crystal. You may want to try swapping in the 10m crystal just to see if you get some receiver noise. If you do, the 15m crystal's definitely bad. Good luck - Steve Wedge, W1ES/4 Time flies like an arrow; fruit flies like a banana. All my computers have my signature with various pearls of wisdom appended thereto. From: Damien Mannix Sent: Monday, August 27, 2012 11:33 AM To: drakelist@zerobeat.net Subject: [Drakelist] Exploding cap? Progress Hi all, It is time I gave all you kind folks a progress report. Found the WB4IQK AC3/4 troubleshooting guide invaluable. Tested all voltages with the covers off, very carefully! All okay. As promised by the seller I found that the two caps and four diodes in the 650v circuit have been renewed. Even though all seems to be well I will follow the advice given and approach Hayseed to see if they will supply the new parts for the 250v part of the unit. Surprise, when replacing the bottom cover I saw on the inside a charred patch about an inch in diameter with a very tiny hole almost in the middle! Never saw that before, silly me. Too busy examining components. The area is directly below the fuse holder. Probably would have been okay at 115v but it looks as though it arced at our voltage. I wonder if it has happened before? Anyway a bit of insulation and several hours running seems to suggest it is now okay. Please though, do not let anyone think they wasted their time giving me all that advice. I have loads to learn and it will all be most useful to me in the future. Fingers crossed it was time for me to try the TR4. First problem was that the MS4 speaker was silent! Fortunately all was well on phones. Turns out someone has rewired the big psu/tcvr socket with the speaker connections now on pins 5 & 8 which lead to the VOX relay socket! Irritating, I believe plugs for those sockets are impossible to find and correcting this in the tight space of that twelve connection socket will be quite a soldering challenge for me. As for the TR4, using a short length of bellwire as an antenna (crude I know) and a 50 ohm load for transmit all seems to be well except for 15 metres which is as dead as can be. Both TX and RX, nothing. It cannot even hear its own calibrator! Oh well, I am quite pleased really. It could be an awful lot worse and is probably good example of a TR4 once sorted. Thanks again all. Damien G3XER -------------------------------------------------------------------------------- _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
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