Hi Glenn,
Normally cheap = a PITA to use.
The trick is very low pressure from the soldering iron no matter what you are doing. That will work for braid, and for the solder sucker. One main advantage about the solder sucker is that it removes most of the heat energy along with the solder. Wick doesn't do that.
-Chris
Normally cheap = a PITA to use.
The trick is very low pressure from the soldering iron no matter what you are doing. That will work for braid, and for the solder sucker. One main advantage about the solder sucker is that it removes most of the heat energy along with the solder. Wick doesn't do that.
-Chris
Thanks Chris. Have replaced those caps, soldered board back in without the shroud and reconnected the Pot for tuning. Lo and behold, can now tune both AM and FM. Amazing. FM is as clear as a bell and in stereo and picking up all local stations. However, tuning display not moving and signal strength meter not registering in FM. AM reception not as good as it was but can still tune stations using small indoor antenna. Tuning display not moving but signal strength meter is working in AM. Still have a transistor out of board and a resistor lifted as per Mooly's instruction to connect pot. Glenn
Hi Glenn,
Okay, pull the tuner pack and put it all together properly, then stick it back in. Once that is done you can try it again and list what is working and what is not. I had assumed you were going to put it all back together except for the shields when you tried it again..
It might not be a bad idea to put those parts back in and try it again without the shield. If the sensitivity is low without the shield, don't worry. Once everything is working, put the shield back on and stick the tuner pack back in for good.
-Chris
Okay, pull the tuner pack and put it all together properly, then stick it back in. Once that is done you can try it again and list what is working and what is not. I had assumed you were going to put it all back together except for the shields when you tried it again..
It might not be a bad idea to put those parts back in and try it again without the shield. If the sensitivity is low without the shield, don't worry. Once everything is working, put the shield back on and stick the tuner pack back in for good.
-Chris
And so am I
but very pleased it is making all the right noises. Are we saying it has 'healed up' with no parts replaced? It does happen that way sometimes unfortunately leaving you wondering...
Edit... it would be interesting to see if the scope now shows the local osc signal at the LM7000. With the tuner working correctly, that signal must be present. Can you now see it?
Hi Mooly. I did replace the two caps on the board linked to AMIN. As it turns out they were not that far out of spec. Maybe there was a cracked solder joint in the tuner and it got fixed with me pulling bits out and putting them back in. Anyway, all looks fine at the moment. Just have to put the metal case back on the tuner. Lots of solder points on that metal case. Hope it goes together OK. I take it the metal case is for shielding. I was looking forward to checking some signals out with the scope to see what I was supposed to see. I'll let you know. Glenn
A sine wave, the frequency will depend on the actual station tuned and I would expect it to be the station frequency plus 10.7MHz which is the FM IF frequency.
I think Rick looked at the data sheet for the LM7000 some while back and mentioned it quoted between 100mv and 1.5 volts as acceptable levels. Those are RMS levels and so should be around 280 millivolts peak to peak as a minimum. Remember this is over the 100MHz bandwidth of the scope and so the actual amplitude you see could be down a little.
Hi Chris. Played if for a couple of hours tonight and all good. Still need to install the case and reassemble. It was an adventure. Thanks for your patience and Mooly's as well. Thanks Nick also- learned a bit about IF transformers last night! I'll check with the scope and report back in a couple of days. Glenn
I thought it had passed the point of no return.
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