G'day fellow prospectors
I have 2 Deepseekers that work well and powers up every time they are turned on A fellow prospector gave me his unit to fix.
Sure enough turning it on it was dead as a dodo. Putting in new batteries didn't help. After fiddling around managed for
detector spring into life. With the detector ON it seems that by unplugging and plugging in the coil the unit would make it work.
Concluded the the problem as an intermittent re-solder all the joints on the Transmit and Receive sides. The problem is
still there.Looked at the plug and socket pins they were a bit corroded some what this just might be the problem. Replaced them
but the startup problem still persisted. Now did notice the plugging coil in and out trick didn't work all the time!
Looking at the circuit the unit wouldn't if the there was a problem in the Tx side. Hooked up a CRO ( digital one) and
there was no output.Doing the the coil trick the Tx oscillator would work and hey presto it works again. Analyzing the
weird circuit it was clear the LM 358 op-amp was tired. After replacing it the detector would fire up consistently over
number days. But after being off for a couple of weeks the Oscillator would not startup again. Starting once restarting
was not a problem. Checked the passive components they were all good. There are not many components in the oscillator so
the only variable is it a faulty coil? has anyone experienced this issue?