repairing faulty detectors

[bigdave]

hi guys, my name is dave. this is my first post on your brilliant website.

i was wondering since you guys know so much about detectors, how do you fix one with a fault in it somewhere?
do you just put a miltimeter on every capacitor and resistor and note the readings?
do you need a schematic to repair them? are schematics hard to make?

the fault i have on my detector is intermittant could this just be a dry solder?

please help me, i only have one detector and the weather is really hot here so i want to get out detecting.

thank you.
dave

[Qiaozhi]

hi guys, my name is dave. this is my first post on your brilliant website.

i was wondering since you guys know so much about detectors, how do you fix one with a fault in it somewhere?
do you just put a miltimeter on every capacitor and resistor and note the readings?
do you need a schematic to repair them? are schematics hard to make?

the fault i have on my detector is intermittant could this just be a dry solder?

please help me, i only have one detector and the weather is really hot here so i want to get out detecting.

thank you.
dave

Your description is a little vague. Firstly, what is the make and model of the detector, and where in the world are you located?

[bigdave]

sorry, the detector is a c scope promet 3.
and im in sunny scotland.

dave

[Qiaozhi]

sorry, the detector is a c scope promet 3.
and im in sunny scotland.
dave

Hi Dave,

In case others are wondering what a C Scope Promet 3 looks like, here it is:
It's an early C Scope IB detector.

In what way is the detector intermittent? If you give a tap in different places - the search head, control box, cables, plug assembly, etc., does this cause the problem? If so, then there's probably a bad connection in that particular area. If the problem is in the control box, then yes it might be a dry solder joint. Bit difficult to tell without seeing it firsthand. Try jiggling the different parts of the detector to try and isolate the problem.

Unfortunately you live some distance from me. I'm in the south of England near Oxford, otherwise I would take a look for you.

[bigdave]

thanks for the friendly welcome overyone!

hi Qiaozhi, sorry for quite an inaccurate description of the fault. it has only done this to me 3 times, its working fine then all of a sudden it stops working, it will pick the find up in the meter but it wont give a bleep for it, as i said the headphones work fine. i dont think it is the batterys either.
it is a very annoying fault, last time i was out with it, it decided to stop working when i was six miles from my house, i had to wait a further 4 hours or so for my lift home!
now its working fine

dave

[bigdave]

forgot to add these

[Qiaozhi]

Ahh! - different Promet model.

I guess wiggling the headphone connector had no effect?
There are two possibilities here that I can think of:
1. There is a bad solder joint/2 wires nearly touching somewhere inside. You should be able to find this by tapping around and wiggling the various parts of the detector.
2. It's a heat related problem. Although it sounds like it still wasn't working after about 4 hours, so I guess it's not that.

It does appear to only affect the audio output. In that case I would suspect either the headphones (but you say these are ok) or the headphone socket. If there was a dry joint on the PCB I would expect the problem to occur more often.

Some more questions:
Does this detector have a built-in speaker? (My guess is no.)
Did you try another set of headphones when the fault occured?

I know it's working at the moment, but you might need to open the control box and poke around to make it go wrong, otherwise it could happen again at an inconvenient moment.

[bigdave]

hi Qiaozhi, it does have a built in speaker, i couldn,t try another pair of headphones when it stopped working as i only had 1 pair on me, then when i got home it was working again.

when it stopped working i first suspected the head phones so i pulled them out and tried putting a coin under the search head, but still no sound. iv looked at the headphone socket and it seems fine to me.
cant think what else it could be really.

dave