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Telequipment Oscilloscope problem

Danielsan

Aug 28, 2012
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Aug 28, 2012
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Hi

I'll just start by admitting that I'm completely ignorant when it come to electronics. However, I have a problem with an old oscilloscope that I'm hoping someone on here will be able to assist me with.

It's a Telequipment D43. I brought this beauty 2nd hand about 9 years ago and apart from smelling bad it worked perfectly. For the past 7 years it's been sitting at the bottom of my mum's cupboard though. A couple of weeks ago I finally managed to bring it over to germany where I now live but when I switched it on it was dead. I found that the glass fuse in the back had broken or blown. It's a 1.5A 16mm x 5mm and I have been unable to find anything similar in Berlin. Instead I tried a 1.6A 20mm x 5mm and held it in with gaffer tape but it blew straight away. The settings at the back of the scope allow you to adjust the voltage for the mains. Mine was set to 220 +20, should I adjust the voltage to 220 +10 to suit the german current? Or do I need to find the correct fuse? After the fuse blew the machine stank like dirty pond water so I don't know if it went mouldy sitting in that cupboard all those years. I did open it up to look inside but apart from some dust it looked ok.

Sorry for being so green, any help would be really appreciated though!

Here is a link to the model I'm using:

http://www.google.de/imgres?q=old+o...nw=84&start=0&ndsp=53&ved=1t:429,r:0,s:0,i:75
 

Harald Kapp

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Nov 17, 2011
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Fuses don't normally blow by themself. The blown fuse is probably only the sign for a deeper problem like a short circuit somewhere. Possible cuases are:
- short circuited overvoltage protection (varistor) in the power supply
- defect capacitor (electrolytic) in the power supply
- conductive dirt on the PCB (e.g. metal filings)
etc. etc.

You'll have to open the scope and inspect it. If you're lucky, you can identify the problem just by looking at the circuit. If not, you can trace the wiring from the mains plug to different sections of the power supply using an Ohmmeter.
The page you linked to shows a circuit schematic. It seems that if you're a registered user of that website you can download the schematic. That will greatly helöp in locating the problem.
 

Danielsan

Aug 28, 2012
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Aug 28, 2012
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Thanks very much Harald. If I do manage to locate the cause how easy would it be to fix the types of issues you listed? I've never soldered anything in my life.
 

Harald Kapp

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Depends on the cause...
If you haven't ever soldered, it might be a good idea to find someone who knows how to just to reduce the risk of further damage.
 

Danielsan

Aug 28, 2012
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Yes that would probably be the best idea, I might know a couple of people who could help out. Last question Harald, do you know where I might find the kind of fuse I'm looking for in Berlin? I've tried Saturn, Media Markt, Conrad and Obi but none of them sell fuses under 20mm. Are there any other german stores that specialise in this type of thing?
Thanks again.
 

Danielsan

Aug 28, 2012
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Aug 28, 2012
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Funny, the guy in Conrad said they didn't do that size. I'll just order it online then.

Thanks for the links Harald, you've been very helpful. :)
 
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