Telequipment d61 scope - UK Vintage Radio Repair and Restoration Discussion Forum

brockencomb · 13th Oct 2010, 10:48 am

Hi all
Anyone know where I could obtain a service manuel for this oscilloscope. On switch on there's no X deflection on some of the timebase ranges, after five minutes all is working well, I suspect a capacitor to be at fault. This has been a well looked after scope and has a yellow trace. I am little bit wary of delving into this without a manual. I am not without a scope as my normal one is a Hameg, but the D61 is great for soak testing of circuits as the main scope is then free for use elsewhere, anyway it's a bit of a family airloom.
Many thanks.

WME_bill · 13th Oct 2010, 12:14 pm

Telequipment D61. Manual attached. Let us know what the fault was please, so that we may all learn. Bill m0wpn

Tim · 13th Oct 2010, 10:16 pm

I have found most scope faults need a scope! Good luck!
Telequipment are notorious for their timbase circuits.

brockencomb · 14th Oct 2010, 9:22 am

Thanks Bill for the manual,the fault was there last night but not long enough for me to put a finger or a probe on it and yes the scope this morning is behaving itself! However a fault is a fault and will eventually pop up again, I still suspect it of being an electrolytic capacitor fault, maybe I should just change them all as this is quite an old scope, anyway I will keep the group informed of my progress and again thanks for the manual.

WME_bill · 14th Oct 2010, 3:45 pm

If it works more or less, then electrolytic capacitors are likely to be good enough for the moment. As it is intermittent, I would suspect dry joints or a bad connection first. That is why I suggested tapping everything everywhere; components and connections, with an insulated rod (=pencil). The fault disappears as it warms up, so could be heat related. So try spraying freezing fluid from Maplin/RadioSpares as this would show up a failing resistor.
A few good pokes should get the fault to re-appear, and then you are nearly home. A good stable fault is "easy" to repair. It is the intermittent ones which are difficult, as they see you coming and hide. Bill

brockencomb · 15th Oct 2010, 2:07 pm

Hi Bill
I'm think you're right as the fault did appear when poked and then promptly disapeared and has not been seen since.I remember some years ago I had a problem when the trace suddenley shortend to half the screen width and it turned to be an intermmitent preset pot.I now suspect this could the problem.
Will keep you informed.

13th Oct 2010, 10:48 am	#1
brockencomb Retired Dormant Member Join Date: Mar 2010 Location: London, UK. Posts: 78	Telequipment d61 scope Hi all Anyone know where I could obtain a service manuel for this oscilloscope. On switch on there's no X deflection on some of the timebase ranges, after five minutes all is working well, I suspect a capacitor to be at fault. This has been a well looked after scope and has a yellow trace. I am little bit wary of delving into this without a manual. I am not without a scope as my normal one is a Hameg, but the D61 is great for soak testing of circuits as the main scope is then free for use elsewhere, anyway it's a bit of a family airloom. Many thanks.

13th Oct 2010, 10:16 pm	#3
Tim Dekatron Join Date: Jan 2003 Location: Bradford on Avon, Wiltshire, UK. Posts: 3,310	Re: Telequipment d61 scope I have found most scope faults need a scope! Good luck! Telequipment are notorious for their timbase circuits. __________________ "Nothing is as dangerous as being too modern;one is apt to grow old fashioned quite suddenly."

14th Oct 2010, 9:22 am	#4
brockencomb Retired Dormant Member Join Date: Mar 2010 Location: London, UK. Posts: 78	Re: Telequipment d61 scope Thanks Bill for the manual,the fault was there last night but not long enough for me to put a finger or a probe on it and yes the scope this morning is behaving itself! However a fault is a fault and will eventually pop up again, I still suspect it of being an electrolytic capacitor fault, maybe I should just change them all as this is quite an old scope, anyway I will keep the group informed of my progress and again thanks for the manual.

14th Oct 2010, 3:45 pm	#5
WME_bill Octode Join Date: Oct 2007 Location: Exeter, Devon, UK. Posts: 1,554	Re: Telequipment d61 scope If it works more or less, then electrolytic capacitors are likely to be good enough for the moment. As it is intermittent, I would suspect dry joints or a bad connection first. That is why I suggested tapping everything everywhere; components and connections, with an insulated rod (=pencil). The fault disappears as it warms up, so could be heat related. So try spraying freezing fluid from Maplin/RadioSpares as this would show up a failing resistor. A few good pokes should get the fault to re-appear, and then you are nearly home. A good stable fault is "easy" to repair. It is the intermittent ones which are difficult, as they see you coming and hide. Bill

15th Oct 2010, 2:07 pm	#6
brockencomb Retired Dormant Member Join Date: Mar 2010 Location: London, UK. Posts: 78	Re: Telequipment d61 scope Hi Bill I'm think you're right as the fault did appear when poked and then promptly disapeared and has not been seen since.I remember some years ago I had a problem when the trace suddenley shortend to half the screen width and it turned to be an intermmitent preset pot.I now suspect this could the problem. Will keep you informed.