Telequipment gone pop! - UK Vintage Radio Repair and Restoration Discussion Forum

Tractorfan · 22nd Jan 2021, 5:58 pm

Hi,
I dug out my dusty Telequipment D1016 'scope to test a signal generator. All was well for about ten minutes when the trace disappeared and something within started hissing with its accompanying release of magic smoke and acrid smell.
I traced it to an elec. cap on the PCB right at the back. Said PCB is on very short leads, and a

to access.
I eventually fished out a very sorry looking 22uF 250volt cap that was on the verge of bursting. The rectifier diodes tested OK, so I'm wondering if the cap was dying of old age, or something was stressing it all of a sudden. Alas, I failed to check the voltage across it when it was smoking.
Any advice welcome. I'm tempted to replace it and try again, Or should I?
Cheers, Pete.

ChristianFletcher · 22nd Jan 2021, 6:50 pm

I would be tempted to change the capacitor and just give it a try it most likely just failed of its own account. Those two resistor pretty much glow red normally when those scopes are in use anyway and always smell like they are about to go on fire. I often use one of the power monitoring plugs they are a good indicator when running up suspect equipment. I think that model was my first ever scope. I bought second hand but it cost me an awful lot of pocket money.

Tractorfan · 23rd Jan 2021, 6:33 pm

Hi,
Thanks for you reply. I did exactly that and fitted a 22 uF 400 volt cap and, so far so good!
So, just an old age cap that had had enough.
Cheers, Pete.

22nd Jan 2021, 5:58 pm	#1
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Telequipment gone pop! Hi, I dug out my dusty Telequipment D1016 'scope to test a signal generator. All was well for about ten minutes when the trace disappeared and something within started hissing with its accompanying release of magic smoke and acrid smell. I traced it to an elec. cap on the PCB right at the back. Said PCB is on very short leads, and a to access. I eventually fished out a very sorry looking 22uF 250volt cap that was on the verge of bursting. The rectifier diodes tested OK, so I'm wondering if the cap was dying of old age, or something was stressing it all of a sudden. Alas, I failed to check the voltage across it when it was smoking. Any advice welcome. I'm tempted to replace it and try again, Or should I? Cheers, Pete. Attached Thumbnails __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

22nd Jan 2021, 6:50 pm	#2
ChristianFletcher Heptode Join Date: Dec 2003 Location: South Yorkshire, UK. Posts: 900	Re: Telequipment gone pop! I would be tempted to change the capacitor and just give it a try it most likely just failed of its own account. Those two resistor pretty much glow red normally when those scopes are in use anyway and always smell like they are about to go on fire. I often use one of the power monitoring plugs they are a good indicator when running up suspect equipment. I think that model was my first ever scope. I bought second hand but it cost me an awful lot of pocket money. __________________ Every Silver Lining Has Its Cloud https://youtube.com/channel/UCvBpiuUUnErJlNBm6DWb3Ww

23rd Jan 2021, 6:33 pm	#3
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Re: Telequipment gone pop! Hi, Thanks for you reply. I did exactly that and fitted a 22 uF 400 volt cap and, so far so good! So, just an old age cap that had had enough. Cheers, Pete. __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."