Grundig A8400 F3026 CUC720 - UK Vintage Radio Repair and Restoration Discussion Forum

xrodney · 13th Sep 2023, 1:49 pm

HI

I have the above mentioned TV. I tried to switch in on, front channel display works but TV does not turn on. After a few minutes I heard a pop and smoke.

are there any service kits readily available for these monitors?

Welsh Anorak · 13th Sep 2023, 2:57 pm

I'm afraid with TVs like this you have to rely on old fashioned fault finding - no such thing as service kits for them.

Looks like a capacitor has failed in your second picture. Remove it and have a look and see what's happened. A spare shouldn't be too hard to come by. However it might simply be a bad connection on the blue coil - hard to tell.

German Dalek · 13th Sep 2023, 3:02 pm

Hi,

At first you have to find the right schematic.
I see a lot of corrosion and rust.

It should have been better, to dry the set out, inside a car which is placed in the sun, has to be no problem on Malta.
I should do that for about a week, then I should switch it in again.

Because of the moisture you have to count on a number of issues.

Are you able to measure?

Regards,

German Dalek

Maarten · 13th Sep 2023, 4:06 pm

The pop and smoke might be the mains suppressor capacitor which will be a Wima or Rifa paper capacitor. It will need to be removed and replaced even if it wasn't the problem this time.

The not fully turning on, might be the hifi relay.

Just two common problems, no guarantee, you might have to do a visual inspection and take measurements.

Edit: the blue capacitor in your second picture looks like a Wima paper capacitor.

Maarten · 13th Sep 2023, 4:48 pm

The other blue capacitor to the right of the coil should be removed or replaced as well.

Nanozeugma · 13th Sep 2023, 5:09 pm

From what I can determine from your image(s) one of the mains filter capacitors appears to have failed. They appear to be 3.3nF 400vac Y rated. Replace both and go from there.

xrodney · 14th Sep 2023, 8:16 am

Thank you all for the input. yes those 2 capacitors seem to have failed. the schematics show they are 0.15uf 250v.

I will take the board out, inspect it and start from there.

Maarten · 14th Sep 2023, 9:03 pm

They can be replaced by 0.15u 275VAC (or higher) X2 rated capacitors. MKT or preferrably MKP, no paper types.

13th Sep 2023, 1:49 pm	#1
xrodney Diode Join Date: Sep 2023 Location: Mosta, Malta. Posts: 2	Grundig A8400 F3026 CUC720 HI I have the above mentioned TV. I tried to switch in on, front channel display works but TV does not turn on. After a few minutes I heard a pop and smoke. are there any service kits readily available for these monitors? Attached Thumbnails

13th Sep 2023, 2:57 pm	#2
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,650	Re: Grundig A8400 F3026 CUC720 I'm afraid with TVs like this you have to rely on old fashioned fault finding - no such thing as service kits for them. Looks like a capacitor has failed in your second picture. Remove it and have a look and see what's happened. A spare shouldn't be too hard to come by. However it might simply be a bad connection on the blue coil - hard to tell. __________________ Glyn www.gdelectronics.wales

13th Sep 2023, 3:02 pm	#3
German Dalek Hexode Join Date: Jan 2011 Location: Düsseldorf, Germany. Posts: 352	Re: Grundig A8400 F3026 CUC720 Hi, At first you have to find the right schematic. I see a lot of corrosion and rust. It should have been better, to dry the set out, inside a car which is placed in the sun, has to be no problem on Malta. I should do that for about a week, then I should switch it in again. Because of the moisture you have to count on a number of issues. Are you able to measure? Regards, German Dalek __________________ And now something completly different: MARC BOLAN, he was/is the real king of Pop Music!

13th Sep 2023, 4:06 pm	#4
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,062	Re: Grundig A8400 F3026 CUC720 The pop and smoke might be the mains suppressor capacitor which will be a Wima or Rifa paper capacitor. It will need to be removed and replaced even if it wasn't the problem this time. The not fully turning on, might be the hifi relay. Just two common problems, no guarantee, you might have to do a visual inspection and take measurements. Edit: the blue capacitor in your second picture looks like a Wima paper capacitor.

13th Sep 2023, 4:48 pm	#5
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,062	Re: Grundig A8400 F3026 CUC720 The other blue capacitor to the right of the coil should be removed or replaced as well.

13th Sep 2023, 5:09 pm	#6
Nanozeugma Heptode Join Date: Nov 2017 Location: London, UK. Bury, Lancashire quite regularly :) Posts: 571	Re: Grundig A8400 F3026 CUC720 From what I can determine from your image(s) one of the mains filter capacitors appears to have failed. They appear to be 3.3nF 400vac Y rated. Replace both and go from there. __________________ Thermionic Emission, warms the cockles of your tubes.

14th Sep 2023, 8:16 am	#7
xrodney Diode Join Date: Sep 2023 Location: Mosta, Malta. Posts: 2	Re: Grundig A8400 F3026 CUC720 Thank you all for the input. yes those 2 capacitors seem to have failed. the schematics show they are 0.15uf 250v. I will take the board out, inspect it and start from there.

14th Sep 2023, 9:03 pm	#8
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,062	Re: Grundig A8400 F3026 CUC720 They can be replaced by 0.15u 275VAC (or higher) X2 rated capacitors. MKT or preferrably MKP, no paper types.