Grundig 3060 Resto in progress 300V ?? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

ms660 · 14th Dec 2019, 1:34 pm

Just to note, the de-coupling capacitor I referred to was the de-coupler for the Mixer AGC, the de-coupler for the IF AGC is the 33nF (C53) that's connected between the grid of the tuning indicator and chassis.

Lawrence.

Phantomrose1999 · 14th Dec 2019, 1:55 pm

I checked the voltage at the junction of R10 and R69 and the 47nf, and pin 7 of the EBF89. The DC voltage is ZERO !!

I measured on the other side of the 22M, that goes to the anode of the ECC81 and is about 80V there.

On FM that voltage dropped to 77.

But the Zero voltage at did not change when turning, nor did the 80V at the anode of the EcC81

So, should this voltage be more than Zero ? and should it change when stations are tuned please?

Phantomrose1999 · 14th Dec 2019, 2:31 pm

Quote:

Originally Posted by ms660

Just to note, the de-coupling capacitor I referred to was the de-coupler for the Mixer AGC, the de-coupler for the IF AGC is the 33nF (C53) that's connected between the grid of the tuning indicator and chassis.

Lawrence.

I checked the voltage at the junction of 53 (33nf) and the Grid of the EM34, the voltage is -3 with static and =5 on a strong AM signal.

C53 has been replaced with a 22+10nf, 630v cap.

There are no more caps to change, all have been changed and one 8.2nf was checked as good and left in.

I think the valves may be bad, but I have never seen a bad valve. Clue may be it takes a very long time after power on to actually receive something. I can't easily find the EBF89 and ECH81.

Station X · 14th Dec 2019, 2:45 pm

Quote:

Originally Posted by Phantomrose1999

C53 has been replaced with a 22+10uf, 630v cap.

Are we at cross purposes here? C53 is 33nF ie nanofarads

Phantomrose1999 · 14th Dec 2019, 3:01 pm

Its late here, been at this all day sat and half a day on friday...time for bed.

Yes, its 33nf ! i do use a digital capacitance checker because i cant decode the 103K number..

Well, it found an original ECH81, put it in instead of the 6Aj8, and its 100% improved, there is a little whistle, but no where near as bad...

Will look for a complete set of valves, this set sat around for several decades but at least AM is ok now, FM is weak, but may improve when its back in the box. But that is for tomorrow, off to bed, 8.30 AM to 1PM is enough of Grundig !

Phantomrose1999 · 15th Dec 2019, 6:16 am

Well, last day of play time.. back to work tomorrow.

https://www.youtube.com/watch?v=kt6yZJoQp8M

It sings, though the radio is not not great. I think the squeal is from oxidised contacts in the band switch, the squeal changes tones if i press harder, so thats the most likely reason. One day will get some proper contct cleaner that can get rid of the black layers on the contact.

Will also get a new EBF89, as putting in a good ECH81 made it super sensitive. It still takes a very long time to hear any reception after power up, and i think its the EBF89

My phone is very old and the mic is not good, the actual tone and quality of the music when playing music from my computer is 1000% better than the youtube video. All the high notes are muted by my phone.

Well, i will be using it as my amp for my laptop on youtube and netflix..

Wont get a chance to touch it again for a very long time, unfortunately.

14th Dec 2019, 1:34 pm	#21
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Grundig 3060 Resto in progress 300V ?? Just to note, the de-coupling capacitor I referred to was the de-coupler for the Mixer AGC, the de-coupler for the IF AGC is the 33nF (C53) that's connected between the grid of the tuning indicator and chassis. Lawrence.

14th Dec 2019, 1:55 pm	#22
Phantomrose1999 Hexode Join Date: Mar 2008 Location: Melbourne, Victoria, Australia Posts: 289	Re: Grundig 3060 Resto in progress 300V ?? I checked the voltage at the junction of R10 and R69 and the 47nf, and pin 7 of the EBF89. The DC voltage is ZERO !! I measured on the other side of the 22M, that goes to the anode of the ECC81 and is about 80V there. On FM that voltage dropped to 77. But the Zero voltage at did not change when turning, nor did the 80V at the anode of the EcC81 So, should this voltage be more than Zero ? and should it change when stations are tuned please?

14th Dec 2019, 3:01 pm	#25
Phantomrose1999 Hexode Join Date: Mar 2008 Location: Melbourne, Victoria, Australia Posts: 289	Re: Grundig 3060 Resto in progress 300V ?? Its late here, been at this all day sat and half a day on friday...time for bed. Yes, its 33nf ! i do use a digital capacitance checker because i cant decode the 103K number.. Well, it found an original ECH81, put it in instead of the 6Aj8, and its 100% improved, there is a little whistle, but no where near as bad... Will look for a complete set of valves, this set sat around for several decades but at least AM is ok now, FM is weak, but may improve when its back in the box. But that is for tomorrow, off to bed, 8.30 AM to 1PM is enough of Grundig !

15th Dec 2019, 6:16 am	#26
Phantomrose1999 Hexode Join Date: Mar 2008 Location: Melbourne, Victoria, Australia Posts: 289	Re: Grundig 3060 Resto in progress 300V ?? Well, last day of play time.. back to work tomorrow. https://www.youtube.com/watch?v=kt6yZJoQp8M It sings, though the radio is not not great. I think the squeal is from oxidised contacts in the band switch, the squeal changes tones if i press harder, so thats the most likely reason. One day will get some proper contct cleaner that can get rid of the black layers on the contact. Will also get a new EBF89, as putting in a good ECH81 made it super sensitive. It still takes a very long time to hear any reception after power up, and i think its the EBF89 My phone is very old and the mic is not good, the actual tone and quality of the music when playing music from my computer is 1000% better than the youtube video. All the high notes are muted by my phone. Well, i will be using it as my amp for my laptop on youtube and netflix.. Wont get a chance to touch it again for a very long time, unfortunately.