Grundig 2x4 880 picture and sound issues - UK Vintage Radio Repair and Restoration Discussion Forum

whaka54 · 2nd Jun 2023, 12:27 pm

hello,

i have 2 of them, more exactly they are philips VR2026 badged clones.
issues they have are small black stripes in picture in sharp details, and muffled sound.

i know what happen for picture, that's very likely the 3 MHz filter drifted.
but the service manual (in german) don't seems to talk about an adjustement for this.

and for the sound, i don't understand what happen
i can only say it's not a dirty head, or azimuth issue. i found a video on youtube showing exactly what happen :

https://www.youtube.com/watch?v=z_tcA4FWtXs

if someone know how to adjust the 3 MHz filter on thoses beasts, or have some clue on what happen with sound, thanks for help

Amtec123 · 3rd Jun 2023, 10:54 am

Hi,
I am not familiar with the Philips models you quote.
However as a general rule black "comet tails" are usually caused by worn video heads, thus reducing the overall frequency response of the replay chain. I say usually, as other factors can cause similar effects, i.e. tape path alignment, and mistracking. The YT video shows that the m/c on the right whilst better still displays what appears to be tape damage. This is far more evident on the left m/c, which certainly does have mistracking errors.
I'm sure others on the forum with knowledge of your m/c's will be able to give a more detailed reply.
Good luck
Les

whaka54 · 3rd Jun 2023, 12:11 pm

hello,

as i said, the VR2026 is a clone of the grundig 880, they are internally the same.
excpetion is the 2026 is a pal-secam BG/LL' variant. so this particular model was designed only for french/belgian/switzerland market and only available for some cross-border region.
a quite unique model

drop-out are more visible on the left, because the drop-out compensation level need to be corrected to make them more transparent than black or white dependig how the variable resistor drifted.
it's a common "failure" on those grundig, and also some philips made V2000.

we can also see the picture look blurry, but it's because you can adjust sharpness on those, and on this video it's set on totally soft.
you can even miss this adjustement exist as the slider pot is well hidden on the bottom left of the faceplate

for the short black stripes, i thought it might be worn heads.
but when you got 2 of them acting the same plus the youtube video not belong to me, but show exaclty the same behaviour that's more likely an adjustement issue than worn heads.
i'm pretty sure that's come from a misaligned 3 MHz filter.

i looked more closely the service manual, used a translator, and finally found where the 3 MHz filter is :

Click image for larger version

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ID: 279126

so i'll try to tweak L835/837.

2nd Jun 2023, 12:27 pm	#1
whaka54 Triode Join Date: Mar 2023 Location: Nancy, France. Posts: 49	Grundig 2x4 880 picture and sound issues hello, i have 2 of them, more exactly they are philips VR2026 badged clones. issues they have are small black stripes in picture in sharp details, and muffled sound. i know what happen for picture, that's very likely the 3 MHz filter drifted. but the service manual (in german) don't seems to talk about an adjustement for this. and for the sound, i don't understand what happen i can only say it's not a dirty head, or azimuth issue. i found a video on youtube showing exactly what happen : https://www.youtube.com/watch?v=z_tcA4FWtXs if someone know how to adjust the 3 MHz filter on thoses beasts, or have some clue on what happen with sound, thanks for help

3rd Jun 2023, 10:54 am	#2
Amtec123 Pentode Join Date: Jul 2020 Location: Reigate, Surrey, UK. Posts: 130	Re: Grundig 2x4 880 picture and sound issues Hi, I am not familiar with the Philips models you quote. However as a general rule black "comet tails" are usually caused by worn video heads, thus reducing the overall frequency response of the replay chain. I say usually, as other factors can cause similar effects, i.e. tape path alignment, and mistracking. The YT video shows that the m/c on the right whilst better still displays what appears to be tape damage. This is far more evident on the left m/c, which certainly does have mistracking errors. I'm sure others on the forum with knowledge of your m/c's will be able to give a more detailed reply. Good luck Les __________________ It's alright leaving me. Last edited by Amtec123; 3rd Jun 2023 at 11:01 am.

3rd Jun 2023, 12:11 pm	#3
whaka54 Triode Join Date: Mar 2023 Location: Nancy, France. Posts: 49	Re: Grundig 2x4 880 picture and sound issues hello, as i said, the VR2026 is a clone of the grundig 880, they are internally the same. excpetion is the 2026 is a pal-secam BG/LL' variant. so this particular model was designed only for french/belgian/switzerland market and only available for some cross-border region. a quite unique model drop-out are more visible on the left, because the drop-out compensation level need to be corrected to make them more transparent than black or white dependig how the variable resistor drifted. it's a common "failure" on those grundig, and also some philips made V2000. we can also see the picture look blurry, but it's because you can adjust sharpness on those, and on this video it's set on totally soft. you can even miss this adjustement exist as the slider pot is well hidden on the bottom left of the faceplate for the short black stripes, i thought it might be worn heads. but when you got 2 of them acting the same plus the youtube video not belong to me, but show exaclty the same behaviour that's more likely an adjustement issue than worn heads. i'm pretty sure that's come from a misaligned 3 MHz filter. i looked more closely the service manual, used a translator, and finally found where the 3 MHz filter is : so i'll try to tweak L835/837.