PANASONIC NV F70 Bad picture: which capacitor?

[promoter2000]

Hello. My VCR Panasonic NV F70 manifests the problem highlighted by the attached photo: just turned the image into play is very dirty but after about 20 minutes back perfectly normal. I am convinced that the problem is caused by a capacitor but I do not know which one. Please someone could help me? I'm not a technical but a simple enthusiast armed soldering station. Thank you all.

[Vauxfan2k]

Have you tried switching the noise filter to edit? If it goes away or is still there then it's the video pcb. It's likely ansurface mount cap and is a right pain to get to as all the boards need to come out and some desoldering of other boards required to gain access.

I have a fs90 that does this but only if the switch is on or off, when edit is selected the picture is fine.

I had found a good site that listed the caps that caused this on each of the Panasonic machines. Will see if I can find it.

[Vauxfan2k]

Unfortunately it doesn't list a video pcb location for the cap like it does for the fs90

This is all I got.

[promoter2000]

Thank you for the reply. I also downloaded that list and in fact in my FS 90 I solved a similar problem (thin horizontal lines) by replacing the capacitor signed C3311 (10uF / 16V) in the small metal container welded in HQ PACK. Unfortunately I can not locate the corresponding capacitor in the HQ PACK FS70 model.

[Vauxfan2k]

That will be the one I need to replace on my fs90 then. Where did you source the replacement cap from? And do you have a part number by any chance?

I have a f70, but as it's working fine haven't had it apart except for servicing and cleaning.

There's one on a popular auction site for £30 plus post, I know from talking to the seller he will accept 25. May be worth your while grabbing it and swapping the boards if yours is in better condition and you know the history of yours.

Fingers crossed for you whichever way you go.

[John123]

I don't think it would cost that much to re-cap the entire HQ pack, just make sure you use good quality ones like Panasonic FC series. Definitely worth a go if you don't have access to an ESR meter (to check capacitors with).

Also given the age of these machines, blanket replacement of all PSU capacitors is highly recommended.

[promoter2000]

Vauxfan2K: I do not know if I understood well the situation of your FS90 (my English is very limited ... I apologize) but I think he knows the phenomenology of all the series of S-VHS Panasonic ranging from FS100 (with which FS90 shares virtually all the electronics) to NV V8000 (i own 2 both broken for the same reason: the capacitors). These machines were built with capacitors totally inadequate for their class and cost. Their first problem: black screen in S-VHS, VHS ok reading. This problem is due to surface condensers 4 welded on the small VEFH05BT form welded half the Y / C adapter. Simply replace that small module (or only 4 small capacitors) and S-VHS is recovered. Another common flaw: poor quality of play (as in the case of the photo that I posted to F70). Just replace the capacitor C3311 (available at any electronics components shop for a few cents), and the play is recovered. Buying equipment can be risky and pointless: these flaws affect all samples without distinction (it happened to me so with a FS90 used bought in Austria).

[SiriusHardware]

Originally Posted by Vauxfan2k

There's one on a popular auction site for £30 plus post, I know from talking to the seller he will accept 25. May be worth your while grabbing it and swapping the boards if yours is in better condition and you know the history of yours.

[Feeling a little bit faint]. My NV-F70 (bought new) cost me over £600.

Still working well, fingers crossed. A capacitor in the PSU startup circuit went dry in the early noughties, but that's the only thing I've ever had to fix on it.

[Rennie93]

Originally Posted by Vauxfan2k

I had found a good site that listed the caps that caused this on each of the Panasonic machines. Will see if I can find it.

Would you mind sharing the website you mentioned? For the list of bad caps?

[Vauxfan2k]

https://www.yumpu.com/en/document/vi...s-r443-6r8-/69

Just scroll across to the required model.

With regards to replacing just the caps, from experience on boards that have tracks damaged/dissolved by leaking caps, it can be almost impossible to get the new caps to take to the tracks or even the board if the solder points come away with the old caps, requiring extensive bridge wires if/when possible. Ideally a whole new board soldered in would be ideal, as said from a donor machine or new old stock. Until you take the board out and inspect you have no way of knowing which way you're going to have to go.

As for the f70 in the original post, try swapping out the psu or replace the cap mentioned in the previous posts.

Cheers

[Rennie93]

Great - thanks

[AC/HL]

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