Panasonic NV-F55B - PSU Capacitor replacement query.
 

Hi everyone I'm new to this great forum of information and very knowledgeable users.

I hoping some of you VCR repair techs might be able to help me with a query I have in regards to a Panasonic NV-F55B VCR I'm trying to get working again. It no longer powers up, a common fault it seems due to bad caps in the PSU. I have started working on the PSU but noticed 2 caps have been replaced before and I believe that they might not be the correct values that were fitted. Both C1109(primary side) and C1111(secondary side) were fitted with 47uf 50v Rubycon 85C. Does anyone know if that is the correct values? I have downloaded a service manual, but it only shows Panasonic part numbers for the caps, not the values.

Cheers, Steve.

Re: Panasonic NV-F55B - PSU Capacitor replacement query.
 

Hello Steve,

Welcome to the forum! I believe the values are actually on the block diagram for the PSU, so for C1109 it says 35V47 (35v / 47uf), and for C1111 it says 63V47 (63v / 47uf).

It's quite possible that C1111 may have failed, as the existing cap is rated under 63v. Also, the fact that both caps have a temperature rating of 85C is not ideal, as power supplies tend to run quite warm. It's possible both may have failed due to this, even though C1109 is actually a little above spec (50v instead of 35v).

I think for continued reliability it will probably be easier to go with blanket replacement of all the caps. I normally use Panasonic FC series from a reputable supplier such as CPC Farnell, RS Electronics, Mouser etc.

Best to avoid no-name caps off eBay, and also branded ones from China as they are likely to be fake. Hope that helps!

Re: Panasonic NV-F55B - PSU Capacitor replacement query.
 

hi, also fit 105degree types rather than 85 degree types

Re: Panasonic NV-F55B - PSU Capacitor replacement query.
 

Isn't this the chassis with the 1uf\400v on the primary. A classic one for failing and causing no power.

Re: Panasonic NV-F55B - PSU Capacitor replacement query.
 

Check the capacitors on the oscillator area and the secondary side. Make sure you fit in 105 degree caps. Are there any voltages comming out of the PSU?

Re: Panasonic NV-F55B - PSU Capacitor replacement query.
 

Indeed, the 1uf start-up cap is a common failure in Panasonic decks of this era, although blanket replacement would 'make-good' any capacitor-related issues.

On saying that, there are numerous things that can go wrong with these PSU's, such as failed IC's, shorted Zener's, poor earthing of the screening can/ dry joints etc, which can make repair rather challenging.

Anyway, start with the caps first, and yes 105C ones to be fitted. I should've made that a little clearer in my initial post!

Common fault list for this model attached:

Re: Panasonic NV-F55B - PSU Capacitor replacement query.
 

Brilliant thank you everyone I owe you all a beer. I feel daft for mistaking the values as part numbers, should've put my glasses on.:-)

So far I have removed all 8 of the old electrolytic capacitors from the PSU, checked the diodes, fuse, and re-soldered a few iffy looking solder joints. I have ordered replacement Panasonic low esr 105c caps for the PSU, and replacing all of them. Hopefully that's all that's needed to get it power up again. I don't know any history of the VCR as I brought it as it is for spares/repair. The rest of the VCR seems untouched and dosen't look like the mechanism has been broken or messed around with, just might need a new pinch roller as the one in it is very shiny looking.

I will let you know how I get on, and thanks again for the help.

Cheers, Steve.

Re: Panasonic NV-F55B - PSU Capacitor replacement query.
 

Replacing the caps has fixed the no power issue, but I've met another issue that might not be so easy to fix. Basically the head drum motor bearings seem to have failed. I had the machine playing fine, but after an hour I noticed the picture was moving slightly left and right. This got worse after another hour of use, then eventually it wouldn't play at all as the motor has too much resistance for it to spin freely. You can feel a bind when turning the drum by hand. Don't know if the motor can be serviced, or to take a chance on another faulty one I could salvage the whole assembly from, provided it hasn't the same issue of course.

Steve.

Re: Panasonic NV-F55B - PSU Capacitor replacement query.
 

Hi Steve

You can replace the bearings. You can find them from SKF or from other suppliers , but you must be familiar with the procedure. It is very easy to damage the video heads or the rotary transformers.
These parts are not available from panasonic.
You can only find NOS part or salvage other vcr.