Panasonic AG-7700E VCR Jumping Picture When Cold

[Darky8]

Hi Folks!

1st post here and I'm pretty new to electronics repair, done the theory though!

I have found myself a nice looking AG-7700E, I quite like this machine to be a keeper (at least till I can find a AG-8700) however it's exhibiting some classic badcaps behavior.

The picture is quite unstable when cold. However, I don't think this is going to be my biggest problem. It seems this machine may have had some issues in the past which someone else might have had a go at. It seems to have random caps soldered on in places that all look rather dodgy.

My question really is, is this normal behavior for someone who would have carried out previous repairs? And should they be removed before any real fault finding is done?

I have attached a few photos to show what I mean.

Any help gratefully received.

Rowan

[selldoor]

Re: Panasonic AG-7700E VCR Jumping Picture When Cold

WoW! As it is still working they must have had some idea of what they were trying to achieve. Perhaps they thought at the time they would keep it until it was scrap so if it worked then it wouldnt really matter. Can you ask whoever you got it off?
I have no knowledge regarding VCRs so cant suggest much.
It looks a weird selection of different makes of caps but I cant make any of them out.
Guess first thing would be to make a list of the values of each and try and see if they just replace ceramic caps or solid caps or have just been added as "enhancement"
I think that bit with the blue wires must be factory fitting. Have you scoured the web for pictures of the boards.
If it was a monitor I would have suggested setting it all up and heating sections before
switching on. if you find a section where it works better after heating then you change the cap/s in that area. I dont know if you will be able to do that in a VCR.
Hopefully someone who knows a bit about them can give better help

[Darky8]

Re: Panasonic AG-7700E VCR Jumping Picture When Cold

Thanks for your reply...

Well I gave it the hot and cold treatment as best I could, but that test was inconclusive. Going to go through the schematics to see if these components are replacements for factory ones, or some sort of mod. If these caps are staying then will probably replace them with some decent ones due to their questionable origin, and tidy things up a bit.

[R_J]

Re: Panasonic AG-7700E VCR Jumping Picture When Cold

That second picture looks like factory mods, the first one is someone who won't go to the trouble of ordering the correct type of caps, the values are most likely correct.
The easiest way to repair this is with a scope and check the video signal etc. on the caps. or if they are bypass (filtering) make sure they are doing there job.

[Darky8]

Re: Panasonic AG-7700E VCR Jumping Picture When Cold

Thanks R_J,

I certainly do need a scope, I'm limited as to what I can do without one so that will be the next step. Many Thanks.