Panasonic NV-HD640 Repair

PetiMaci

Novice Member
Hello all, I'm into many things from 4K Blu Ray to Laserdisc. I've recently got hold of a couple of VCRs and one is a little worse for wear.

It's a Panasonic NV-HD640 PAL VHS VCR, the head spins and usually the tape gets offered up the head. However the tape won't start moving. Other times the tape tries to offer up to the head and gets mangled, the machine then rejects the tape.

I've some minor repairs to LD players and some cassette decks, such as swapping belts and so on. Unfortunately VHS is a bit more of a mystery to me. My main memory of it is my Dad being able to clean the heads, but anything else really went in for repair.

If anyone could sign post me useful generic guidance that would be great or any advice about this unit.
 

Gavtech

Administrator
Welcome to the forum.

This deck uses the Panasonic Z mechanism.

Be careful about being misled as to whether there is forward transport or not.
If you have the top off, too much light can leak in to the tape photo-sensors and the tape will stop forward motion.

Cleaning the mode switch is probably a good way forward, and doing so will lead you to any other problems if they exist.

The Service manual for this machine is available online if you search for it - not that it will help much.

This video should help too. It deals with cleaning the mode switch on a Z mech.
 

PetiMaci

Novice Member
Thank you @Gavtech - the video is really helpful. I actually have discovered a wheel that was sitting loose near the opening. I have cleaned it with alcohol, but doesn't seem to get completely clean.


Without the wheel:

20210523_104828.jpg



With the wheel:

20210523_104824.jpg



Now it seems to work!

20210523_105018.jpg



I'm guessing there is a clip missing that holds the wheel in place. As I'm sure that's liable to fall out if I moved the machine to another room. Also I found if I fast forward whilst playing - it moves upwards and falls off!

I've found the machine seems to accept tapes OK if pushed firmly and with both hands on edges -so I'll hold off until cleaning the switch until it's useless.


Would anyone happen to know what would work well to hold that wheel in place but keep it rotating?
 

Gavtech

Administrator
I presume the wheel you are referring to in the rubber Pinch roller.

This wheel presses the tape to the driven capstan and is what drives the tape through the machine in play mode.

This is what the assembly should look like. Is the white nylon piece missing?

Z Mech Pinch roller assy.jpg
 

PetiMaci

Novice Member
Apologies, I even knew that was a pinch roller from cleaning cassette decks - I'm a bit slow today. Yes, I'm missing the nylon piece. As you might have guessed I don't know much about the history of the machine. I'll hunt inside of the chassis on the off chance a piece of it still is there. I'll try find that service manual to get the part number too. I'm thinking if the part is expensive I might have to improvise, as I'm not aware if this is even considered a particularly high quality machine. I was mainly attracted to it as it offered Nicam and NTSC playback on PAL.

Thank you for your help so far.
 

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