National NV-850-A Hi-Fi Stereo VCR (1984 Model)

derek92994

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#1
Just acquired this unit. It is in need of some gold capacitors. I may have to do more fault finding yet but am determined to get her up and running.

My father bought one back in 1988 and I used it to death, some nights would record up to 12 hours of music videos with it and then play them back throughout the day. That machine worked HARD. Went through 3 belt kits, a head cylinder, 3 power supply repairs (one due to power surge in 1989, they ran HOT anyways), and a mode switch.

It is a 1984 model and by the time it got to 2008 there was just too much wrong with it to justify the cost of repair. I do regret not taking the near new head cylinder off it before I threw it out. I still have the original head cylinder here, many many hours on that. These machines in working condition have incredible sound quality, it was a huge hit in Japan when this machine was released as it could pretty much match CD quality in the recording department, it was one of the first. Quartz Direct Drive Motor. Wow/Flutter 0.005%.

This is the new one I just acquired, Cosmetics are beautiful, and some mechanical parts look brand new, mainly the idler tyre, tension felt and pinch roller.




























Here's a Picture of the old cylinder from the previous NV-850 my father bought in 1988, quite a few miles on this head:











Here are some pics of the old NV-850 my father had and that I later acquired when he was done using VHS, notice the wear and tear, many of the parts are faded and tension belt/felt is rather worn. Although the head cylinder is near new (because I replaced it, cost me $180 for repair around 2001).










I'm determined to get this next unit restored to its former glory, they really were a fantastic machine, even though there is no picture video noise filter, the Hi-Fi sound is outstanding on these machines.
 
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gadget73

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#2
Something about that has a Matsushita / Panasonic look to it. Here in the US, National was a company mostly known for shortwave radios in the boatanchor era.
 

derek92994

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Something about that has a Matsushita / Panasonic look to it. Here in the US, National was a company mostly known for shortwave radios in the boatanchor era.
National Later became Panasonic =)
 

derek92994

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#4
Power Supply Care Package arrived for the NV-850 today. Thank you so much Lee, it is very appreciated and will be keeping me busy.
Also included a new Fuse Holder for the WOPL and some Solder, great stuff, thanks bud.
This will be the first power supply recap I have done.

 

derek92994

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#6
Still need to get 3 more types of caps. Replaced what I could in the power supply section and the unit is powering up now. Mechanism has been serviced and is operating perfectly. Even picks up Hi-Fi Tracks consistently. All tape functions work but there is no sound from the Line outs, just a faint hum, the headphone out is the same. VU meters aren't functioning correctly, sitting constant with about 2 bright bars, and the rest faint except for 0db mark, may be something to do with that hum. Need to investigate further but not sure where to look. Gremlin in the audio section.

Soldering is getting a little better



















 

derek92994

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Picture is great, just how I remembered it when the previous 850 was working well.







 

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#8
I sent enough caps to do the entire board. Use the higher voltage caps where the uf is the same. There is some Kester44 wound on the silver spool over the silver stuff. The idea was to get you both kinds and all I had was full spools.
 

derek92994

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Thanks Lee, what is kester44? I will get back to work on those caps once the machine cools down. I have been running it to see if that audio problem would go away and to break in the other caps. Can't believe I found an NV-850 with a good head cylinder and stable Hi-Fi Tracking.
 

derek92994

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I was wondering if you could use higher voltage caps with same uf, you taught me something here Lee. Is there is a limit to how high the voltage value can go at the same uf?
 

orange

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#12
THIS IS KESTER '44' (63/37 or 63/40 rosin core solder). Not that nasty old ROHS-compliant crap, REAL tin/lead solder that makes environmentalists change their diapers.



So awesome and manly it had to be made in CANADA as lead is not for WIMPS.
 
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derek92994

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#13
ITS ALIVE!!!!!

The close up shot of the counter looks weird as the value changed just as I snapped the camera, its working perfectly though. That world class sound is back, I'm actually playing a music video I recorded in my previous NV-850 from around 1994, perfect picture, as good as a single AV cable can get anyways. Hi-Fi sound is awesome with absolutely no 'head chatter' from the Hi-Fi Heads.

Thanks so much Lee, my first recap attempt is successful.













 

derek92994

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#14
Will test the recording capabilities of the machine after I have given it a good run. Will mainly be recording audio with this machine and playing back old video clips from back in the day, good memories. Back when we had analog tv broadcasts with Stereo sound. Love it.
 

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#15
Will test the recording capabilities of the machine after I have given it a good run. Will mainly be recording audio with this machine and playing back old video clips from back in the day, good memories. Back when we had analog tv broadcasts with Stereo sound. Love it.
D2
Solder looks sketchy on D1101, 1103, 1104, 1152.

Whenever you see board discoloration as you see under the central junction of this diode bridge construct, solder oxidation goes along with it.

You should touch up these joints while you are in there. Unfortunately you see this board discoloration far too often on the consumer stuff they turn out these days. Part of the warranty/obsolescence process that manufacturers use to get you to buy new.
 

derek92994

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D2
Solder looks sketchy on D1101, 1103, 1104, 1152.

Whenever you see board discoloration as you see under the central junction of this diode bridge construct, solder oxidation goes along with it.

You should touch up these joints while you are in there. Unfortunately you see this board discoloration far too often on the consumer stuff they turn out these days. Part of the warranty/obsolescence process that manufacturers use to get you to buy new.
I've already put it back together. How do I fix these joints? I'm a beginner.
 

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#17
I've already put it back together. How do I fix these joints? I'm a beginner.
Use a solder sucker or solder wick to remove the original solder. Reapply fresh rosin core solder (the K-44 stuff) and ensure that the new solder correctly whets to the component leads and to the circuit board trace.

Do it one pad/connection at a time.
 

derek92994

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Use a solder sucker or solder wick to remove the original solder. Reapply fresh rosin core solder (the K-44 stuff) and ensure that the new solder correctly whets to the component leads and to the circuit board trace.

Do it one pad/connection at a time.
That's what I did last time, what did I do wrong?
 

derek92994

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#19
I'll touch these up and post pics within the next day or two. Got some stuff to do. Thanks for the advice. Any harm in running it like this for the next day or so?
 
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