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-   -   Refurbishing a junk JVC S-VHS HR-S7600AM (https://www.digitalfaq.com/forum/vcr-repair/9533-refurbishing-junk-jvc.html)

dave_van_damn 03-13-2019 12:13 AM

Refurbishing a junk JVC S-VHS HR-S7600AM
 
Hello all,

A few months ago I bought a cheap JVC HR-S7600AM from a street seller here in Hong Kong. They usually sell junk and it can be hit or miss as to whether things work, but luckily this does -mostly!

Tapes play and rewind/ff without issues (although the reel wobbles a bit some times). I'm aware that this is considered to be a pretty good machine so I'd like to refurbish it to tip top condition.

I don't have a remote to test the extra functions, but the remote will cost like 4x the price I paid for the VCR so I want to make sure it's capable of being my main unit before I splash out on the remote! :laugh:

Here's a 2 min video high lighting the issues described below https://youtu.be/XXtQmzAZ514

Issue 1: Tape not being accepted by VCR
When I try to insert a tape, the VCR doesn't detect it very well and I have to push it in quite far before it begins to load it. Sometimes, on rare occasions it gets half way through the loading process and spits the tape back out. Can anyone point me in the direction of a reputable guide on how to fix this? I've seen posts suggesting changing of belts but the same guy was way off the mark when it came to their other repair posts, so I wanted to ask the experts here! :cool:

Issue 2: Roller guides getting stuck
When I load a tape, the roller guides generally move the tape to the drum without getting stuck, but when I eject you can clearly see the left roller gets stuck returning the tape to the cassette. I've looked at the roller path and there doesn't seem to be much grease on there. Is that what's causing the problem? If so, what grease do people recommend? I've read that silicone white grease is good but others suggest lithium grease...?

Issue 3: Composite output loose
As you can see in the video, the composite output isn't sturdy and won't output a picture unless I tilt the cable upwards. In the video, you can see that by doing this, the yellow input connector moves upwards and makes better contact with the board. Would I be right in assuming I need to solder this back into place? My soldering skills are passable but I'm worried about taking the board out in case I can't put it back together! It looks relatively straight forward though...is this repair as simple as it looks?

Potential Issue 4: No output from S-Video
I hooked the machine up via the S-Video out and plugged it into my TV and....no picture. Nada. Do I need a remote in order to switch on S-Video output? Does the S-Video output work for regular VHS tapes or only S-VHS tapes?

I'm sorry for the super long thread. I'm anxious to get this working as it's easily the best VCR I own and I'd hate to have to trash it.

Thanks for your help!

latreche34 03-13-2019 01:39 AM

Unfortunately there is no such guide on how to fix VCR problems, It requires repair skills and troubleshooting and the know how the VCR mechanism works.

You will need to take it a part, Pull the front face plate out and disconnect the ribbon cables, Take the mechanism out of the VCR, clean it, Lube it and reset the timing cam by spinning the loading motor by hand and observe all the modes , Also it could be a dirty encoder wheel which requires taking the cam gear assembly a part to get to it to clean it, There are timing marks and holes to help you set it correctly.

The main board and the back connection plate comes out in one piece, Re solder all connectors including the Y-C board S-Video connectors.

If you don't feel confident doing it yourself I'm afraid that you will have to pay a professional, Someone can help you find one based on where you live.

latreche34 03-13-2019 01:55 AM

After watching your video, The loading mechanism works fine, That's how it suppose to work, The tape guides are getting stuck because there is no grease in the tracks and to grease the back side of those slots you will have to pull the entire mechanism out. Also to soldier the S-Video jack the whole chassis needs to come out, You can probably get away with soldering the yellow RCA jack without pulling anything out.
To change the inputs use channels up and down buttons.

ofesad 03-14-2019 04:47 PM

One word: LUBRICATION.

At first sight your deck needs a lot of grease and oil.

Check DrCassete youtube channel he has a JVC and Panasonic tutorial of how to properly set em up.

About the grease, the best is lithium grease. Silicon based is good but not for this kind of equipment.
DO NOT use common (red) lithium grease. I don't know how you call in in english, here we call it "Super lithium grease", its green and softer than the common, it's the kind of grease used for treads and bearings.

Just resolder the RCA soldering points adding more material to so it wont move.


Svideo output should work with common VHS's and SuperVHS's.

dave_van_damn 03-14-2019 11:21 PM

Thank you guys so much for your replies. I'll keep an eye out for green super lithium grease and I'll try and find the YouTube guide. I figured it was a grease issue but wanted to get a second opinion!

As for the composite jack, I'm confident I can solder it well, I'm just a bit nervous about taking the board out. I've got no idea re: the s-video output as it doesn't seem to be wobbling, but I'll take a closer look at it this weekend.

I'm excited to get this machine up and running! If anyone else has any tips or advice about re:lubing or fixing the s-video output I'd be keen to hear! :)

dave_van_damn 03-21-2019 11:21 PM

I wasn't able to find green super lithium grease but I've found some white lithium grease - do you think that will be suitable?

I'd like to remove the board with the composite/s-vhs outputs (AV board) on, however, there's another board in front of it which is in the way. I can remove all the screws from the AV board except for the one which I've circled in the attached photos.

http://www.digitalfaq.com/forum/error.gif

http://www.digitalfaq.com/forum/error.gif

As you can see, there's a metal clamp of sorts in the way which is connected to the board in front of it. Is there an easy way I can remove the board in front of the AV board? I assume I need to remove the metal clamp from the mother board.

The problem is that I tried to take the entire motherboard and mechanism out but there are two screws at the front of the tape transport which are blocked by initial loading mechanism. Does anyone know how I can remove them? The only way I can get to it is if the loading mechanism moves forward - I tried moving the loading belt but it wouldn't move the mechanism forward enough.

Sorry if that's a bit vague - I'm not entirely sure of the terminology for each part!

dave_van_damn 03-23-2019 05:18 AM

2 Attachment(s)
Sorry, here are the pictures of the screw I'm trying to remove.

latreche34 03-23-2019 02:18 PM

First you will have to remove the face plate, disconnect its ribbon cables from the main board and release all catches (top, bottom, sides).

You have to use two fingers to release two latches in the cassette well, While pressing those latches on, spin the loading motor by hand from the pulley until you see the cassette carriage moving towards the back of the VCR, Move it enough to clear the screws, remove the screws out of the way and bring the carriage back to it's initial position.

Disconnect all ribbon cables, remove the mechanism first by removing the screws under the cassette well and the two large ones towards the rear, Also there is two white plastic studs attach the mechanism to the main board, Squeeze the head with a needle plyer to detach the studs from the mechanism. Be careful not to break the drum's ribbon cable attached right underneath it to the main board. The mechanism is connected with several snap in connectors to the main board you will feel some resistance.

With the mechanism out of the way you can proceed with removing the main board, Disconnect the remaining ribbon cables and screws, Remove all three black screws, two on top of the connectors board and one on the back of the VCR, The main board should come off. An alternative way is to remove the mechanism and board together and release the plastic studs, Drum's ribbon outside the VCR housing.

On the Y/C board or S-Video board you have to untwist the metal shield tabs to release the board from the main board, I Have never taken this a part myself but I would assume it uses a snap in connectors to the main board.

Now you have access to do the lubrication and re soldering jobs, Check for any leaky capacitors and replace as needed.

Warning:
Do not remove any mechanism parts or you will screw up the alignment
Do not get grease or oil on the hubs' brakes, Pinch roller or anything that touches tape.

dave_van_damn 05-27-2019 09:15 PM

3 Attachment(s)
Quote:

Originally Posted by latreche34 (Post 60343)
First you will have to remove the face plate, disconnect its ribbon cables from the main board and release all catches (top, bottom, sides).

You have to use two fingers to release two latches in the cassette well, While pressing those latches on, spin the loading motor by hand from the pulley until you see the cassette carriage moving towards the back of the VCR, Move it enough to clear the screws, remove the screws out of the way and bring the carriage back to it's initial position.

Disconnect all ribbon cables, remove the mechanism first by removing the screws under the cassette well and the two large ones towards the rear, Also there is two white plastic studs attach the mechanism to the main board, Squeeze the head with a needle plyer to detach the studs from the mechanism. Be careful not to break the drum's ribbon cable attached right underneath it to the main board. The mechanism is connected with several snap in connectors to the main board you will feel some resistance.

With the mechanism out of the way you can proceed with removing the main board, Disconnect the remaining ribbon cables and screws, Remove all three black screws, two on top of the connectors board and one on the back of the VCR, The main board should come off. An alternative way is to remove the mechanism and board together and release the plastic studs, Drum's ribbon outside the VCR housing.

On the Y/C board or S-Video board you have to untwist the metal shield tabs to release the board from the main board, I Have never taken this a part myself but I would assume it uses a snap in connectors to the main board.

Now you have access to do the lubrication and re soldering jobs, Check for any leaky capacitors and replace as needed.

Warning:
Do not remove any mechanism parts or you will screw up the alignment
Do not get grease or oil on the hubs' brakes, Pinch roller or anything that touches tape.

Thank you SO much for your detailed reply. I apologize for not replying earlier, but I wanted to take the time to reply properly once I had some time to try out your instructions.

I followed your steps and was able to take everything out HOWEVER I still can't take out the Y/C board (Illustrated on the photos as board B) as there is another board in front of it blocking access to it (Illustrated on the photos as board A). If you have a chance, please take a look at Boards 01 so you know what I'm talking about.

Do you have any suggestions as to how to get board A out so I can access the S-Video output on board B? I thought it was fastened on by metal tabs but when I twisted the tabs, the shield came off but the board remained attached! It appears that board A is attached to the main board via two black "things" (See Boards 02 for a top down view. The black "things" are circled) which are soldered to the underside of the mother board (See Boards 03). It almost looks as though the black "things" (sorry, I have no idea what they're called!) in Boards 02 are just slots which could be pulled out (similar to a SNES game cartridge) but I applied a reasonable amount of pressure but was unable to pull it out.

Any idea what my next move is? I'm assuming I'm going to have to de-solder every point circled in photo Boards 03 but that would be a disaster considering my amateur soldering skills! Surely there must be an easier way?!

Thank you all for your time. I really want to get the S-Video up and running because right now it's just an expensive paper weight.

latreche34 05-28-2019 01:17 AM

2 Attachment(s)
If you look in the service manual it is clearly that the board has mounting sockets. Just try carefully to separate them a part, I've attached the service manual:

http://www.digitalfaq.com/forum/atta...1&d=1559024007

dave_van_damn 06-27-2019 01:32 AM

I think I may have somehow killed the player.

I followed latreche34's excellent instructions and was able to remove the SVHS board. I resoldered the loose SVHS output and re attached the main boards sans the VCR mechanism in order to test the output. Sadly, SVHS still wasn't working. Dammit.

So I re-installed everything figuring that it may have recognised the VCR mechanism wasn't installed and plugged it in to test. The lights on the front of the unit lit up but I noticed the LED display wasn't working. So, I opened the player back up and the damn ribbon cable that connects the front panel to the main board had somehow torn. Anyway, after that I put the front panel back on and plugged it in and.....nothing. No lights this time. Tried to insert a tape and it won't accept one.

Have I killed it? And if so, how do I bring her back to life? The ONLY thing I can think of is that I may have possibly pulled the plug on it while it was powered on (no tape inside) upon noticing the LED screen wasn't on. However I checked the plug fuse and the internal fuse and both are fine!

latreche34 06-27-2019 02:57 AM

Check all your ribbon cables make sure they are not broken, are clean and fully seated, If everything looks fine start checking voltages according to the attached service manual, Possibly a blown circuit protector. I myself one time fried the drum circuit protector while trying to re-seat the drum motor ribbon cable while the VCR is on. It is not a good idea to mess or disconnect VCR components while it is still powered up.

dave_van_damn 04-04-2020 03:38 AM

Quote:

Originally Posted by latreche34 (Post 62227)
Check all your ribbon cables make sure they are not broken, are clean and fully seated, If everything looks fine start checking voltages according to the attached service manual, Possibly a blown circuit protector. I myself one time fried the drum circuit protector while trying to re-seat the drum motor ribbon cable while the VCR is on. It is not a good idea to mess or disconnect VCR components while it is still powered up.

I finally bought a multimetre and tested the continuity of the power board and found the following components were now showing continuity:

C5001 QFZ9051-683 F CAPACITOR 0.068µF,250V
C5005 QCZ9071-222 CAPACITOR 0.0022µF,400V
QAF0026-621 VARISTOR v10621u
QETN1HM-105 E CAPACITOR 1µF,50V


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