Few days ago the power went off and on several times and all my devices were fine except my JVC VCR which went off and didn't turn on, so I thought it is the fuse, so I bought a fuse and replaced the bad one, but it didn't turn off, so I thought maybe the fuse is defective, so I shorted the fuse and I had a spark which I don't know if it made more damage, so again I replaced the fuse and brought a volt meter and I was checking the volt to see were it stops then I might find the damaged part, and here are the result:
- I had 7.6v every were and when I compare it with other JVC VCR that I have it was the same.
- There is 2 main parts the printed circuit board and the tape compartment which has the head, so I left the tape compartment to check more parts.
- Again I had 7.6 every where, what I don't understand is the led in the front is off but it had 3 legs and each one I test has 7.6v, so why it doesn't turn on.
- Any ways, I press the power in the front and nothing chages, it is always off.
- I don't know if any part in the tape compartment is damage doese that affect the VCR power?
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Most likely a power surge hit your vcr and fried a part in the psu,not worth repairing.I think,therefore i am a hamster.
It sounds like you don't know what you are doing or looking at so the best advice I can give is to follow what the others said. Not worth repairing yourself and to just replace it.
FYI, If all leads on an LED have the same voltage, of course it would be off. An LED doesn't do anything other than indicate. It requires a voltage difference across it in order to come on. Equal voltage on all terminals will not turn it on. One has to go to 0V. That is not your problem. Your problem is that something got fried and without an uderstanding of how things work and without a correct schematic, chances are you won't be able to fix it.
Another thing, never bypass a fuse. It went out for a reason. To bypass it may cause further damage.
First, thanks to all who try to help, second I know it might not worth to fix and I already bought another VCR, but I thought it is fun to find a problem and fix like a puzzle specially that I have another JVC VCR that has good parts but it doesn't work properly, so I though if I find the fried part I will replace it from the one in the other VCR.
kimco52, yes I am not an expert nor technician but I thought I will use a common sense by checking the voltage before and after each part and when I got voltage before but not after it means that this is the fried part, but I was confuse when I found the voltage every where, another thing I know I suppose to get 7v one leg and 0v in the other but since it is not working I thought it will be 0v in all legs not 7v, and that is why I am asking.
Anyways, I tried and I didn't loose any thing.
Thanks again and best regards,
If this is an extra VCR, and you're wanting to learn more about electronics with a no-risk-of-loss device, go for it. I wish you well. It's always fun to have something close to play with. I keep a couple of VCRs that are broken, just to tinker with. I'll never fix them, but it's good to experiment with, maybe steal parts from.
Normally, with LED's, the high voltage is always applied and when it is supposed to turn on, one lead gets pulled down to 0V. It is simple to do electronically.
Because you have some voltage, that means the fuse is not in the line but in some other circuit in the vcr. Comparing one deck to another does not always yield the defective part. It depends on how it is wired. You need a schematic to trace the problem and find the bad part. It is not always obvious. The way many things are in one chip nowadays, it is usually easier and cheaper to just replace the whole thing or shotgun it.
While its always useful to figure out the exact "why" of something, it can veer off into an unproductive timesink. This kind of damage is usually "repaired" by simply replacing entire subassemblies, it isn't usually worth the time and effort required to isolate the exact component that got fried. If the second VCR you picked up is identical to the one that was damaged, you could try swapping the good power supply into your dead recorder: theres a 50/50 chance that would repair it. Beyond that you would need an extensive suite of test probes and the schematic, a level of service even JVC itself doesn't bother with anymore. Now and then, you come across something truly weird like the loading carriage stripping a gear and its jam sensor preventing the VCR from ever powering on. That can take a really long time to troubleshoot and may not be repairable. Loading systems on many VCRs were mostly nylon and welded together by robots: there aren't any replaceable parts and the VCR was deigned to be disposable in such instances. This is surprisingly true even of some expensive SVHS editing models by each mfr in certain years..
Let me thank you again all for your comments.
I would like to remind everybody that I know it is not worth to spend a time and money but I am doing that only for fun, therefore, I don`t mind at the end I will junk bother VCRs, but let us do it vise versa, my old VCR is working but has too much tracking, freezing sometimes and turn off by itself, so what is the part that cost those problem so I can use the same part from the one that is not working?
BTW, they are not identical, otherwise I would change the whole PCB, but parts like the head is the same.
You have to first determine if it is electrical or mechanical.
A good head cleaning wouldn't hurt, either.
Originally Posted by orsetto
Originally Posted by lordsmurf
Actually the first "disposable" VCR I was made aware of by my service guys was an early-90s Panasonic. I forget the year, but I think it was when they first introduced a basic "color noise filter" as the big new feature throughout the line. I had the unit just below the top of the line, and when its loader broke 18 mos after purchase I was amazed when the repair shop showed me a service bulletin from Panasonic itself, suggesting repairs not be attempted out of warranty, because there were no replaceable parts in the loading assembly: the entire guts of the VCR would have to be replaced as a module at a cost exceeding a new replacement VCR. Needless to say I was non-plussed, having spent $400 on a non-repairable VCR. At least I hadn't blown $700 on the top model, a rare consumer-grade unit with flying erase and a crude TBC. Shortly after this, Mitsubishi started in with loading mechanisms that decayed and cracked with use and JVC cheapened the 9911 beyond the pale. Thats why I recommend only known-repairable models when shopping used high end VCRs: the Panasonic AG1980 or 1970, wide-body metal chassis JVCs like the 9600, and perhaps very recent DVHS units by JVC and Mitsubishi. Everything else out there, you just toss when it breaks.
mishtag, we do understand you want to play around for fun, to see if you can fix your particular VCR. What we're trying to explain is that without proper mfr schematics and test instructions, you won't have any fun: theres little you can do if the power surge fried something, and perhaps nothing you can do if its mechanical. Most VCRs since 1997 have used modular subassemblies that are replaced all at once, so unless you have a very similar model you can swap PCBs or entire mechanisms with you may not be able to accomplish much in the way of repairs. Usually a power surge fries one of the tiny surface-mount microprocessors: these are not replaceable, you have to change out the entire board or power supply- assuming you can identify which board has the fault. If the power board is not sealed, and you can visually see a burned or leaky capacitor, you should be able to repair that. But anything involving IC chips would be almost impossible.
Originally Posted by lordsmurf
Panasonic could be sneaky as well: after 1996, they would just plop the same mechanics and electronics from the compact "discount series" into wider-body midrange and SVHS cabinets- if you looked under the cover, you'd essentially find the small VCR glued into the larger cabinet with a lot of empty space around it. This wasn't necessarily bad, the small Panasonics were decent then, but you didn't really get what you thought you'd paid for either. From the mid-90s forward, only the semi-pro AG1970, AG1980, AG2550, and AG2560 had the all-metal transport and repairable parts. The final 2001-2003 run of Panasonic AG "semi-pro" models that looked like the all-plastic JVC 5912, were the all-plastic JVC 5912 with a Panasonic badge on them. Disgusting crap and a must to avoid.
orsetto, I will take your advise and give up and save my time, I really enjoyed this discussion and learned a lot, thanks again and I will continue checking the subject just to learn more if more info to be posted.
Thanks to all again,
Some many years ago, a friend and I were really frustrated by some broken computer hardware, VCRs, etc .... we got on top of his three-story house and watched them smash all to hell on the driveway. Quite therapeutic.
A number of colleges actually have engineering and computer programs where they do similar things. Skeet shooting old hard drives, discus with keyboards, etc. Pull!
Plenty of ways to still have fun with an old POS.
to mishtag, all VCRs including that JVC, has a switching mode power supply (SMPS). An electronics professional will be aware of some things that SMPS in domestic VCRs will have in common, like some likely voltages in standby and operation, etc.
I have become familiar with such because I record live events for a hobby. Mic outs from the insert posts of mixing boards individually go to the analog inputs of two M-audio Delta 1010LT PCI soundcards in a PC (16 analog tracks total). This arrangement has never failed me, but ultimately the recording device is a full-fledged PC that can hang and misbehave in an unpredictable manner, so the backup is an analogue recorder. The only low-cost viable stereo audio recorders left are hi-fi VHS VCRs, and I connect the rec outs of mixing boards to the line-ins of such a VCR.
One such VCR I currently use is a JVC HR-S5600M, which, like all consumer VCRs of late have no headphone outputs. This is essential for monitoring if audio is really getting to the VCR and being recorded; audio levels that are too low will not register on the VCR audio meters at all. I make headphone amplifier circuits based on an NE5532 op-amp, which I stash in any of the wide spaces inside the VCR. I find space in front where to put the headphone socket and volume control. The accompanying pic shows the JVC with a headphone 1/8" jack and volume control.
One problem with putting such a circuit in the VCR is its supply voltage. Testing the SMPS outputs show that JVCs have a +5V standby, a main +5V, a +8V, a -30V, and a +12V. Those voltages should tell you the +5v will likely be for the logic, the -30V is for the vacuum fluorescent display, the +8V is for some exotic circuitry, and the +12V will be for the motors and other power ersatz. These voltages will always be found on the SMPS output, and you know they are the outputs because there will be some big-value electrolytic capacitors there (1000uF or so).
My headphone amplifier is powered off the +12V line. I've even put balanced audio outputs in some JVC VCRs powered from the same.
The LED in front is not an LED but the remote receiver phototransistor circuit (sometimes shielded in a metal can), which has three legs (+V, gnd, and out). If pressing the power button doesn't wake the VCR up, the first voltage to check is the +5V standby. On some JVCs I have come across, the heart of the SMPS is a hybrid power IC; others have a DIP switching IC driving a power MOSFET. Power surges like the ones you encountered sometimes fry the hybrid in the former, or the MOSFET in the latter. Since you're getting +7.6V though, the SMPS could be oscillating but the +5V line is down, because a MOV protective device has shorted, or the diode from the main switching transformer providing the +5V line has opened, or heaven forbid, the logic devices were exposed to something higher than +5V, which indeed means you have to junk your JVC out of necessity.
On the other hand, in many cases, the large electrolytic output filter capacitors I mentioned earlier have gone dry or physically ballooned (common to SMPS, including that of PCs) and they marginally work until a power surge tips them off into the void, so they must be replaced.
You seem keen on this maybe you should study electronics professionally if you haven't started so.
img_0170.jpgFor the nth time, with the possible exception of certain Intel processors, I don't have/ever owned anything whose name starts with "i".
This thread has been a real eye opener. This has explained some quirks with my last SVHS deck which is a JVC 3800U and why it's slowly going bad (intermittantly). My Sony SLV-R5U is proabably dead for good unless it can be repaired at a larger factory repair center. The local one doesn't handle VCRs anymore. If it was just mechanical things like idler tires or belts, I can probably do those repairs myself as one of the last local electronics shops still has a ton of old rubber parts in sealed packages depending on the model/make. I'm figuring the big IC in the PSU went when we had a local power outage. I have protected power bars and filters but that is a really old deck now and it is probably time to retire it. Probably unlikely that I'll find any of the replacement decks mentioned on this and other sites though unless I get really lucky. Guess I'll just have to play it by ear....
If it's "slowly" going bad, you're probably witnessing the effects of gravity on the deck. It's developing an alignment issue as tie goes by. That's all.
Of course, you've not stated the exact error, so I'm blindly guessing.
The Sony SLV-R5U is a special case. It is legendary worldwide for being arguably the best SVHS deck ever made (definitely the best Sony SVHS) with the worst PSU design ever put in a VCR. This SLV-R5U's biggest albatross is its rotten, overcomplicated, fragile PSU: it self-destructs to the point of catching fire in some cases. Back when it was made, Sony lost a small fortune on warranty repairs, and out-of-warranty PSU replacement was common (and hideously expensive). Today almost no repair shop will touch it at any price, but if you're technically inclined there are DIY tipsheets floating around online explaining how to disassemble/repair/upgrade the PSU. Not a project for the faint-at-heart, to be sure, but those who love this VCR love it passionately so it may be worth it to them. Unfortunately another caveat with the SLV-R5U is the mechanics: not so great either. Parts can be had or repurposed from other Sonys, but its a PITA to repair and align, and alignment is practically guaranteed to drift every few months (shes a notorious tape eater). One of its other perplexing issues is a gradual decline in standard (non-SVHS) playback performance as the unit ages, which apparently cannot be restored and is unaffected by servicing. Overall, not a recommended choice as a source deck for DVD transfer: it was prized for its SVHS recording abilities back in the day, but as a general-purpose player it can't hold a candle now to the JVC 9600 or Panasonic AG1980.
That may be but the unit I inherited from a friend who got out of tape a few years ago has never eaten a tape. Probably because I had the entire mechanical section replaced at the time I got it by the last of the Sony factory trained techs in the city. He was meticulous in making the repairs and the deck worked flawlessly up to a couple weeks ago when the PSU went out. I've since located another unit in another town that I might get to cannibalize the parts I need. The other pro units are now out of my price range and are mostly unavailable or not worth shipping them across the border. Pity that....
Now if I could only find someone to fix my Hitachi Studio Edit deck. I can't even find part numbers for that unit and have since retired it as well....
Between the economy tanking and most of the "early adopter gearheads" being done with their "VHS library to DVD" transfer projects, some of the better VCRs are being dumped by the dozens every week. If you love your Sony, and can jerry-rig repairs cheaply enough, it makes sense to keep it going. But if you can afford about $150 (US) total, scour eBay every day for a few weeks and look for a Panasonic AG1980. Two years ago you could rarely find one below $400, between September and today I picked up four of them for under $100 each + shipping. If you shop carefully you can easily find one with a crummy-looking cabinet and perhaps a dim display panel for under $100, shipping to Canada should not run more than $50 if you match yourself with a seller on the same coast. Upper-end JVCs have also come down in price, but not to the same degree, and JVCs are twitchy beasts that are difficult second-hand purchases at best and not a great bet for a border crossing.
Good luck with your Sony: hope the PSU swap works for you!
Thanks Turk690 and as I said I gave up and I thought it was as easy as finding a diffective part and replace it, but looks like it is more complecated than that.