JVC SR-MV45 Service Manual?
 

Not seeing the SR-MV45 service manual on the pinned post here. Also not finding it on the interwebs. Very surprising, considering most JVC service manuals are easy to find.

Anyone have it? Likely a combined MV45/MV55 manual.

Closest I've found is this post, but I haven't looked particularly hard:
https://www.digitalfaq.com/forum/vcr...5-service.html

That has a link to the mechanism's service manual, but not the rest of the deck.

The SR-MVs are pretty straightforward (though tedious) to service, you just have to hope that the digital board hasn't gone bad from the power supply going bad first which may cause problems much more difficult to chase down. I haven't gone the route of making some sort of testing rig that would allow you to see the bottom side of the digital board while it is powered on, but I suppose it is possible that a certain surface mount (non-electrolytic) capacitor goes short on them and that would be pretty easy to identify with a thermal camera. If all your machine says is "loading" and does so for over 90 seconds, that's a possibility. I'd say the digital board is fried 25-30% of the time from the power supply going bad first and then harming the digital board. I've never seen a digital board go bad AFTER one of my refurbs.

Also for that reason, I won't even power on an SR-MV until the power supply and the digital board at a minimum have been recapped first. I usually do recap some other areas, but I think doing those two at least prevents the possibility of the digital board from being fried if it isn't already.

Other "non digital board" thing that can give the same "persistent loading" error is If the DVD drive doesn't work enough to get past the loading sequence. It does have a few of its own SMT caps that you can try changing, but doing so often doesn't save those. Best way I've found to see if the drive is the issue is to just have a known good spare drive to swap in. I'd say the drives are bad 15% of the time and I also suspect that they tend to be damaged if the power supply goes first as I've also never seen one fail after a power supply/digital board recap either.

Good news is that if your machine doesn't already have the "loading" error, it's not too late to prevent them with a recap, though I'd be particularly careful of static during the repair as that can also damage ICs permanently.

Thanks!

My issue was the VHS tape loading, threading the tape around the video head and then not moving it all. I was prepared to chase down a bad mode switch, sensor, etc. Turns out the pinch roller had simply fallen off... Fortunately I was able to find it and the tiny plastic bushing that holds it to the shaft floating around in the unit. Voila, back in business.

Side note, it's always talked about that the VHS side of these is the same as an SR-V10/101, but the mechanism is different. Same mechanism as the DR-MV and DR-MX series of VHS/DVD(/HDD) recorders, except with the DNR/TBC circuitry added.

The mechanism on the SR-MVs is the same as what is used on the HM-DH5U, They would be a good source of parts for those, but the mechanisms usually aren't what go bad on the DH5U's in my experience and the one part that could wear out is different (the head drum). Usually the digital boards go bad on those which I've observed to get extremely hot during normal use (like over 150F if I recall correctly).