I'm working on a Mitsubishi HS-U51.

http://i1052.photobucket.com/albums/s451/apples555/81DABE76-09D6-4251-B723-17A9DFB38AD7_zpslpscskp6.jpg

This is the left spool. What is that belt? It is loose, and it isn't clear where it's supposed to be.

It can also be somewhat seen on the studio sound electronics page.

http://i1052.photobucket.com/albums/s451/apples555/Mitsu_zpsiosdvk22.jpg

Not a belt, a back-tension band that adds a controlled tension on the tape. It's supposed to be loose in eject mode. It engages when the machine is in play-record, controlled by the back tension arm that rides on the tape and a tension spring.

Got it. Thanks.

Be sure to read my edited version.

I had to re-read and look closer at your pic before I finally got it right and did a few edits.

Sometimes the back tension band fails, the felt lining comes unglued and falls down in the mechanism, but that one looks good.

Check the belt on the bottom of the deck, commonly failed, stretched or turned to goo. If that slips or is no good it won't front load the tape.

Yeah, the belt on the bottom is completely loose. The motor spins by itself. I'll replace it with a belt from studio sound electronics.

Looks like a nice deck.

Yep those were nice decks. I have a HS-U52 here I've kept in operable condition. Similar mechanism. Another problem was the plastic pulley pressed on the capstan motor. It would crack and slip, and then no go. They used to sell a brass pulley kit to fix that.

Capacitors like to fail in these too. Sometimes you can see discolored blackened foil traces on the top of the board from the leaky cap underneath.

That's the problem with 25 year old VCRs.

I had a couple of Mitsubishi's here one was a HS-U48 and a SVHS model which I cant recall the model number at this moment.All bought new. They did not last here as the capstan motors fried on both of them since i do alot of tape shuttling and they had a habit of bad solder joints.Basically they fell into the same dept as the NEC's I had here.They were great to use but they dont last. I has the pulley coming off the capstan here too.I just super glued it back on.

HS-U48 is a completely different mechanism and overall build compared to the HS-U51.

No leaky caps as far as I can see.

I ordered a new belt and we will see how it behaves.

HS-U48 is a completely different mechanism and overall build compared to the HS-U51.

OK thanks .

I recall the 51 has the "F deck" with a power transformer linear power supply, the 48 has the" J deck" with a switch mode power supply.

I have a S-VHS HS-U790 with the J mechanism. Just a few years after I bought it, I had to replace the entire deck mechanism. The plastic guides for the cassette holder would crack and warp, and cause it to hang up. No glue would hold that slippery delryn type plastic. Fortunately Mitsubishi realized the error and changed the design, and made the whole mechanism available for about $60 dealer cost as I recall. Had to transfer the capstan motor, cylinder assy, AC head assy and align the tape path and X-value of the AC head. Still have that VCR too. Last time I used it I had to replace the bottom belt which had turned to goo.

New problem. Belts are now good, but VCR does this (click for vid).

The tape doesn't get caught by the guides and doesn't get pushed against the drum.

http://i1052.photobucket.com/albums/s451/apples555/th_48E9D264-E088-4ACD-B071-BAA4CA0C0A6A_zpsbbi9s2eq.mp4 (http://i1052.photobucket.com/albums/s451/apples555/48E9D264-E088-4ACD-B071-BAA4CA0C0A6A_zpsbbi9s2eq.mp4)

??

You zoom in just as it loads, and I can't see what the reels are doing. Looks like maybe the brake on one or both reels isn't releasing. Not very good on the tape!

Good call. Let me post another video.

That's a sacrificial tape. It has seen much worse.

Here it is.

http://rs1052.pbsrc.com/albums/s451/apples555/F4310002-000C-41DE-9EC4-AB817B5A5AC5_zps7gqs5do7.mp4?w=160&h=160&fit=clip (http://i1052.photobucket.com/albums/s451/apples555/F4310002-000C-41DE-9EC4-AB817B5A5AC5_zps7gqs5do7.mp4)

I sure don't like the ratchet sound it makes. Is the post there on the deck that pushes the cassette's brake release?

I think when one of these loads the TU reel stays fairly stationary so it comes up roughly the same place on the tape when ejected. The Supply side should go free to fed the tape with just a bit of tension from a soft brake to keep a little tension on the tape as it loads.


Do you have a "dummy" test cassette, one with no tape or reels and the windows cut out so you can see better and feel what's going on? With that you could pull the plug just as the TU and Supply arms start their move, to check things like what the reels and brakes are doing at that point. Also handy in fully loaded play position then unplug you can at least see if the back tension arm and band are working OK. I used to replace a lot of back-tension bands, and reel brake arms too, the black pads on them wear out.

The ratchet sound is from the loose tape bouncing on the drum.

I see that when the tape loads, the right tape guide is in front of the tape and not behind. Also, I don't see anything that would take the tape to the pinch roller.

I don't think the brake release is not working, because FF and RW are fine.

In this Mitsu VCR, I see an arm that takes the tape to the pinch roller.

https://www.youtube.com/watch?v=RHsAe9JxfhA

However, there is no such thing in mine. Even if I force the tape onto the guides, it doesn't even make it close to the pinch roller.

Sub-loading or half-loading arm is missing? Not good! It has to be there to work.



http://www.videokarma.org/attachment.php?attachmentid=193018&stc=1&d=1479862729

That is definitely not there. LOL.

When I got the deck, it still had a blue's clues tape loaded inside (albeit with the same loading path as now). Where could the arm have gone?

Someone removed it? Or the post that it mounts on fell out? Is that post there? Sounds like you need a donor machine!

There is also supposed to be a plastic arm sector gear that rides along with the pinch lifter cam gear and actuates that sub-load arm. Those being plastic used to strip or break likely from insertion of a jammed tape.

Also if my memory is working right, pretty sure there's supposed to be a spring under that sub-load arm too, to make it go back to rest position and also to push up on it because there is supposed to be a small nylock nut on top to hold it and adjust the arm height when in Play or Reverse search for smooth tape travel no curling of the top or bottom of the tape.

You got it, Ed. I found the arm, except it was permanently in loaded position. Once I broke it free, everything worked perfectly. The spring is probably weak. Good picture, and sound.

The only thing left is a very annoying squeak coming from the pinch roller (I think) when the tape plays.

And with that last one I hit 1,000 posts. I usually don't notice milestones like that...


http://www.videokarma.org/attachment.php?attachmentid=193019&stc=1&d=1479865899

Haha!

Good going! You made it work!

It could well be seized from old grease. That spring is pretty lightweight.

Sonys were bad about the sub-load arm seizing on the shaft but not so much the Mitsu's.

Some of those Sonys would be so stuck and seized almost like the grease they used turned into JB Weld! I would take my soldering iron down on a low heat to warm the shaft and arm pivot to loosen it up to safely get it apart.

Yesterday, I tried to feed in a tape, but the door wouldn't close all the way and the tape ejects.

I tried giving a little push when the tape was half in which seemed to make it accept the tape, but there was no picture or sound, and after ejection the tape got a little chewed up (brand new tape too).

If I insert the tape with a little force (I usually gently feed it in until the mechanism grabs it), the tape gets loaded and everything plays fine.

I installed a new belt back in 2016 and haven't had problems with moderate to low use since then. What would cause a mechanism to behave like this? How long do belts last in these mechanisms?