Mitsubishi DVR620 - Strange scanlines affecting image

[moonman88]

Hi all,

I have a VCR related question I am looking to get some input on.

I have a Mitsubishi DVR620 combined VHS/DVDR unit, I know this is going to be considered fairly modern by this forums standards but hoping somebody can give me some opinions on what could be happening.

After unseizing the drum motor (a common issue on this model apparently) and cleaning the heads I am now able to play tapes and have a really nice looking picture outputting through HDMI.

However, on some tapes, I get strange scanlines affecting the entire image, almost as if it is flicking from interlaced to progressive.

If I enable the OSD I can see that sometimes they are also being affected, but other times they seem ok.

Does anybody have any idea what could be causing this? Some tapes are unaffected and others it happens intermittently every few seconds. Could it be something to do with the control track reading head?

I have attached some images demonstrating what I am seeing...

[John123]

Hi, and welcome to the forum!

This could be some sort of frame jitter, possibly because the head was seized, and perhaps isn't running as smoothly as it once did. Double-check the drum bearings; it should make barely any noise when rotated by hand, and the head should 'free-wheel' a little.

Also give the entire tape path a thoroughly good clean, paying particular attention to the lower drum, pinch roller/ capstan, and take-up reel/ brake. Check the condition of the back-tension band on the supply reel.

Then let it play a few tapes from start-to-end as it might clear up with use. Also check PSU caps as Mitsubishi machines were a little notorious for leaky caps in the power supply.

[Graham G3ZVT]

Interesting.
By any chance, are the affected tapes commercial movies with Macrovision® copy protection?

[whaka54]

Originally Posted by moonman88

almost as if it is flicking from interlaced to progressive.

hello,

it's indeed what happen, it's an artifacting of interlaced content.
but very likely because vertical sync is unstable, and internal TBC of the DVR try to stabilize as best as it could.

if you can try on a CRT to see if there's vertical instabilities?
it might be tape itself if there's damage in the VBI portion, or mechanical issue.

[gallowfields]

another problem with most mitsubishi vcr,s that i have seen over the years is loose tape guides [there are no securing screws on them ] its quite possible to be just a shade out of spec . i used to reset all the ones we had with an official prerecorded tape [usually a warner one as a matter of interest] obviously with the tracking in mid position.
brian

[samjmann]

I take it all is well with the display of DVD sourced material?

As pointed out tape path can be a problem. Move the tracking control each side of centre and see if you can induce the fault. The drum lead-in is where this problem could be. Noisey/low signal may affect the interlace etc.

[Red to black]

Originally Posted by gallowfields

another problem with most mitsubishi vcr,s that i have seen over the years is loose tape guides [there are no securing screws on them ] its quite possible to be just a shade out of spec . i used to reset all the ones we had with an official prerecorded tape [usually a warner one as a matter of interest] obviously with the tracking in mid position.
brian

Not quite true, yes the the earlier machines could and did often suffer from loose guides, the securing screw/s were however at the bottom of the guide/slant pole diecast bit with the allen screw ( the actual securing screw) unlike the JVC decks of the same era, I must admit I thought the same until I had cause to buy a manual for a Mitsubishi HS302

[gallowfields]

Originally Posted by Red to black

Not quite true, yes the the earlier machines could and did often suffer from loose guides, the securing screw/s were however at the bottom of the guide/slant pole diecast bit with the allen screw ( the actual securing screw) unlike the JVC decks of the same era, I must admit I thought the same until I had cause to buy a manual for a Mitsubishi HS302

all the jvc decks of that era certainly did have a securing screw at the bottom of the tape guide assy usu ally needed a very small watchmakers philips driver unlike the sharp ones where you needed the 1.27mm allen keys
brian

[Red to black]

Yes the JVC decks did have the securing screw at the bottom of the guide not disputing that at all, maybe I badly phrased it in my earlier post?, the Mitsubishi ones were an allen screw in the bottom of the diecast pole piece is what I was trying to say, just a slightly different way between the two makers but they both did have means of securing the guides from unscrewing just the Mitsubishi version was not as obvious as the JVC machines if this helps

[gallowfields]

Originally Posted by Red to black

Yes the JVC decks did have the securing screw at the bottom of the guide not disputing that at all, maybe I badly phrased it in my earlier post?, the Mitsubishi ones were an allen screw in the bottom of the diecast pole piece is what I was trying to say, just a slightly different way between the two makers but they both did have means of securing the guides from unscrewing just the Mitsubishi version was not as obvious as the JVC machines if this helps

HI, i understood you meant that the jvc vcr,s of that era did not have securing screws .anyway i think we are both on the same page now . i think the problem with the mitsubishi is probably down to the entry guide being slightly out . but i usually checked both in all vcr,s and resecured them