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Old 12-10-2021, 08:54 PM   #1
SluggerB
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Default Ancient Memorex VCR/DVD Combo device with strange display issue

This is a 14 year old Memorex DVD/VCR Combo.

I got a new LG TV. I pulled the Memorex out to hook it up. it only has composite out, so I go composite to a little composite > HDMI device, then HDMI to the TV.

In VCR mode, it works fine. The display quality is what you would expect, but I can play tapes just fine

In DVD mode is where the issue started. In the main DVD screen, prior to it loading any DVD (or with no DVD even in) I am getting diagonal black lines scrolling diagonally across the screen. These continue even if I play a DVD.

So I took it back to my work bench and hooked it up to a little 5 inch display I have there for testing. It is also HDMI input and I use the exact same cables to hook everything up. I opened the device up, reseated the ribbon cables, powered the device on with the cover off, and viola, picture is clear. I put the cover back on, go hook it up the TV, and the lines are back

So I go back to the workbench, take the cover off, power it up, and it is working again. I then pull the plug out, plug it back in, power it on, and now it is getting lines. I pull the plug again, wait 5 min, plug it back in, it works again. Unplug it, plug it back in, still working. Unplug it, plug it back in, lines again. So the lines are intermittant.

On my little test display, I have on occasion gotten a perfect picture. I have also gotten lines. On the TV I have never gotten a perfect picture, always lines.

I took a look at the board that appears to the the DVD player, and it's just a few chips, and a whole bunch of caps. They all looked good to me, except for 2 that looked to have some sort of gunk on them. I didn't know if they blew up, or if it was just some sort of hot glue from the factory. I replaced both, went through my testing routine, and the results were unchanged.

Any ideas on what it could be? If there is a high degree of confidence that recapping the entire board will fix it, I can do that, but thats a lot of time for a little novelty project. I don't think it is anything to do with the main video output since the VCR mode works flawlessly and that uses the same composite output as DVD mode. I would also assume the power supply would not be at fault for the same reason but that is a guess. There is a small black 4 prong chip on the power supply that had some brown on it, but I think it was just gunk from the factory, I scraped it off and it looked normal underneath


Any ideas? I can post photos over the weekend if requested

Last edited by SluggerB; 12-10-2021 at 09:17 PM..
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Old 12-12-2021, 05:07 PM   #2
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Well in classic "me" fashion, I fixed it until it broke

I swapped out about a dozen caps,, a pair of diodes, but the board was so cheap/old pads kept coming off, so it was a real pain to get components in, and in the end it just started throwing an error. So in the bin it went
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Old 12-14-2021, 06:38 AM   #3
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Oopsie, to the landfill then.
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Old 12-16-2021, 12:23 PM   #4
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Quote:
Originally Posted by angelos View Post
Oopsie, to the landfill then.
Well, never one to quit, I pulled it out of the trash to try it again

I redid the connections where the pads were bad and confirmed they were all good with a continuity test. One pad was completely gone so I had to run a jumper wire but was successful in doing so. I confirmed there were no shorts.

I was getting a "ERR" message on the display, but after going over the thing with a fine tooth comb, it turns out the VCR tray had popped out of place. So I manually slid it back in like a tape was in there, and that cleared the error. The unit is now back to where it was

2 things I have learned since before:

I noticed one way I can reproduce the issue is switching modes between VCR and DVD. If I start the machine up and it happens to be showing a good picture on the DVD player, if I switch to VCR mode, it shows a fine picture, but then switching back to DVD, it will ALWAYS then show the scrolling lines again

Another thing, this unit has sVideo out. if I hook up sVideo out, the DVD display is perfect. But, if I then plug in the composite cable (while the sVideo cable is still inserted) the lines appear. If I remove the composite cable, the picture reverts to perfect.

I have recapped all the capacitors near the composite output area of the board, made no difference. I have gone over the board with a fine tooth comb and see no other visual issues. Any ideas what to check next?
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Old 12-20-2021, 12:23 PM   #5
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

I managaed to pull a video signal directly off the CVBS pins on the DVD player daughterboard, and it looked clear. So to me that means the problem is on the main board somewhere.

I traced the pins and replaced all the caps along thier path, but no change

What other component would be faulty to cause an intermediate isue like this?
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Old 12-26-2021, 01:41 PM   #6
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

I did another test and pulled a video signal directly off the DVD boards CVBS pins, and switched to VCR mode and back, and the picture stayed fine. So the problem must be with the main board

For Christmas I bought myself a solder sucker pump, so when that gets here next week I'm just going to finish recapping the entire mainboard, I think I have about 25% of them done already, and the traces are getting torn (the board is in bad shape) and I think the pump might do a safer job of desoldering the old caps.
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Old 01-01-2022, 06:55 PM   #7
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Partial success!!

Using my new desoldering pump (which is now my most favorite thing in the universe) I recapped the board along the pathway from the CVBS pins to the composite output, and it solved the diagonal lines problem!!!

However the tape deck has a problem: When I put a tape in, it plays with a LOT of visible tracking issues, and then automatically switches to SP mode, which is incorrect for the recording, resulting in sped up video and chipmunk voices. I saw a youtube video on how adjust the roller pins, I am going to try that

Also the DVD player will not recognize a DVD is inserted and gives a no disc error. I believe this is ribbon cable related since the ribbon cable had a torn trace and I had to scrape back to a new bare contact, and the blue tab that gave it a snug fit in the connector broke off, and my 5 layers of kapton tape is probably not a great fit. I could not find the exact same cable (AWN 20798) so I ordered a similar cable with the same # of pins and position of pins but a different AWM (20624). Hopefully it will work, it will be here in a few weeks.
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Old 01-04-2022, 06:58 PM   #8
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

So tonight I:

* Thoroughly cleaned the tape head (using the "strip of paper" method to avoid damaging the heads), the rollers, every moving part, every sensor, every moving part I could find. Nothing helped, the tape will start playing on SLP mode with crazy static, then switch to SP mode. There is a chance the tape has failed, the last time I watched it on this device was around 3 years ago and the tape itself is probably 20 years old or so

* I refurbished the DVD ribbon cable again, and I plugged it into the DVD daughterboard, and tested for continuity for every contact on the cable to the pins on the board. 24 pins, 24 beeps. So I know that end of the cable is good. I could not get my meter probe on the the DVD side if the pins to test. Still got a No Disc error

* cleaned the laser lens and every other optical component I could see. Still No Disc.

* I measured the resistance of the 2 laser screw terminal things, they were 1.3 Ohms and .910 Ohm respectively. I adjusted them down to increase the laser power, I didn't want to to far and risk burning it out, I got them down to .9-ish and .799 respectively. Still no disc I confirmed the laser is still working, I put a sheet of paper over it and turned the unit on and could see the red flashes from the laser hitting the paper.

This weeked I may see if I can find a VHS tape at the local farmers market to pick up to rule out my tape being bad, and I ordered new ribbon cables just in case something is wrong with mine, they are on the way. Any other ideas?
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Old 01-04-2022, 07:24 PM   #9
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

In most case with optical pickups it is the pickup sensor that fails not the laser diode
as for the tape, check the bottom of the tape, is it wrinkled? if it is that is the problem as that is where the control pulses are recoded.
In post 1 you said:
Quote:
In VCR mode, it works fine. The display quality is what you would expect, but I can play tapes just fine
What did you do to to change this?
I suspect you now have the tape path out of alignment when the problem was caused by something else with the mechanism, post some pictures of the mechanism with the tape in playback mode.
It could be the back tension is not working or the back tension band is misaligned.
What is the model number?

Last edited by R_J; 01-04-2022 at 07:39 PM..
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Old 01-05-2022, 12:41 PM   #10
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Quote:
Originally Posted by R_J View Post
In most case with optical pickups it is the pickup sensor that fails not the laser diode
I also saw a youtube video which said to check for a bad cap not allowing the full 5V to the laser, I'm going to check that tinight

Quote:
as for the tape, check the bottom of the tape, is it wrinkled? if it is that is the problem as that is where the control pulses are recoded.
Some areas of the top of the tape have occasional wrinkles in them. The bottom is smooth

Quote:
In post 1 you said: What did you do to to change this?
I suspect you now have the tape path out of alignment when the problem was caused by something else with the mechanism,
Well it played tapes the last time I tried... which was 3 years ago

Quote:
post some pictures of the mechanism with the tape in playback mode.
It could be the back tension is not working or the back tension band is misaligned.
Will do. It all looks OK to me but thats just a layman observation

Quote:
What is the model number?
MEMOREX MVD4544 DVD/VHS Combo Player. I found this service manual for a similar model https://www.manualslib.com/manual/21...x-Mvd4540.html
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Old 01-10-2022, 03:04 PM   #11
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Well, I thought I was down and out as I all of a sudden getting zero video signal. And when I went to turn an adjustment knob, the screw threads just vaporized and the roller head was no longer adjustable.

So I went back and checked my previous fixes and a lot fo them had re-broken, so I fixed them more carefully, and used a broken capacitor leg in the screw hole to give the screw something to bite into, and I am dumbfounded that I actually recovered a video signal. It is still garbled, but I still have a bunch of caps to replace.
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Old 01-11-2022, 02:35 PM   #12
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

I want to congratulate you for not giving up trying to fix this item.

Personally, I could care less for the DVD, but the VHS is a total different story. Those are not made anymore and probably will never be made again. So, these devices will get rarer and rarer and it will be very hard to obtain and not to say very expensive too.
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Old 01-12-2022, 12:59 AM   #13
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Transfer all video tapes to dvd as soon as possible to stop the deterioration of the tapes themselves. I had priceless home movies that were transferred from film to video. Years later I put them all on dvd disc to save them. I'm glad I did.
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Old 01-15-2022, 10:08 AM   #14
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Unfortunately this is true from my latest personal experience with VHS.

I have been trying to find a "perfectly working" 6 head VHS recorder and constantly failing.

In the 90s we had 2 AKAI made in Japan in the 80s VHS video devices that worked OK and there was no such thing as a bad tape. And I had a lot of tapes on my own and I used to rend tapes from the video club and watch them with my family. There was only 1 tape that would stress the VHS video players due to being quite scratched in some place that I usually skipped.

Now, after all those years, tried to find a perfectly working device and all of those worked for some seconds then gave no image. Trying to find out what's wrong, I came to the following conclusions:

1) Modem TV sets very aggressively block the signal when the image processor thinks it is too messed up and show no signal message. That way you are totally unaware of what is happening on the VHS and a lot happened that I couldn't know. So, please try to test VHS devices/tapes on CRT Tvs or LCD that are very forgiving of the video input they receive from SCART/RCA/S-VIDEO and allow a lot of snow and/or tracking errors.

2) Unfortunately some of cassettes that are 20 or 30 or more years old are starting to deteriorate. Sometimes it is not visible if you open the cover and look at the tape, other times it is (check attachment). These is also a chance that the magnetic material is fine but the tape is just demagnetized, due to poor storage near magnets, or moisture creeping in. In my case, I was very unlucky because I tested 4-5 VHS machines with a bad cassette that stressed the heads and made my Samsung LCD show no image after a couple of seconds. This is the definition of bad conditions of testing. My testing conditions were totally flawed and didn't help to test the devices. At least I realized it in the end. So please make sure your tapes are bad and don't demagnetize video heads.

3) On many more tapes than the ones belonging to the previous paragraph for some reason (more testing needs to be done and I have no clue how to verify) it appears to be very difficult to rewind them to the start of the tape. I have identical tapes as fas as the brand, model and duration is concerned and one of them fails to get re-winded properly. The other has no issues. To make sure this is due to the tape and not an old rewinding mechanism (mainly idler rubber getting hard) I tested the same tapes that had this issue on several VHS VCRs and they failed on almost every one of them. Please pay attention: Those tapes had a high rate of VHS machines chewing the tape during playback/FF/rewind. This cannot be a coincidence.

4) Give some time to the heads. If you get to have a Known good VHS tape and try it on a device that has not worked since 2004, the video head will first appear dead, you will get absolutely no image at first, then 2-5 minutes later you will get some image but it will be too snowy, then after more minutes of playback it will be less snowy and after 30-45 minutes the image will get crystal clear (well for VHS standards). So, don't write off the VHS recorder too soon.

So, this technology unfortunately is getting old. Need to digitize what is important for you asap. And please don't throw away any old equipment you have. The value will increase.
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Old 01-18-2022, 08:44 AM   #15
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

Quote:
Originally Posted by tvtimmy View Post
Transfer all video tapes to dvd as soon as possible to stop the deterioration of the tapes themselves. I had priceless home movies that were transferred from film to video. Years later I put them all on dvd disc to save them. I'm glad I did.
Did that years ago As I mentioned before getting this working is more important to me as a sentimental project than a practical one. The unit is one of the few things I have from my mother who passed away suddenly many years ago.

So I finished recapping the main board, which houses the VHS side of things. I *think* that electrically, it is sorted on the video side at least. The picture is still bad, but, it is steady, and the distortion looks like tracking distortion, so I think I possibly could be able to manually adjust the head roller pins to get a decent picture. I need to do that on a CRT TV, probably get to that this weekend. I did find a VHS shop at my local farmers market that sells VHS tapes for $1, so I have been picking up some sealed tapes to make sure I'm not seeing errors due to tape degradation

The Audio is completely dead. No sound whatsoever. I have no idea why, the head looks good, I messed with the alignment a zillion times, I checked all contact points and the audio cable for continuity and it all checks out. I will need to focus on that next. I will try and make an audio probe I can use to try and pick up a signal off the board directly.

The DVD Drive is still giving me a No disc error. I verified 5V is going to the laser unit. While doing that I did see some brown staining by a cap, thinking that might be a leak I recapped everything in that area and cleaned up the stain. After that, the DVD spun more, but still eventually just errored out on no disc. I moved the potentiometers back to their defaults, no change. After that my replacement ribbon cables came in, they don't seem to be 100% matching the original one but 99% matching. They do fit. However using those, or the old cable, neither gets me past the no disc error.

I would like to get the DVD working so at least I can verify the source of the VHS audio problem, if it is just the audio pickup head on the VHS side, then DVD audio should still work. But I can't get it to recognize discs. I have recapped about 1/2 the DVD daughterboard, I will be doing the rest this week and hopefully that brings the DVD drive back to life. If the laser is dead, It looks like you can get new pickup units on eBay for less than $20.

So down but not out, and I'm not giving up yet!

Last edited by SluggerB; 01-18-2022 at 08:47 AM..
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Old 01-19-2022, 09:28 AM   #16
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

I went browsing on eBay and found another identical model for sale that was broken. The listing said the VHS side works, but the DVD side will not open. Now my unit had that issue before and I know what the problem is, the rubber belt dries up and breaks, you slip on a new one and it works fine. I've done the repair myself twice on my unit. So I went ahead and bought the unit to use it for parts.

But now I'm in a conundrum. I'm almost certain it would be far easier to fix the broken one I just bought off eBay, rather than scavenge it for parts to fix my much MORE broken one. But then I'm not fixing my mothers items, it's a new item. But even if I switched out the VHS head and DVD drive over into my unit, is it still the same unit? I'm in a kind of "VHS/DVD Player of Theseus" dillema.
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Old 01-19-2022, 01:49 PM   #17
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

hmm... I still have

three working vcr's (at least of last check) though one has dry cracked pinch roller, still works...
one vcr with a jammed mechanism (can't figure out how it's jammed...)
one combo dvd/vcr whose vcr section has tracking problems (top of screen looks fine, bottom is garbled)
one pretty worn out time lapse VCR, still works okay.
one combo dvd-r/vcr combo that seems to work fine.

Been wanting to fix that one vcr that has tracking problems but no luck. It was worse than this prior - it wouldn't even turn on due to water damage, but got it to turn on at least (and hence DVD works.)

Not sure what I will do with these things... I do have some tapes however - not many, but enough so I can actually use them. I think I have two good commercially recorded tapes, one broken commercially recorded tape, and a bunch of uncommitted tapes. And that's not counting the VHS-C's...

Last edited by eccerr0r; 01-19-2022 at 01:52 PM..
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Old 05-22-2022, 02:17 PM   #18
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Default Re: Ancient Memorex VCR/DVD Combo device with strange display issue

My unit ended up being damaged beyond repair. I think in my efforts I ended up destroying the audio heads, the video head, and the DVD laser pickup.

I ordered an identical model off eBay with a broken DVD tray mechanism and no remote and a scratched up case, and fixed that one with parts from mine.
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