AG-1980 clicking noise, audio distortion?

[aramkolt]

Hello all,

I know AG1980's are popular here and it must be that someone else has experienced the noise I'm getting from mine. Tape plays fine and I have lubricated all of the pivot points in the K mechanism, but I'm now getting a sort of clicking noise which sounds almost like the clutch mechanism gripping and slipping over and over as opposed to a smooth drag which I think it's supposed to do while playing.

I have attached a sound clip of the noise it makes if you put your ear right up to the K mechanism as it plays. You'll also sometimes get distorted video and audio artifacts that are consistent with when the mechanism is being more noisy like this. Tried it with a few different tapes and they all do it. Sometimes It won't have the issue at all the first time a tape is put in, but then can develop it after fast forwarding or rewinding.

So my question is, is this VCR in need of a clutch replacement, or is there a way to remedy this without replacing parts, or is what I'm hearing something else completely?

Odd thing is that the VCR played for a few hours just fine after refurbishing the mechanism and then sort of spontaneously developed the issue.

Thanks in advance!

[lordsmurf]

Quote:

Originally Posted by aramkolt

it must be that someone else has experienced the noise I'm getting from mine.

Those are some of the best VCRs in terms of image quality and EP mode tracking -- while also being one of the worst VCRs ever engineered. It's a trade-off, and a huge money pit deck.

I think you'd be surprised at just how many errors can be found on it. So no, "must be" is actually not as likely as you'd think.

This is why only buying refurb'd decks, or having non-unknown-lineage (ie, not eBay buys) refurb'd by Deter is suggested. Both Deter and TGrant have become very strict in the sort of units they will accept now, and do reject units (especially botched DIY repair attempts). Some techs, like the butthole at John's TV Repair, even become irate when discussing AG-1980 repair.

I know you're trying to DIY repair these, and I wish you luck, we'll all give you whatever info we can. But it's not something easy to troubleshoot or repair. Repairs frustrate even the best techs.

[aramkolt]

Oddly enough, I found the clicking was actually some sort of odd feedback from the computer (most likely the AIW 9000 card). The moment I connected either S-Video out or Composite out to it, the clicking starts with audio and visual issues ensuing immediately. Unplugging it from the AIW made the clicking go away completely. Plugging into a different capture card or directly into a CRT also did not reproduce the issue. The issue actually progressed to whenever plugging in the S-Video cable that the speed of the capstan motor would slow by 50% and the image and sound was very garbled.

Sounds like some sort of voltage or short is present where it shouldn't be on within the AIW 9000 card. Tried multiple different input cables to the AIW9000 as well, and they all did it. MMC or virtual dub didn't even need to be running to reproduce the issue, just plugging it into the AIW card while the computer was on is all it took.

So further down the rabbit hole - I'm going to try fully recapping the AIW9000 card, several capacitors did test "leaky" in circuit, but that can be a false result depending what else is in the vicinity of the capacitor being tested.

Fun fact, there's about 35 SMT capacitors on that card lol.

I'll probably buy another AIW 9000 just to verify that it is indeed my card that is bad and not something else with the computer, though there's no guarantees the caps on that one will be any better.

Could also be a non-cap thing or a motherboard cap issue which I sure hope isn't the case. Was working fine for about 8 hours total then started doing that, so seems possibly caps dried out the rest of the way or something with actual use. The card was actually new in box and supposedly never used before I got it. I've heard "unused" capacitors are more likely to fail than ones that are used periodically, so that could fit the picture here as well.

I did install some of the macrovision disable hacks, but pretty sure it started doing this prior to any of that.

Anyone else ever have an AIW card fail like this?

[aramkolt]

Update - After fully recapping the AIW 9000 card (which took several hours by the way due to the many SMT caps), it gives exactly the same issue, so hopefully the issue is with something else on the card and not something wrong with the rest of the capture PC..... Going to try a AIW 9200 SE next and see if that also has the issue, just awaiting it to arrive in the mail. That one has kind of an odd duck in that it has more video ram (128mb) but has a lot less memory bandwidth, but hoping it will be fine for capture.

[timtape]

It can save time to have on hand an ESR meter to quickly test the condition of the electrolytics rather than replace them all as a fault finding technique. For fault finding purposes easier to just replace any which measure faulty IMO.

[BarryTheCrab]

In the defense of John’s TV, I have found him to be pleasant, smart, prompt and skilled with 2 JVC, 1 Philips (all S-VHS),
my Elite BVP4, and my CMD-1200. I am happy to continue bringing him my electronics if he still lets me in the door after seeing his name sullied.

[aramkolt]

Yes, I agree it's typically a lot faster to just replace faulty caps, but I'd like things to remain reliable/rock solid rather than require periodic repairs. I have 3 different ESR meters and use them more "after the fact" to see if what I replaced was faulty when it comes to SMTs in particular since the in-circuit readings can be off or they'll read as good ESR, but "leaky" according to the Atlas ESR-70. I will say that probably 10 or so of the 30 caps replaced had leaking electrolyte on the AIW 9000, but most tested fine ESR-wise and capacitance-wise (or were obscured by other capacitors in parallel) while in-circuit.

The in-circuit use of the ESR meter can't really tell if there are other caps in parallel that bring down the ESR reading they get and the "leaky" part can be due to non-cap components in the circuit and potentially read the same after you replace it with a known good cap.

Also seems that the lower value SMT caps are more likely to be bad in general, while it is known they should have a higher ESR to begin with, they just always seem to have physical evidence of leaking much more often as well.

There's a fair amount of radial/through hole caps that will read significantly below rated capacitance but have normal ESR and I'll go ahead and replace those as well.

[aramkolt]

Possibly solved!

Not sure why I didn't think of trying this before, but I tried unplugging the monitor from the capture PC while it was otherwise connected and producing plenty of audio/video distortions/clicking noise from the VCR beforehand and they all stopped immediately (Well, at least the clicking and audio distortions which I could still hear without the display plugged in).

Seems like the feedback causing whatever issue is most likely coming from the monitor which was one of the few low end components I didn't think I'd have to worry about in my setup and is pretty old.

So.... I have a new monitor on the way and will see if the issue doesn't happen with it and I'll report back.

Must not be too common for this to happen since I haven't really heard of audio/video distortions during a capture being caused by some odd feedback or noise on from the capture PC monitor on these forums or elsewhere.

Could still be that there's an issue with the AIW 9000 card that only happens when a monitor is plugged in, but hoping that is not the case.