Problem with JVC HR-S9800U VCR

[jdmack]

I am using a JVC HR-S9800U VCR for capturing VHS tapes. All of a sudden, it cannot play the hi-fi audio track of any tape. All it will output is loud white noise. If I set the audio to "norm" it works fine (though the audio does not sound as good). Is this likely a fried circuit or something I might be able to fix myself?

[hech54]

Take it apart and clean the heads.

[jdmack]

I should have mentioned in my original post that cleaning was something I already tried (chamois tipped sticks and alcohol). But I thank you for your response none the less.

[hech54]

I've come across some tapes where the Hi Fi portion is terribly distorted, and when set to normal lo-fi the distortions turn into drop-outs(on two VCRs).....so my experience with this problem is on a tape by tape basis.

[jdmack]

It seems to be all VHS tapes with a hi-fi soundtrack.

[wulf109]

VHS hi-fi is recorded by a method called "depth Multiplexing". It uses a separate pair of heads to record the hi-fi audio. Seems likely those heads are worn out from your desription. Did you open the VCR and physically swab all the heads on the head drum? Remember that you should only swab the heads in direction they rotate,never with an up/down motion.

[jdmack]

I did swab all four heads on the drum (by rotating the drum as I gently held the swab so that all four gaps passed it by several times) as well as the two stationary heads (I have no idea what they do, though I suspect one of them reads the linear audio track).

[wulf109]

The stationary heads are for full erase and linear audio. The head drum on JVC 9800 should have at least six heads,2 for each record speed and two for hi-fi audio. If memory serves my JVC 9500 has eight heads. There's usually extra heads for the special effects. Check your head drum you might have missed some. The 9800 is the top model and should have flying erase heads on the drum also. Four heads dosen't seem like enough.

[turk690]

VHS video and hi-fi audio heads are exceptionally intentionally fragile. They are made of material designed not to erode but which also makes them brittle. Even a casual brush of a cleaning tip may break them. That's why it's best to use specific VHS cleaning tapes. Failing this, I'd take a piece of paper, soak a spot in isopropyl alcohol, hold it against the drum while manually spinning it. The heads should gently swish against the paper. If there was contamination, it should be evident by black streaks on the paper.

[orsetto]

It can be hard to determine the true number of heads just by looking at the drum. Later models like the 9800 employed composite heads, where eight heads might be shoehorned into four physical locations. No matter, as you tried cleaning and still don't have hifi audio. Either the hifi heads are dead, or you have a circuit gone bad.

You are still getting normal audio performance from the linear track, so it isn't an overall audio failure. The hifi heads could be so seriously clogged they resist cleaning efforts, but in such a case the video heads would usually be out of commission as well. Since you have normal video, the issue lies somewhere between the hifi heads and the main audio output circuit. Physical head damage disconnecting them from the circuit, or failure somewhere along the hifi signal path (cold solder failure, ground failure, capacitor failure). This would be difficult to address as a DIY repair: you should probably have a competent tech look at the VCR for you. I've searched my usual sources for an HR-S9800 service manual, but can only find the bare schematic which is of little use in DIY service. You could try contacting LordSmurf here on VH or at his DigitalFaq site: he might have a link to the service manual.

If you confirm the problem is head damage, it might not be cost effective to repair at this late date. Replacement head drums are scarce, and priced at $200 or more + labor. You might be better off buying another 9800 altogether, or a newer JVC or Mitsubishi DVHS with similar TBC/DNR feature.

[jdmack]

Orsetto, I think you may be right. I'll have to look into the Mitsubsihi DVHS which I did not know about. I have a JVC DVHS deck, and it drives me crazy that there is no display on the front showing minutes and seconds.

[orsetto]

That's interesting about your JVC DVHS display not showing a tape counter, jdmack: I was not aware there were such models in their lineup. That seems an odd omission for such a high-end deck, although with so many JVC DVHS models its hard to figure out sometimes. Which model do you have? Perhaps you could try another with better display.

The only Mitsubishi model with TBC/DNR was the HS-HD2000U. I have two, they've been very reliable for me over the past seven years. I was a bit leery at first, because similar SVHS Mitsus I'd owned previously had a nasty habit of self-destructing their loading slot mechanics within four years. Evidently, they changed the composition of the plastic in the DVHS units to be more stable, as I see no trace of deterioration when I check the insides every year.

The control interface and performance of the Mitsu TBC/DNR is near identical to JVC (if it isn't directly licensed, its a pretty good copy of the design). Overall, I find it hard to distinguish between the Mitsu and JVC TBC/DNR with average tapes played into an encoder or on a television display. However, you should be aware that a couple of uber-geeks here on VH once did an exhaustive comparison using all manner of testing gear, and concluded the Mitsu 2000 was "vastly inferior." In my experience, that seems a greatly exaggerated statement: there is far more difference between a Panasonic AG1980 and a JVC than a Mitsu and a JVC. Just as with other AV gear, test performance doesn't necessarily correlate with practical day to day use. But everyone sees differently: if interested, be sure to buy your HS-HD2000U from a seller with a clear return policy.

The Mitsu 2000 does have a front panel tape counter display. The transport is very gentle on tapes. The DNR has a soft-normal-sharp setting. HiFi audio tracking can be a little more fussy than a Panasonic, but is on par with the average JVC. The remote is rather "blingy" but has every imaginable control on it. Prices for the Mitsu 2000 vary greatly depending on spot demand: it is highly prized as a reliable unit by the few people who still actually use the DVHS format. Be careful not to overpay, you should be able to find one under $300 if you're patient.

[jdmack]

orsetto, my unit is a JVC HM-DH4000HU.

I appreciate all the info about the Mitsubishi HS-HD2000U. I will keep my eyes open for one. In the meantime, I have other VCRs I can use for capturing video, so I'm not under pressure to buy something immediately.

[Deter]

no tapes will play in HI-FI? Sometimes it is the tape. Have repaired a few of theses units before. You do have plastic gears near the head that sometimes break or snap, however this problem causes the unit to shut off. This is a nightmare problem with these units. The JVC VCR's are not as complex as the AG-1980's, however finding parts for replacement is not easy. I can repair this machine, it just may take a while and would have to look at it to find out what the real problem is.

[lordsmurf]

Take it apart and clean the heads.

That almost never does anything.