Panasonic AG-1980 audio issue - where did it go?

[talonhead]

Hey guys. This forum has been a great help to me! Very nice.

Anyway, I have a AG1980 that works great...looks great. It plays tapes wonderfully. BUT after bringing it out of the closet after about 3 or so years to do some conversion jobs, it now won't output any audio. The meters on the display aren't even displaying audio is present. I haven't used it that much to recall if those meters show input signal or output? idk But that's what I see on the display FWIW.

Any ideas on what is going on? And yes, the tape really does have an audio track to begin with.

Many thanks!

[lordsmurf]

Been there, done that, have the $350/each TGrant repair bill to prove it.

That's just life with an AG-1980 in the 2010s. The machines are failing, and need a refurb to last another decade or so. Anytime this machine even sneezes, "CAPS!" is the automatic answer. That's just the main issue these days.

I'm assuming that you've already eliminated audio output issues (connect to TV, not just computer capture workflow), and try various known-working tapes.

I sometimes wish TGrant would come here and post about these decks.

Perhaps Quasipal will have some answers. He's seemingly the Europe equivalent of TGrant. And PAL/NTSC has a lot of overlap.

[dpalomaki]

The AG-1980 meters will show input (record) or playback audio level depending on operating mode and tape audio content.

Does the tape have both linear track and stereo audio?

If you try to record, do the meters show the audio?

[lordsmurf]

Forgot about dpalomaki. More knowledge here that I can recall offhand.

He brought up another thought -- did you try the AUDIO OUT (on deck or remote) to see if the audio will come out on HiFi or mono, and isn't completely mute? I've seen tapes that only have 1 available track, and the HiFi or mono was present but mute (and why the deck missed the auto selection of the correct track).

[talonhead]

I've tried different tapes. Same issue. For yucks I've plugged in some cans in the headphone jack while playing back...same problem.

But if the meters show both input signal and output, that pretty much tells me it's something internal? For some magical reason while it sat dormant it decided to break?

Mono button....HI FI/Linear Mix switch...all makes no difference.

When popping in a tape and trying to record something from a second VCR playing into it, nothing. No meter movement...no audio recorded. Tried various combinations of switch selections with no changing results.

That's about all I know at this point. Weird.

[dpalomaki]

Is there any audio output from "linear audio" output RCA jack on the back when playing a known good tape? You will need to connect it to an amplifier to hear it, the output is at consumer line level. That audio takes a somewhat different path through the machine, and may survive issues with the circuits that mix and switch linear and Hi-Fi tracks feed to the L/R audio output jacks.

FWIW: The meters on the front panel monitor the audio signal that appears at the L/R audio output jacks on the back. They see the linear track audio only if the audio mixing circuits work properly.

[talonhead]

I haven't tried that yet because that...but I will once I get home.

Is the "linear out" jack a mono signal? I don't quite understand what "linear" means in this case.

[dpalomaki]

On the AG-1980 (and most other VHS VCRs) the linear audio output is mono).

VHS/S-VHS has 2 main types of audio.

- The stereo Hi-Fi signal that is recorded as an RF FM signal under the video signal in the helical scan. Found only on VCRs identified as Hi-Fi. This signal is recorded/read by heads on the spinning cylinder
- and an analog linear track recorded along the edge of the tape much like the recording on a cassette tape. This track is recorded/read by conventional tape heads located between the cylinder and the capstan.

This second is typically a mono signal, but a few older VCRs could record on it in stereo. It is commonly referred to as the linear track, or normal audio track, and is the only audio track on the non-Hi-Fi VCRs. In some cases it was used to record linear time code for use in editing, but that was uncommon.

[talonhead]

Thanks for the explanation of Hi Fi/Linear switch.

I connected to the Linear output...and it still doesn't work. No audio there either.

I guess we can say at least it's consistent.

[dpalomaki]

At this point it becomes a matter of popping the lid and tracing signals through the system, not a trivial task, that requires a good bit of electronics tech skill.

The Hi-Fi track signal mainly passes though the cylinder PC board, head amp, main board, Hi-Fi audio board, back to the main board, and then to the timer board (display board) and I/O boards.

Basically the linear track audio connects from the head to the main board to the normal audior board, back to the main board and then to the timer board (display board) and back I/O board.

There is some switching of the signals that is controlled by the syscon board, and the signal paths are a bit convoluted and would take a bit of time to trace out the first time.

I would suspect an issue with the main board or syscon board as a first guess..

Has the system ever been worked on? I gather that the video output is OK? It almost sounds like a board or connection is loose or partly dead.

[talonhead]

To the best of my knowledge...no...it never has been worked on. But I bought it in '13, and the unit has been out a long time. So who knows about those sort of things.

That's way out of my league to fix this issue from what you have just described.

My luck....I probably have two of the most highly regarded VCR machines out there....a Panny AG1280 and a JVC HR-S9800U. And both are dead right now for reasons unknown. I guess I'm not supposed to complete this job. Ugh...

[lordsmurf]

Send the AG-1980P to TGrant. Odds are, even if it "worked", it has issues. The $350 fix is well worth it.

In a similar vein, after 5+ years of not playing any video games, I got a craving to play Street Fighter II again. After finally digging out all the parts, cleaning them, etc -- my XBOX won't boot. Just the red/green flashing button. Fine. I put it up, grabbed my PS2. It took probably 20 tries to pry the DVD-ROM drive out so I could insert SF2 Alpha. That's what happens when electronics sit untouched for years.

[talonhead]

350 eh? That's more than I paid for the machine. lol Then tack on the shipping fees both ways, and you have a hefty amount invested in this ol' turd.

Is that the guy's flat rate for ANY repair? A catch-all figure?

Sad part is...I had planned to sell it. Between the two, the Panny gave me the best sound and picture for conversions.

I'll have to think about that. Might just cut my losses if it will be *that* much to repair.

[Quasipal]

Sadly the 1980 is electrically very different to any of the PAL decks so sorry, I can't be of help. I will add though that if the CTL pulses are weak or missing then most Panasonic models mute the sound - linear and HiFi. I had this with a D80 - a capacitor on the servo board had failed, muting the sound. The giveaway was the occasional drift in tracking (noise at to and bottom of image) which told me that the problem was servo, not sound related. I know you said that no sound is recorded either, which probably points to another section, but muting has caused me problems in the past.

[talonhead]

Thanks a heap for the input Quasipal. I'll keep that in mind.

[jwillis84]

I used Tgrant to service mine.

Tgrant does a good job and takes good care with the return packing and shipping. If you use them read the packing and shipping guide for how to prepare yours for shipping to them, its good. I found U-haul sold everything I needed including a perfect box size. Don't trust UPS or any other shipper to properly pack it, and use painters blue tape to secure the cassette flip door and the flipdown control panel closed.

Tgrant won't always take on a job if they are currently full up with VCRs being worked on (they might have a waiting list at some times of the year) and they are selective (I'd call it realistic) about the models they agree to work on. Their website is a pleasure to browse and full of information.

Whatever you do, you need to find a good reliable partner to help service and maintain your machine.

I don't have a lot of experience with service providers, but my experience with Tgrant was very good.

Good luck

[talonhead]

Thanks for the insight there jwillis. FYI...I did contact Tom in regards to the JVC and no power up, he replied with:

I'm sorry, we no longer repair the JVC HR-s98000 any more since parts are not available. They are notorious for having cracked plastic gears on the Dynamic Drum, this causes the unit to fail or shut down.

Best regards,
Tom Grant

So all in all, I guess he's pretty much a AG1980 fanboy. Which is alright too. But I will still look around to fix this JVC. I think it's worth it.

[jwillis84]

Sorry to hear that.

I think your right they are specializing more and more in the AG-1980, business has been very good for that model.

[lordsmurf]

I have my eyes on Shapeways, and will soon attempt to replicate some non-gear video parts for replacements. Too many old devices are getting issues, cosmetic or otherwise, and a few plastic pieces is all that are needed. I still have serious doubts about 3D materials working on those fine cogs, but it's worth a test if the VCR is essentially non-functional anyway.

[dpalomaki]

Has anyone found a glue that will work effectively on these nylon gears, perhaps with an added gusset, or is all of the gear gone "soft" including the teeth, not just at the split?