VZ-2000 Speaker extension cables

[Dago]

Hi Guys

I've got a problem with the left speaker on a VZ-2000 I'm trying to restore. I've owned the VZ since the 80s but it's been sitting collecting dust for about 30 years!
Up to now I've restored power to it after teaching myself how to solder and identified that the leaf switch for the door is broken and ordered a replacement. It's seems I was looking at the switch for the tone arms originally, which is intact, and didn't see the switch for the door sensor, which I can now see is broken.

The speaker was working when I first turned the unit on, although only the tuner was working at that point. I've fitted new turntable and cassette belts and replaced the pinch roller, which as you can imagine after 30 years, had disintegrated, or in the case of the pinch roller, had seized up. The cassette now plays, although it only FFs very slowly and RW is shutting off after a few seconds. Does anyone have any idea why that might be?

Back to the speakers - after reading advice given on sound issues, I've cleaned the function switches with contact cleaner, including the INT/EXT speaker switch and headphone jack socket. A had a strange situation with the headphone jack in that when I initially put the headphones in, I also only had sound out of the right headphone, same as the speaker. When I was pulling the headphone jack out (I still had the headphones on) I noticed that sound appeared in the left headphone and the right speaker on the unit which seemed a bit weird. I cleaned the headphone socket some more but that didn't fix the issue, other than a faint sound now coming out of the left speaker. I desoldered the headphone socket and cleaned all the pins with a small file and there was a lot of dirt/oxidisation on them. Tested again with headphones and sound had returned to both sides of the headphones but left speaker still not working.

Finally, I've now decided to follow some advice from mmcodimino in an old thread and will try and desolder the balance slider and check for loose brushes.

What I'd really like advice on is, because the speaker connections have to be unplugged in order to separate both sides of the VZ, whenever I want to test anything speaker related I have to put both sides back together and reconnect the speakers. I'm sure I must be able to connect the speakers with some sort of extension cable without having to put both sides back together, I just need to find out the name of the cable so that I can try and buy one (in the UK). Would anyone know the exact name of the cable I need, that would fit those speaker connections please. It would be a big help if I didn't have to put everything back together every time and could test the speakers without doing that. Also, I'm sure that constantly disconnecting/reconnecting the speaker connections will be putting additional strain on them, which probably isn't a good thing given their age.

After reading, and re-reading, the service manual again and again, and by reading advice given here and what the various components do via the internet, etc, I'm finally starting to understand the service manual and the schematic, and have replaced all the capacitors on the power board and re-soldered all the joints on it, which got power back after it failed not long after I first switched the VZ on.

Any advice is greatly appreciated with regards to the name of a speaker connection extension cable (and maybe also the FF & RW issue on the cassette player, although the speaker is my main priority at the moment)

 

[docs]

To eliminate the speaker itself being an issue you can do an ohm check across the speaker terminals. Put the dmm into lowest ohm setting, probably 200. If they are rated at say 4 ohm, you should get a reading close to that. Compare with right speaker. Should be 3.6/7 or something similar.
If the reading is way off, or zero, or infinite, its broke and needs replacing.
If it is good, then we can start looking at the schematic for possible issues.

 

[Dago]

Cheers Docs. These are the readings I got from the ohms checks:
Left speakers:
Woofer reading = 3.9 Ohms
Tweeter = 3.6 Ohms
Right Speakers:
Woofer reading = 3.8 Ohms
Tweeter = 3.1 Ohms

 

[docs]

Thankfully they appear to be good.
And you say you now have audio in both from headphones when fully plugged in?

 

[docs]

If so, I think you need to 1. Spray that speaker selection switch and work it thoroughly and/or 2. Do a continuity check on the left speaker wires from one end to the other.

 

[Dago]

Yes, both sides

 

[docs]

I believe the only thing between headphone socket and speakers is the int/ext switch and the wires used to connect. Give that switch some love.

 

[Dago]

I've just checked the headphones again before replying. I'm getting audio from them but it's very quiet but the speakers are currently disconnected. Would that affect the volume output to the headphones? Sorry if it's a dumb question.

This is what's currently happening with the headphone audio, other than low volume, and it seems to have changed again.
If I slide balance fully to 'Left' I get close to nothing in the left headphone. I can hear something very faint but hardly anything, although volume is reduced possibly because of speaker connections being disconnected..
If I centre the balance slider I get audio in both sides, although it's hard to tell if both left and right are equal because of the low volume.
If I slide fully to 'Right', I get all get audio in both sides, again, it's hard to tell if both left and right are equal because of the low volume.

Obviously I can connect both sides of the unit together again to check the speakers if you want me too. I'm just a bit concerned about continuously disconnecting & reconnecting the speakers because they can be a bit stubborn.

 

[Dago]

Sorry, I messed this sentence up:
If I slide fully to 'Right', I get all get audio in both sides, again, it's hard to tell if both left and right are equal because of the low volume.

Should be: f I slide fully to 'Right', I get all get audio in both sides, again, it's hard to tell if both left and right are equal because of the low volume.

 

[docs]

Audio should not be reduced at all by disconnecting the speakers.
Just to be sure the balance slider is the issue, does flicking the internal/external speaker switch have any impact on the audio level or getting the left output to work?

 

[docs]

According to the block diagram, the sequence goes

balance -> volume -> tone amps -> bass -> treble -> muting -> power amp

The loudness switch is in there too between balance and volume.
If you suspect the balance slider, you can do ohm checks across the wiper and the end to see if it gives you close to the value it is.
It's a fairly good call it is the balance slider but don't be surprised if it isn't as it could equally be another part after there.

 

[Dago]

Just changed my headphone jack adapter and volume through phones now normal so first adapter is obviously faulty) . Plugged speakers back in also (didn't realise connection would reach with both sides apart until now). No, flicking the INT/EXT switch doesn't make any difference. Headphones still have audio on either setting but still only out of the right channel.

 

[docs]

Ok fingers crossed its the balance pot.

 

[Dago]

Sorry, was doing a reply to you and didn't see your last but one reply before I sent it.
Thanks for the info but being a newbie to this type of thing, I'm not sure I understand how to do this bit 'you can do ohm checks across the wiper and the end to see if it gives you close to the value it is'. I don't know if I can work out how to inspect/repair the brushes in the balance slider either but if your suggestion helps me not doing that, I definitely want to try it first. Thanks for your help. If I'm asking one too many questions, I know it's not always easy to pin down, but if you could just point me in the right direction with slider ohms check that would be really appreciated before I attempt looking at demounting the slider. Thanks again

 

[Dago]

I just noticed too that the record button won't depress on the cassette. I'm sure someone mentioned in a different thread that pressing play and record several times together was worth trying because there seems to be some sort of connection with the speakers. Do you think it could it be that the cassette mechanism is causing the issue if that's the case?

 

[docs]

are you trying with a blank cassette in?

 

[Dago]

Just realised my dumb mistake re the record button. There's a lockout unless the tab is present on the tape to stop it being recorded to. I had a tape in there with tabs removed so wouldn't record button wouldn't depress. So many years since I've used cassettes, it's a learning process all over again!

 

[JVC Floyd]

Sometimes these balance problems can be caused by function switches and band selectors on these models.it's a big fat pain in the ass to work on these switches because they're closed and you have to disassemble them to even have access to the parts that are f***** up.

 

[Dago]

Cheers JVC. You're telling me it's f****d up, it's doing my head in!! The function switches and selectors obviously cause problems because everybody seems to have issues with them, I can't seem to work out why though. What is the reason for that?

In any case because I hate to be beat, I've now desoldered and removed the balance slider (eventually). The brushes hadn't come away and looking at them, they were made up of four metal contacts, two on each brush. Difficult to explain because I didn't take a photo of them but if you can image (if you don't already know that is) the 4 fingers on your hand, finger 1 and 4 being on the outside, and 2 and 3 being on the inside. Brush 1 was say, fingers 1 & 2, and Brush 2 was fingers 3 & 4. Fingers 2 and 3, so to speak, were lying quite flat, and I couldn't see how they could make contact with the slide bar above, so I gently bent them upwards. Not sure if I did the right thing because some here have said the brushes sometimes just become detached and you need to glue them back, but the brushes hadn't come loose or detached. In any case, I couldn't see how the inner two parts of the brushes could be making contact with anything at all, but having thought about it as I'm reading this, maybe they are there to just steady the upper part? Probably didn't explain that great so tried to make a rough sketch of what I mean, which might not make things much clearer either!

If anyone thinks I should have left them as they were, could you let me know please before I solder the slider back into the board, it was a nightmare to get it off and I don't want to do it again if I can help it!

 

[Dago]

JVC can I ask you, when you say function switches are a constant problem with VZs, do you mean just the tape. phono, aux and radio band switches, or do you also mean the sliders and record player switches. I've demounted the balance slider, checked the brushes, mounted it again and re-soldered it, but it's made no difference, still no sound out of left speakers or headphones. I'm obviously just going to have to keep putting contact cleaner on the switches and keep pressing for a while and hope that works. Just wondered if, in your experience, is it just certain switches or all switches & sliders. Cheers