Let's See Your Great JVC Gear!
- Thread starter GD70
- Start date
Sounds Great Glenn. Woodwork is stunning. I just love that vintage style.
Garry
Garry
GD70
Lunatic Member
Thanks Garry! The dinky 7s sound pretty good for what they are!
GD70
Lunatic Member
I have a thread going about the AX-Z1010 I bought a couple weeks ago, and was damaged during shipping. The volume shaft was slightly bent. UGG! I straightened the shaft, but it has volume issues and I am trying to track down an original motorized volume pot. I'll have my tech look at it, and hopefully its repairable but just in case. So please keep an eye out for one. I know a 1010 was parted out and listed on epay, and I think I found the seller, but no luck yet. Otherwise, the amp is in near new condition. Almost no dust on the PCBs!
Really a shame.
Cheers, Glenn
Really a shame.Cheers, Glenn
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Ziinda
Active Member
Recently while searching for parts to repair my power supplies for my electrostats I rember seeing a motorized volume control in one of the many bins full of old electronics boards and gutted organ parts. My best guess is it's either from a Yamaha or a Radio Shack receiver. I might have another in my removed pots box but I know I have one for sure. Do you have a picture or a model number of the part to cross-reference the pins or maybe a pin count. Without a direct replacement it can get tricky but not impossible.
If it's even close I can send it to you since I'll never be using anything that will have a motorized volume control. I also have a stack of Sony AV receivers that have no value and could have those. Also a few old Panasonic all in one DVD systems that could use that, made in like 2002. What year is that receiver? If the years are close the technology used among makers is similar making better odds for a close match. That applies to all components through time, size becomes an issue with newer stuff.
Ziinda
Active Member
This isn't the one I was thinking of so that means I have another. I think this is the smaller one.
knifeswitch
Active Member
This one arrived yesterday in non-working order. It’s somewhat of a bruiser. Someone’s been in there and their work was rather dodgy. It’s in protection currently. No matter, I think it’ll make a fine addition to my JVC herd. 1979 A-X5.
knifeswitch
Active Member
Nice to meet you Ambi
GD70
Lunatic Member
Bummer, but well worth the effort to get it singing again.
GD70
Lunatic Member
Look here, post 7, has pics of the volume pot. The one you posted is definitely smaller.
Cheers!
https://old--fidelity--forum-de.tra...l=auto&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp
Ziinda
Active Member
It looks like the real difference isn't the size douch but the number of posts. Mine has 6 total on the pot and that one has 8 total.
The other one I spotted a few weeks ago was definitely larger but I can't say if it has more posts or not.
Is the problem with the motor that drives the gears, the gears themself or is the pot bad?
It looks easy enough to take apart and see, replacing anything but the gears will be quite simple. I would consider just using a different 8 post pot for now. Without reading through I'm going to assume that it must be the gears that are bad since the rest looks to be simple to repair. My gearbox looks identical to the one in the picture, but basically any gear box that moves freely and has a center that's the same or less to center of box should work. As long as it's the same thickness of thinner would be fine too, just need to extend the wires to reach the motor. I'd just use some thicker single core copper wires that will act as a mounting piece as well. It looks like that rear board supports the entire assembly along with the shaft nut. So the assembly can be shorter going by that but I don't know if that board is actually mounted onto another board or if there's a jumper running to it or a screw that secures it onto a metal frame? Either way as long as it's shorter or the same it won't be hard to make it work.
I never sweat the small stuff, exact fitting parts are nothing but a dream to me. Close enough works when it's mechanical but not when it's an electronic component carrying sound.
GD70
Lunatic Member
The motor and gears are fine. Once I straightened the shaft, about 98-99% straight now, it pretty much has unassisted full rotation, except for a spot around 4 o'clock position where it get's stuck. I assist and it finishes to about the 5 o'clock position.
The assembly is soldered to a large PCB, the small board at the back of the motor, and all the pot tabs are soldered to it, shaft nut mounted to the front of the amp.
The second resistive board (4 pins) I think is the issue, shown with the repaired spot in the link. Once it's opened up, I hope it's clear what's causing the sound output issue on the left channel. It's so odd the volume level stays the same regardless of the volume knob position.
knifeswitch
Active Member
Every intention of resurrecting this one! I knew it was dead when I bought it and people will say what they say about Super-A’s but I really like the sound. I had a couple A-X1’s I brought back from the dead that I ended up giving to friends. I found when they were gone, I really missed them.
GD70
Lunatic Member
This series are terrific and mostly under the radar. The A-X9 is amazing. My A-X5 has been great, going on about 7 years now. The 9 had needed work, due to age, and just about every board has had major rebuild work done.
GD70
Lunatic Member
Pic of the Motor Drive Circuit PCB board the Volume pot assembly is mounted to.
I tried to remove it, but can't figure out how to unplug some of the connections. The two top grey ones, and a couple smaller white ones connected to a lower board. I don't want to break anything.
I tried to remove it, but can't figure out how to unplug some of the connections. The two top grey ones, and a couple smaller white ones connected to a lower board. I don't want to break anything.
GD70
Lunatic Member
That’s wild! This is the first time I’ve dealt with plugs like this.
Much appreciated for the diagrams.
Cheers!
GD70
Lunatic Member
I attempted to try one of the smaller connectors and it started to break a little bit, so I pushed it back to original position. I’m meeting my tech in the morning to pick up my M-7050, and give him the Z1010. He’s better adept at how to deal with these fasteners than I am. It will be in good hands.
Ziinda
Active Member
Did you ever see it working correctly or did you get it like this?
If it needs help it'll never work, are the gears nylon or a plastic, if you look closely are the gear you'll most likely see a tiny crack that goes to where it stops. Right where to 2 gears mesh mark it and look under a high powered magnifying glass and I'll bet there's a crack. I've seen this on many older plastic type gears. That tiny gap that's hardly able to be seen is just enough to make it bind and the motor won't have power to overcome it or be able to do it for very long, it will cause the tips on any other gears that it touches to wear or tilt each time it passes that spot furthering the binding. If the shaft was bent that's a huge problem, how could it be bent? Someone lose their temper and smack it? I know I have been known to do that with mixed results but at the very least I ended it either way.
I guess worse would be bending due to gears binding.
There are all kinds of newer type pots that have 4 posts (not too many double stacked though many have 8 posts in the same row) but make sure to use a volume pot not a balance pot (which is what I thought possibly may have been replaced by previous owners attempt to repair but balance pots are not very common and less with 2 rows of 4)
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