JVC QL-A7 problems

UlrichN · Posted: Sat Nov 07, 2009 8:09 pm Post subject: JVC QL-A7 problems

Hi
I've just got a JVC QL-A7, in very good condition.

But unfortunately it has a couple of problems Sad

1. The speed of the platter is not correct. According to the strobe, it's running a bit slow on 45RPM, but most of the time, it runs correctly on 33RPM. If I give the platter a gentle push, it gets spot on and stays there. Is this just an adjustment issue or something more serious?

2. The strobe lamp is flickering quite a bit, so I guess it needs replacement soon. Is the lamp availible or maybe an alternative?

Thank in advance

Ulrich

caligari · member Joined: 29 Jun 2008 Posts: 45 Location: Chicago

UlrichN · Posted: Sun Nov 08, 2009 1:49 pm Post subject:

Hello

Thanks for your reply.

I've adjusted the speed now, and it seems to run stable on both 33 and 45RPM. It was enough just turning the VR803 a bit back and forth, and the speed was correct. Smile

Now I need to find a spare strobe lamp. That seems to be a bit of a problem, as it's not on the parts list, in the service manual. It has number 70 on the 10-2 diagram, but 70 is not on the parts list. Brick wall

Which cartridge do you use for your A7? As a Dane, of course I prefer Ortofons. Maybe a 2M Red.

Shoji · senior member Joined: 06 Nov 2002 Posts: 420

Hello Ulrich. Before make the change of neon lamp make the check for correct voltage both side for neon lamp plus also condition of 1 watt resistor R663. If not able to make check for self ask for good technician. If require neon lamp look for replacement with corect strike voltage plus amperage by use figures measure across R663.

fscl · Posted: Sun Nov 08, 2009 6:12 pm Post subject:

Try somehow cleaning the On/Off and 33/45 switches. These are pushbutton type and may be sealed? not allowing cleaning w/ contact cleaner, however, the speed drift and quartz lamp flickering is indicative of dirty contacts.

If these are sealed buttons as my Y55F is, then just try pushing the buttons rapidly and perhaps the action will rub contacts / contactors enough to shine / wear some oxidation off of the electrodes.

Check out this recent thread with speed control and quartz bulb flickering problems:

http://www.vinylengine.com/php.....hp?t=22751

Hopefully, this will help? before performing further electronic troubleshooting.....

Good luck.

Fred
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stpa · contributor Joined: 15 Feb 2007 Posts: 105

Ulrich

I would never play with those variable resistors in most control boards of these turntables if I have no way to properly adjust them using the recommended manufacturer procedures, as it may really mess up the rotation control. Just read the QL-A7 service manual to understand why; the service manual is available here, at http://www.vinylengine.com/library/jvc/ql-a7.shtml .

Also, many times these erratic rotation issues can be solved just by cleaning with a good contact cleaner, as Craig Dexoit, all contacts, including knobs or buttons. As our member fellow fscl suggested, try to clean the switches, then read the service manual, check the tensions on the board, and so forth.

UlrichN · Posted: Mon Nov 09, 2009 8:19 am Post subject:

jvc_graz · contributor Joined: 24 Jun 2005 Posts: 37 Location: Graz

here http://amp8.com/amp-etc/record/victor/tt-71.htm you can see what to do, also at the page http://forum2.magnetofon.de/sh.....eadid=4782

regards, jvc_graz
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fscl · Posted: Fri Nov 13, 2009 2:48 pm Post subject:

j_graz,

Great first link. The second URL does not seem to work. Has it been withdrawn?

Fred
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Music is Everything....Except Predictable....WFUV Fan.

jvc_graz · contributor Joined: 24 Jun 2005 Posts: 37 Location: Graz

http://forum2.magnetofon.de/sh.....eadid=4782

i've tested it- it works Wink

klaus
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fscl · Posted: Sat Nov 14, 2009 1:24 pm Post subject:

Thanks Klaus,

Somehow when separating the 2 links, they DO work.

I admit, I've become lazy typing a URL instead of just clicking on it and complaining..... Embarassed

NICE work and great write up. How old were your caps before you had to replace them......

Fred and wondering if I'm on borrowed time w/ the Y55F Think

so far speed is ROCK solid, knocking on wood as I type......
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Music is Everything....Except Predictable....WFUV Fan.

Paladin · Posted: Sat Nov 14, 2009 4:25 pm Post subject:

Since 1975, I was told from day one that I’m going to be sorry because I use GEAR DRIVES. Stubbornness on both sides, perhaps. ‘The electronics will go wild and smoke, I’ll be rumbling nonstop, my speed will waver, my tonearm will grab me & lock, and I will be shunned in the audio world.’ That stuff didn’t phase me a bit. Since then THEIR jumper-drives are long gone into the pit yet I still take daily spins around the block with my QL-Y7. My Dual lost its automatic control; I guess it needs a bladder. That’s 1 in 10 odds, 10%. Perhaps one day one will quit completely.

They are good investments with daily rewards but I still can’t carry them in my pocket or listen to them in a car.

I gave up waiting to be sorry so I can concentrate on enjoying the music more.
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Will