JV90 Crashes down...

Forum for JD, JV, XP and XV synthesizers from 1990's
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ASB
Posts: 1
Joined: 20:32, 8 May 2016

JV90 Crashes down...

Post by ASB »

Hey guys,

I have an old (and beloved) JV90, but lately it seems tired, because every time I turn it on, it runs for 20-30 seconds, and then just freezes. (That means that the screen still works and the lighting on the buttons work, but there is no sound and all of the buttons are inactive. In other words, the light is on, but no one's home.)

When I turn it off and on again, it goes back to operate as usual, but only for another 20-30 seconds, and so on...
Is anybody familiar with the phenomenon? does someone has a solution?

Of course I tried to restore to factory settings, and opened it up to find something faulty inside, but I saw nothing unusual, so I just cleaned up some dust. (did not help)

The local music shops and electronics labs don't know the VJ90 and don't want to deal with something this old, so I thought maybe someone here will be able to direct me towards the desired solution.

Thanks in advance for any kind of help.

A.
Horizonsound
Posts: 5
Joined: 00:40, 28 January 2016

Re: JV90 Crashes down...

Post by Horizonsound »

I have a similar problem, but the unit does not seem to fire up. Screen lights up then dies.
Lucky I have a second one, so will switch out a few modules to narrow it down.
Probably the power supply, and hopefully not the main board.

Anthony.
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CesarsoundOne
Posts: 203
Joined: 21:29, 9 October 2014

Re: JV90 Crashes down...

Post by CesarsoundOne »

In old electronics, the first rule is to replace all electrolytic capacitors, from main board and power supply. These components have a limited life time.
Horizonsound
Posts: 5
Joined: 00:40, 28 January 2016

Re: JV90 Crashes down...

Post by Horizonsound »

True. It's on the list.
My XP50 had a cap in the reset circuit and exhibited the same symptoms the JV is having. But the JV does not seem to have the reset circuit.
Luckily the JV does not have SMD caps.
Horizonsound
Posts: 5
Joined: 00:40, 28 January 2016

Re: JV90 Crashes down...

Post by Horizonsound »

Turned out to be a connecting cable was pinched under the frame that supports the display in the PCB. Must have been shorting out. Fixed, reset and all good to go.
FYI - I also had the red goo issue on this one. It is easy to clean off the key bed, but harder of the metal casing.
Use sodium hydroxide solution and soak the keys for 24 hours. It dissolves the epoxy away. Then re-glue the weights on.
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