Jands 250/600 slow to boot

[Kinkele]

I volunteer at a teen center nonprofit, old opera house. We have 12 movers, 12 conventionals and 6 LEDS, I want to keep my Jands 600 alive. Recently it started taking up to 4 minutes between the time you turn on the power switch and any signs of life, no button lights, menu, nothing. Then is comes to life and behaves normally. Does anyone have an idea of what is failing? Capacitor? software hang up?

 

I would appreciate any assistance

 

Kinkele

[DrV]

If there are absolutely no signs of life then it seems the power supply is not starting up. First place I would look is the reservoir capacitor for the PSU control chip Vcc supply, but that is territory for someone with the experience and tools for switch mode PSU repair. They utilise very high voltages (even those running from 115 volt supplies). Not something to be undertaken lightly without understanding the risks and associated safe practices.

[Kinkele]

If there are absolutely no signs of life then it seems the power supply is not starting up. First place I would look is the reservoir capacitor for the PSU control chip Vcc supply, but that is territory for someone with the experience and tools for switch mode PSU repair. They utilise very high voltages (even those running from 115 volt supplies). Not something to be undertaken lightly without understanding the risks and associated safe practices.

 

Understood, and the risks involved with capacitors is understood. I have the technical manual and I will look up the location you mentioned. If the problem is in the OEM PSU, perhaps I can find a new drop in replacement for the whole thing. I was reading the tech Manual about the battery and there is a not about another capacitor. Anyway thanks for responding. If you think of anything else just post and I too will post my progress.

 

Thanks,

 

Kinkele

[Brian]

Before you start swapping capacitors I'd checked what the actual power rails do on switch on. Four minutes before any desk activity seems more than just power supply related.

[DrV]

Before you start swapping capacitors I'd checked what the actual power rails do on switch on. Four minutes before any desk activity seems more than just power supply related.

Absolutely - you need to check whether the PSU is actually faulty before delving inside.

 

The long delay is indeed odd but I have seen precisely this. The fault was that the small capacitor which supplies Vcc to the chip was a bit leaky. On power up this gets charged straight off the HT via a high resistance. Once the chip has started switching, Vcc is supplied from a separate winding on the transformer. Because the cap was leaky it prevented Vcc from reaching the start up threshold but it would get there eventually.

[Kinkele]

Before you start swapping capacitors I'd checked what the actual power rails do on switch on. Four minutes before any desk activity seems more than just power supply related.

Absolutely - you need to check whether the PSU is actually faulty before delving inside.

 

The long delay is indeed odd but I have seen precisely this. The fault was that the small capacitor which supplies Vcc to the chip was a bit leaky. On power up this gets charged straight off the HT via a high resistance. Once the chip has started switching, Vcc is supplied from a separate winding on the transformer. Because the cap was leaky it prevented Vcc from reaching the start up threshold but it would get there eventually.

 

 

 

 

 

Where is that capacitor? I do have the technical Manual with schematics. Post Power Supply?

 

That was I was thinking. I read in the technical manual that there was a cap off the IC13 circuit that was involved in switching. The one thing that didn't make sense was the manual said look here if your battery was good and you were still loosing your show in the memory. I am not loosing my show.

 

Another theory I am testing is a corrupt show file. The logic being the show file would cause a hangup that would eventually timeout. The problem in that logic is I would expect the sequence of operation to be, power, operating system, leds, menu, load show. I did a deep clean and reload. I figure it was worth the time to try. The board have been off a few days so tonight might be a good test of this theory.

 

Thanks for al the feed back. I keep you informed

 

Kinkele

 

[martinw]

One thing to try here is to unplug and replug the low voltage power cables inside the console. I've seen this fix Hog2s, where over time, the wire-to-PCB connection built up resistance resulting in the 5V rail being significantly less than 5V on the PCB.

 

Martin

[DrV]

The cap to which I was referring is on the Vcc supply to the switching chip which is at the heart of the PSU. The way I would approach it is to identify the chip then look up the datasheet for it and find the cap connected between the "0v" or "common" pin and the "Vcc" pin. If you post the chip number and/or a picture of the PSU internals I might be able to point you at the pins.

The safety warning I posted on post #2 still stands of course. Sorry to labour the point but it sounds as though you don't have much experience of PSU repairs and I don't want you to hurt yourself.

HTH Dave

[Kinkele]

The cap to which I was referring is on the Vcc supply to the switching chip which is at the heart of the PSU. The way I would approach it is to identify the chip then look up the datasheet for it and find the cap connected between the "0v" or "common" pin and the "Vcc" pin. If you post the chip number and/or a picture of the PSU internals I might be able to point you at the pins.

The safety warning I posted on post #2 still stands of course. Sorry to labour the point but it sounds as though you don't have much experience of PSU repairs and I don't want you to hurt yourself.

HTH Dave

 

 

My experience with internals of a PSU are limited, but I have a lot of experience with 277/480 motors and controls as well as theatrical lighting, precautions with capacitors is understood and your repeated reminders are respected.

 

As for my software deep clean and reload. It appears to be working. The console booted up without hesitation last night. I will test again on Friday, and at least twice a week for a while. I appreciate all the support and expect that at some point, with a console this old, I will have to break into that PSU. My experience with many different types of controls and PLCs is that the problems often start at the Power supply.

 

I will continue to post updates for a few weeks.

 

Thanks ALL

 

Kinkele

 

One thing to try here is to unplug and replug the low voltage power cables inside the console. I've seen this fix Hog2s, where over time, the wire-to-PCB connection built up resistance resulting in the 5V rail being significantly less than 5V on the PCB.

 

Martin

 

Next time I flip the console over and open it up I think I will do this on general principles, Thanks

 

Kinkele

[DrV]

Glad you got it sorted.

Dave

[Kinkele]

Glad you got it sorted.

Dave

 

Update: the software, deep clear and reload, worked over the weekend, the console booted up normal, but the problem appeared again on Monday. I deep cleared and reloaded again and will continue to check.