JVC Videosphere Model 3240 - No video (sometimes) but has sound - UK Vintage Radio Repair and Restoration Discussion Forum

Jayjay21 · 14th May 2017, 3:11 am

Hello everyone, first time poster

I recently brought an old Videosphere off Ebay that had taken what looks like a bad tumble. I had hopes of repairing and refurbishing it, in fact I still do.

When it arrived it was in a sorry state but with a little TLC I've managed to make it look presentable.

I'm sure that it's 90% there but I could just use a little help with the final 10.

When I first powered it on - No video, but it had sound.
The screen was blank... no Vertical or Horizontal lines, nothing.

I tried again and "let there be light and there was"

When inspecting the internals I noticed that both the boards had jumped their housings and re-seated them. I also noticed that a previous owner was a super smart cookie and had installed a Composite input... wow lucky, it worked and I hooked a Set TopBbox up to it and presto TV.

So at this point I was super happy thinking all is good, I even spent an evening watching TV on it.

But the next day, it was back to no video. I opened it up again and poked around, I managed to get it to turn on again (no idea how though). I closed it up but still after that I again couldn't get it back.

Any Ideas.

JJ.

hans · 17th May 2017, 12:28 am

Quote:

Originally Posted by Jayjay21

I recently brought an old Videosphere off Ebay that had taken what looks like a bad tumble.

Do you think it has damage after falling? Impacts can make the print crack and give faults like this. I would have checked the print for closely for cracks. (and dry joints)

Nickthedentist · 17th May 2017, 12:59 pm

Yes, cracked print is almost certainly the cause.

Unplug, open it up, dust the PCBs and inspect them under bright light.

You can also run it with the covers off and prod the PCBs with something insulated (e.g. a wooden dowel) BEING WARY OF THE HIGH VOLTAGES WITHIN. Don't do this if you're not au fait with working on live equipment.

Nick.

Jayjay21 · 17th May 2017, 1:10 pm

Thanks for the reply Hans.

I'll have a check of the solder joints and redo any I find, seems likely because it looks like it was a serious fall.

I'm pretty happy with how its gone.

It went from this.

Click image for larger version

Name: s-l1600 (1).jpg
Views: 312
Size: 45.4 KB
ID: 142717

To this.

Click image for larger version

Name: 18518472_1457310137658980_311801194_n.jpg
Views: 315
Size: 64.0 KB
ID: 142718

Interestingly after using it for a couple of hours a day, it seems to be getting better. Only takes about 40-60 seconds to turn on, but I can live with that.

JJ

hans · 17th May 2017, 9:24 pm

If it is some kind of bad contact it can create sparks which in the worst case can seriously damage (burn) the set. A serious check is necessary.

Hunts smoothing bomb · 17th May 2017, 10:26 pm

Yes, please don't carry on using it like this, it will only get worse and you could end up with a set that is damaged beyond repair.

Cheers

Jayjay21 · 18th May 2017, 12:40 pm

Gotta, I'll have a detailed look this weekend. Thanks for the replies guy.

Jayjay21 · 26th May 2017, 4:58 am

Hmmm, no luck.

After looking my hardest at all the solder joints I can see, nothing stood out. I even re-flowed a couple that I wasn't 100% sure of. None of the capacitors or other components seem burned or bulged, but it's still hit and miss on whether the tube turns on.

Not sure what else I could do with my level of knowledge, expect enjoy it when I can, until it dies then gut it and install an LCD.

Unless anyone has got any other suggestions.

JJ

Maarten · 1st Jun 2017, 1:35 am

Gutting it would make no sense at all for a historic (not especially rare but iconic and worth some money) set like this. Finding intermittent faults is always hard, but the more it stays in the defective state, the easier it is to take measurements. Isn't there someone more near by who can help you through?

Hunts smoothing bomb · 6th Jun 2017, 10:12 pm

It is possible that it could be a defective solder joint as it is the CRT that is affected, reflow the solder to all the LOPT (line output transformer) pins on the board if you have not done so as this is a heavy component that is most likely to break away from the board when the set was dropped, this component generates the high voltage for the CRT so any breaks around here will give you your described symptoms.

Failing this though it will be most likely be a cracked PCB (printed circuit board)
The cracks can be very hard to spot as they can be so fine, a tip is to use a magnifying glass and a strong light, even with this method you are looking for something finer than a human hair!

Another tip is to run the set with the case removed if you are confident in doing so and then flex the boards gently by pushing them in different areas noting where it is most troublsome, use something insulated such as a wooden dowel, also doing this in a very dimly lit room can sometimes make it possible to see little sparks on the print side where the crack is, once located the affected tracks can be scrapped to reveal the bright copper and then bridged with wire and reflowed with solder.

It would certainly (in my mind) be a bad move to gut the set and insert an LCD screen as these sets are iconic even if not rare and they do command a price.

Cheers

Records · 8th Jun 2017, 12:56 pm

My thoughts for what they are worth would be to strip it down and rebuild it, it has obviously been dropped sometime in its life and the only way to sort this kind of fault is to strip it down and look at everything.
It could be something simple and it would be a shame to see something like that gutted and have modern junk put in it.

Jayjay21 · 1st Jul 2017, 11:59 am

Thank you all for the info and tips.
I'll will definitely work through the ideas you have posted.

But that won't be for along time unfortunately, I'm deploying in a few weeks
and will be very far away from my shed (very far).

But I do intend of trying my best to fix it.

JJ.

P.S. The gutting option was only if I ever let the smoke out and was left with a heavy piece vintage plastic.

14th May 2017, 3:11 am	#1
Jayjay21 Retired Dormant Member Join Date: May 2017 Location: Darwin, Northern Territories, Australia Posts: 5	JVC Videosphere Model 3240 - No video (sometimes) but has sound Hello everyone, first time poster I recently brought an old Videosphere off Ebay that had taken what looks like a bad tumble. I had hopes of repairing and refurbishing it, in fact I still do. When it arrived it was in a sorry state but with a little TLC I've managed to make it look presentable. I'm sure that it's 90% there but I could just use a little help with the final 10. When I first powered it on - No video, but it had sound. The screen was blank... no Vertical or Horizontal lines, nothing. I tried again and "let there be light and there was" When inspecting the internals I noticed that both the boards had jumped their housings and re-seated them. I also noticed that a previous owner was a super smart cookie and had installed a Composite input... wow lucky, it worked and I hooked a Set TopBbox up to it and presto TV. So at this point I was super happy thinking all is good, I even spent an evening watching TV on it. But the next day, it was back to no video. I opened it up again and poked around, I managed to get it to turn on again (no idea how though). I closed it up but still after that I again couldn't get it back. Any Ideas. JJ.

17th May 2017, 12:59 pm	#3
Nickthedentist Dekatron Join Date: Jan 2005 Location: Oxford, UK. Posts: 17,840	Re: JVC Videosphere Model 3240 - No video(sometimes) but has sound Yes, cracked print is almost certainly the cause. Unplug, open it up, dust the PCBs and inspect them under bright light. You can also run it with the covers off and prod the PCBs with something insulated (e.g. a wooden dowel) BEING WARY OF THE HIGH VOLTAGES WITHIN. Don't do this if you're not au fait with working on live equipment. Nick.

17th May 2017, 1:10 pm	#4
Jayjay21 Retired Dormant Member Join Date: May 2017 Location: Darwin, Northern Territories, Australia Posts: 5	Re: JVC Videosphere Model 3240 - No video(sometimes) but has sound Thanks for the reply Hans. I'll have a check of the solder joints and redo any I find, seems likely because it looks like it was a serious fall. I'm pretty happy with how its gone. It went from this. To this. Interestingly after using it for a couple of hours a day, it seems to be getting better. Only takes about 40-60 seconds to turn on, but I can live with that. JJ

17th May 2017, 9:24 pm	#5
hans Heptode Join Date: Jan 2008 Location: Oslo, Norway. Posts: 632	Re: JVC Videosphere Model 3240 - No video(sometimes) but has sound If it is some kind of bad contact it can create sparks which in the worst case can seriously damage (burn) the set. A serious check is necessary.

17th May 2017, 10:26 pm	#6
Hunts smoothing bomb Octode Join Date: Oct 2005 Location: Wimborne, Dorset, UK. Posts: 1,407	Re: JVC Videosphere Model 3240 - No video(sometimes) but has sound Yes, please don't carry on using it like this, it will only get worse and you could end up with a set that is damaged beyond repair. Cheers __________________ Lee

18th May 2017, 12:40 pm	#7
Jayjay21 Retired Dormant Member Join Date: May 2017 Location: Darwin, Northern Territories, Australia Posts: 5	Re: JVC Videosphere Model 3240 - No video(sometimes) but has sound Gotta, I'll have a detailed look this weekend. Thanks for the replies guy.

26th May 2017, 4:58 am	#8
Jayjay21 Retired Dormant Member Join Date: May 2017 Location: Darwin, Northern Territories, Australia Posts: 5	Re: JVC Videosphere Model 3240 - No video(sometimes) but has sound Hmmm, no luck. After looking my hardest at all the solder joints I can see, nothing stood out. I even re-flowed a couple that I wasn't 100% sure of. None of the capacitors or other components seem burned or bulged, but it's still hit and miss on whether the tube turns on. Not sure what else I could do with my level of knowledge, expect enjoy it when I can, until it dies then gut it and install an LCD. Unless anyone has got any other suggestions. JJ

1st Jun 2017, 1:35 am	#9
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,199	Re: JVC Videosphere Model 3240 - No video(sometimes) but has sound Gutting it would make no sense at all for a historic (not especially rare but iconic and worth some money) set like this. Finding intermittent faults is always hard, but the more it stays in the defective state, the easier it is to take measurements. Isn't there someone more near by who can help you through?

6th Jun 2017, 10:12 pm	#10
Hunts smoothing bomb Octode Join Date: Oct 2005 Location: Wimborne, Dorset, UK. Posts: 1,407	Re: JVC Videosphere Model 3240 - No video(sometimes) but has sound It is possible that it could be a defective solder joint as it is the CRT that is affected, reflow the solder to all the LOPT (line output transformer) pins on the board if you have not done so as this is a heavy component that is most likely to break away from the board when the set was dropped, this component generates the high voltage for the CRT so any breaks around here will give you your described symptoms. Failing this though it will be most likely be a cracked PCB (printed circuit board) The cracks can be very hard to spot as they can be so fine, a tip is to use a magnifying glass and a strong light, even with this method you are looking for something finer than a human hair! Another tip is to run the set with the case removed if you are confident in doing so and then flex the boards gently by pushing them in different areas noting where it is most troublsome, use something insulated such as a wooden dowel, also doing this in a very dimly lit room can sometimes make it possible to see little sparks on the print side where the crack is, once located the affected tracks can be scrapped to reveal the bright copper and then bridged with wire and reflowed with solder. It would certainly (in my mind) be a bad move to gut the set and insert an LCD screen as these sets are iconic even if not rare and they do command a price. Cheers __________________ Lee

8th Jun 2017, 12:56 pm	#11
Records Hexode Join Date: Jul 2011 Location: Harwich, Essex, UK. Posts: 429	Re: JVC Videosphere Model 3240 - No video (sometimes) but has sound My thoughts for what they are worth would be to strip it down and rebuild it, it has obviously been dropped sometime in its life and the only way to sort this kind of fault is to strip it down and look at everything. It could be something simple and it would be a shame to see something like that gutted and have modern junk put in it.

1st Jul 2017, 11:59 am	#12
Jayjay21 Retired Dormant Member Join Date: May 2017 Location: Darwin, Northern Territories, Australia Posts: 5	Re: JVC Videosphere Model 3240 - No video (sometimes) but has sound Thank you all for the info and tips. I'll will definitely work through the ideas you have posted. But that won't be for along time unfortunately, I'm deploying in a few weeks and will be very far away from my shed (very far). But I do intend of trying my best to fix it. JJ. P.S. The gutting option was only if I ever let the smoke out and was left with a heavy piece vintage plastic.