UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Television and Video

Notices

Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

Closed Thread
 
Thread Tools
Old 8th Jan 2013, 10:35 pm   #1
michaelj6464
Retired Dormant Member
 
Join Date: Jan 2013
Location: Worcestershire
Posts: 3
Default Sony Betamax C5 Jittery Picture.

Can any one help with advice or service manual for Sony Betamax C5? Unit works mechanically and heads seem to be in good condition, but get a lot of jitter on playback. I believe this could be down to leaky capacitors on sync board possible A3 or A2. Does this make sense to anyone, how are these boards identified?

Many Thanks.
michaelj6464 is offline  
Old 11th Jan 2013, 7:37 pm   #2
don200002
Pentode
 
don200002's Avatar
 
Join Date: Sep 2011
Location: Bideford, Devon, UK.
Posts: 196
Default Re: Sony Betamax C5 Jittery Picture.

Hi Michael,
It's a long time since I looked at one of these but unlike VHS heads which have a snug fit on the center post the sony heads required centering using an engineering clock guage. If they are slightly off center it will produce a jittery picture. Is it possible they have come loose or been changed without centering them properly?

Don.
don200002 is offline  
Old 11th Jan 2013, 8:47 pm   #3
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Sony Betamax C5 Jittery Picture.

It's an ecentricity gauge that's need for correct head adjustment. Though there can be a number of other things if no one's been at it.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 11th Jan 2013, 11:49 pm   #4
Stuart R
Heptode
 
Stuart R's Avatar
 
Join Date: May 2011
Location: Letchworth Garden City, Hertfordshire, UK.
Posts: 690
Default Re: Sony Betamax C5 Jittery Picture.

Hello Michael,

Just checking you specifically mean "jitter" as opposed to a general servo problem.

With my C7, I found some common faults listed here,

http://www.palsite.com/tech.py?model=slc5tech.html

Mine was suffering with wow on sound and a noise bar, cycling every few seconds. Changed the recommended capacitors which improved playback.

Of course, there could be many things wrong, including the previous suggestions offered by the other more experienced members. Maybe I just got lucky?

It certainly helped that in the C7, once you take the base off, each section of the circuit board is labelled with its function.

Good luck,

SR
Stuart R is offline  
Old 12th Jan 2013, 2:52 pm   #5
Welsh Anorak
Dekatron
 
Welsh Anorak's Avatar
 
Join Date: Apr 2005
Location: North Wales, UK.
Posts: 6,884
Default Re: Sony Betamax C5 Jittery Picture.

Hi
I agree with Stuart - the most common fault on an elderly C5 is a side-to-side wobble which points to servo problems, usually stemming from a worn ACE head. There are several mods to make the circuit more sensitive.
Up and down shake tends to suggest a path fault, pinch roller hardening or a tension problem. The history of the machine is a good pointer here - if it's just happened or you're confident it's not been got at then it's more likely to be a wear problem as opposed to a path fault. If it's been standing a while then capacitor problems are favourite - it's amazing how warming a machine up and running several tapes through it can loosen things up and cure faults.
Glyn
Welsh Anorak is offline  
Old 12th Jan 2013, 4:56 pm   #6
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Sony Betamax C5 Jittery Picture.

There are two tantulum caps on the servo panel that cause trouble, normally wowing. I think they are either 2.2uF or .22uF. Certainly on the C7. It's a long time since I fixed one!
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 12th Jan 2013, 4:57 pm   #7
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Sony Betamax C5 Jittery Picture.

Think ACE head mod was for dropout?
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 12th Jan 2013, 5:38 pm   #8
steptoesyard
No Longer a Member
 
Join Date: Jul 2011
Location: Tavistock, Devon, UK.
Posts: 147
Default Re: Sony Betamax C5 Jittery Picture.

I am 100% sure that it's the light blue Sanyo electrolytics in the servo circuit (there are 3 or 4 of them). I've just repaired and restored one and now it's perfect. I have done countless restorations like this in the past and it's always been these same capacitors. I've never had an issue with pinch rollers or head alignment.

Just as a guide, a horizontal jitter will be caused by the head drum servo, and usually a vertical problem is caused by the capstan motor servo circuit. To make sure you cover both, change all of the mentioned capacitors. The circuits are clearly labelled and are located on the smaller of the two PCB's that are on the bottom of the machine - you will see they are screwed together but are separated approx 60/40.
steptoesyard is offline  
Old 17th Jan 2013, 6:58 pm   #9
michaelj6464
Retired Dormant Member
 
Join Date: Jan 2013
Location: Worcestershire
Posts: 3
Default Re: Sony Betamax C5 Jittery Picture.

Thank you very much for all your prompt and informative replies. I note what is being said about head alignment. I will certainly check this, but I'm inclined to favour capacitor replacement as the unit has only been lightly used and is in very good condition, but is clearly old and so caps are prone to leakage after all this time.

Stuart, when I say "jitter" I'm referring to a rapid sideways, or horizontal displacement of the picture. Palsite, incidentally, is very ood,but doesn't quite address my problem. When I solve it I'll post up a solution.

I'll have the covers off it again in the next few days and let you all know how I get on.

Many Thanks - Michael
michaelj6464 is offline  
Old 18th Jan 2013, 11:46 am   #10
Andy Doz
Hexode
 
Andy Doz's Avatar
 
Join Date: Feb 2011
Location: Gloucestershire, UK.
Posts: 376
Default Re: Sony Betamax C5 Jittery Picture.

Quote:
Originally Posted by steptoesyard View Post
I am 100% sure that it's the light blue Sanyo electrolytics in the servo circuit (there are 3 or 4 of them).
Whilst they look like Electrolytics, there are, in fact, tantalum.
Andy Doz is offline  
Old 22nd Jan 2013, 7:56 pm   #11
michaelj6464
Retired Dormant Member
 
Join Date: Jan 2013
Location: Worcestershire
Posts: 3
Default Re: Sony Betamax C5 Jittery Picture.

Things are moving on.

I've had it apart,heads seem OK mechanically and clean. Replaced most electrolytics and tantalums on Capstan and Drum Servo Boards. Powered up and it's improved a bit so I'm on the right track.

After replacing all these parts the servo boards will need re-aligning. I'm now waiting for some pre-recorded tapes to arrive to adjust against. At present I only have a blank tape and therefore no standard to work to - record and playback on the faulty machine will get me nowhere.

Incidentally, I am electronics capable, I have scopes, sig generators and measuring equipment but no manual for the C5. It would be helpful if anyone could point me towards a manual or just any advice on adjustment.

My guess would be to go for a small adjustment of the drum free speed, followed by the phase locking as it appears to me that the speed is maintained by a phase lock circuit and the symptoms suggest instability in the drum speed.

Does the C5 have an ACE head? If so this could be a cause of my troubles.

Many thanks,
Michael.
michaelj6464 is offline  
Old 18th Jun 2013, 6:20 pm   #12
craigie2k
Diode
 
Join Date: Jun 2013
Location: Chatham, Kent, UK.
Posts: 7
Default Re: Sony Betamax C5 Jittery Picture.

Quote:
Originally Posted by steptoesyard View Post
Just as a guide, a horizontal jitter will be caused by the head drum servo, and usually a vertical problem is caused by the capstan motor servo circuit. To make sure you cover both, change all of the mentioned capacitors.
Hi. I also have the "jittery picture" problem and was wondering if you know where to get hold of the mentioned capacitors. I've looked on a number of websites with no luck. Is there a modern replacement perhaps? Thanks, Craig
craigie2k is offline  
Old 18th Jun 2013, 7:42 pm   #13
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Sony Betamax C5 Jittery Picture.

These are Tantulum caps and easy obtained 2.2uF comes to mind.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 2nd Sep 2015, 4:50 am   #14
kiwi_ME
Retired Dormant Member
 
Join Date: Sep 2015
Location: Napier, New Zealand
Posts: 1
Default Re: Sony Betamax C5 Jittery Picture.

I'm happy to report that this solution has fixed a sudden loss of sync on my C5.
Replace on AS-6 board (accessed from underside of unit.)

All yellow tants and all replacements were 35V in my case:

C041 0.33 / 25V
C043 1.00 / 25V
C011 0.47 / 25V
C045 0.47 / 25V
C052 0.22 / 25V

Thanks to steptoesyard for the "100% sure" comment, those are good odds.
kiwi_ME is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 1:51 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.