Sony Betamax C9 and 950s - UK Vintage Radio Repair and Restoration Discussion Forum

davyrocket2 · 12th Apr 2011, 2:32 pm

Hi to everyone.

I am trying to talk to any engineers with experience of Sony C9s. I have rebuilt the DC-DC convertors and these are working okOK. I am trying to deal with issues on the tape carriages. I have got replacement metal gears and having fitted them it now works OK.

Fault 2, cassette cannot be loaded and there are 2 arms with rubber rings on them that have springs attached to them. These seem to be preventing the tape being pushed in all the way.

Fault 3 is a nasty chattering sound and the tape will not load on a Sony SL-HF 950. Fault 1 is the tape is playing but I ony get a black screen if I freeze frame or pause there is a picture and fault 2 is tuning in the TV station presets the picture is good but to get the sound you have to sacrfice almost losing the picture by pressing the +/- fine tune buttons so you have picture/no sound or sound but picture nearly breaking up. Any tips or help greatfully received.

I just do this to maintain my own collection.

David Grant.

Red to black · 12th Apr 2011, 8:30 pm

Hi Davy,

I used to repair Betamax machines many years ago, but tend to forget the faults, most of these were of a mechanical nature, which were pretty staight forward to repair at the time (as spares were readily available).

Later on as spares dwindled/and/or became expensive (Sony in particular), as well as to most customers this was a 'dead format', most refused to pay for anything other than the simplest of repairs (Sanyo 5000 idler etc.). The odd customer was however willing to pay for the 'more expensive repair' (Sony C7 PSU repair, Sony C9 DC-DC converter, Sony C9,C20,C30 cassette housing repair, Sony C9 head replacement etc.)

I was still repairing (commercially) the odd Beta machine (Sanyo 5000 etc.) subject to spares availability, up until about 2007-08, but then CHS stopped stocking the idler ass'y and belts for these machines (5000's).

Anway back on topic, have you seen the Palsite website ?, as this has a fault list for the Beta models. see:

http://www.palsite.com/tech.py

Cheers,
Baz

Ps.

Quote:

Fault 1 is the tape is playing but I ony get a black screen if I freeze frame or pause there is a picture

This is usually caused by a dirty or worn ACE head, (no or low control track pulses)

PPs. There are others on the Forum who are/were into Beta machines, I think Murphyv310 worked for Sony at one time, there are others still into these machines

Mooly · 10th May 2011, 8:11 am

Hi David... just a thought with you saying two C9's exhibit line tearing etc is that it may be a compatability problem with your TV/monitor. I experienced this first hand with my own C9 on a Philips TV that worked perfectly with other machines (VHS) on channel 0 ut not with the Sony.
In the end I ended up changing the time constant network in the sync separator on the TV which worked a treat.

Your carriage problem... you need to check (with power off) that the carriage micro switches (two I think from memory) are both operating correctly. If thats OK then you need to check/confirm operation of the motor drive circuit... that its receiving the input from these switches correctly.

Maarten · 14th May 2011, 5:32 pm

Excessive pulling despite the TV being configured for VCR input, can also indicate a problem with the VCR's backtension.

derbeian · 11th Jul 2011, 12:17 am

Hello David - Great to hear that you have managed to restore your C9. I also have one of these models with the infamous broken plastic gears on the tape carriages. I note that you have been successful in sourcing replacement metal gears. Are you at liberty to say where you obtained them? Thank you and regards, Ian.

Mooly · 12th Jul 2011, 7:38 pm

Hi Ian... if you still have the split plastic gears, gear kit C I believe (and I am going from memory now) you can repair them by fitting a correctly drilled metal washer over the flange of the gear. It needs to be a very tight fit. I have a vague recollection of then fitting the gear "opposite way about" so the flange is on the outside. Worked a treat though in the early days.

derbeian · 15th Jul 2011, 12:14 am

Hello Mooly01. Thank you for your reply and suggestion. Unfortunately, I gave the broken gears to a friend who said that he would arrange for someone to cut some new ones........but he lost them! So I have a recorder that is in excellent condition except for two little gears and I no longer have a pattern. Regards, Ian.

Mooly · 15th Jul 2011, 8:29 am

That's a pity... maybe hold out for a "scrapper" to come up.

12th Apr 2011, 2:32 pm	#1
davyrocket2 Pentode Join Date: Apr 2011 Location: Westgate On Sea, Kent, UK. Posts: 246	Sony Betamax C9 and 950s Hi to everyone. I am trying to talk to any engineers with experience of Sony C9s. I have rebuilt the DC-DC convertors and these are working okOK. I am trying to deal with issues on the tape carriages. I have got replacement metal gears and having fitted them it now works OK. Fault 2, cassette cannot be loaded and there are 2 arms with rubber rings on them that have springs attached to them. These seem to be preventing the tape being pushed in all the way. Fault 3 is a nasty chattering sound and the tape will not load on a Sony SL-HF 950. Fault 1 is the tape is playing but I ony get a black screen if I freeze frame or pause there is a picture and fault 2 is tuning in the TV station presets the picture is good but to get the sound you have to sacrfice almost losing the picture by pressing the +/- fine tune buttons so you have picture/no sound or sound but picture nearly breaking up. Any tips or help greatfully received. I just do this to maintain my own collection. David Grant. Last edited by Station X; 12th Apr 2011 at 3:03 pm. Reason: Email address removed. GI.

10th May 2011, 8:11 am	#3
Mooly Octode Join Date: May 2011 Location: Lancashire, UK. Posts: 1,351	Re: Sony Betamax C9 and 950s Hi David... just a thought with you saying two C9's exhibit line tearing etc is that it may be a compatability problem with your TV/monitor. I experienced this first hand with my own C9 on a Philips TV that worked perfectly with other machines (VHS) on channel 0 ut not with the Sony. In the end I ended up changing the time constant network in the sync separator on the TV which worked a treat. Your carriage problem... you need to check (with power off) that the carriage micro switches (two I think from memory) are both operating correctly. If thats OK then you need to check/confirm operation of the motor drive circuit... that its receiving the input from these switches correctly.

14th May 2011, 5:32 pm	#4
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,199	Re: Sony Betamax C9 and 950s Excessive pulling despite the TV being configured for VCR input, can also indicate a problem with the VCR's backtension.

11th Jul 2011, 12:17 am	#5
derbeian Retired Dormant Member Join Date: Jul 2011 Location: Derby Posts: 3	Re: Sony Betamax C9 and 950s Hello David - Great to hear that you have managed to restore your C9. I also have one of these models with the infamous broken plastic gears on the tape carriages. I note that you have been successful in sourcing replacement metal gears. Are you at liberty to say where you obtained them? Thank you and regards, Ian.

12th Jul 2011, 7:38 pm	#6
Mooly Octode Join Date: May 2011 Location: Lancashire, UK. Posts: 1,351	Re: Sony Betamax C9 and 950s Hi Ian... if you still have the split plastic gears, gear kit C I believe (and I am going from memory now) you can repair them by fitting a correctly drilled metal washer over the flange of the gear. It needs to be a very tight fit. I have a vague recollection of then fitting the gear "opposite way about" so the flange is on the outside. Worked a treat though in the early days.

15th Jul 2011, 12:14 am	#7
derbeian Retired Dormant Member Join Date: Jul 2011 Location: Derby Posts: 3	Re: Sony Betamax C9 and 950s Hello Mooly01. Thank you for your reply and suggestion. Unfortunately, I gave the broken gears to a friend who said that he would arrange for someone to cut some new ones........but he lost them! So I have a recorder that is in excellent condition except for two little gears and I no longer have a pattern. Regards, Ian.

15th Jul 2011, 8:29 am	#8
Mooly Octode Join Date: May 2011 Location: Lancashire, UK. Posts: 1,351	Re: Sony Betamax C9 and 950s That's a pity... maybe hold out for a "scrapper" to come up.