Sony SL-C7 Betamax VCR - UK Vintage Radio Repair and Restoration Discussion Forum

TheGMan · 24th May 2016, 4:51 pm

Hi All,

A few years back I bought a job lot of about six old VCRS - three of which were Betamax. I was initially after a half decent Betamax and the lot contained 2 X SL-C7's. One's a C7 and the other is a C7UB.

The C7 worked (in a fashion - see below) The C7UB didn't but I figured I could use it as a donor machine as both machines look identical apart from one having UB on it!

Anyway, the C7 has been in the loft now for about 3 years and the C7UB in the shed (the rest I binned) and it would be nice to be able to restore the C7 to full working order.

I have a belt kit for it. The problem it had when I stuck it in the loft (besides having sluggish winding of the tape due to perished belts) was that the picture had a rolling noise bar on it that appeared every few seconds. As if the control track on the tape was damaged and the VCR can't read it and lock onto the control track. From what I remember, the tracking wheel does nothing.

The problem affects all tapes (even pre-recorded ones). I've read that these machines are prone to this fault due to dry caps on the servo board?

Has anybody restored one of these with similar symptoms and if so could you give me any pointers as to what you had to replace please?

TIA

dj_fivos_sak · 24th May 2016, 9:21 pm

Hi. The "UB" means it's a UK model. The other one could be a C7E, EC, EI etc. You can see the full model number in a sticker on the back of the VCR. First, check if the capstan motor speed is correct and steady. If not, you will hear wow and flutter in the audio and the tracking will be unstable. Repace the capstan belt (the flat one) then check the servo board for bad capacitors and clean all the heads, pinch roller, capstan shaft and the rest of the tape path. This model is very problematic and unreliable but it produces an excellent picture when it's working OK! Hope this helps you.

Fivos

steptoesyard · 25th May 2016, 3:40 pm

+1 for the above post.

Just to help you a bit more, change the pale blue "Sanyo" electrolytic capacitors (typically small values such as 0.1uf, 0.47uf etc) in the two servo areas - these WILL be shot and will cause the problem you have. Change these before making any electrical adjustments, and you will find it will be pretty much spot on.

The sluggish rewind will be due to the idler being worn, roughing up and cleaning the rubber surface should make a big difference.

Keep us posted!

dj_fivos_sak · 25th May 2016, 8:00 pm

Quote:

Originally Posted by steptoesyard

in the two servo areas - these WILL be shot and will cause the problem you have. Change these before making any electrical adjustments, and you will find it will be pretty much spot on.

Where is the servo board on this model? It is at the bottom next to the video board?

TheGMan · 27th May 2016, 4:32 pm

I believe (from what I've read) the servo section is labelled on the main board (should be a white line round it on the solder side and should say 'servo' inside) I know I had a Baird VHS VCR from the 80's which was the same (all bits were clearly sectioned off with white lines & labels)

Thanks guys, I'll try and have a look at it this weekend. Hopefully I'll be able to get it up and running properly. Would just be nice to be able to own a working Betamax

I'll post my results here soon.

steptoesyard · 29th May 2016, 9:48 am

Yes that`s it. It`s the drum and capstan servo sections you need to look for, they are clearly marked

24th May 2016, 4:51 pm	#1
TheGMan Retired Dormant Member Join Date: May 2016 Location: Birchwood, Cheshire, UK. Posts: 2	Sony SL-C7 Betamax VCR Hi All, A few years back I bought a job lot of about six old VCRS - three of which were Betamax. I was initially after a half decent Betamax and the lot contained 2 X SL-C7's. One's a C7 and the other is a C7UB. The C7 worked (in a fashion - see below) The C7UB didn't but I figured I could use it as a donor machine as both machines look identical apart from one having UB on it! Anyway, the C7 has been in the loft now for about 3 years and the C7UB in the shed (the rest I binned) and it would be nice to be able to restore the C7 to full working order. I have a belt kit for it. The problem it had when I stuck it in the loft (besides having sluggish winding of the tape due to perished belts) was that the picture had a rolling noise bar on it that appeared every few seconds. As if the control track on the tape was damaged and the VCR can't read it and lock onto the control track. From what I remember, the tracking wheel does nothing. The problem affects all tapes (even pre-recorded ones). I've read that these machines are prone to this fault due to dry caps on the servo board? Has anybody restored one of these with similar symptoms and if so could you give me any pointers as to what you had to replace please? TIA

24th May 2016, 9:21 pm	#2
dj_fivos_sak Heptode Join Date: Mar 2015 Location: Lefkada, Greece Posts: 969	Re: Sony SL-C7 Betamax VCR Hi. The "UB" means it's a UK model. The other one could be a C7E, EC, EI etc. You can see the full model number in a sticker on the back of the VCR. First, check if the capstan motor speed is correct and steady. If not, you will hear wow and flutter in the audio and the tracking will be unstable. Repace the capstan belt (the flat one) then check the servo board for bad capacitors and clean all the heads, pinch roller, capstan shaft and the rest of the tape path. This model is very problematic and unreliable but it produces an excellent picture when it's working OK! Hope this helps you. Fivos

25th May 2016, 3:40 pm	#3
steptoesyard No Longer a Member Join Date: Jul 2011 Location: Tavistock, Devon, UK. Posts: 147	Re: Sony SL-C7 Betamax VCR +1 for the above post. Just to help you a bit more, change the pale blue "Sanyo" electrolytic capacitors (typically small values such as 0.1uf, 0.47uf etc) in the two servo areas - these WILL be shot and will cause the problem you have. Change these before making any electrical adjustments, and you will find it will be pretty much spot on. The sluggish rewind will be due to the idler being worn, roughing up and cleaning the rubber surface should make a big difference. Keep us posted!

27th May 2016, 4:32 pm	#5
TheGMan Retired Dormant Member Join Date: May 2016 Location: Birchwood, Cheshire, UK. Posts: 2	Re: Sony SL-C7 Betamax VCR I believe (from what I've read) the servo section is labelled on the main board (should be a white line round it on the solder side and should say 'servo' inside) I know I had a Baird VHS VCR from the 80's which was the same (all bits were clearly sectioned off with white lines & labels) Thanks guys, I'll try and have a look at it this weekend. Hopefully I'll be able to get it up and running properly. Would just be nice to be able to own a working Betamax I'll post my results here soon.

29th May 2016, 9:48 am	#6
steptoesyard No Longer a Member Join Date: Jul 2011 Location: Tavistock, Devon, UK. Posts: 147	Re: Sony SL-C7 Betamax VCR Yes that`s it. It`s the drum and capstan servo sections you need to look for, they are clearly marked