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Old 7th Aug 2023, 10:13 pm   #1
19Seventy7
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Default Ferguson 3V22 / Baird 8292 - Striations on colour

Good evening all

Some of you may remember that I had the above VCR restored a few months ago by 1100 Man, and it has been giving fantastic service since, up until a few nights ago, when I noticed a new fault, but one I could fix this time!

I noticed that at switch on, the playback picture would be B/W, however flicking the power control on the front of the unit off and on again quickly would bring the colour back (for a couple of hours before it'd fade out again) and containing striations, most noticeable on strong reds and/or blues, not too sure about green. I believe I have fixed this by changing some capacitors around IC202 after finding a mention in an article somewhere. The unit sat for 4 days without use and colour came up instantly, so I think that's fixed!

However, the colour still contains striations. I can't remember if this is normal or not and I just never noticed it before. It's nothing that I can't live with, but would naturally like to repair it if I can. Switching the switch on the rear to B/W removes the striations.

One of my B/W sets show the striations very well, so I thought to include it to help give a better understanding as I've not been able to capture it all that well with colour sets.

And now for the question you've all probably guessed by now! Does anyone have any ideas of what could be causing this?

Edit: I've just noticed that the 2nd image doesn't portray it very well over my PC screen, but they're just noticeable on the red coat. The 1st and 3rd photos show it quite well though.

Thanks
'77
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Old 8th Aug 2023, 7:09 am   #2
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

Perhaps if you show the test card in colour we would see it better.
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Old 8th Aug 2023, 12:12 pm   #3
19Seventy7
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

I had struggled to get a decent picture using the test card, but this shows it quite well.

Please excuse the banding and poor contrast/brightness. My new phone doesnt seem to take too kindly to CRTs.

Thanks
'77
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Old 9th Aug 2023, 8:30 pm   #4
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

Hi '77,

I had been wondering how you had been getting on with the machine - it's good to know it's been working Ok up until the colour fault!

No, it certainly shouldn't have striations in the colour areas. It is a fault I've seen in the past on other machines, but sadly, I can't really offer any useful advice as to how to fix it!

If the effect is not there when switched to B/W, it's safe to say the issue is in the playback chroma signal path. It's quite probable that the problem is related to the components around IC202 that you replaced. I imagine it will have something to do with the reference oscillator.

Could you specify which components you replaced? I'll dig out the circuit and have a look at the chroma path which might shed some light on the problem.

All the best
Nick
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Old 10th Aug 2023, 5:09 pm   #5
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

Hi Nick

Great to hear from you again. It’s been great! It’s been recording and playing back without a hitch! It’s been brilliant - so thank you again!

I didn’t think it should have the striations, I couldn’t fully remember if I had noticed them before or not, but I didn’t think they were there.

I will check anything around the Ref. Osc. when I can. My replacement meter turned up with a broken screen, and now I’m to-ing and fro-ing with the seller about a refund or replacement.

I’m not home at the moment to check the machine itself. But I do have a photo of the caps I replaced (only electrolytics) admittedly I got a little carried away as I rather enjoy recapping boards. I actually find it quite therapeutic!

I had changed a few by the time the photo was taken, they were all the original purple caps beforehand, and all component numbers were C2XX, if that makes any difference.

I have marked the ones changed in the photo, in hopes that helps, but can get a better list later on if needed.

Thanks
‘77
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Old 10th Aug 2023, 6:52 pm   #6
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

You could try moving the 3V22/8922 VHS further away from the TV to see if this is causing the problem. Proximity interference.


Paul
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Old 10th Aug 2023, 7:29 pm   #7
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

Indeed, I'd also consider the possibility of interference from nearby Wi-Fi routers, phones, etc. Perhaps try moving the machine to a different part of the house to see if the problem goes with it.

Also, be careful with blanket replacement of capacitors in signal processing areas, as you might end up changing the tolerances of the circuits to the point where it may need a setup and re-alignment.

I believe the IC itself could also fail, though this usually lead to a no colour fault (Matsushita part: AN305).
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Old 11th Aug 2023, 4:49 pm   #8
19Seventy7
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

Hi all

Thanks for the replies

I took advice from both of you and moved the VCR. Unfortunately neither worked. The striations still appeared, and on several sets in another room.

I did make sure I didn’t knock anything out of tolerance by turning the VCR back on after replacing a few caps so I could easily retrace my steps if needed. Fortunately it had nothing but good results!

I’ve not forgotten about the list of caps, I’ve just not had chance to open it up yet!

Thanks again
‘77
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Old 12th Aug 2023, 7:28 am   #9
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

This may be a stab in the dark, and its a long time since I serviced one, but was there not a earth spring on the shaft (not the one on the top of the upper drum) of the Drum motor or underneath its Fly wheel that gave weird faults like this
I am sure the 3V23/29 were first generation to have Hall affect Drum motors.
Long time ago, memory not good.
Ken G6HZG.
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Old 14th Aug 2023, 2:10 pm   #10
19Seventy7
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Default Re: Ferguson 3V22 / Baird 8292 - Striations on colour

I will look for something like that, and see if I can figure it out. I'll get to that ASAP.

Thanks
'77
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