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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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14th Oct 2020, 6:59 pm | #21 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
The Bipolar caps are 47uf 25v capacitors. Can I stick with these values or increase the voltage? I have ordered like for like for now, will it cause any problems?
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15th Oct 2020, 9:19 am | #22 |
Dekatron
Join Date: Sep 2006
Location: Kilmarnock, Ayrshire, UK.
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Re: Sony SL-HF950 expert needed
Hi.
Sticking with the original spec is the correct way as this is what the circuit designers have used and these circuits are given rigorous testing, there is no harm at all to use a higher voltage component but going considerably higher in voltage can in some cases cause issues, 30-50v though is fine in this application so long as they fit physically.
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15th Oct 2020, 1:38 pm | #23 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
That's great advice! Thanks very much 👍
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15th Oct 2020, 2:57 pm | #24 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
I have bitten the bullet and bought that very expensive resistor but I had no choice as it is so hard to find! Probably the most I have ever spent on a resistor! Will let you all know how I get on with this repair. Thank you for all your help and advice
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17th Oct 2020, 1:11 am | #25 |
Hexode
Join Date: Feb 2012
Location: Lowestoft, Suffolk, UK.
Posts: 256
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Re: Sony SL-HF950 expert needed
I probably should've said you can go to a higher voltage or the next one up from original.You must always stay the same for the uf rating though.
Please do keep us posted. ....Kev |
17th Oct 2020, 10:53 am | #26 | |
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Re: Sony SL-HF950 expert needed
Quote:
Cheers Mike T
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17th Oct 2020, 11:35 am | #27 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
Thanks all. I am really scared to even touch the thing!
The bipolar capacitors are currently 47uF and 10v (and have a high ESR of between 1.2 and 1.3) so would it be ok if I go to a 47uf and 25v? |
17th Oct 2020, 10:48 pm | #28 |
Pentode
Join Date: Apr 2011
Location: Westgate On Sea, Kent, UK.
Posts: 246
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Re: Sony SL-HF950 expert needed
As Kevin has said do not change the uF rating you can go up slightly on the volts. What you can do is ask for capacitors with a higher temperature rating most are 85C what you can request is for some 105C which will withstand more heat, which I am sure Noel does being in a hot country.
Do make sure to replace those transistors, apply heat sink compound and make sure the solder area is clean, but yes a sight increase in voltage is OK provided there is enough room. |
18th Oct 2020, 2:42 pm | #29 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
Thanks @davyrocket2. I already replaced the transistors, haven't yet applied the heat sink compound as theybare mounted durectly onto the rubber membrane. This will be the last step for me before I screw everything back together. I cleaned as much as I could from the glue near the solder pads for the transistors but a lot still remains. Will this cause a problem longer term? Are they electrically sensitive components when soldering or can I handle them with my fingers?
I have noted your comments on the capacitors. Ordered the 25v already but will see if I can get something nearer the 10v rating. |
18th Oct 2020, 9:18 pm | #30 |
Pentode
Join Date: Apr 2011
Location: Westgate On Sea, Kent, UK.
Posts: 246
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Re: Sony SL-HF950 expert needed
if it was me I would clean the holes insert them as ready end just gently solder ensuring it flows well after inserting the membrane and heat sink compound
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22nd Oct 2020, 8:20 pm | #31 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
I know this looks a bit of a mess but would this pass as an ok job for the transistors?
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22nd Oct 2020, 8:53 pm | #32 |
Dekatron
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,642
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Re: Sony SL-HF950 expert needed
A solvent such as IPA, and a fairly stiff brush will clean that up. Cosmetic though, it won't work any better!
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25th Oct 2020, 2:57 pm | #33 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
All working thank you all so much!!!!
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25th Oct 2020, 5:48 pm | #34 |
Dekatron
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Location: W.Butterwick, near Doncaster UK.
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Re: Sony SL-HF950 expert needed
Small glass fibre brush if you can get one.
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25th Oct 2020, 9:29 pm | #35 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
Only slight issue with rew picture scan where I am getting these awful noise bars. Any further advice appreciated.
Fwd, still and play all work fine |
27th Oct 2020, 11:34 am | #36 |
Hexode
Join Date: Feb 2012
Location: Lowestoft, Suffolk, UK.
Posts: 256
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Re: Sony SL-HF950 expert needed
Congrats Willow on getting this classic working again.
Your comments on that board area that's a bit scruffy.i always use an old toothbrush and rub lightly with IPA and it cleans all that off nicely. Some who like to go the extra mile like to replace that protective coating as it get's damaged by the heat. As for those thick noise bars during reverse search.Could either be the back tension,partly worn heads or heads that need a clean. I would avoid cleaning them manually though unless you really know what you are doing. I've had two of these models sent to me where a couple of the head chips have been broken in half or completely off,no doubt by the over zealous cleaning.These not only have three visual heads for clean trick functions but the two other ones for the Beta hi-Fi and are expensive IF you can find any. If it's just a slight clog then playing a really good quality tape will clean them 99% of the time. Without the risk of damage. Also i would recommend switching this off from the power when not in use for long periods of time and also switching OFF the VU level LED's as they are notorious for failing led's after time.Just use them for critical Hi-Fi recordings. Also keep all modern gear away from these too.Some models readily pick up signals from Wi-Fi often blamed on the vcr itself. Keep items off of this too as some like to cram as many bit's of gear into one stack as they can and keep those heat vents clear too Regards...................Kev |
28th Oct 2020, 12:05 pm | #37 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
Hi Kev
Many thanks for your message of support! I didn't do any more on that circuit board as I already put the thermal paste and left well alone! Now the issue with the picture scan is that when in rew, the tape appears to leave the drum for some reason. Also general rewind is slow as the supply reel gets heavier with tape especially near the start of the tape. I think these 2 issues are possibly linked but upon closer inspection, the top drum is totally shiny which could mean the tape is sticking to the drum? I tried rubbing the top drum down but now getting a line across the screen in play mode. I took extra care not to touch any heads during this cleaning process |
28th Oct 2020, 12:11 pm | #38 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,935
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Re: Sony SL-HF950 expert needed
Shiny is just normal or wear and tear,tapes do not stick without major problems.
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28th Oct 2020, 12:34 pm | #39 |
Triode
Join Date: Oct 2016
Location: Hayes, London, UK.
Posts: 38
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Re: Sony SL-HF950 expert needed
I saw a video here where scuffing the surface actually decreased the friction.
https://youtu.be/sxRVnr2mSsg |
28th Oct 2020, 1:52 pm | #40 |
Dekatron
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
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Re: Sony SL-HF950 expert needed
The only thing is with the lower drum assembly and they do drag and if lucky can be cleaned with Dura Glit.
Never had to polish upper drum,only marks have been caused by too much back tension which wears the head tips very quickly.
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