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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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3rd Jan 2021, 5:47 pm | #1 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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JVC HR-7700EK / Ferguson 3v23 Issues
Hello,
I was messing with this machine today and suddenly the whole mechanism lost power it seems. The bulb no longer lights and it won't take a tape. I have tested the reset pin on the CPU as suggested in the manual and it looks good. The bulb connection is giving < 1v. I am going to continue to troubleshoot back from this, but if anyone has any quick suggestions / ideas or common faults with these, that would be appreciated. Thanks |
3rd Jan 2021, 6:03 pm | #2 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 418
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
At least 30 years since I last repaired one, is the Clock lit up ? From memory, there's a few fuses in the Power supply, and of course check the Cassette Lamp, when they go O/C the clock lights, and you get E to E but not a lot else Its been a long time sorry.
Ken, G6HZG.
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3rd Jan 2021, 6:06 pm | #3 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Yes sorry shouldve stated, the thing powers up, all the clock etc work.
It might be some issue with the lamp circuitry then, as the clock etc lights and tuner works. Do you know the voltage the lamp should be at? |
3rd Jan 2021, 6:08 pm | #4 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 418
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
12 Volts from memory, not gone o/c has it ? But I dont think think you can measure 12v across it as its a earth return, we did short them out for a quick test!!
Ken G6HZG
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Life is not Hollywood, life is Cricklewood. Last edited by its ur aerial; 3rd Jan 2021 at 6:23 pm. Reason: forgot some thing |
3rd Jan 2021, 6:17 pm | #5 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
I don't think so as it was not reading 0v, but I will double-check
where does it usually go open? To me it feels just like the bulb is gone. Will it not take a tape with no bulb? I am going to test it independently with a bench supply. |
3rd Jan 2021, 6:18 pm | #6 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 418
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
At the time, they were a mind numbingly complicated bit of kit, but surprisingly very few suffered with difficult faults, I did do a two week training course on the 3V23 back in 1982 but 38 years has passed away.
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3rd Jan 2021, 6:21 pm | #7 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 418
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
It was dead common, the lamp it self just fails. Stops every thing, except the clock and the E to E signal.
Ken G6HZG
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4th Jan 2021, 5:31 pm | #8 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
These machines are fairly interesting to me, because they were one of the first 'high end' VHS decks right?
I really want to see the 2x speed play |
4th Jan 2021, 7:33 pm | #9 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Looks like the bulb is good, do you know if there is a 12v test point or if there is anything else which uses the 12v rail?
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4th Jan 2021, 8:23 pm | #10 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
After some probing, looks like 12v rail is dead.
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6th Jan 2021, 7:06 pm | #11 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
Posts: 418
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Scratching my memory here, but I am sure you cant read 12 v on that lamp because, as I previously mentioned I am sure its basically part of a earth return, there are also several fuses in the PSU, have you checked all these?
I cant find a Circuit on the Web so cant advise much, have you got a manual , you really could really do with one. The other thing worth trying is manually loading it up till its fully laced then applying power, and see if it unlaces and ejects, this might give a few more clues . Failing this theirs a American Website, thats name escapes me, which has down loads of all the old Practical Television Mags, they must have done a article on the 3V23 at some time . I will try and contact a old Ex RR Bench Engineer Colleague, he might remember more than me. As I stated before although they were as complicated as Apollo 11, apart from the Mechacon Board, it was unusual to get a really tricky fault. Ken G6HZG
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6th Jan 2021, 7:09 pm | #12 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
I have gotten the 12v rail working!
Now a couple of mechanical gremlins, do you know how you would run this machine without a tape? I have tried covering the 2 light sensors but it just laces then delaces straight away. I found a service manual online, which has helped me immensely. That has full schematics. |
6th Jan 2021, 8:18 pm | #13 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Again thinking from a not very good memory, if you fool it into loading, with out a tape you will need to turn one of the spools, and I cant remember if its the Supply or Take up Spool to make it think its has a tape, it will be the spool that operates the Tape counter. Back in the day we used to get a damaged Cassette, remove the tape, but keep the Spools and Housing.
If its not counting pulses from the Counter, it thinks the Tape has broken, hence it stops. Why was there no 12 Volt then Ken G6HZG
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6th Jan 2021, 8:20 pm | #14 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Just remembered, it the Loading belt worn, slipping ?
Ken G6HZG
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6th Jan 2021, 8:26 pm | #15 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Brilliant! Will try that
I have already replaced the load belt as that was the initial issue with it. I have no idea on the 12v, I had it down to the rectifier not outputting the 12v, but I unplugged to test then reconnected and it was working Maybe it was a bad contact or something. |
7th Jan 2021, 6:33 pm | #16 |
Hexode
Join Date: May 2009
Location: Ryde, Isle of Wight, UK.
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Some times its not obvious the Loading belt is slipping, it just slips before its finally finishes lacing, so try giving it some assistance to engage fully, make sure there is no grease on the belt or hard grease on the Worm Gear.
I spoke to my Ex RR College, and like me cant remember a no function one that was not the Cassette Lamp, but he did vaguely recall a micro switch fault on the Cassette Carriage. Not one I remember though And also apparently I was correct, you wont measure 12v across that Lamp, it is in a earth return. Back in the mid 90`s I meet some one who was part of the 3V23 Design Team, and he informed me they were really designed to show case how sophisticated they could make a VCR back in 1980, well it was certainly not for their Pic quality Only one other common fault was no clock display, caused by dry joints to a tiny XTALS on a PCB at the RH side Good luck with it. Ken G6HZG
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7th Jan 2021, 6:44 pm | #17 |
Tetrode
Join Date: Apr 2011
Location: Cheshire
Posts: 79
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
I have had it playing! very briefly, it looks like the rw/ff is not working correctly so I need to look into this.
I love all this info, very interesting and stuff you can't find elsewhere I measured the 12v directly from the power supply and it was bad, I will bear that in mind about the lamp, it looks like it has been replaced already on this. You can tell about the design! it does feel like they have just seen how many features they can put on, was impressed by the meter showing how much tape is remaining, surprised there is no real time counter on this because I always thought they were similar. Appreciate all the help |
7th Jan 2021, 7:17 pm | #18 |
Heptode
Join Date: May 2006
Location: Accrington, Lancashire, UK.
Posts: 977
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Many years since I've seen a 3V23, very heavy, and the bucket brigade idea to give you sound in double speed play too!
But just fill me in, why can't you meter across the lamp? For presence of voltage or the bulb for being o\c. Have dementia now but this is just jumping out at me, ta. |
7th Jan 2021, 7:38 pm | #19 | |
Heptode
Join Date: Jan 2007
Location: Luton, Bedfordshire, UK.
Posts: 891
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Quote:
Yes, I remember the time-remain dots. They used to do a merry dance on ours - quite distracting! Though we never got it, or the eventual missing clock repaired as the machine was already 15+ years old, by then. One day it just stopped accepting cassettes but you could hear the familiar power-up 'whizz' of the capstan motor at random intervals. Off it went to VCR heaven! Good question!
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Regards, John Last edited by John123; 7th Jan 2021 at 7:58 pm. |
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7th Jan 2021, 8:20 pm | #20 | |
Heptode
Join Date: Jan 2007
Location: Luton, Bedfordshire, UK.
Posts: 891
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Re: JVC HR-7700EK / Ferguson 3v23 Issues
Quote:
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Regards, John |
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