Thorn 8924/Ferguson 3V23  

 
Jayceebee
(@jayceebee)
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Due to some time off work after a small operation on my back I thought I would dig out my 8924 VCR which I believe as with Chris's N1500 came from Luke at Lancaster university. I've set up a small temporary workbench in the bedroom and my daughter has kindly placed the monster on top for me. I certainly couldn't have lifted it from the floor without risk of pulling out the stitches but I'm able to manhadle it once on the makeshift bench with relative ease.

The 8924 is the Thorn Rentals version of the Ferguson 3V23, these are also some of the many clones of the JVC HR-7700, it's a beast and very heavy. Out of the box they weren't branded, this was added at the time of installation and this one appears to have never had a badge fitted. If anyone has a badge of any brand name please let be know.

We at Thorn had just come to grips with the 3292 and 3V00 in 1978/9 and this monster landed on our benches around late 1980, to say it was a shock to the system was an understatement. As with the previous JVC models the electronics were incredibly reliable, mainly mechanical issues in the early days.

Ok so with the covers removed let's have a peek inside and see what's needed.

8924 1
8924 2
8924 3

John.

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Posted : 10/02/2019 3:10 pm crustytv and Red_to_Black liked
Red_to_Black
(@red_to_black)
Noble Member Registered

Most of the ones we got from TP were de-badged, we still had a few with mainly either DER or Multibroadcast badges on from time to time, also the odd one with a Baird badge on, I think these must have slipped the net wrt de-badging.

I still think this is one of the best looking VCRs ever made, the chain drive FL carriage is something to behold.

Ps, TP added their own Teleprice badge to those machines they retailed direct to the public.

Ps. 2 it also looks like you need 2 knobs for the tracking and still controls too.

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 10/02/2019 3:18 pm
Jayceebee
(@jayceebee)
Prominent Member Registered

I already knew that the loading belt was snapped and after a rummage around I manged to find something suitable, the capstan belt seems ok but the belt that drives the chain drive is hard and stretched a replacement is definitely required. A good clean of the rubber components was carried out with platten clean, a sort of rubber restorer. The rollers on the housing and the pinch roller now feel good but the idler and reel table tyres still feel a bit hard so I'm not sure how successful this will be. Replacements for the reel table tyres will be pretty near impossible, I've also buffed up the felt on the soft brakes and I think these will be fine.

BTW removal of the cassette carriage is best done in the down position, almost impossible up and not easy if the belt is stretched like mine.

8924 4
8924 carriage2
8924 carraige
3v23cas

A whole afternoon gone and still not applied power yet, just as well I don't have a workshop manager breathing down my neck.

Hi Baz, yes it is a shame about the missing tracking knobs. Something else for the wanted section.

John.

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Posted : 10/02/2019 5:52 pm crustytv and Red_to_Black liked
Jayceebee
(@jayceebee)
Prominent Member Registered

After an initial power on all seemed well, the display was showing all the stuff I was expecting, the cassette lamp which was always a problem with early VHS machines was lit so I thought I would see what the tape transport situation was without a tape.

8924 cdetect

With the carriage out of the machine, although it still needs to be connected and pressing down the plunger that detects the presence of a tape (ISTR we had a rectangular piece of metal with clips at the end to facilitate this)and after blanking off the tape end sensors transport functions were tested. Unfortunately although the machine entered play with the heads and capstan running ok it was apparent there was no takeup reel drive. This was also missing in FF and no supply reel drive when unloading, there was some rotation in REW but very weak.

As I don't have the circuit for the later mehacon tracing the feed back from the reel motor took me to a bunch of transistors. Q15,16,21,22 in what appears to be a bridge circuit, removing and testing clearly show obvious damage to Q15 and 21, 2SB772 and 2SD985 . Probably not too bad to fault find but does anyone have the later mechacon circuit? Anyway an order for belts and transistors has been placed.

mecha
2sd9

My el cheapo transistor tester shows the result for the suspected good 2SD985 in the bridge, it correctly shows a diode between c-e but not that it's a Darlington. I'll compare when the replacement arrives.

2SD

John.

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Posted : 10/02/2019 9:47 pm Red_to_Black liked
Red_to_Black
(@red_to_black)
Noble Member Registered

Hi JC,

If the manual in the library is the same as the ET one (it is 😉 ) then this has the modified/later Mechacon diagrams towards the end of the manual, starting around the page 321 mark or thereabouts 🙂

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 11/02/2019 7:11 pm Jayceebee liked
Jayceebee
(@jayceebee)
Prominent Member Registered

Hi Baz, thanks for that. I wasn't aware that the manual in the library was different from the one I had downloaded, using Paint I've tidied it up a bit and things are much clearer.  👍 

bridge

 

John.

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Posted : 11/02/2019 7:37 pm Red_to_Black liked
Jayceebee
(@jayceebee)
Prominent Member Registered

Well the parts arrived today and were fitted, I'm pleased to say this restored reel drive but there were still problems with tape transport. I now had correct FF/REW operation, rewind search was fine as was take up reel drive in play but forward search produced only a slight judder then no tape travel although the motor could be heard spinning. The drum bearings sounded a bit noisy also so attention was paid to this and the reel tables, the spindles they sit on were pretty dry requiring a smear of fresh oil. The idler and reel tyres were given a fine sanding using a piece of wet and dry moistened with IPA,  followed by further treatment with rubber restorer. The back tension band was removed during the process and the felt buffed up with an old toothbrush, thankfully JVC tension bands didn't have a habit of the felt pad coming away from the metal bad due to poor adhesive as happens on some early Panasonic models. After reassembly and testing tape transport is now seems to be functioning fine.

reels

Reel2

Lower Drum Bearing

One item on these machines that can catch out anyone not familiar with them is the earthing screw on the rear of the PRE/REC board, if slack it can give the same effect as worn video heads on the playback picture. Sure enough when checked on this machine a good quarter of a turn was required to tighten it. To gain good access to it involves removing the rear panel and lowering the audio board.

earth

All is now looking pretty good and we'll see how good Playback and Record performance is hopefully tomorrow.

John.

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Posted : 14/02/2019 8:43 pm Marc, malcscott, Red_to_Black and 1 people liked
Jayceebee
(@jayceebee)
Prominent Member Registered

So with tape transport fully sorted I managed to connect some signals to test E-E, record and playback. Whilst discussing the HR-7700 in TVJON's thread earlier I said that lot's of people enthused about this machines sophistication and I warned that in my experience although an excellent machine playback quality could be rather variable. Well as usual I have egg on my face, take a look at these pictures, sorry about the LCD set as it was the only small colour display I had

E-E, tthe input is very clean as it's from Mickey405's test card DVD but all connections are RF.

E E

Playback of  a test card, a harsh test for any VCR. I would place a sizeable bet if I were a gambling person that the head drum is original.

Playback

And Freeze Frame!

Freeze frame

 

To say I'm happy with the outcome is an understatement, every feature appears to work correctly. Audio playback at X2 speed,record and playback cue pulses, insert edit all work very well without any attention, even adjustment from myself. Result.

Some playback from a classic film (forgive the pun!)

Film
Film2

John.

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Posted : 15/02/2019 5:17 pm malcscott, Red_to_Black and crustytv liked
crustytv
(@crustytv)
Vrat Founder Admin

Great work John and an interesting thread to follow, thankfully we can just about still get parts for these fine old machines, though for how much longer is the question. Many thanks for entertaining us, your VCR is a fine example for you're collection. Now is it the start of many? Are there any other VCR's you would like to have up on the bench?

p.s.
Time Machine, one of my very all time favourites, in fact back around 1982 when I bought my first VCR a secondhand Fergy 3V16. I remember recording that off TV along with day of the Triffids. Back when late Friday night was Sci-fi night on CH4. Happy days!

Crusty's Collection: Read the repair blogs
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Posted : 15/02/2019 5:41 pm Red_to_Black liked
Jayceebee
(@jayceebee)
Prominent Member Registered

Thanks Chris, yes I wonder how long it will be possible to keep these Dinosaurs running. Substituting alternative components such as drums and the like in the same way as LOPTs and CRTs in TVs will be somewhat challenging I would image, even getting the correct belts is a struggle now and of course rubber components degrade with age not just use. 

Maybe I should start collecting VCRs though, other than a fairly late Panasonic Z mech model the 8924 is the only other one I have, they are much more manageable than TVs with limited space I have but TVs appeal more. There is one other machine I would love to own and that would be the Akai VS5.

The tape showing the film is likely to have been the original recording made on that tape on my 3V00 helping the quality, the adverts during the breaks are very 80s and it looks to have been recorded over the Xmas period. Good possibility the tape was a Xmas present.

Thanks must go to LukeG83 for kindly donating the machine.

 

John.

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Posted : 15/02/2019 6:55 pm
crustytv
(@crustytv)
Vrat Founder Admin
Posted by: Jayceebee

There is one other machine I would love to own and that would be the Akai VS5.

 

Crusty's Collection: Read the repair blogs
VRAT-Tube: Please subscribe and help the channel grow.

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Posted : 15/02/2019 7:33 pm Red_to_Black and Jayceebee liked
crustytv
(@crustytv)
Vrat Founder Admin

and not forgetting the Akai brochure here

 

Crusty's Collection: Read the repair blogs
VRAT-Tube: Please subscribe and help the channel grow.

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Posted : 15/02/2019 7:59 pm Red_to_Black liked
Red_to_Black
(@red_to_black)
Noble Member Registered

I remember the Akai VS5, with their beep-beep-beep and breakdown symbol flashing, this was of course because I only ever got to see faulty ones, they were a proper Akai machine not being a clone of anything else.

I never saw that many to be fair, not because they were any more reliable than their counterparts of the day by any means, more likely they had a smaller market share in my area at least.

I saw even fewer of the VS10 which looks like a clone of the JVC HR-7700/Thorn 3V23, again up here we never saw many of the original JVC versions of this machine that the others were based either, almost all being Thorn types and most of them being de-badged 8924 or 3V23 ones.

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 16/02/2019 10:52 am
Red_to_Black
(@red_to_black)
Noble Member Registered

I often wondered if JVC lost money on these machines ? They were heavily over engineered for a domestic machine, as I have said before they were almost industrial or "broadcast standard" looking and build in a lot of respects, they must have cost a fortune to make.

They also had what I would call a few "gimmicks" the X2 playback feature with the sound correction circuit being only one of them, although impressive was of little use practically in a domestic machine.

I was really impressed by these machines and thought they were fantastic, I don't think another domestic machine came close in build quality either before or since. Some Sony machines of the Beta era came close, also the Philips V2000 machines were impressive too in this regard.

"This is my multimeter. There are many others like it, but this one is mine. My multimeter is my best friend. It is my life. I must master it as I must master my life. Without me, my multimeter is useless. Without my multimeter, I am useless."

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Posted : 16/02/2019 1:28 pm
Jayceebee
(@jayceebee)
Prominent Member Registered

This evening I've had a good look around but have been unable to find and cannot remember the UK list price for the HR7700 or 3V23,  I did find that when JVC launched it in W.Germany it was around DM2000. Further searching suggests this would have equated to around £1600 in 1983. Don't you wish you have kept those two page broadsheets that Comet had printed when it was a sort of warehouse operation, I'm sure I saw on one of them which featured in 1978 the very first Ferguson VCR, the 3292 which I think was around £600.

Here's a link to some extracts from the Boots catalogue of 1982 featuring the 3V23 successor, the 3V31.

https://www.theguardian.com/lifeandstyle/2014/dec/19/price-christmas-past-boots-catalogue

 

The x2 playback with corrected audio pitch was certainly a gimmick although the technique popped up sometime later on a couple of Sanyo machines which gave snippets of sound in FF and REW.

John.

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Posted : 16/02/2019 10:45 pm crustytv liked

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