Ferguson Videostar 3V29 fault

[Simon_m74]

Hi,
I have been servicing a FVS 3V29.
All mechanics were `stuck`.
Head would not turn easy (even by hand)
Capstone motor struggling to rotate.

I dismatled the head and cap motor, cleaned them both, cleaned and freed all mech parts and now it `almost` works. (although for some reason the capston motor was running in reverse, so I have to swap the wires?)

I put a tape in, FF & RW work ok.
Play:
Head spins up nicely, tape is threaded well - but:

The tape front spool is not turning so the machine gives up and unthreads the tape.

Reason : the solenoid (under the deck, top right) does not function.
What this does, is move the pinch roller down to the capstone pin, and moves a wheel down to rotate the front spool.

Any idea why this solenoid is not working?
It has 3 wires going to it, so I`m not keep on just trying to power it manually.

[Electricdreams]

Id check the power rail. I’ve seen this before on one of my machines years ago.

[Nickthedentist]

One of the little circuit protectors (n15) gone open circuit?

[Simon_m74]

@ Electricdreams.
Thanks, do you remember where abouts to check and what voltages to expect?

@Nick
Thanks also - to help, can you tell me where N15 is hiding?

[Mooly]

Long time since I worked on these but one common fault was sticky 'tropicalised' grease on a slide plate on the top of the deck (if I'm remembering correctly) that caused many problems. Did that cause the drum to run all the time?

Three wires to a solenoid probably means a 'hold' winding which is simply a tapped winding with a midpoint somewhere being pulsed to fire the solenoid and then a maintaining current is supplied via the 'top' end of the winding.

[Simon_m74]

Originally Posted by Mooly

Long time since I worked on these but one common fault was sticky 'tropicalised' grease on a slide plate on the top of the deck (if I'm remembering correctly) that caused many problems. Did that cause the drum to run all the time?

Three wires to a solenoid probably means a 'hold' winding which is simply a tapped winding with a midpoint somewhere being pulsed to fire the solenoid and then a maintaining current is supplied via the 'top' end of the winding.

Hi Mooly,
All mechs (including that one) have been cleaned and regreased.

So if I apply voltage to any of the two pins on the soleniod, I guess I should get a repsonse to test.

I-I-I (I=wire, -=coil) - if thats what you mean by mid tap. I think I`m right as I work at a company which make high power resistors - which some have `tapping` points.

If thats correct, any 2 wires should get a repsonse?

[Electricdreams]

[QUOTE=Simon_m74;1583482]@ Electricdreams.
Thanks, do you remember where abouts to check and what voltages to expect?

If the pinch roller solenoid is firing but not staying in place, it could be due to ageing capacitors in the PSU unit.

Otherwise it would be either a lacing contact fault which would need cleaning or a fault in the logic circuit on the main board (underside of vcr)

If I were you, I'd check the caps in the PSU first. Do you have the schematics?
I think I gave mine to bobbyball but I think you can still get them online.

If the takeup spool is not turning, you can try the following, take the cassette carriage out, tape up both tape end sensor with insulation tape, press down the white sensor found just at the bottom end of the tape deck (sometimes you can lock it in place) and press play.

If the machine runs then either the play idler is weak (just clean the tyre) or the pressure roller is slipping. Did you replace the counter belt? The counter has a sensor to check that the takeup spool is running.
If the solenoid fires and then gives up immediately it'll be insufficent power to run everything.

Now when you say the capstan motor is running in reverse, how did you swop the wires?

[Welsh Anorak]

Might be a silly question, but are you sure the loading cycle is complete? You didn't mention changing the loading belt.

The 3V29 pre-dated those small circuit protectors - good old fuses here!

[HamishBoxer]

The notorious loading belt!

[Nickthedentist]

Originally Posted by Welsh Anorak

The 3V29 pre-dated those small circuit protectors - good old fuses here!

Sorry to disagree with my tv and video hero, but it definitely had them. Well, mine did! Allegedly shown as a 10R fusible resistor in some manuals.

I had one at uni in the mid 1990 and can remember finding one open circuit on the mechacon board. Got a new one from JJ components then all good again! The "15" represents a rating of 600mA.

See the RH column on the last page of Joe Ciezynski's excellent article here:
https://www.vintage-radio.net/forum/...2&d=1401009755

Failure of the reel motor to operate can be due to a defective circuit protector (CP2) on the mechacon panel

Although the solenoid symptoms don't back this up, it would still be worth a glance IMHO.

Nick

[Welsh Anorak]

Oops! Not so heroic now...

You are of course right - I'd forgotten the one on the mechacon board.

The later models had them all over the place and would fail as soon as you looked at them. Exacly what possessed them to use 40mA as a base unit eludes me.

As far as I remember the clonk of the solenoid meant the loading was complete.

[williamsunique]

Loading motor fault. Belt stretched. You might get away with smearing silicone grease on the worm drive. To prove it is the fault before going any further help the loading motor to finishe it's cycle, use your finger. The loading motor is the one on the top, not underneath.

Paul

[Mooly]

Originally Posted by Simon_m74

Hi Mooly,
All mechs (including that one) have been cleaned and regreased.

So if I apply voltage to any of the two pins on the soleniod, I guess I should get a repsonse to test.

I-I-I (I=wire, -=coil) - if thats what you mean by mid tap. I think I`m right as I work at a company which make high power resistors - which some have `tapping` points.

If thats correct, any 2 wires should get a repsonse?

You would really need to quickly look at the circuit to see how its configured but I would imagine that the two wires giving the highest resistance are the 'hold' winding and the other wire the one to initially pulse it hard to get to engage. You would have to determine which of the first two wires is the common one as the tapping is unlikely to in the middle.

The circuit will show how it works in seconds.

[Electricdreams]

Originally Posted by williamsunique

Loading motor fault. Belt stretched. You might get away with smearing silicone grease on the worm drive. To prove it is the fault before going any further help the loading motor to finishe it's cycle, use your finger. The loading motor is the one on the top, not underneath.

Paul

Paul could be right.. I forgot about that and it can be the reason why the solenoid isn't firing at all. I remember after replacing all the belts I forget the loading one!

[Sideband]

First fault I had on one of these...a soggy loading belt! I didn't notice it straight away until I noticed that the loading cycle wasn't quite finished. A satisfying click with a little help from a well-placed finger! I used to order belt kits from Grandata in London.

[Simon_m74]

Hello all again.
I shelved this repair as I `needed` to get other stuff repaired ready for the coming weekend. (Big event at the Retro Computer Museum).
As all the `above` have been repaired/sorted, I now have this VHS back on my workbench, and in bits again.

Loading mech - it seems to load the tape ok - but I`ll check it goes all the way to its `stop`.
Grease : all mechs can be moved manually with mininal reisitance (unless its mechanically locked!)

Solenoids:
I tried to fire up the solenoid manually with a bench PSU. I can see it `trying` but not moving... but I guess I have the incorrect voltage set (I dont want to go too high - 12v). I also tried the `working` solenoid which does the same when I manually power it - hence I think the solenoids are both ok, as they are acting the same with 12v from the gnd pin to either or both other pins


Fuses:
PSU - I`m sure I checked them all... but I will check I have not missed one.


Motors:
There 3 motors on this deck (not including the one in the Head).

1: is the FF/RW motor, thats under the deck, and between the spools. The `working` Noid swings a wheel left or right (depending on motor direction) to activate the left or right spool for FF / RW.

2: Is the one that loads the tape around the head - this is a gear driven mech I think (I`ll check for a belt here)

3: is the on top - back right, what I`m calling the `capstan motor`.
This one feeds the capstan pin, and the capstan roller as well the wheel that would turn the takeup spool when the top left `Noid` is activated - but its not activating - the desk then resets, by unloading the tape.


From what I have read from you all, as well as that service document - I think I`m barking up the wrong tree, with it a solenoid fault; it looks like I need to investingate the tape threading/loading motor & mech instead!
I`ve read a portion of that document, and it states` after about 10 seconds` it will unload the tape, if the belt is loose or switch not activated

That is exactly how its happening - so thanks for that!

I`ll change the belt, and check the switch!

I hope to confirm that tonight!

[Welsh Anorak]

Your'e absolutely right about the motors' functions.

The key motor is no 2 - the loading motor. That sits under the deck You'll see it has a small belt running between its spindle and a second pulley/gear. This is the loading block. You must change that belt.

I have a procedure to do this - others have their own methods.
1. With the machine in stop and disconnected, open the cassette carriage.
2. Using an old belt or elastic band, hold the two loading arms in the rest position by hooking the belt over them and the two spools. This way the loading arms can't move and lose the timing.
3. Unscrew the loading block and remove the circlip holding the driven pulley. There should be two shims on either side of the pulley/worm gear, though these could well be missing by now - not to worry.
4. Replace the belt and refit the spindle, shims and circlip..
5. Re-engage the loading block, replace the screws and remove the temporary belt/elastic band.

That sounds a bit involved, but that's how we used to do it and we've changed hundreds!

I'd like to think this will cure your fault, but if not it's something you'd have had to do anyway.

I think the solenoids are 24v but couldn't swear to it. Never had one fail.

Good luck!

[Horris]

If it’s any help I have. Service manual for the 3V29 for sale for £5.00

Dave

[Simon_m74]

Hi all,

Belt changed.
Switch cleaned.

Loads fine!

Thanks......but

Picture is not perfect.
Photo attached.

Slightly loosing colour in patches, 'pulses' of interference going down the screen.

I tried tracking and it has little effect.

Any ideas for this next fault ?

[Simon_m74]

Originally Posted by Horris

If it’s any help I have. Service manual for the 3V29 for sale for £5.00

Dave

Hi Dave,

I think I actually found one online.
If its not what I think it is, I`ll get back to you on this offer