Televisor kit

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Postby Panrock » Mon Sep 29, 2008 8:34 pm

I should mention that when I chose my '3000mcd' LED I was also careful to specify one with the appropriate radiant angle to match this application. I recall there were indeed higher millicandela LEDs of narrower angle available, but I resisted the temptation! 8)

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Postby Steve Anderson » Mon Sep 29, 2008 9:02 pm

The comments within this thread seem quite atypical of others made elsewhere regarding this kit. Now without wishing to infringe copyright or any other legal issue is there a way I could get a copy of the circuit diagrams to have a 'look-see'?

Please use the e-mail button below rather than post them here. If someone would care to scan them I'll see if I can make any sensible modification. It should be a really quite simple mod...but I could be wrong.

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Postby lemke » Tue Sep 30, 2008 10:03 pm

Steve Anderson wrote:The comments within this thread seem quite atypical of others made elsewhere regarding this kit. Now without wishing to infringe copyright or any other legal issue is there a way I could get a copy of the circuit diagrams to have a 'look-see'?

Please use the e-mail button below rather than post them here. If someone would care to scan them I'll see if I can make any sensible modification. It should be a really quite simple mod...but I could be wrong.

Steve A.


Steve, first of all, thanks for all of your useful information.

It would be great if you could make some improvements to the circuit. But, I'm sad to say they do not provide schematics with this kit at all. The manual provided with this kit provides absolutely no circuit information. About the only thing I could suggest is to examine the actual circuit board.
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Postby Viewmaster » Tue Sep 30, 2008 10:49 pm

lemke wrote:Steve, first of all, thanks for all of your useful information.

It would be great if you could make some improvements to the circuit. But, I'm sad to say they do not provide schematics with this kit at all. The manual provided with this kit provides absolutely no circuit information. About the only thing I could suggest is to examine the actual circuit board.


.........or maybe writing/phoning Middlesex University saying we are the NBTV group and asking if the circuit is available.

Middlesex University Teaching Resources
Unit 10
The IO Centre
Lea Road
Waltham Cross
Herts EN9 1AS

Tel: 01992 716052

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Postby dominicbeesley » Tue Sep 30, 2008 11:16 pm

I've received one of these today and got it working after a few false starts. I have to say the sync circuit is critical to say the least.

I find I can't get it to synchronise well unless I turn the brightness (or volume of the driving signal) right down. The sync circuit seems to be quite sensitive to picture content too.

I've emailed the University asking for a circuit diagram, will report back if I get any joy.

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Postby DrZarkov » Wed Oct 01, 2008 3:46 am

The problem is known. The trick is the distance of the disc to the photo-sensor. It must be the exact distance, relative close to the sensor, not too close, but different from the manual not as far as possible.
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Postby dominicbeesley » Wed Oct 01, 2008 4:47 am

Thanks yes, I'd spotted that earlier in the thread.

I've tried all the different distances and have found the "sweet spot" but the sync is still pretty ropey and I have to fiddle with the controls quite a bit to get it to lock. The manual looks to have been changed, it now says as close as possible, which is also wrong as then it doesn't work.

I'm going to get a 'scope out in a bit and see if I can see what's what.

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Postby DrZarkov » Wed Oct 01, 2008 5:25 am

That is a common bug, too. Solution: Give it time. After a "few hours", when the motor is warm, it will work fine. I've been this weekend at the "Classic-Computing 2008" and I've demonstrated the kit there again. (And minimum one is now very enthusiastic about NBTV :-D)

Another thing very disturbing is strong sunlight, which does not only make viewing difficult, but will have a bad influence on the sync, too...
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Postby Steve Anderson » Wed Oct 01, 2008 12:55 pm

Hmmm...with all those comments above it seems that this kit not really that well thought out. It should work first time, be stable and reliable. The above suggests quite the opposite.

If no circuit diagram is available someone could scan/photograph both sides of any PCB along with whatever useful data is in the manual.

The concept of this kit is a good one, it's simple and the end product looks...err, attractive. It's shame that it seems so hit-and-miss operationally. Not a good way to get newcomers interested.

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Postby lemke » Wed Oct 01, 2008 1:47 pm

Steve Anderson wrote:Hmmm...with all those comments above it seems that this kit not really that well thought out. It should work first time, be stable and reliable. The above suggests quite the opposite.

If no circuit diagram is available someone could scan/photograph both sides of any PCB along with whatever useful data is in the manual.

The concept of this kit is a good one, it's simple and the end product looks...err, attractive. It's shame that it seems so hit-and-miss operationally. Not a good way to get newcomers interested.

Steve A.


My experience was that it worked fine right out of the box. I am impressed by how simple it was to get running. Some things - like using standoffs to power the LED - were ingenious, IMO.

They should have used a white LED, but I guess they were looking to make it somewhat authentic - to look as though there were a neon light source, like original.

I plan to use a true optical quality lens in place of the plastic one supplied, as it has molding flaws. They had to keep it at a reasonable price and I'd say they did a great job in doing so.

Actually, if the kit was "perfect", right of the box, I may be somewhat of bored with it. It is fun and challenging to "upgrade" it.

John
Last edited by lemke on Tue May 31, 2016 7:08 am, edited 1 time in total.
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Postby Steve Anderson » Wed Oct 01, 2008 2:27 pm

lemke wrote:Actually, if the kit was "perfect", right of the box, I may be somewhat of bored with it. It is fun and challenging to "upgrade" it. John


There is that aspect to be considered but it appears you were luckier than others. It is apparently simple so it is a good starting point.

However many have reported it as being tricky to adjust and fussy with video levels and sensor positioning. The poor quality lens you remarked on is a new one to me, but as you say considering the price....

And at that price I would buy one myself if it weren't for the hassle of getting it into this country (customs, excise and duty). Maybe the next time I'm in the UK I will, but by then they might have stopped making it. The last time I checked they had few in stock with the implication of no more to come.

Steve A.

I've just had a look at the MUTR site, there's no mention of stock quantities anymore or for how long it will be produced. Also the shipping costs to here are more than the actual unit!
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Postby gary » Wed Oct 01, 2008 2:42 pm

Steve Anderson wrote:Hmmm...with all those comments above it seems that this kit not really that well thought out. It should work first time, be stable and reliable. The above suggests quite the opposite.

If no circuit diagram is available someone could scan/photograph both sides of any PCB along with whatever useful data is in the manual.

The concept of this kit is a good one, it's simple and the end product looks...err, attractive. It's shame that it seems so hit-and-miss operationally. Not a good way to get newcomers interested.

Steve A.


Well, it seems to vary a bit. My unit worked, and worked well, straight after assembly. Sync is achieved within a few seconds and remains rock solid. My only mod was to add a high brightness LED and a new diffuser.

The main problem I have had is warping of the disc due to temperature changes. This has required straightening using compression from time to time.

In Newsletter 32 No. 2, mention is made that Peter Smith has traced the circuit and confirmed that it used the Club's standard circuit designs.

In Newsletter 32 No.3 there was mention of 4 recommendations for modification (and that these were submitted to MUTR).

I hope it is not breaching copyright to mention here that the first 2 recommendations were in reference to the LEDs and diffuser as already mentioned, the third involved the addition of a 0.1uF decoupling cap across the 5V rail (pins 8&16 of the 4046) and, in the case of the strobe disc not running true, a 22K resistor was added across R17 (presumably as per PCB overlay) to improve sensitivity.

Steve, would it really attract customs, excise, and duty costs as a one off purchase? Seems rather OT. Doesn't attract those here in Oz (currency exchange bites a bit tho'). Certainly it couldn't be justified as protecting local manufacturing...
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Postby Steve Anderson » Wed Oct 01, 2008 3:01 pm

gary wrote:Steve, would it really attract customs, excise, and duty costs as a one off purchase? Seems rather OT. Doesn't attract those here in Oz (currency exchange bites a bit tho'). Certainly it couldn't be justified as protecting local manufacturing...


A bit off-topic but anyway...In a 'sensible' country the above would be true but this is Thailand. If the government of the day can squeeze any cash out of you they will. Something familiar like clothing would pass through un-noticed. A televisor would attract attention..."Eye eye, what's this then son?"

Just getting valves/tubes/CRTs in through customs requires several hoops to be jumped through. The joys of living in a banana republic!

It's better to bring the stuff in yourself when you travel, the cost of excess baggage is worth it. I've never been stopped at customs at the airports here.

Protecting local manufacturing...there is just one cheese producer in Thailand, they only make Motsorella for the two local pizza companies. Yet all imported cheese (any type) attracts a 220% duty. A license to print money.

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Postby Viewmaster » Wed Oct 01, 2008 6:43 pm

Steve Anderson wrote:Hmmm...with all those comments above it seems that this kit not really that well thought out. It should work first time, be stable and reliable. The above suggests quite the opposite.
Steve A.


I don't have this kit but if it syncs for some and not for others, the variable factor seems to be either the spacing of sync sensor or whether the sync holes are all 'clean.' It might be enlightening if two with these machines, one OK and the other not, where to swop discs.
My 2p worth.
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Postby gary » Wed Oct 01, 2008 7:14 pm

Viewmaster wrote:
I don't have this kit but if it syncs for some and not for others, the variable factor seems to be either the spacing of sync sensor or whether the sync holes are all 'clean.'


Whilst the distance of the disk from the sensor is important it doesn't seem to be all that sensitive, and certainly doesn't take very long to get right (my disk wobbles like your sister Kate and it still works fine).

There are no sync holes. The sensor is of the reflective type and the disk has a strobe type encoder disk on the back.
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