Microvitec Cub (Review)

roy_bates

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AmiBayer
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everyone knows the acorn bbc had its own monitor,and for most anyway it was remembered from their school days.

this thread will show some pictures of a couple of my cubs,my thoughts on the built quality,and a bit later more pictures of the internals of them for anyone that may be interested:)

so,lets have a short look at the external casing of a couple of microvitec cubs.

overall,they are a basic monitor and could be got in an array of configurations.
here are just two.

we will be looking at the iconic metal cased versions that most remember from their youth..


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metal case is very strong folded steel construction,which i suppose was a good thing as these where used in schools.

lets have a look at the rear of a couple shall we.


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this one is standard in the sense its the one that most remember,TTL input no sound etc with mains on/off rocker switch..
again build quality is very nice in my opinion,and is very serviceable...back and top can be removed to get at the innards etc.
without very much hassle..


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this one is not so common i suppose,this has TTL and analogue inputs as well as audio...
personally,i have only ever seen two of these my entire life...not that there wasnt a few about,its just i know there was one that had inputs for the spectrum as well,converter board was internal..i dont have one...yet.
just to show they did come in different configs.
top half of this case was/is a bit different as there is slots for the audio on one side from the internally mounted speaker yes its mono,for the sound to get out..there was a stereo config.

ventilation for heat dissipation is provided by vents at the bottom and top of the side panels.
cases also come with four sturdy large feet for the monitor to sit on..

later,i will take the back off them both and take pictures of the innards.
 
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roy_bates

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AmiBayer
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so...

here is the internals of a standard cub most remember


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back panel is removed by unscrewing seven screws,here you can see the wiring loom for the mains switch,contrast and input for TTL RGB signals above.


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top half of the case is removed by unscrewing two screws located at the front top of the case.
here you can see pcb for the crt tube assembly,and partly see the main board...

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this a picture from the side you can see the output from the tripler/focus unit etc.

NOTE: red wire from the tripler input from the LOPT has been removed in this one as the lopt is faulty,it is normally connected to the overwind stage for the high voltage that this set needs to function.

main board is removed by simply pushing some clips outward and pulling gently upward to remove it after pulling out all the cables that are plugged into it.and removing the pcb from the neck of the crt is just a case of pulling it gently out off the pins of the neck of the tube.

i wont show the main board out of the set as both of these are down for a service and repair at a later date,so i didnt see the point of taking them apart to put back together to take apart again...you get the idea:)

next up will be the internals of the other monitor.

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ok,here is the other one...


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removing the back is exactly the same as the other one,here you can see the wiring loom for the controls etc.




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this a picture of the side of the case to show the cutout in the case for the speaker.



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top half the case is removed in exactly the same way as the the other one.
it uses the same main board pcb and same pcb the neck of the tube...


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this is picture of the one side of the other one,you can see the tripler.

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this is from the other side,i have pulled some wires to the side so you can see a fuse,this one is f3

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this one is from a slightly different angle,here you can see the other two fuses,f1 and f2


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this is a picture of the triple standard pal board,top section is the audio you can see there is space for components to make it stereo...


NOTES:if there is no history when buying these second hand or otherwise and the seller dont know if they work or not,i normally ask they dont power them up,there are a few reasons i do it this way,although i wont go into it much but if asked here ill try to explain why.
even if you mange to find one or any monitor being sold as new,same thing apply's it wont mean itll work out the box so dont listen to the bs that gets peddled about somethings..
there are a few critical areas that can be checked safely before trying anything and without it being plugged in,i check for blown fuses and i check the right hand side for burn marks etc on components such as the lopt as a very basic check.
if the mains lead has been cut off or shortened it may of been a condemned unit...although that may not be the case but its something to be aware of,condemned equipment was condemned electrically for a reason most of the time,but it dont mean it cant be repaired and serviced to full working condition..i get a few monitors this way...

dont run them without the earth or with shoddy cabling you will be risking your life,try to fit it with a low amperage fuse on the plug end at around 3 amps.
same goes for extension leads,they have to be earthed.

ill get out my bbc and take a picture later with my conclusion etc on these with my other cub...

so far,i can tell you they are well built very well infact lots of earth points on the case and when working are very reliable after a good service picture is sharp and clear,they have there limitations with units that have no audio but its a cub so im not really going to use it with anything else.a basic unit is a colour tube with ttl level inputs,very nice.
easy to take apart and put back together,its a no brainer..
servicing them from my point of view is very easy,and very pleasant to work on.
although that part is and shouldn't be left to amateurs for obvious reasons... and afty precautions should be taken at all times.
overall a very good colour monitor.for its age..

another note on these,if your thinking about building them into some kind of shelving unit,you will have to leave approximately 3 inches of space around the sides and top for ventilation,its not a good idea to block those vents...
youll have to trust me on that.
sure, the mains switch is on the back and may make this impossible for some and can be got around as its just a isolation switch that can turned on elsewhere, but i thought i would mention it.


i may do reviews of other monitors at a later date if anyone was interested?,their good, their bad and the ugly side..
common failings etc included...
 
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KBQ

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God you could kill someone with one of these buggers... How well do the analogue input ones do with something 16 bit?
 

roy_bates

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a couple of pictures of another one in use with my bbc....



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nothing more to say really:)

a picture dont really do any justice these are far nicer close up.

and thats it hope you liked it:)

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God you could kill someone with one of these buggers... How well do the analogue input ones do with something 16 bit?




probably the same as any other analogue 15khz monitor i suppose,they can be converted to analogue there is jumpers on the main board for that.
so it is supported.

i might knock up a cable and find out when i have time.
 
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roy_bates

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ok,since the question was asked and i was curious about the triple standard pal board.

monitor didnt work before this video,and at this time is down for a full on service which ill do at a later date.

i made a quick and dirty cable to connect a playstation to it...via rgb.
ill post a video in a bit,its not great or anything as my camera dont like crt's and youll have to take no notice of rolling or distortion in the video as that is the camera, the picture on the crt is stable and clear apart from height,centering,width..or any other geometry problem that may be seen in the video...

here is the video:

https://www.youtube.com/watch?feature=player_detailpage&v=w62Z0pW11RQ
 
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Station240

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The case is actually strong aluminium, not steel as everyone thinks.

Your CUBs are the MS (medium resolution), there is also a HS (high resolution) version, which is rarer and has a very dark almost black tube (slight green tinge).

I'm in the process of repairing a CUB myself, which includes cleaning up the circuit diagrams. I'll post the results of both tasks when I finish.
 

roy_bates

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AmiBayer
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fire away bud,the more the merrier:)

yep,that was my mistake i forgot to edit the post,it is aluminum:)
i think there was a 20 inch model as well.

also,as a small note,thanks for the help with the lopt mate...i was having a blind day looking at the service manual over on stardot.

ive got the main board out of the one of them now and its on my bench...i think this one is going to need a good look at as i think its been tampered with before i had it.(the one with the arcing lopt)

yes,i would definitely like a look at the schematics that you revised for these,i think there is a few mistakes in the ones ive seen while i was checking components...
 
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