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Re: NBTV Television Analyst

PostPosted: Mon Jun 08, 2020 5:29 pm
by Harry Dalek
Steve Anderson wrote:I have a book which covers the evolution of the CRT from the very early days up until (almost) its demise....

"The Cathode-Ray Tube", Peter A. Keller, ISBN 0-9631559-0-3, 1991. It's worthwhile read , but may be hard to find. I got my copy direct from the author as he had a few spare copies. I think it's probably out of print now. I don't recall the cost, maybe US$50 including postage from the US. How I got in contact with the author I don't remember. He worked for Tektronix is the US, so I think you can assume it's authoritative.


I had a look if its about must be here you got it from doe's look like a good book ,These days i rather books as a PDF don't have to worry about storage space.
https://www.sm5cbw.se/tubes/books/thecrt.htm

I still have a few CRTs to work out future projects with .
I enjoy the challenge i will end up with a few CRTS monitors i suppose ! for me its not that you need them all but good to see if i can improve on the last one and learn a bit more with this project keep the mind busy !.
On the to do list is recase some of the first ones and make one that is a little less fussy with correct video and all valve job would be interesting to.

Re: NBTV Television Analyst

PostPosted: Tue Jun 09, 2020 2:24 pm
by Steve Anderson
Good find Harry! I sent Peter the money as cash, got the US$ from a currency exchange here and sent it recorded delivery - worked perfectly. A bit risky, true, but at the time there weren't many other options. Ask him if there's a better way if you're interested in the book.

Steve A.

Re: NBTV Television Analyst

PostPosted: Tue Jun 09, 2020 4:28 pm
by Harry Dalek
Steve Anderson wrote:Good find Harry! I sent Peter the money as cash, got the US$ from a currency exchange here and sent it recorded delivery - worked perfectly. A bit risky, true, but at the time there weren't many other options. Ask him if there's a better way if you're interested in the book.

Steve A.


Have to see one of those things yes sure like it but i like a lot of stuff unfortunately the price is pretty good for a book like that .
Not as good but found this one from the 40s
https://frank.pocnet.net/other/docs/The ... ndbook.pdf

Re: NBTV Television Analyst

PostPosted: Tue Jun 09, 2020 4:53 pm
by Steve Anderson
Just a note:- Peter's book is about the CRT only, it doesn't cover any external circuits, timebases, amplifiers or power supplies. There's no technical data at all, it is really solely about the history and the application of CRTs, not a practical "How-to-do-it" guide. But it is good bed-time reading!

The link is quite good, but because of the publication date (1945) it's tubes/valves only, which puts a lot of people off. Even I (being somewhat of a "Tube-Head") think twice before using them. It's a whim, a link to the (my) past, there are few practical reasons to use them these days...that I have to concede.

Steve A.

Re: NBTV Television Analyst

PostPosted: Wed Jun 10, 2020 12:11 am
by Harry Dalek
Steve Anderson wrote:Just a note:- Peter's book is about the CRT only, it doesn't cover any external circuits, timebases, amplifiers or power supplies. There's no technical data at all, it is really solely about the history and the application of CRTs, not a practical "How-to-do-it" guide. But it is good bed-time reading!

The link is quite good, but because of the publication date (1945) it's tubes/valves only, which puts a lot of people off. Even I (being somewhat of a "Tube-Head") think twice before using them. It's a whim, a link to the (my) past, there are few practical reasons to use them these days...that I have to concede.

Steve A.


OH i see Steve on the book well that is different .

Well on the tube thing i suppose even the crt will put people off to just a massive high voltage valve .

I noticed thinking about these i saw a monitor you made a while ago using both ics and valves i am not sure its on the forum in the same form as the cq mag
i will review it after .
Did it get scrapped ? out of interest tends to happen in time .
https://batc.org.uk/wp-content/uploads/cq-tv205.pdf
cq-tv205.pdf
(2.32 MiB) Downloaded 91 times


I have a draw full of valves i like them think its still worth building with them in a neater way than original air wiring, i am the other way i dislike the newer side of electronics little bits of plastic squares more complex more i dislike them :roll: they do wonderful things and use what i have to but for hobby electronics i do live in the past reason i like early Television ...how Tv works these days is who wants to make a 8k plasma .

Re: NBTV Television Analyst

PostPosted: Wed Jun 10, 2020 1:46 pm
by Steve Anderson
Harry Dalek wrote:Did it get scrapped ? out of interest tends to happen in time .

It was re-built a few times, it's now been boxed up and stored...somewhere! One day I may trip across it...in my recent blitz on my office/workshop I've come across all sorts of things, a board for example, "Now what did I build this for?" Most times I'll eventually remember, but there's a couple that defy me. I'm usually very good at documenting everything, except I forget to label the physical thing as to what it is!! Eventually I'll marry up the paperwork to the board, but there's a couple that are a complete mystery...

I had completely forgotten about those two CQTV items, well over a decade ago I think. Interesting to see the screen-shots of my old analogue 'scope. I still have it and it still works (the last time I powered it up anyway), The only thing wrong with it is the input attenuator switches, basically worn out. I bought it in Hong Kong when I was working there, around 1991 I guess...

Steve A.

Re: NBTV Television Analyst

PostPosted: Wed Jun 10, 2020 2:10 pm
by Steve Anderson
In having a hunt around for the original versions of those CQTV items I came across this...I don't think it has ever been published...but I may (probably) am wrong....this was one of those re-builds I mentioned...

Steve A.

Re: NBTV Television Analyst

PostPosted: Wed Jun 10, 2020 4:58 pm
by Harry Dalek
Steve Anderson wrote:It was re-built a few times, it's now been boxed up and stored...somewhere!


I know what that's like ! its a nice monitor .....i have a DG7-32 as well just had a lot more 3bp1s handy only have one of those ,i noticed there's a bit on the forum on this CRT more than likely mostly you .

One day
I may trip across it...in my recent blitz on my office/workshop I've come across all sorts of things, a board for example, "Now what did I build this for?" Most times I'll eventually remember, but there's a couple that defy me. I'm usually very good at documenting everything, except I forget to label the physical thing as to what it is!! Eventually I'll marry up the paperwork to the board, but there's a couple that are a complete mystery...


Yes i don't do that either i should mark boards that work ,they get put in a safe place then i try and remember least the forum is my good memory if i do post it up. :roll:

I had completely forgotten about those two CQTV items, well over a decade ago I think. Interesting to see the screen-shots of my old analogue 'scope. I still have it and it still works (the last time I powered it up anyway), The only thing wrong with it is the input attenuator switches, basically worn out. I bought it in Hong Kong when I was working there, around 1991 I guess...


Got to keep the old scope but they don't make them easy to fix just about have to pull it to bits to get and any thing .
Your CQ mag NBTV Valve deflection circuit i posted ,the circuit isn't very sharp must of been a small copy of the circuit used ...wonder if others tried it ? The valve part interested me reason i went looking for it ,i think there's the odd valve NBTV project in the Newsletter ..
I was looking a your next post i see where the deflection amplifier came from...

Re: NBTV Television Analyst

PostPosted: Fri Jun 12, 2020 2:49 pm
by Steve Anderson
There's a few advantages with the DG7-32, you can still get them and they're quite low-voltage CRTs compared to those that came before, and quite compact. The two I have were as good as new, both in unopened boxes and I was able to get the sockets for them from the same supplier in the UK. I think the paperwork that came with them even has a serial number for each...both made by Mullard from their works in Hammersmith, London...my birthplace by coincidence! Probably around the same age as me, from the mid-50s...

For NBTV/SSTV you're most unlikely to need C301 or C305, only needed in faster applications...that's a circuit I think I drew well over a decade ago! These days I tend to date them and also give them a version number...

Steve A.

Re: NBTV Television Analyst

PostPosted: Fri Jun 12, 2020 5:05 pm
by Harry Dalek
Steve Anderson wrote:There's a few advantages with the DG7-32, you can still get them and they're quite low-voltage CRTs compared to those that came before, and quite compact. The two I have were as good as new, both in unopened boxes and I was able to get the sockets for them from the same supplier in the UK. I think the paperwork that came with them even has a serial number for each...both made by Mullard from their works in Hammersmith, London...my birthplace by coincidence! Probably around the same age as me, from the mid-50s...

Steve A.


Yes i have one of those thanks to Andrew also still a fair few 3bp1's to use ...i have seen the projects on the forum with the DG7 32 mines still in its plastic bag does not look like it was ever fired up .

I also have a 3AP1A its very long and thin on the electron gun side ...still thinking about that one .

One CRT i have this brute of a CRT..from a scope i would think ,i would love to make a monitor out of it if possible ,i never really looked into it much due to its size and lack of data .
Of late i found this old PC that's died the case it seems has a LCD screen which just happens to be a nice fit for some thing like this monster and the tube just fits.
i would think this is not a low voltage thing ! but i think i am up to what ever it needs now to build some thing like this safely if i find data for the thing ,the Analyst has been useful if any thing working with voltages up to 2000 volts and being able to adjust that to my needs think this thing would be up the 3 to 4kv or more looking at some other Tektronix scope power supplies .
...thinking of deflection supply this must be higher as well 600v a guess might even be low for this thing .
This is one of those cases where you think about what you want to do with it for some time and plan ahead or toss away the idea if its just not possible , reviewing your Brute build some time back the use of valves would be something i have not tried and on a bucket list ,any case i need to find some more out on the type of crt perhaps its just wishful thinking .
ON the current project i finished the second lot of deflection amplifiers and tested that today ,my problem is now the BC547s that control the ramp size also effect the others circuits control this .... comes down to another 2 4040s and DAC ics for each deflection circuit ....then it will work :roll: in hindsight this makes sense so have to rebuild the circuit below ...just the 4 ics part lucky there's room it all just fits on the new deflection board .Yes another oh hum but getting there .

Re: NBTV Television Analyst

PostPosted: Sat Jun 13, 2020 5:48 pm
by Steve Anderson
Hmmm, that CRT could quite well turn out to be a bit of a challenge, those made from the late 60s onward often had more than one stage of electron acceleration. Without the datasheet for it I don't think I'd attempt it. I would also expect more than 4kV of final anode/PDA voltage. As it's an "house number" CRT it probably was only supplied to Tek who for commercial reasons kept the data to themselves. But given a manual for whatever 'scope it was used in you could probably reverse-engineer it.

Also, does it have an internal graticule? You should be able to see that with no power on the tube. That would spoil any picture.

Also these were often fitted with 'rotate' coils so you could line up the green trace with the internal graticule. This a slight effect on all CRTs due to the Earths magnetic field, you move a later CRT 'scope such that the tube has an East-West orientation from North-South you need to adjust the DC current through the rotation coil(s)..even my retired Goldstar CRT 'scope has a rotate pot. It's only a few degrees, say three, but it is noticeable if it does have an internal graticule.

Thankfully more recent displays are not subject to this...

Steve A.

Re: NBTV Television Analyst

PostPosted: Sat Jun 13, 2020 9:07 pm
by Harry Dalek
Steve Anderson wrote:Hmmm, that CRT could quite well turn out to be a bit of a challenge, those made from the late 60s onward often had more than one stage of electron acceleration. Without the datasheet for it I don't think I'd attempt it. I would also expect more than 4kV of final anode/PDA voltage. As it's an "house number" CRT it probably was only supplied to Tek who for commercial reasons kept the data to themselves. But given a manual for whatever 'scope it was used in you could probably reverse-engineer it.


i found some tube data on the brand of crt but nothing on it there are some schematic for scopes but again without know what it was in hard to track down , Yes 4kv is high i think i would be more worried at the deflection side ,just some thing i was thinking about as i forgot i had it till the other day .
OH it could be older than i thought i was thinking it was some late 80s or 90s scope ..it was 10 dollars as i recall .

tek_crt_data.pdf
only bit of data i could find as a data sheet on this brand of tube
(223.43 MiB) Downloaded 86 times



Also, does it have an internal graticule? You should be able to see that with no power on the tube. That would spoil any picture.


I can't see one or noticed one .


Also these were often fitted with 'rotate' coils so you could line up the green trace with the internal graticule. This a slight effect on all CRTs due to the Earths magnetic field, you move a later CRT 'scope such that the tube has an East-West orientation from North-South you need to adjust the DC current through the rotation coil(s)..even my retired Goldstar CRT 'scope has a rotate pot. It's only a few degrees, say three, but it is noticeable if it does have an internal graticule.

Thankfully more recent displays are not subject to this...


I noticed the coil on some of the schematics i looked at yesterday i wondered what that was for ...makes sense ! The vcr139a when i had it on a low voltage the raster would change position with where i placed it on my table .

On the Analyst good and bad news the new deflection circuit works now with out effecting the other well the short time i got to see it i have no problems on the 3bp1 monitor side power supply but i keep killing on the flying spot monitor sides 75 volt zener ,this time i found also the 1N4148 going as well conductivity measurement showing both are like a wire ... i am going to pull the board out and see whats up i think i have a sparking problem as i seems to happen when i tried to increase the HV negative the vcr139a was on around 800 volts or so reason i had had no problems with it ,the 3bp1 is bit over 1400 v its fine but try to get to 1000 the FSS duplicate circuit and it plays up you can tell also my panel light flickers i know its sparking worse part i found it caused a raster burn i thought ! EDIT looking more closely its a lite scratch on the glass ...thats a bugger . thinking back i did drop a small screw driver near it that other day may be i can polish it out its very fine just doing that i can hardly see it now thank goodness!

DSCN6689.JPG
DSCN6689.JPG (220.46 KiB) Viewed 1746 times

Trying to look on the positive side least it will work when the power supply problem is fixed ..i will just have to live with the disaster and keep at it i will also remove more of matrix from the power supply side in case spark was jumping via those.

Re: NBTV Television Analyst scope problem during build

PostPosted: Sun Jun 14, 2020 5:11 pm
by Harry Dalek
Another bit of bad luck today my good oscilloscope well good for 30 years ! boy time go's fast, it keeps blowing fuses which can only mean something has died ,i get the pilot light for a sec before it happens ,i don't have a schematic so i don't know if its the transformer or not yet but it seems likely .
all it can do is unplug the supply to a board at a time and see ..not having much luck this week .
I am trying to check if these things just have been rebranded no schematic is a real pain .
not my scope it the picture but same model just grabbed am image quick mines a lot cleaner!
10257006.jpg



http://bee.mif.pg.gda.pl/ciasteczkowypo ... ps-205.pdf

I wanted to test the Analyst after rebuilding the FSS CRT power supply but this has happened so there go's that plan !

Edit i just found out what it could be this is close and some scraps of a schematic
Heatkit SO-4552 scope
A Pintek 200

Re: NBTV Television Analyst

PostPosted: Mon Jun 15, 2020 1:10 pm
by Steve Anderson
The circuit appears to show that the output of the transformer and the rest of the power supply is connectorised, unplug the secondary winding(s) and see if the fuse still blows. Hopefully it wont. Transformers are usually very reliable unless overloaded.

Does your house have a RCCB/ELCB in the 'fuse box' (these days called a 'consumer unit'), does it trip when you plug in the 'scope and turn it on?

Steve A.

Re: NBTV Television Analyst

PostPosted: Mon Jun 15, 2020 7:20 pm
by Harry Dalek
Steve Anderson wrote:The circuit appears to show that the output of the transformer and the rest of the power supply is connectorised, unplug the secondary winding(s) and see if the fuse still blows. Hopefully it wont. Transformers are usually very reliable unless overloaded.

Does your house have a RCCB/ELCB in the 'fuse box' (these days called a 'consumer unit'), does it trip when you plug in the 'scope and turn it on?

Steve A.


Yes the good thing it looks like the power supply to the boards have plugs as you mentioned ,later this week i will give your procedure a go ,i was surprised at how small the transformer is . what i can see of the transformer it looks clean no burning ...i am crossing my fingers the transformer is ok .

I would think the DC part power supply would be the likely cause but you never know , we have safety switches that will turn off on something faulty what ever plugged in and you can reset them ...your question makes sense i would think if the primary of the transformer were faulty the house fuse would trip ...since it doesn't we know the primary of the transformer is fine ? secondary another story .