405 analogue standard converter kit
 

Good evening,

here is the schematic of the clock board of the do it your self standard converter. The board is routed and I want to give it in production next week. It is planed to use one UVB at the input. It removes teletext and Macrovision from the vertical flyback. The output is usefull for 625 and drives the analogue ccd PCB and separates the 625 sync. The analogue PCB contains the interpolator, the switched delay ccd‘s and one half of the V- sync replace circuit. An other UVB will be used at the output. It contains the other half of the V- sync replace, drives the modulator , is 405 input for the modulator and 405 output of the standarts converter. The colck board generates all neccessary pulses and the clock frequencys for the delay ccd‘s .

I am sure there are only a few people who wants to build a converter. So I’ll make only a few PCBs. I’ll build up one with the high and one with the low clock frequency to try out the exact values. Than comes the analogue delay ccd PCB and the kit is finished. Maybe I’ll make a PCB for the modulator too.

If you find mistakes or have some helpfull ideas please let me know.

Kind regards
Darius

Re: 405 analogue standard converter kit
 

Hi Darius,

This sounds great!

I am sure I will be building one of these as soon as you are ready!

I think the modulator would be best built as you already do - otherwise how does anyone learn basic RF engineering;D

However, A PCB would make the project more accessible to those members that lack the confidence to have a go from the start!

I am just working on a varicap oscillator for the modulator - makes tuning easier......

73
Sean

Re: 405 analogue standard converter kit
 

Hi Sean,
did you see the OIRT modulator on the german UVB website?
It is quasi parallelsound (SO42) and has a switchable oscillator.

I hope a kit brings more people back to do it your self.:)

Kind regards
Darius

Re: 405 analogue standard converter kit
 

Good evening,
the clock boards arrived and I am testing them now.
The one at the top is compleately loaded for the low clock frequency,
except the V-sync monostables. First I need the delay ccd board to
find out their RC values.
I am loading the other board for the high clock frequency. Both work
fine. Both kinds of synchronus dividers can be loaded, the big and the
small one.
I started drawing the schematic for the ccd board and I am routing
sumultaniously. So I can see what can be loaded and what additional
features are possible. The problem for me is, I am limited to 8cm x 10cm
board size. I am making a board for the cxl 5508/6M. I am optimistic to
get all analogue parts on it, so no other additional board (UVB) is neccessary.
I hope.;)

Kind regards
Darius

Re: 405 analogue standard converter kit
 

Wow these look realy posh Darius i think this would be a good project and yes i would have a go just to say ive built one myself and it will be a good buz to see the results.
very well done.
Danny

Re: 405 analogue standard converter kit
 

Almost tempting enough to make me want to find myself a 405 telly;)

Re: 405 analogue standard converter kit
 

I'm happy to hear that there is still some interest.:)

Kind regards
Darius

Re: 405 analogue standard converter kit
 

There certainly is! I have followed your development of the Converter with interest for as long as it has been posted here. I think it has helped to foster my interest in old TVs. I am getting a 405-line GEC soon, and am interested in your Converter Kit. For me it is more interesting to build something yourself than to buy a box to do it - often you gain a greater understanding of what goes on inside the box! ;D

How close to completion is the kit, or is is ready? As yet I'm not (no TV), and I am going to wait until I have a Pay-cheque coming in regularly rather than relying on my Student Loan! :-)

Sam

Re: 405 analogue standard converter kit
 

Hi Darius,

This looks very promising - I look forward to the arrival of a kit very soon!

I would be very happy to construct one here.

Cheers
Sean

Re: 405 analogue standard converter kit
 

Hi, as I toled in another thrad, I stoped the development for some time
thus I lost a few month. I think I'll be a bit later than Darryl (L.C.Aurora).
I expect the converter kit is finished in May.
At the moment I am routing the interpolator.
It takes a lot of time. It must all be done by hand, to make it as small
as possible and to get a good layout. The autorouter is not able to move
the components and change packages. Until this is not possible, forget
the autorouter. I am learning a lot making this. This is my second PCB
project after making the UVB - Kit.

Kind regards
Darius

Re: 405 analogue standard converter kit
 

You can still put me down for one. ;D

Well done Darius

Andi

Re: 405 analogue standard converter kit
 

http://hometown.aol.de/freddurst50/NW/NwBlatt3.JPG

Hi, I need some help. I want an opamp replacement for Q35.
See link attached.
In the schematic below you can see how I want to use it.
The opamp must work with asymetrical 5V. The input is 0.55Vpp
and the output should be -2Vpp (405- vision signal).
8 pin DIP prefered. Any suggestions which one to use?

Kind regards
Darius

Re: 405 analogue standard converter kit
 

Analog Devices AD805x series or AD809x series are both excellent video opamps. You may be forced to use SM parts. Darryl and I have used them professionally.

Re: 405 analogue standard converter kit
 

Hi Jeffrey, I looked at the AD8052 you suggested in Kat's thrad.
But I did not find a cheap souce. (Kenwood 35.- Euros)
The other ones I found at RS are 7,00 € or so.
The cost of a BC557/547C is 0,02€.
I think I'll make it with transistors again. It takes the same size on board
and the amount of external components is the same.

Something like this:

Kind regards
Darius

Re: 405 analogue standard converter kit
 

The problem with a lot of these devices is that they are expensive in small quantities. I think the AD8052 is under £1 in 100+ from an Analog Devices distributor.

Re: 405 analogue standard converter kit
 

Indeed!

...... I can't see what's wrong with the "discrete" option - There will be good PTH discrete trannys around for a while yet IMHO. It’s, odd, but truly “retro” components like the 741, 555 and 2N2219 trannies, that I worked with when I first started work in the early 80s, are still with us while more modern components have come and gone without a trace.

It's looking good Darius.:D

Re: 405 analogue standard converter kit
 

Good morning, Evingar is right.
Over night I decided to use the transistor arrangement.
But it'll make a bootstrap input to eleminate the damping of R80 22K Ohms.
I want an input resistance of 200K Ohms there. In the MK 1 I used bipolar
22uF electrolytics and now I use 1uF MKT caps.C38/39/40.

Kind regards
Darius

PS: The numbers of the components will change in the next schematics.
Don't care about strange values and notifications, because parts are
copied with "cut and past" (Eagle).

Re: 405 analogue standard converter kit
 

Hi Darius,

When was building your converter I found that DigiKey were very competitive
for price. http://uk.digikey.com/scripts/DkSear...273428&Site=UK
They have high fixed costs up front for handling etc but the part costs are very low so if you are buying a variety of parts (say for the complete converter) then they do make sense.

Kind regards,

Peter.

Re: 405 analogue standard converter kit
 

Hi Peter, I know digikey. But I decided not to use the opamp.
Three SMD parts (the cxl's) are enough for the kit. I think it is much
easyer to load three transistors. Following now is the V- sync replace
and modulator biasing stage an inverter for the input signal to give
a vision signal on the converter bypass switch Q15.
Than I'll look how much space is left on board to add some other features.

Kind regards
Darius

Re: 405 analogue standard converter kit
 

90% is done now. It seems there is enough space on the 10cm x 8cm board.
Next is the vision inverter for the bypass mode, (two transistors) and
a switchable colour filter at the input. (three transistors, switch and schmittrigger)
If there is space left, I'll make a second vision input. Or what ever.
Suggestiones are welcome.
I think it is better to say 10KHz vision for 405/441/455etc. and 16KHz vision
for PAL/SECAM/NTSCetc.
If you find mistakes, please let me know.
The output stage is similar to the UVB, a second output a filter (switched off
in bypass mode) and the sync replace is added.
Hope you do understand what is going on.

Kind regards
Darius