Author Topic: EEVblog #553 - Mailbag  (Read 17351 times)

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Offline Stonent

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Re: EEVblog #553 - Mailbag
« Reply #25 on: December 03, 2013, 08:55:47 pm »
Yeah, I have a raging erection, that Tek is awesome.

If it was any longer I would've pissed myself. Awesome stuff!
1975 ... and true RMS to boot.
BRB, nature calls :-)

If symptoms appear for more than 4 hours call your doctor.  I never understood those warnings. There's a lot less embarrassing ways to fix the problem than calling the doctor.
« Last Edit: December 04, 2013, 07:20:55 am by Stonent »
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Offline Scott

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Re: EEVblog #553 - Mailbag
« Reply #26 on: December 03, 2013, 11:18:34 pm »
I've got four of the 200 series Tek scopes (214, 221 storage, and two 213 DMMs). I'll give away my secret: buy the ones on eBay that are not working at all. Usually the only thing wrong is the NiCd battery pack. If the battery pack is shot, the units often wont even run on AC power. Also, don't power the unit from AC power unless an battery pack is installed.

They are great little scopes. I was able to fit three scopes in my carry on luggage for Maker Faire last year!
 

Offline synapsis

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Re: EEVblog #553 - Mailbag
« Reply #27 on: December 03, 2013, 11:31:31 pm »
But now that Dave's had one on his channel, the price of the scopes will go through the roof!
 

Offline Stonent

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Re: EEVblog #553 - Mailbag
« Reply #28 on: December 04, 2013, 03:34:41 am »
But now that Dave's had one on his channel, the price of the scopes will go through the roof!

Bonus if someone can figure out how to build a small scope board that connects to the back of a Sinclair TV!
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Offline Zad

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Re: EEVblog #553 - Mailbag
« Reply #29 on: December 04, 2013, 03:48:52 am »
You could probably run a (functional) Sinclair TV quite easily off the Raspberry Pi composite video output. Someone has to try that!

Offline amyk

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Re: EEVblog #553 - Mailbag
« Reply #30 on: December 04, 2013, 06:31:48 am »
Hi,
    GK mentioned this in his home brew analog computer thread, specifically :

 https://www.eevblog.com/forum/projects/home-brew-analog-computer-system/165/

GK links to http://www.nixiebunny.com/crtgen/crtgen.html about half way down page 12 of the thread.

Regards, TJW.
That's the one! :-+

I was able to easily find the PDF version after seeing that: http://www.thecorememory.com/GenCharforCRR.pdf
 

Offline Stonent

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Re: EEVblog #553 - Mailbag
« Reply #31 on: December 04, 2013, 07:21:36 am »
You could probably run a (functional) Sinclair TV quite easily off the Raspberry Pi composite video output. Someone has to try that!

You'd need an RF Modulator to convert the Comp to RF signals.
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Offline Zad

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Re: EEVblog #553 - Mailbag
« Reply #32 on: December 05, 2013, 03:29:39 am »
It depends on what goes on inside the chip. It has a composite video output pin that you should be able to tap onto to inject the Rasp Pi's analogue output. It may be that the chip samples the signal before this point to derive synch etc.

Offline N2IXK

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Re: EEVblog #553 - Mailbag
« Reply #33 on: December 05, 2013, 03:50:21 am »
There is a block diagram of the ZN401E-2 chip here:

http://www.thevalvepage.com/tv/sinclair/ftv1/announc.htm

Looks like the composite video could be injected right at the detector output, feeding both the CRT drive and the sync separator.

Does anyone have a copy of the actual Ferranti datasheet for the chip, or was this a proprietary design just for Sinclair? A really interesting design, using what appears to be a synchronous detector for the audio, and a PLL with dual DACs to produce the deflection waveforms.
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Offline EEVblog

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Re: EEVblog #553 - Mailbag
« Reply #34 on: December 05, 2013, 04:09:24 am »
There is a block diagram of the ZN401E-2 chip here:
http://www.thevalvepage.com/tv/sinclair/ftv1/announc.htm
Looks like the composite video could be injected right at the detector output, feeding both the CRT drive and the sync separator.

The chip is needed to generate all the timing though. Could be done manually, but messy.
 

Offline N2IXK

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Re: EEVblog #553 - Mailbag
« Reply #35 on: December 05, 2013, 04:20:15 am »
Yes, without the magic chip, getting anything on the screen would be a LOT of work. Almost the entire signal processing system (video, audio, sync, and sweep generation) is contained in that little guy...
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Offline JoannaK

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Re: EEVblog #553 - Mailbag
« Reply #36 on: December 05, 2013, 04:36:55 am »
Sounds a lot like Fpga.project.. or Propeller.
 

Offline amyk

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Re: EEVblog #553 - Mailbag
« Reply #37 on: December 05, 2013, 06:40:08 am »
I remember seeing online a schematic + datasheet for a Chinese-made portable CRT TV (recently) that had everything on one chip... but can't find it now. :(

Edit: found it!
http://shiximm.com/baogaofanwen/261729.html
http://datasheet.seekic.com/PdfFile/D29/D2915.pdf
« Last Edit: December 05, 2013, 06:47:46 am by amyk »
 

Offline SeanB

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Re: EEVblog #553 - Mailbag
« Reply #38 on: December 05, 2013, 07:25:30 pm »
n the late 1980's Maplin was selling off the boards as spare parts, possibly working but without the CRT, main chip and tuner. Probably ones that were DOA from the assembly line, where they would pull the most expensive items ( Tuner, CRT and the ASIC) from them to reuse. Probably the main reason the ASIC was in a socket is that they were heat sensitive, and were the single highest cost item in the set, probably costing more than the CRT.

I watched the Andie Davies memories about Sinclair, was very entertaining on how difficult those were to make.

As to the battery packs, they were a part of instant film packs, used to drive the camera motors, focussing system and the flash circuitry. Pretty impressive for the first mass produced pouch cells, they were nice to use in projects as discards from camera packs, still having a lot of power left in them after the 120 shots from the film unit. Only issue was connecting to the aluminium foil tabs as they were not solderable. I generally used a crocodile clip or paper clip as a contact with a piece of magic tape as a cover for the clip.
« Last Edit: December 05, 2013, 07:30:35 pm by SeanB »
 

Offline peter.mitchell

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Re: EEVblog #553 - Mailbag
« Reply #39 on: December 10, 2013, 03:52:47 pm »
I have that chip Dave if you want it. Don't know how long it would take to get there from the UK at this time of year but if you want to do a follow-up to that mailbag and get the thing working, I can stick it in the post for you.

Jon.

My experience with UK-> Aus any time of year is very quick. I'd say it would take a week, maybe 2, tops.
 

Offline beounet

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Re: EEVblog #553 - Mailbag
« Reply #40 on: December 13, 2013, 09:07:15 pm »
 
Hey Dave!! About the camera zoom issue, why don't you make a foot-pedal zoom switch????
 

Offline delmadord

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Re: EEVblog #553 - Mailbag
« Reply #41 on: December 27, 2013, 08:36:19 pm »
Just a quick GIF
 

Offline delmadord

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Re: EEVblog #553 - Mailbag
« Reply #42 on: January 08, 2014, 10:36:44 am »
and just one more pic

 

Offline wilheldp

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Re: EEVblog #553 - Mailbag
« Reply #43 on: January 08, 2014, 06:33:23 pm »
As crazy/stupid as some people are with body modification, it would surprise me if a craze started where people were trying to get struck by lightning to get a "cool" Lichtenberg figure "tattoo."
 

Offline SeanB

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Re: EEVblog #553 - Mailbag
« Reply #44 on: January 08, 2014, 06:56:07 pm »
At least that would be self limiting, most do not survive the experience.
 

Offline IanJ

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Re: EEVblog #553 - Mailbag
« Reply #45 on: January 08, 2014, 07:17:14 pm »
As crazy/stupid as some people are with body modification, it would surprise me if a craze started where people were trying to get struck by lightning to get a "cool" Lichtenberg figure "tattoo."

If Doc Brown can do it (albeit unintentionally) then surely Dave will give it a go........



Ian.
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