| Electronics > Repair |
| Vintage chip Programmer : " Micropross ROM 3000U " |
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| pcprogrammer:
Hi Vince, I think you are overthinking it :) It is just standard old TV signals but with the frequency slightly of. It should be 64us but the main clock might be a bit slow. Look at the datasheet of the MC6845 and see what the clock frequency is there. Most likely the gadget you ordered will be able to handle the signal. Edit: Early TV (PAL) worked with interlaced screens, so a full screen refresh rate was only 25Hz and our eyes did not see it flicker :-DD |
| Vince:
I like your optimism, may you be right, crossing fingers ! :-DD Interlacing hmmm..... yep, forgot about this thing, good point ! Very.... good point :-+ Got an e-mail from ebay, says the seller has already shipped the video converter. Guy sends it via regular mail, not a parcel. I paid 30 cents extra to get a red stamp / priority mail... so could be here on Monday ! 8) The datasheet for the CRT controller doesn't give a fixed crystal / clock frequency. It just says the clock can be " up to " 2.5MHz. So since we have a 8MHz crystal on the board, I guess the CRTC probably runs on 2MHz... of course I could measure that. 8) |
| Vince:
Just received my video board ordered here : https://www.ebay.fr/itm/304639100056 ... or did I ?! In the enveloppe NO board, just the big loose connector wired to the board, but not the board itself !! :o 30 Euros for a freaking connector and some wires ?! OK I will return this thing immediately to get my money back.. :palm: |
| alm:
My French isn't very good, but seems to me like it is as described: --- Quote ---Adaptateur Jamma CGA2VGA (Attention CGA2VGA non inclus) --- End quote --- |
| pcprogrammer:
Yes that is how I see it too. But almost 30 euros for just that cable bit is ridicules :palm: Hope you can indeed return it and tell the bloke to make it more clear that it does not include the board within the first picture on his listing. I guess Aliexpress looks real good now in comparison :-DD Edit: The same seller has the needed board for just 3 euros more: https://www.ebay.fr/itm/303522687731 So maybe you can make a deal to exchange things. |
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