*** M E M O R U M ***

Voltages look ok ZD3 replaced but was ok anyway , voltage across the diodes were 12V I can't figure exactly how to measure -5V At some point I got screen with white vertical lines (I have seen that before) sometimes with blue background but never stable screen , I made the mod with 4164 chips that w...

Quick question
I took some voltage measurements and I have +12 +5 but -1.5 instead -5
same across ZD1 , is this a zener problem ?

Hi to all Ok I had a major progress (thought not end yet ,due to my fault), I'll try to show my progress with couple photos ,perhaps will help some fellows to resurrect their mtx's First of all a big Thank you to Mr. Andy Key he send me one of his memorycards and testcard rom , which was a definitiv...

That xls was great I finaly can say I figured out what I must do
only a final question what to do with the already cuted tracks , and wiring ?
leave them as is or restore them ?

as I see the photo are all 3 eproms Pin 2 joined together ?
little hard to make it out from photo

pin 27 , 2 and ground (pin 14?) cut from top side tracks on all 3 eproms ?

thanks to mention the 27 to 28 join , I would never noticed this otherwise

Which is odd as the "lower" one of those (which I think is the B rom ??) is following the same path as the cut track. Yes I noticed this , If I see right in your motherboard the same track is uncut but also "yellow wired" over (although the track look to have covered with solder...

a small observation
I just removed the "spain" rom or 1B most propely
and the cut on the track was already there
I inspect the other points that Mark mentions and all were already cut
is this correct ?
and one more question if I replace with eproms I must replace all 3 correct ?

I have a friend with an Willem programmer he can help me with the eproms from what I saw from the photos it is more easy to cut the track and solder the wires than all 16 Ic sockets I soldered so far so I give it a try ,from what I saw only 1 track cut on ROM 1B and rest wired from under side right ...

many thanks for all the info you provided all of you , although little hard to follow as I'm not familiar with Eproms but I'll study several times your info and hope at least to learn something for now I can confirm that the "Spain" chip select does not touch the underneath rom pin I have ...

this one is a -05 too