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And we're done: 20210207_195128.jpg I have performed the tests that you prescribed on earlier pages, Mark. 16.0V DC on the nose, from the yellow wire. Combined AC from both 7.5V lines is 17.1V. The AC reading from the 16V DC is 34.4mV. Without load, the 7.5V AC reading is around 8.4V. I tested with ...

Hi Mark, That is very helpful, yes, thank you. Normally, in the case where I hit a knowledge gap that I can't seem to fill by some research, I try to make an educated guess and carry on (or obtain the right component!) but this being a PSU, I'm being way more cautious. I don't want to create a dange...

Ok, so I have a question :?: It seems I have foolishly bought the wrong type of LED; instead of a Kingsbright L-53gd I bought a Kingsbright L-7113id-5v, which is a 5v LED with a built-in resistor. I can't work out how on the one you specified, there's need for a 1.2K resistor and that's because I ca...

Actually Mark, I retested this morning the diode reverse polarity protection and the reading was 0.03 to 0.04V. I used the LM2577 dialled to 9.8V and repeated, the reading was the same. Must have been my eyes late last night :roll: Using the higher voltage meant that my load test was much better, th...

Hi Mark, Thank you for your replies and your time, much appreciated. So, I have done as much testing of the AC/DC transformer as I can, but I only have a 5v DC power supply (I've looked for a higher rated one to cannibalise, but came up short) and lockdown here in Denmark is making life safer, but m...

And we are off to the races! Here's my (slow) progress, so far. I have started making holes in the case. I tried a different approach than scoring or scratching the shapes into the plastic. I used a sheet of A4 sticky label, cut down as required and Isketched out the holes with pencil. I did this be...

Sorry to dig a thread up from the dead Claus, but wasn't the abundance of Comal 80 due to it being homegrown, i.e. locally designed/invented in Denmark?
https://en.wikipedia.org/wiki/COMAL

Hi Schmit,

Welcome to the forum. I am new here and a recent MTX owner (maybe you could say a long-time devotee? ).

Good luck getting your tapes dumped.

Steve

Actually, Mark, regarding the transformer, I managed to source that was 40VA which is obviously less than the 50VA you specified, but it was all i could find and I saw that earlier in this thread, you said the requirement was for 40VA, but 50VA was all you could source. Is that okay or is it a bit t...

Turns out the retaining nut was just loose.

Gave her a good clean. The keyboard sub-strata was utterly rank. More work required to clean up the keyboard base and motherboard.