Hello.
I've just bought an ADA MP-1 in a flea market.
For 10 Euro I decided to give it a try.
The unit is in real bad shape but I'm gonna restore it just for fun.
The transformer is no more present, diode D38 is burnt.
The 12AX7 tubes are missing.
The led segment display is totally gone, no one of the leds are working.
I pulled out all the diodes from psu and slowly gave 8V DC, with a bench power supply, at the cathodes of D38 and D39.
The voltage regulators are working ok, giving me steady 4,9V at their outputs.
The current draw is at 550mA with a pair of new tubes in their sockets.
I saw, from the original ADA drawing, that the original transformer can give a maximum of 650mA. Is this current consumption right, in your opinion or Experience?
The clock signal is present: 12MHz 2,5Vpp (sine) at the crystal
1MHz 6Vpp (square) at pin3 of U37
2KHz 5vPP (square) at pin12 of U36
The first thing I'm going to do is building a new display, since the original one is no longer available.
Does anybody know if the display is a common cathode or anode?
I'm more into vintage tube amp rstoration than digital units, so i will need a little help.