Hi Guys -
I am a rather long time lurker hoping to get a few tips on a repair I am attempting. My friend handed me an MTI Auto-Orchestra, which is a late 70's drum-machine/synth described here:
http://jpsongs.com/troubadortech/pkbd.htm#MTI
This one seems to have a power-supply problem wherin it turns off after a short interval (20 seconds at first, about 1/4 second now) I have some basic build/repair skills having buit a number of DIY pedals, fixed and modified some instrument amps, PA power amps and mixers.
Right off - I do not have nor can seem to find a schematic anywhere on line - anyone out there have one (Go Fish!)
I have ruled out:
Fuse - not intermittent, checked against known good, same value. Does not blow.
Power switch fault - no fault
power receptacle - fine, continuity tested - tested by bypassing it.
The power supply is weird to me - It uses a filament transformer and there seem to be not filter caps (or big electolytics at all) The lines coming off the tranny run into a massive cable harness and to the degree I have been able to trace, appear to run directly to various circuits, whith no obvious power supply board. The whole thing really looks old style computer to me.
Can anyone give me some further trouble-shooting tips? At least point me towards info on what type of power supply this is so I can read up elsewhere on line. I'd love to get this guy running and by golly, I have had a pretty good track record as a tinkerer - hate to come up empty here, at least without a really good try.
Thanks in Advance,
Ape
I am a rather long time lurker hoping to get a few tips on a repair I am attempting. My friend handed me an MTI Auto-Orchestra, which is a late 70's drum-machine/synth described here:
http://jpsongs.com/troubadortech/pkbd.htm#MTI
This one seems to have a power-supply problem wherin it turns off after a short interval (20 seconds at first, about 1/4 second now) I have some basic build/repair skills having buit a number of DIY pedals, fixed and modified some instrument amps, PA power amps and mixers.
Right off - I do not have nor can seem to find a schematic anywhere on line - anyone out there have one (Go Fish!)
I have ruled out:
Fuse - not intermittent, checked against known good, same value. Does not blow.
Power switch fault - no fault
power receptacle - fine, continuity tested - tested by bypassing it.
The power supply is weird to me - It uses a filament transformer and there seem to be not filter caps (or big electolytics at all) The lines coming off the tranny run into a massive cable harness and to the degree I have been able to trace, appear to run directly to various circuits, whith no obvious power supply board. The whole thing really looks old style computer to me.
Can anyone give me some further trouble-shooting tips? At least point me towards info on what type of power supply this is so I can read up elsewhere on line. I'd love to get this guy running and by golly, I have had a pretty good track record as a tinkerer - hate to come up empty here, at least without a really good try.
Thanks in Advance,
Ape
