tusntuk2
Active Member
Merry Christmas AK'ers! I could use a little help solving a blown fuse problem on a SX-727.
This unit was my first recap project, done 4 years ago. Following AK threads I bravely dug into a SX-727 to recap it, but little did I know how hard/easy it was! I figured even if it blew up it could be a cheap education in restoring an old unit. It was a great education! The results were great, it has sounded wonderful for years, but lately blew the internal 3A fuse.
Reviewing threads on this type of problem, I have done some extra work on the protection circuit and the power supply circuit. I did not know to do this the first time around. But while replacing transistors and diodes I came to the parts connected to the fuse post - and they are not detailed on the s/m. Can you help identify the diode looking part underneath the 330 cap? It's just black, I can't make out any lettering, and if it's burned I would need to replace it. And there's the rub. What is it?
This unit has the multiple voltage transformer, and a AWM-027-D protection circuit. I have not yet fired it up (I have a DBT) to test my work, I was hoping to identify this part first. I also feel the need to replace the trimmers, which are still original, and reset bias, etc., which is not yet done.
View media item 29306View media item 29308View media item 29307
Thanks for your assistance!
Jim
This unit was my first recap project, done 4 years ago. Following AK threads I bravely dug into a SX-727 to recap it, but little did I know how hard/easy it was! I figured even if it blew up it could be a cheap education in restoring an old unit. It was a great education! The results were great, it has sounded wonderful for years, but lately blew the internal 3A fuse.
Reviewing threads on this type of problem, I have done some extra work on the protection circuit and the power supply circuit. I did not know to do this the first time around. But while replacing transistors and diodes I came to the parts connected to the fuse post - and they are not detailed on the s/m. Can you help identify the diode looking part underneath the 330 cap? It's just black, I can't make out any lettering, and if it's burned I would need to replace it. And there's the rub. What is it?
This unit has the multiple voltage transformer, and a AWM-027-D protection circuit. I have not yet fired it up (I have a DBT) to test my work, I was hoping to identify this part first. I also feel the need to replace the trimmers, which are still original, and reset bias, etc., which is not yet done.
View media item 29306View media item 29308View media item 29307
Thanks for your assistance!
Jim
