callanbrown
Well-known member
Hi all,
Just wanted to put this here in case anyone else gets to the same point.
I got an MS9-29 from a member here, sold as testing and working. Board arrived in absolutely beautiful condition but appeared dead.
Checking the B+, it would rise to about 109V and then steadily discharge. If I turned off the power, it would discharge pretty low, I would hear a lil click and it would jump up to about 70V, and discharge to 0. Guessing this was the protection circuit disengaging.
Checked the HOT and other transistors, everything appeared to be ok. People seem to generally blame the HOT with this sort of issue.
Decided it must be a mechanical problem, checked the underside thoroughly and touched up a few suspect soldering points. Eventually noticed the secondary of the transformer right near the HOT had really bad solder, bad enough that it was probably isolated. Removed and reapplied the solder, monitor came up perfectly.
Also of note, working fine on an MS8 tube (Toshiba A68KJE...). I had read issues related to the yoke but I don't see any trouble with the geometry at all, and I really love having all the adjustments of the MS9 (parallelogram, trapezoid, barrel etc).
Just wanted to put this here in case anyone else gets to the same point.
I got an MS9-29 from a member here, sold as testing and working. Board arrived in absolutely beautiful condition but appeared dead.
Checking the B+, it would rise to about 109V and then steadily discharge. If I turned off the power, it would discharge pretty low, I would hear a lil click and it would jump up to about 70V, and discharge to 0. Guessing this was the protection circuit disengaging.
Checked the HOT and other transistors, everything appeared to be ok. People seem to generally blame the HOT with this sort of issue.
Decided it must be a mechanical problem, checked the underside thoroughly and touched up a few suspect soldering points. Eventually noticed the secondary of the transformer right near the HOT had really bad solder, bad enough that it was probably isolated. Removed and reapplied the solder, monitor came up perfectly.
Also of note, working fine on an MS8 tube (Toshiba A68KJE...). I had read issues related to the yoke but I don't see any trouble with the geometry at all, and I really love having all the adjustments of the MS9 (parallelogram, trapezoid, barrel etc).