Have you got a scope? So to see the output and we get to know? Anyway, I would hook up one by one first to see if it is an interaction between the two, or which one board is the culprit dragging the other. I would check the boards if I could not find a dead semi, any. Is there rosin flux residue at the pads that may had cooked in the hot tube pre and suddenly got mildly conductive? Cold joint that played up with use? There must be something part defect or build defect wise going on for it to suddenly go ballistic hopping up and down. Check grounds, rework and clean up PCBs. But be sure about the semis first.
I have both regulators checked separately last night and both behaved the same. Since I had one channel 350/840 been changed. I query could there been the fault of the 12v zeners ??
Every semi could fail including Zeners. Although I am not familiar with that board's possible weak spots, I always made it P2P, its 3 things that can fail in previously working boards. The semis, the passives, the joints. Else something else changed in the served circuits (but you said no new mods) then it should be traceable eventually. Being both regs ill, its suspicious it was a transient and they got the same hit.
Salas,
The only way I could do is blind touch now for the voltage swing quite seriously. It goes the way up to the supplied voltage even I have the voltage tuned to the desired 150v. Since I made changed 350/840 on one channel, I'll keep changing all others parts, procedure wise, to see if I could source the problem.
Albert
Check these parts out on Mouser.
Mouser #: 567-647-10ABP
Mfr. #: 647-10ABP
Manufacturer: Wakefield
Desc.: Heat Sinks TO-220 W/PINS BLK 1"
567-274-1AB
Mfr. #: 274-1AB
Manufacturer: Wakefield
Desc.: Heat Sinks TO-220 LOW PROFILE
RoHS: RoHS Compliant
Mouser #: 571-7969494
Mfr. #: 796949-4
Manufacturer: TE Connectivity
Desc.: Fixed Terminal Blocks 5.08MM VERTICAL 4P wire protector
Mouser #: 571-7969492
Mfr. #: 796949-2
Manufacturer: TE Connectivity
Desc.: Fixed Terminal Blocks 5.08MM VERTICAL 2P wire protector
SSHV
Sorry for my typo in fact is irfp9240...
In this schematics take out D4 and D5, other changes are needed?
http://www.diyaudio.com/forums/powe...stic-mosfet-hv-shunt-regs-97.html#post2084348
Thanks.
Alberto.
Sorry for my typo in fact is irfp9240...
In this schematics take out D4 and D5, other changes are needed?
http://www.diyaudio.com/forums/powe...stic-mosfet-hv-shunt-regs-97.html#post2084348
Thanks.
Alberto.
Attached my finisfed SSHV2, heatsink IRF840 1C/W isolated from chassis with bitumen car dampers self-adhesive, heatsink DN2450 4,5C/W, for caps I used the ones I have on my stash: 10uF 400V Solen & 0,33uF 425V Infinicap Wonder Signature TRT, resistors & semis are from Mike (aka Tea-Bag) minikits
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