- 1920s radio - 3 Updates
- Help identifying a blown transistor - 2 Updates
- McMaster-Carr ROCKS! - 1 Update
| tabbypurr@gmail.com: Aug 29 02:08AM -0700 On Wednesday, 28 August 2019 16:55:29 UTC+1, Phil Hobbs wrote: > Probably intended for a 67 V B battery. > Cheers > Phil Hobbs Thanks. I may need to make a variable PSU, don't have one that goes high. Or I could just go up in steps with what I've got - that sounds quicker. NT |
| Geo <nhhu-o3hu@dea.spamcon.org>: Aug 29 11:41AM +0100 >Thanks. I may need to make a variable PSU, don't have one that goes high. Or I could just go up in steps with what I've got - that sounds quicker. Just put a few poundland PP3s in series. |
| "pfjw@aol.com" <peterwieck33@gmail.com>: Aug 29 05:16AM -0700 On Wednesday, August 28, 2019 at 11:55:29 AM UTC-4, Phil Hobbs wrote: > Probably intended for a 67 V B battery. > Cheers > Phil Hobbs 'Ideal' B+ voltage is determined by the specific tube installed. Peter Wieck Melrose Park, PA |
| Jon Elson <elson@pico-systems.com>: Aug 28 01:51PM -0500 On Mon, 26 Aug 2019 03:11:40 -0700, janniebrand wrote: A lot of these power supplies use some form of a TL431 shunt regulator, that drives the LED of an optocoupler to control the switch-mode FET driver. Jon |
| tabbypurr@gmail.com: Aug 29 02:11AM -0700 On Wednesday, 28 August 2019 11:22:26 UTC+1, Jannie wrote: > @whit3rd: Thank you for confirming the TL431 part. Not sure if you meant to paste a link for the optoisolator part, but it is the same link as the one for the TL431 part. @Phil did however mentioned that any "xx817xx" opto-coupler part should work. > > If the diodes are short-circuited, they'll look bad in-circuit; if a multimeter that does diode check is available, use that. > I have tested the diodes in circuit with a multimeter and some of them (D1, D2, D3, D4 & D6) looks bad (shorted), but as mentioned, they could be fine. I can also confirm that the few diodes where I could actually see the number, are in fact 1N4007 diodes. I reckon I just go buy a pack of 10 x 1N4007 diodes with the other parts (once confirmed) and then tackle the diodes tested as shorted in circuit 1 by 1, removing, testing and replacing if needed. You asked for a suggestion, I have one. SMPSUs are not the simplest things for beginners, and this one sounds well knackered. I suggest picking up another piece of e-waste & fixing that. You're not gonna fix them all. NT |
| "Ron D." <ron.dozier@gmail.com>: Aug 28 01:30PM -0700 Totally agree with you on Mcmaster. EssentraComponents now ReidSupply isn't bad either. Digikey has always been good. Mcmaster stuff always arrives very quickly, MSCdirect has raised their prices, but usually I get next day service. Sometimes I pick up locally, if I don't want to pay for postage. |
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