- Anyone used one of these? - 5 Updates
- Audio Power Amplifier Solid State Relay - 9 Updates
| Cursitor Doom <curd@notformail.com>: Jan 26 02:00PM Given the shortcomings of low power battery testers/meters for checking certain components that typically run at considerably higher working voltages where any fault may only become apparent, has anyone any thoughts on the utility, or otherwise, of these devices? http://www.ebay.co.uk/itm/Transistor-Diode-Curve-Tracer-Component-Tracker- Tester-Probes-BNC-Cables-/161294643173? hash=item258de8efe5:m:miccP4BhvzYiDpcErFn7FDw |
| ggherold@gmail.com: Jan 26 06:19AM -0800 On Tuesday, January 26, 2016 at 9:03:11 AM UTC-5, Cursitor Doom wrote: > http://www.ebay.co.uk/itm/Transistor-Diode-Curve-Tracer-Component-Tracker- > Tester-Probes-BNC-Cables-/161294643173? > hash=item258de8efe5:m:miccP4BhvzYiDpcErFn7FDw Never used one.. but it says octopus. I recall this curve tracer that a navy tech showed me once. A couple of transformers and R's.. Google octopus curve tracer and maybe you'll end up building on of your own. George H. |
| Cursitor Doom <curd@notformail.com>: Jan 26 02:32PM On Tue, 26 Jan 2016 06:19:13 -0800, ggherold wrote: >> voltages where any fault may only become apparent, has anyone any >> thoughts on the utility, or otherwise, of these devices? >> http://www.ebay.co.uk/itm/Transistor-Diode-Curve-Tracer-Component- Tracker- > Google octopus curve tracer and maybe you'll end up building on of your > own. > George H. Thanks. I wouldn't have thought there was much to these things, especially since they rely on an external scope display. I'm just curious as to how useful they are compared to more common test kit. |
| "Ralph Mowery" <rmowery28146@earthlink.net>: Jan 26 10:08AM -0500 "Cursitor Doom" <curd@notformail.com> wrote in message news:n87u5i$4lt$5@dont-email.me... > http://www.ebay.co.uk/itm/Transistor-Diode-Curve-Tracer-Component-Tracker- > Tester-Probes-BNC-Cables-/161294643173? > hash=item258de8efe5:m:miccP4BhvzYiDpcErFn7FDw All this ammouts to is a transformer, capacitor and resistor in a box. Just do a search for an Octopus component tester. Years ago it was of some use and may be today if you have a known good board and one you are testing. Today there are much beter component testers out. For about $ 20 you can get the circuit board of a component tester that is much beter for testing components out of the circuit. This ebay number is one of many of them. 291585134524 |
| legg <legg@nospam.magma.ca>: Jan 26 10:28AM -0500 On Tue, 26 Jan 2016 14:00:18 -0000 (UTC), Cursitor Doom >http://www.ebay.co.uk/itm/Transistor-Diode-Curve-Tracer-Component-Tracker- >Tester-Probes-BNC-Cables-/161294643173? >hash=item258de8efe5:m:miccP4BhvzYiDpcErFn7FDw Common commercial unit is the Huntron 'Tracker' with built-in display. Can be of some use on production test bench, but doesn't replace visual inspection and simple open/short or bias testing. RL |
| "Gareth Magennis" <sound.service@btconnect.com>: Jan 25 10:13PM Hi, this is really annoying, but a good opportunity to learn something useful. I have an old Urei Power Amp that needs its DPDT 10A speaker output relay replacing. It's annoying because the relay fitted has a totally non conventional pin configuration, so the usual generic cheap replacement is going to involve drilling holes in the PCB and isolating pads and using glue and stuff because some solder pads will have to go etc. So I thought about maybe using Solid State relays, which should be physically smaller and lighter, and could be mounted in little patches of available free space. I've never seen a solid state relay in a Power Amp. Maybe there's a good reason for that - AC transmission, Inductive loads, back emf etc. A quick look at Farnell shows you don't generally get DPDT ones, so you need 2 for a stereo amp, and they are not that cheap. Any experience welcome. Cheers, Gareth. |
| dansabrservices@yahoo.com: Jan 25 02:55PM -0800 I have some NOS relays around. Can you post the specs on the bad one? I will check to see if I have one. Dan |
| John Heath <heathjohn2@gmail.com>: Jan 25 03:30PM -0800 > I have some NOS relays around. Can you post the specs on the bad one? > I will check to see if I have one. > Dan Golden rule never put the original factory part in if possible. If the original factory part failed then why repeat the same mistake? Most of the time the factory part is over priced as that company can not stay in business on product alone so they resort to over priced non generic replacement parts that should not have failed in the first place. In fairness they should apologize for your need to replace the part and offer the part for free. The real world is not fair but do not add to it by giving them money they not deserve. I will now get off my soap box. I would put in the cheap generic sub with wires going the the PC board and tie wrap it to the nearest post hole or what ever. This amp is headed for the garbage bin within the next ten years so who cares is it is meat ball fix. This amp is to be used and enjoyed not line the pockets of some manufacturer who put a non generic parts in to make money in the service after market. |
| dplatt@coop.radagast.org (Dave Platt): Jan 25 04:30PM -0800 In article <k6xpy.305540$Mi6.74057@fx35.am4>, >good reason for that - AC transmission, Inductive loads, back emf etc. >A quick look at Farnell shows you don't generally get DPDT ones, so you need >2 for a stereo amp, and they are not that cheap. SSRs which can handle reasonable-to-high currents are typically triac designs, I believe (or possibly back-to-back SCRs in some cases). I don't think they're going to be able to handle speaker-level audio without introducing a great deal of noise and distortion, associated with the switching on and off of the triac at the zero-crossing points. Before you try doing this "for real", try an experiment with an external SSR first (between an amp's speaker outputs and a speaker). Probably best to use throw-away components all around. I doubt you'll like how it sounds. Also, remember that a typical SSR won't switch off (open) anywhere but at the zero crossing. If your amp's relay-drive circuit is part of a speaker-protection circuit (to turn off the relay if DC is detected at the output), using an SSR would defeat this protection. If an output transistor shorts to the + or - rail, you'd end up dumping DC into your woofer with no cutoff and probably destroy the woofer. I'd strongly suggest using a real relay. If necessary, build a small interposer board to convert the original relay's pinouts to those of a high-quality commodity relay. |
| Kaz Kylheku <609-576-4089@kylheku.com>: Jan 26 12:48AM > configuration, so the usual generic cheap replacement is going to involve > drilling holes in the PCB and isolating pads and using glue and stuff > because some solder pads will have to go etc. You could make a small PCB for the relay, and mount that somewhere. (E.g. standoffs rising from main PCB.) Then connect that to the original pads with hookup wires. > available free space. > I've never seen a solid state relay in a Power Amp. Maybe there's a good > reason for that - AC transmission, Inductive loads, back emf etc. Possibly also: distortion. |
| Kaz Kylheku <609-576-4089@kylheku.com>: Jan 26 12:49AM >> Dan > Golden rule never put the original factory part in if possible. If the > original factory part failed then why repeat the same mistake? Golden rule of break-ups: this time it will be different, I promise! |
| Phil Allison <pallison49@gmail.com>: Jan 25 05:54PM -0800 Gareth Magennis wrote: > A quick look at Farnell shows you don't generally get DPDT ones, so you need > 2 for a stereo amp, and they are not that cheap. > Any experience welcome. ** Don't let the name fool you, SSRs are not replacements for regular relays. SSRs use triacs or SCRs and are intended for AC supply switching and the like - where voltages are high and fixed and a discontinuity around zero is not a big problem. Simply will not work with speakers. .... Phil |
| Phil Allison <pallison49@gmail.com>: Jan 25 06:10PM -0800 John Heath wrote: > Golden rule never put the original factory part in if possible. > If the original factory part failed then why repeat the same mistake? ** Very true, but you must be sure you have something better available. Not too hard with transistors where you can sub American or European brands like Motorola, Philips or ST. But ICs, mechanical parts and wound components are harder to substitute successfully. My parts bins are stocked with what I have found to be the best available in each category, so they will cover a huge range of jobs. It is only as the very last resort that I go to the maker or importer for a spare part. .... Phil |
| N_Cook <diverse@tcp.co.uk>: Jan 26 07:58AM On 25/01/2016 22:13, Gareth Magennis wrote: > Gareth. hard wiring a big relay or two, to wherever there is space in the amp? its not as though it is switching RF |
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