- Mystery temperature sensor - 1 Update
- SMPS wall wart failure. - 9 Updates
- Installing FTDI drivers? - 1 Update
| Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat>: Jun 07 11:52AM -0400 On Thu, 4 Jun 2015 09:37:21 +0000 (UTC), the renowned Andre Majorel >instant 30% jump in the resistance. Hours of fun. >Whatever this is, it's probably defective. >Thanks. You can't expect a device that switches mains voltage to be very consistent when measuring those eroded contacts with a multimeter. If the element is stuck on it's possibly been busy preventing a fire. From s.e.c.: --- It's an entire thermostat, made by Ka Wo in Dongguan China. Differential is quite wide (10-35°C). maybe the 70 is the set temperature. It will switch a few amperes at mains potential directly. This looks more like an overtemperature cutoff device than a control device to me, but then I have no idea how a yoghurt maker works. --- I would be looking for a different kind of temperature sensor than this part. To determine if his is working, pass mains voltage through it to a suitable load such as a small light bulb (or measure it in-circuit at mains potential). Please do it safely. -- Best regards, Spehro Pefhany Amazon link for AoE 3rd Edition: http://tinyurl.com/ntrpwu8 Microchip link for 2015 Masters in Phoenix: http://tinyurl.com/l7g2k48 |
| "David Farber" <farberbear.unspam@aol.com>: Jun 06 08:41PM -0700 I have a Netgear cable modem. It is powered by a Jentec Technology AF1205-B power adapter. The adapter failed and I replaced it with another adapter but of course I was curious what the fault was. I opened up the case and found a bad (bulging) 1,000uF 10V filter cap. I did some other circuit tests to make sure there were no shorts because I was getting extremely low ESR readings (less than 0.1 ohms) around the bad cap, Eventually I found an SMD zener diode that was shorted. There are no identifying marks on the diode other than its color which is the standard looking orange. I am fairly sure it's a zener because the pc board has it marked as ZD-2. Its location in the circuit is in parallel with the 5 volt power supply diode that comes off of the secondary of the switching transformer. The power diode has two sets of numbers. The top row is marked 540 (perhaps an SB540?) on the bottom row is marked 849. That diode is ok. Only the zener is shorted. I was wondering if there was some ballpark zener voltage that I could use to replace the old one. It's always good to have a spare 5V supply. Thanks for your replies. -- David Farber Los Osos, CA |
| N_Cook <diverse@tcp.co.uk>: Jun 07 08:04AM +0100 On 07/06/2015 04:41, David Farber wrote: > there was some ballpark zener voltage that I could use to replace the old > one. It's always good to have a spare 5V supply. > Thanks for your replies. Could it be a VTS, ie designed to go short circuit in overvoltage situation? Perhaps the ovelay component character set does not allow for VTS . |
| "Gareth Magennis" <sound.service@btconnect.com>: Jun 07 09:53AM +0100 "N_Cook" wrote in message news:ml0qcb$rh8$1@dont-email.me... On 07/06/2015 04:41, David Farber wrote: > there was some ballpark zener voltage that I could use to replace the old > one. It's always good to have a spare 5V supply. > Thanks for your replies. Could it be a VTS, ie designed to go short circuit in overvoltage situation? Perhaps the ovelay component character set does not allow for VTS . I had to look that up. You mean TVS. Gareth. |
| N_Cook <diverse@tcp.co.uk>: Jun 07 10:09AM +0100 On 07/06/2015 09:53, Gareth Magennis wrote: > I had to look that up. > You mean TVS. > Gareth. Brain-fart, I end up typing VTS a lot in another subject area of marine flooding issues, standing for (Southampton) Vessel Traffic Services, and also Voltage Transient sounds more appropriate than Transient Voltage |
| Phil Allison <pallison49@gmail.com>: Jun 07 06:00AM -0700 David Farber wrote: > marked 849. That diode is ok. Only the zener is shorted. I was wondering if > there was some ballpark zener voltage that I could use to replace the old > one. ** Never seen a rectifier diode and zener in *parallel* before. Only purpose I can think of is the main diode is a Schottky type and needs protecting from excess reverse voltage spikes. Schottys range at about 30V up so maybe try a 27V zener. ... Phil |
| "Arfa Daily" <arfa.daily@ntlworld.com>: Jun 07 03:21PM +0100 "Phil Allison" <pallison49@gmail.com> wrote in message news:cb6f774e-22d4-4abb-bd6a-68a2192f46ce@googlegroups.com... > ... Phil I think it's maybe a 'lost in translation' thing Phil. Although he does suggest that the 'zener' -if indeed it is one - is in parallel with the rectifier diode, I think the intention was to convey that it is in parallel with the 5 volt rail, immediately *after* the rectifier. So I guess that would be in parallel with the main filter cap, depending on whether there is a choke before or after it ... ?? Arfa |
| Phil Allison <pallison49@gmail.com>: Jun 07 07:54AM -0700 Arfa Daily wrote: > with the 5 volt rail, immediately *after* the rectifier. So I guess that > would be in parallel with the main filter cap, depending on whether there is > a choke before or after it ... ?? ** That was my first idea - main electro goes belly up, feedback loop loses control and fries the safety zener. Standard failure mode of many SMPSs. But the OP's post is very specific. Maybe the zener shorting the main diode fried that electro rather quickly. .... Phil |
| M Philbrook <jamie_ka1lpa@charter.net>: Jun 07 11:05AM -0400 In article <ml0ed9$vou$1@dont-email.me>, farberbear.unspam@aol.com says... > there was some ballpark zener voltage that I could use to replace the old > one. It's always good to have a spare 5V supply. > Thanks for your replies. THat is a protection device.. could be a MOV but it sure is a protection device design to clamp if voltage exceeds, that is, if it is truely across the output.. The caps are bad and caused higher than desired voltage from the switching signal, thus shorted the protection device. Basically, it did its job. You may be able to get by using a 5 watt zener but you still need to replace the caps. btw, it seems a very common problem for the switching wallwarts to fail in this manner for routers, I replaced my 3 times, now I have a transformer 60hz type and works great... Jamie |
| "David Farber" <farberbear.unspam@aol.com>: Jun 07 08:47AM -0700 Arfa Daily wrote: > rectifier. So I guess that would be in parallel with the main filter > cap, depending on whether there is a choke before or after it ... ?? > Arfa Apologies folks. Looks like I misread the pc traces. The anode of the power diode is only in common with the secondary of the transformer. The cathode connects to one end of the zener diode, the filter cap (which I replaced), then goes to a choke, then to the output wires. Checking further, I've discovered that the shorted zener diode was in parallel with the filter cap. That explains the low, in circuit ESR reading. The negative side of the filter cap and zener are also connected back to the secondary of the transformer. I imagine the zener is used to protect the cap and output circuit from voltage spikes? Thanks for your replies. -- David Farber Los Osos, CA |
| rev.11d.meow@gmail.com: Jun 06 12:13PM -0700 On Thursday, March 26, 2015 at 8:51:09 AM UTC-7, DaveC wrote: > If not, where to get drivers for OS X? > Thanks, > Dave I did a little digging and found this with regard to using FTDI drivers on fake chips. "The licence only allows use of the Software with, and the Software will only work with Genuine FTDI Components (as defined in the Licence Terms). Use of the Software as a driver for a component that is not a Genuine FTDI Component MAY IRRETRIEVABLY DAMAGE THAT COMPONENT." oh well live and learn |
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