Latest Find - Streets of Brazil - Page 1
Forum section: electronics / repair

author: vidarr
author_rank: Frequent Contributor
timestamp: December 01, 2018, 09:57:44 pm
content: My collection of electrical stuff is slowly growing. The latest find is a hair steamer. It has a nice potentiometer (working), a BT137 500 TRIAC, an electric coil steamer, and a timer.The timer is what I want to figure out to use. The connections to all these components were undone when I found it. It was all held together with masking tape. It looks like the tape wore out and it failed. I cannot figure out the wiring for the timer. It looks like it would be simple, but when I connected it, the breaker went off. The green and red wires have continuity when the timer is on. The black wire (hanging end) has no continuity with the green and red at all. So the supply power goes into the red or green. Then I don't know anymore. I tried what I thought it was but it didn't work. I think I messed up the TRIAC connection. Can someone help me please?Thanks.

author: vidarr
author_rank: Frequent Contributor
timestamp: December 01, 2018, 10:49:48 pm
content: Tried some other connection attempts and I think it might really be broken. The two black wires do not have continuity. Maybe I will take the timer apart.

author: PKTKS
author_rank: Super Contributor
timestamp: December 02, 2018, 10:59:17 am
content: Dont guess. you may fry your AC or trip the fuses...TRIACS for heaters (including blowers and IRONs) in generalare QUADRACs (they have a companion DIAC)The basics to test the SCR itself (no matter 136/137/138) isto test the GATE as a SIMPLE DIODE (0.7v drop one direction)Then you MUST put that on the proper trigger tester (figure)Any "timer" thing my guess is purely "external" to the mains lineas a simple switch (ON/OFF)not much to add to the TEST CIRCUIT which BTW is defacto schematicsalmost 90% of dimmers or heaters... or..The DIAC part is tricky to test - oscilloscope will helpBTW the typical add-in DIAC is the ST DB3 or DB4 for almost anyTRIAC operating on the typical AC mains.some EXOTIC bundles may contain the DIAC builtin as wellthese are mostly advertised as QUADRACsPaul

author: vidarr
author_rank: Frequent Contributor
timestamp: December 02, 2018, 03:30:24 pm
content: Thank you that is very helpful. The schematic you provided is almost identical to the built circuit I found. I am trying to test that part of the circuit now. I don't have an oscilloscope so...I wired together the latest attempt to test the timer switch component. Hopefully this works.

author: vidarr
author_rank: Frequent Contributor
timestamp: December 02, 2018, 05:01:52 pm
content: That would be the DIAC soldered to the gate right? I tested it with a DMM and get "1" both directions. According to something I read, this means it is working.There is a test for the TRIAC I read about, but it requires a variable voltage supply up to 50v. I do not have anything over 12v. Could that work?Thanks

author: vidarr
author_rank: Frequent Contributor
timestamp: December 02, 2018, 07:33:40 pm
content: The timer switch circuit works as shown, so if there is a problem it must be in the TRIAC circuit. The circuit was not connected as I said, and I cannot find a matching circuit anywhere to copy. So, now, I am trying to connect the TRIAC circuit to the timer switch and light. I need an application to draw circuits quickly. I know it is a pain to try and help without a schematic.

author: janekm
author_rank: Unknown
timestamp: December 02, 2018, 10:07:45 pm
content: Try EasyEDA, perhaps?

author: PKTKS
author_rank: Super Contributor
timestamp: December 03, 2018, 12:06:53 pm
content: Well it is hard to say from here..But that BLUE FOLK IS TYPICAL the ST-DB3 DIAC indeedThe schematics is plain that and rarely need changesmay be an inductor or a different CAP but very same basic.THE TEST LOAD (good to mention) SHOULD BE A INCANDESCENT BULBeven if all fails the BULB still works just fineBTW testing w/12V will not do the trick - the semiconductor may failat higher voltages short circuitingTHEY ARE ALL CHEAP.!!! VERY CHEAP - in doubt change both anddrive a TEST LAMP.Should be the start point of the proper circuitPaul

author: vidarr
author_rank: Frequent Contributor
timestamp: December 03, 2018, 02:21:35 pm
content: Quote from: janekm on December 02, 2018, 10:07:45 pmI tried this once a while back and stopped using it something I didn't like. I will give it another try.Got this Eagle app from Autodesk.

author: vidarr
author_rank: Frequent Contributor
timestamp: December 03, 2018, 02:26:22 pm
content: Quote from: PKTKS on December 03, 2018, 12:06:53 pmOK, I will use an incandescent bulb and hook this circuit up. Nothing of the hair steamer was burnt, or any marks of failure, so probably was not this kind of failure. I think the masking tape wore out and came disconnected and they tried to hook it back up but couldn't figure it out. So, they threw in the street -- not even in the trash. Thanks Paulinho. Rs.

author: PKTKS
author_rank: Super Contributor
timestamp: December 04, 2018, 10:01:55 am
content: OK welcomeBut actually that "alias" no longer fits since late 70s ...You see I am over 50About 1.80 trying to keep more or less 80KgHardly will match the aliasPaul

author: vidarr
author_rank: Frequent Contributor
timestamp: December 04, 2018, 11:55:27 pm
content: Quote from: PKTKS on December 04, 2018, 10:01:55 amNo, that makes it even better!I got the whole thing to work. Was just masking tape problem apparently. Since I don't need a hair steamer, I took back apart and plug the sandwich maker into it so I don't burn my food anymore. The TRIAC/DIAC and potentiometer I am going to use to make a dimmer circuit for incandescent lights/lamp. My wife wants to use the dome to cover the bananas to keep the bats from flying into our condo and eating them. Hair steamer was a good find. Ahhh Brazil.... What next....