EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: Daxxin on November 19, 2017, 09:48:52 am
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cannot hear the relay switch , looking around this circuit i found CR17 (1N4150) open , since the panel is totally off , can be this the cause of trouble?
just finish to replace it with 1N4148 ..
(http://oi65.tinypic.com/r86ozo.jpg)
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Isn't it there to stop "back emf' from the relay when it de-energizes, if you measured it in circuit and it's open , isn't the relay coil also open?
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To start with, the reverse voltage spec of 50 V for the 1N4150/1N4148
seems to me a bit low for this application. I'd use a jelly bean 1N1007
with a reverse voltage spec of 1000 V here. But that will not solve the
problem you have.
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Relay is working , desoldered and tested all contacts with external psu , just replaced with 1N4007 , outside from the circuit cr17 was open
anyway the problem remain , measuring TP about 5V+ rail too weird dont have voltage at the input of regulator , the link is realized with wires and connectors and tested
it was OK , the relay i tested before it was working und UNREGULATED +5V is present , what you think if i connect with crocodiles jumper?
(http://oi67.tinypic.com/2myw39k.jpg)
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With the jumper its working even no output but now dispay is ok ..meaning the relay is gone died |O , what trouble if i short the traces under the pcb relay contact? ..really not worth 60 euro relay
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This step attenuator was reworked by someone i dont know what they did but this pin marked wirh arrow remained unconnected
do you have schematic or detailed pic to fix?
(http://oi64.tinypic.com/ji1j6u.jpg)