Cornboats
Dave
Last Activity: 08-26-2024, 08:42 AM
Joined: 10-23-2010
Location: Worcestershire
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The leds are in banks of 5 wired in series with a15 ohm resistor. Theres 18 banks all supplied in parallel. -
Bench inspection lamp- replacing with LED
Decided to change broken flourescent ring with an led alternative bought off Ebay. It came without any details of required supply. The supplier
does not have this information, just that its been stored in warehouse for 10 years. I want as bright a light as possible but am concerned that at too high a voltage will burn out the led's.
There are 90 led's each with a small yellow spot in the centre of the inside of each led lens. Could these be mains tolerant led's. I've put 9-14v DC on the circuit and lamps glow but not to their full luminance. How much voltage can I apply without fear...Last edited by Cornboats; 08-25-2024, 02:54 AM. -
Chuffed to bits. Works like a dream with only a new 1N4007.
Cheers....Leave a comment:
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OK. Thanks for all your inputs. I'm going solder in a thro hole new 1N4007 as I have 9 in stock. Will return with result.Leave a comment:
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Thanks for your help. In the cold light of the morning the identification markings read differenty , A1 X9D - still doesn't give any google results.
The diode in in the negative cicuit . Does that make any difference?
Voltage rating for cap c27 IS 50V so 1N4007 with a voltage max of 1000v is well capable....Leave a comment:
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Power board for a roller shutter door motor
Could somebody suggest an alternative diode (I think its a diode). It says A3 N93 but doesn't google anything similar. It has burnt board and is open circuit. It goes in between 1000mf 50 capacitor and a relay RLY1 connecting to bridge rectifier....
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Thanks for your advice. I've tried my bench magnifier but I'll try a fluorescent light for a brighter view. If all the tracks check out with a multimeter I guess I'll have to go for the last option of scrapping what could be a perfectly good tda 2822 chip and soldering in a replacement. I haven't got one so will have to order one....Leave a comment:
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I've checked all components and haven't found any faulty ones. I've pull the capacitors and their within 10% of stated values. Ic checks. Pin 1 is 7v Pin 2 is 16v pin 3 is 7v. Would you expect to see voltages on pin 1 and 3 which are the speaker outputs?
How do you manage to check the traces against the drawing? Turning the board over everytime to check the component impossible.Leave a comment:
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Thanks for the diagram. Did you just work out the schematic by looking at my photos? You are really clever if you did. I'll work thro and let you know how I get on.Leave a comment:
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How do you delete photo's once published. 2 I've just uploaded are better....
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faulty loudspeaker amplifier-no sound output
I've several amplifiers of different sizes which are faulty. I haven't fixed them because I haven't a clue. This is the smallest culprit. 240v in (UK) and 12v dc to the board. Small neon lights when power button is on. Different dc voltages across all of the capacitors. Where do I go from here? -
Re: Garage door opener-safety cutout faulty
Les from electro-tech has pointed out pin 5 on the socket is broken. I'll resolder everything and once I've sorted out how to replace the broken pin I'll retest. 2 out of the 3 connections on the phototransistor are shorting aswell. The data sheet for CNY 70 shows I should be getting a diode test result so I'll check the known working operator to see if the result is the same.
I've attached my interpretation of the schematic for the small torque adjustment board. Could you explain how this design works to interpret torque of the...Leave a comment:
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Re: Garage door opener-safety cutout faulty
No I didn't try the operator with the other main board, only the torque setting board.
The transisitor is ZVN 330 6A
To test your theory on the bench could I connect to an oscilloscope, (I have an old analogue) to see the pulse width setting?
I've sketched a schematic of the torque setting board which I'll upload today which may help.Leave a comment:
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Re: Garage door opener-safety cutout faulty
Thanks for taking the trouble to reply
There was a black cover concealing the parts. I wrongly assumed this was a 1 piece component and so desoldered to lift off the board.The black cover prised off using a sharp trimming knife, but only after I'd desoldered the components.
I've serviced the operator for many years paying attention oiling to metal on metal parts. Alignment is ok and upper and lower limit settings are working. The limits aren't shown as close and open limits are installed on the chain track.
The door...Leave a comment:
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Garage door opener-safety cutout faulty
I have vintage Slavedor garage door opener that has stopped closing the door. If I disable the up/down current control to the motor it works fine. I've attached the larger control board which is for everything and the smaller current control board.
Normally the current control is set slightly above the maximum current normally used. If the door exceeds this it should stop and reverse when closing or just stop when opening. Can someone please explain how the current control board works so that I can try and repair or replace the defective parts.
I see my self as an interested novice... -
Re: Samsung 32 changes source on its own
Thanks for both of your suggestions. I'll look at both areas and report back asap.Leave a comment:
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Samsung 32 LE32B450C4WXXU changes source on its own
Samsung 32 LE32B450C4WXXU, manufactured 2009
This set changes source without being asked. Turn the set on and tv channel comes on for up to 20mins then set changes to ext1 for a couple of secs then PC for a couple of secs then back to tv for the same same. Then the cycle starts again. I turned on today and there were no channels saved so I had to rescan.
I'm guessing the faults on the main board so have included a photo.
Any thoughts or ideas would be welcome.... -
Re: EVO car radio -blank screen
Just an update. I found a transistor BD438 with a shorted leg. I've replaced but still have a dead set. There are 3 voltage regulators on the board 1 of which is adjacent to the transistor BD438 I've just replaced. I'll test these with the voltage on next. There is a smd transitor 3F P23 connected to the BD438 which is giving correct readings but then so was the BD438 until I pulled it. I'm reluctant to pull the smd transistor for fear that being so small I'll never get it back.Leave a comment:
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Re: EVO car radio -blank screen
Nothing happening. No sound, no light. If you take out the removable button the led flashes, which its supposed to.Leave a comment:
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EVO car radio -blank screen
I've had this in my Isuzu since I bought the truck in 2003. Stopped working and now on my bench for fault finding. Fuse at the back of the set is ok, testing using a 12v DC supply. 1st port of call was a disable button that you can remove which is supposed to deter theft. Looked at this first. When you insert it shorts 2 pins to make a circuit. Shorted pins out with white wire just to confirm.
2nd was the volume control which is pushed to activate a momentary switch to turn on /off. Test ok with ohmeter but ran white leads from pins just to check. Voltmeter shows 4.8v on to one of the pins...
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