Forum: Troubleshooting Power Supplies and Power Supply Design
10-17-2021, 07:25 AM
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Replies: 4
Views: 760
Re: DV-PF4E(UK) Power suppy repair
I do now seem to have output, the only voltage that seems low is the AL-30 all the others seem fine.
The buzzing is worse when the power supply is connected to the main board.
This text is from...
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Forum: Troubleshooting Power Supplies and Power Supply Design
10-16-2021, 10:03 AM
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Replies: 4
Views: 760
Re: DV-PF4E(UK) Power suppy repair
I found that the transistor Q1003 was shorted between base and emitter so I replaced that and changed Q1001 again, but I'm getting a loud buzzing I think from T0011 the power transformer and still...
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Forum: Troubleshooting Power Supplies and Power Supply Design
10-15-2021, 01:35 AM
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Replies: 4
Views: 760
Re: DV-PF4E(UK) Power suppy repair
I've replaced the mosfet Q1001 with the same part as was installed originally, but resistor R1043 keeps failing going open circuit.
Does anyone know what other component could be causing this?
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Forum: Troubleshooting Power Supplies and Power Supply Design
10-10-2021, 05:17 AM
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Replies: 4
Views: 760
DV-PF4E(UK) Power suppy repair
Hi
I'm trying to repair an internal power supply in a Hitachi DV-PF4E video/dvd combi player.
I've narrowed the fault down to Q1001 a N channel mosfet (2SK3566) which seems to be shorted, when...
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Forum: Troubleshooting Power Supplies and Power Supply Design
08-25-2020, 03:16 PM
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Replies: 5
Views: 1,083
Re: Powerline Network Adapter power Issue
I agree I should just throw this away, but my curiousity gets the better of me at times.
Just out of interest on page 4 of the datasheet for the LNK623 it shows a reference design schematic with the...
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Forum: General Electronics Technical Discussion
08-23-2020, 04:29 AM
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Replies: 32
Views: 1,936
Re: Back to Back Transformers
The transformers do get hot after a while with no load especially the input transformer. I think when I was testing before I got more of a voltage drop with them the other way around.
Disconnecting...
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Forum: General Electronics Technical Discussion
08-22-2020, 10:35 AM
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Replies: 32
Views: 1,936
Re: Back to Back Transformers
I've attached an image from my scope.
This was captured with no load.
Yellow trace is connected to the output transformer.
Blue trace is connected to the 12V side.
I don't seem to be...
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Forum: General Electronics Technical Discussion
08-22-2020, 07:50 AM
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Replies: 32
Views: 1,936
Re: Back to Back Transformers
I've just tested and indeed when connected to a load the frequency does drop to 50Hz
Just for testing purposes am I ok to connect my oscilloscope on the output transformer, do I connect the ground...
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Forum: General Electronics Technical Discussion
08-21-2020, 11:28 PM
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Replies: 32
Views: 1,936
Re: Back to Back Transformers
Yes the schematic is how I have it wired up.
I don't have an earth connection.
I will test later today with a load.
I have an image somewhere of how, what is now my output transformer was...
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Forum: General Electronics Technical Discussion
08-21-2020, 09:04 AM
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Replies: 32
Views: 1,936
Re: Back to Back Transformers
Do you mean that the output transformer's 240V side has dual windings in parallel, as I am only connected to one of them.
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Forum: General Electronics Technical Discussion
08-21-2020, 04:03 AM
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Replies: 32
Views: 1,936
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Forum: General Electronics Technical Discussion
08-21-2020, 12:03 AM
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Replies: 32
Views: 1,936
Re: Back to Back Transformers
Yes with direct connection and no diodes my multimeter is showing 100Hz
Yes I have a scope
I only get 50Hz on the 12V windings
Even if I disconnect the energy/power meter I still get 100Hz...
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Forum: General Electronics Technical Discussion
08-20-2020, 04:40 PM
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Replies: 32
Views: 1,936
Re: Back to Back Transformers
Thats how I've got them setup.
I've attached an image of how there wired. The transformer in the bottom of the image is the 240V in, with a fuse before it, then the two 12V's are connected together...
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Forum: General Electronics Technical Discussion
08-20-2020, 02:21 PM
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Replies: 32
Views: 1,936
Re: Back to Back Transformers
Both the transformers are from old 12V battery chargers both of which had rectifiers in them aswell.
If the transfomers had rectifacation would they still need a seperate rectifier.
I'm just...
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Forum: General Electronics Technical Discussion
08-20-2020, 11:30 AM
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Replies: 32
Views: 1,936
Back to Back Transformers
Im currently building an isolation transformer from 2 240v-12v transformers, wired with the 2 12V secondaries joined to give 240V out, which I am getting.
The Issue I have is that I'm getting...
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Forum: Troubleshooting Power Supplies and Power Supply Design
08-16-2020, 05:57 AM
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Replies: 5
Views: 1,083
Powerline Network Adapter power Issue
Hi
Im trying to repair a D-Link(DHP-300AV) powerline adapter which is not powering up.
I've only done some basic tests at the moment to confirm its getting mains in through the fuse which it is....
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Forum: Troubleshooting Power Supplies and Power Supply Design
02-16-2020, 02:09 AM
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Replies: 13
Views: 950
Re: Amazon Basics Laminator design
The unit doesn't heat in the off position it only starts heating when the rocker switch is placed in the low temp or high temp position as the heater is switched on the neutral side at the same time...
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Forum: Troubleshooting Power Supplies and Power Supply Design
02-15-2020, 02:55 PM
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Replies: 13
Views: 950
Re: Amazon Basics Laminator design
Yes the DPDT switch is centre off.
I still don't get how the heater could be preheating until I've switched to either side as the heater is switched on the neutral side. Sorry I may be just being...
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Forum: Troubleshooting Power Supplies and Power Supply Design
02-15-2020, 02:26 PM
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Replies: 13
Views: 950
Amazon Basics Laminator design
Hi
I've just purchased an Amazon Basics laminator, to use for PCB toner transfers but thats not the reason for my post.
I opened up the unit to see what was going on inside to find that it...
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Forum: General Electronics Technical Discussion
02-10-2020, 07:35 AM
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Replies: 10
Views: 1,640
Re: Rework station pcb design
Thanks for the idea, but I don’t see how you would be able to control the rate of rise of temperature with this setup
I’m still doing more reading than anything at the moment and just making a...
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Forum: General Electronics Technical Discussion
02-03-2020, 05:14 PM
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Replies: 10
Views: 1,640
Re: Rework station pcb design
Well I've been reading as much info on this as I can, but being honest alot of it goes over my head.
Anyway I was just going to order a few parts to have a mess around with but I'm unsure on the...
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Forum: General Electronics Technical Discussion
01-27-2020, 12:58 AM
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Replies: 10
Views: 1,640
Re: Rework station pcb design
Thanks for all the info.
According to the guys hackaday page he has tested it but I don't know to what extent.
https://hackaday.io/project/10541-diy-infrared-rework-station
I would like to...
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Forum: General Electronics Technical Discussion
01-24-2020, 12:45 AM
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Replies: 10
Views: 1,640
Re: Rework station pcb design
I've wanted to build one for ages's but never found the time, I mess around repairing game consoles and mobile phones so it would mainly be for that.
This is just a hobby for myself so an other...
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