Re: Sumvision PXPRO800 ATX PSU - partly repaired
@redwire, @goodpsusearch, @PeteS in CA, @momaka
Thank you all for your comments and advice, I haven't had much time this week to look at the PSU but I'll get back to it shortly.
Regarding the discolouration near D31: you may well be correct, but there is a low value resistor directly behind D31 (I think it was 100-ohm - I don't have the details to hand) and that seemed to be the centre of the scorching although the resistor tested ok.
I'll double check the labelling on the diodes too, I...
jarsudsco
Member
Last Activity: 04-16-2014, 04:33 PM
Joined: 03-13-2014
Location: Tyne & Wear
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Re: Hitachi HDR505 - no antenna signal
Does anyone happen to have or know where I could find a proper datasheet for the chips I mentioned above - MXL5007T? They appear to be made by Maxlinear but everytime I think I've found a datasheet it turns out to be really just a sales brochure. I've found one image sort of showing the pinouts but it's such a poor image I can't actually read the writing.
Cheers,
- jarsudscoLeave a comment:
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Re: Sumvision PXPRO800 ATX PSU - partly repaired
@redwire - Thanks for the reply. You are quite correct - in fact both the power transistors (originally 3DD13009) had gone S/C B to C - they've both been replaced by MJE13009. I don't recall another resistor in the same location on Q02 but I don't have the PCB to hand - I'll check shortly. Thanks for the confirmation on R7 - it's currently 2K7 and that's were I've got to. +5SB line up, nothing else. I need to do some further checking/measuring.
Any other suggestions would be appreciated.
Regards,
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Re: Sumvision PXPRO800 ATX PSU - partly repaired
@goodpsusearch
That was an estimate, I was building a machine with dual graphics cards. The cards were each specced to require 2 x 75W PCI-e power connectors, but I actually made up some PCI-e extension leads with 0.01-ohm shunt resistors in the 12V lines so I could measure the actual current and they maxed out at around 4.5A per connector so, 9A per card = 18A in total, x 12V = 216W.
The CPU according to Intel was rated at I think it was 70W, and I assume this is predominantly drawn from...Leave a comment:
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Re: Sumvision PXPRO800 ATX PSU - partly repaired
@Agent24 - All the Schottky's looked OK when I inspected them and all seemed OK when I checked with a DMM diode tester - there are 2 different device types - D30 & D33 are STPS2045CTC and D31 & D32 are ZA13P59 - junctions were all between about 0.2 and 0.5 volts ISTR (I can't find my notes!)
+5SB seems stable at 5.11V.
PS_ON unconnected reads 4.94V.
All other outputs read 0V (with PS_ON grounded).
Thank you for the link - method 1 was a good idea but unfortunately R7 was a sub-miniature...Leave a comment:
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Re: Hitachi HDR505 - no antenna signal
The two smaller chips nearest the jacks are both marked MXL5007T the two larger chips beneath are both marked D61541GB.Leave a comment:
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Sumvision PXPRO800 ATX PSU - partly repaired
I have a quite new Sumvision PXPRO800 ATX PSU. I apparently over-loaded it, even though my calculations said it should be fine, which resulted a bang, a flash and some smoke.
It took a little while to find anything obviously burned-out but hidden under the hot-side heat-sink was a burned out resistor (R7). The middle band was almost completely gone but my best guess was it was 2K7 so I replaced it and it (optimistically tried powering up) - it promptly burned-out again.
Some further inspection revealed that R4 appeared to be cracked and although it was marked as 1-ohm... -
Re: Hitachi HDR505 - no antenna signal
@tom66 - Thanks for the quick reply. The external PSU is only 12V so I guess the 35V must be generated on the board but I can't even see any capacitors rated greater than 25V - would you happen to know where I could check?
Regards,
- jarsudscoLeave a comment:
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Hitachi HDR505 - no antenna signal
I have an Hitachi HDR505 Freeview+ Recorder. It uses a Vestel 16MB835N-4 T385 041109 PCB.
It powers up ok and can access the existing recordings on the HD, but it reports there is no antenna signal - so re-tuning results in no channels found, and there is no signal at the aerial output socket (JK2) with a known good aerial connected to the input (JK1).
I have tried re-touching the solder on those discrete components obviously in the signal path from JK1 to the tuner IC's (? MXL5007T) and back out to JK2 with no success.
Any suggestions on what to try... -
Re: Dell E173FPf partly resurrected
Just an update to say success! The replacement PWM controller chip arrived in today's post and after some very fiddly de-soldering and resoldering the monitor is up an running again.
@Rtech - You were spot on. Thank you again for the advice and the Schottky diodes.
Inspired by today's result, I'm now waiting eagerly for some other replacement components to arrive.
- jarsudscoLeave a comment:
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Re: Dell E173FPf partly resurrected
@Rtech
Wow, that's very kind of you to offer.
A sand-dancer eh...
I'm from just down the road in Jarrow.
I'll pm you - that'll save me scouring data sheets this afternoon
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Re: Dell E173FPf partly resurrected
@Rtech - thank you for your reply.
The mosfet testing guide you referred to had basically the same info in it I'd found previously but it was good to have it reinforced so thanks for the link.
Q850 passed the test from the link you suggested so it went back on the board. I replaced C857 although the original did register a value of close enough to it's stated value of 10uF not to worry about it, so I suspect it was ok.
I double checked for bad/dry joints and even retouched the solder on U850 just in...Leave a comment:
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Dell E173FPf partly resurrected
I'm a newbie here and a trying to get back into repairing things rather than binning them. So please bear with my first attempt at posting...
This is a board from a Dell E173FPf 17" monitor. I've not been able to find a service manual or schematic online.
It's original fault was simply completely dead. There were no obvious burned-out components or bulging caps so I decided to try the heavier silicon stuff! I removed Q850 marked '27611' a MOSFET I believe ('A' in my component side image) and D854 marked 'SRF10-10' - a Schottky Barrier Rectifier (B).
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Re: New Members - please post your introductions here
Hello, I've used my Jedi name to login here - Jarsudsco, but my real name is Keith.
I was tinkering with electrical things from the age of 4 or 5 and progressed to digital electronics as a teenager, I seemed to skip over transistors altogether...
I originally studied microelectronics at university but I found all the theory really boring - having got used to blowing up electrolytic capacitors for fun - so I dropped out, and went back a few years later to do computer science instead.
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