EEVblog Electronics Community Forum

EEVblog => EEVblog Specific => Topic started by: EEVblog on April 23, 2018, 08:48:39 am

Title: EEVblog #1077 - Dumpster PC Repair
Post by: EEVblog on April 23, 2018, 08:48:39 am
Power supply repair attempt on an i7-2600 Dell Optiplex 990 dumpster PC.
An update on previous dumpster PC's.
And the bunker to the rescue.

http://www.youtube.com/watch?v=Z9itl1M75_Q (http://www.youtube.com/watch?v=Z9itl1M75_Q)
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: Electro Detective on April 23, 2018, 10:41:58 am
Nice DD score and fix, do you reckon a twofer is possible and the repaired PSU 'may' work in that Core 2 donor box even though no go in the 990?

Did the foam perish and or get hot/melt and stick to those components in the bottom of PSU and create a conductive path perhaps?   :-//


Idiots or product saboteurs still putting foam and amber glue inside electronics in this millennium should be Tar and Feathered with it  :popcorn:

Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: Stefan Payne on April 23, 2018, 01:32:48 pm
Power supply repair attempt on an i7-2600 Dell Optiplex 990 dumpster PC.
An update on previous dumpster PC's.
And the bunker to the rescue.
A couple of things, since you probably don't read Youtube Comments that much:

1. The Formfactor is called TFX, so you could replace it with a "named brand" TFX PSU form like FSP.

2. The Foam is probably Anti Insect foam, that prevents Insects from creeping under the PCB, commiting Suicide and killing the PSU in the process.

3. The Processors aren't that great...
I7-3770 is Ivy Bridge, that one was replaced in 2012 or 2013 by Haswell. the i7-2k and 3k units use the same socket by the way, so you could change them however you want, if you want to.
Anyway, we are talking about something like 6-10 Year old Computers.
The sad thing is that you can use them even today and use it for gaming without any problems. The newest ones aren't that much better (well, at least the 4 core ones)...
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: Tek_TDS220 on April 23, 2018, 01:33:26 pm
Dave is at his best ~13:30 when he puts in the replacement power supply and it works.  I think he went through his whole repertoire of Aussie-isms.  He is educational in many ways.
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: alxpo on April 24, 2018, 04:04:48 am
But why 6.3 amp fuse? Not 6 and not 6.5. What horse ass is buried here?
PS: Really? Is it because it is 1 horsepower for 115V?
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: glarsson on April 24, 2018, 05:59:34 am
But why 6.3 amp fuse? Not 6 and not 6.5. What horse ass is buried here?
But wait, it is more.
Tube/valve filaments are commonly 6.3V.
Light bulbs are available for 6.3V.
Electrolytic capacitors with working voltage of 6.3V are also available.
Power supplies with max current of 6.3A are available.
Perhaps the flat earthers have an answer?
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: thm_w on April 24, 2018, 05:59:59 am
But why 6.3 amp fuse? Not 6 and not 6.5. What horse ass is buried here?
PS: Really? Is it because it is 1 horsepower for 115V?

Because standard fuse sizes of 5A is too low and 7.5A is too high, so lets go with something in the middle of those.  :-+
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: Brumby on April 24, 2018, 04:51:01 pm
6.25 is halfway between 5 and 7.5 - but two decimals for a fuse rating at that level is a bit much, so round it up to 6.3 - simples.
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: Electro Detective on April 24, 2018, 06:57:24 pm
The expensive fun starts when a 6.3 'T' fuse goes where a 6.3 'F' fuse should be

and vice versa    ;D

Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: GerryBags on April 24, 2018, 07:12:15 pm
The expensive fun starts when a 6.3 'T' fuse goes where a 6.3 'F' fuse should be

and vice versa    ;D

Is that slow and fast blow?
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: Brumby on April 24, 2018, 07:57:05 pm
(http://www.eevblog.com/forum/beginners/a-beginner_s-beginner/?action=dlattach;attach=360905;image)
Title: Re: EEVblog #1077 - Dumpster PC Repair
Post by: sibeen on April 25, 2018, 04:26:50 pm
For those wondering about the 6.3 amp value, it is one of the preferred values. Comes from the Renard series of which the most basic is the R5 series, which consists of 5 numbers between 1 and ten and which are: 1.00 1.60 2.50 4.00 6.30. Powers of the the 5th root of 10, rounded to two digits, for those with a nerdish mathematical bent :). Circuit breakers, at least in IEC world, follow the same series. Resistors, capacitors etc also have their preferred values but these don't use the Renard series but the E-Series instead.

Wikipedia has a decent article on the Renard series.

https://en.wikipedia.org/wiki/Renard_series