Re: Successful P4 478 OEM Gateway to retail Intel bios flash...
hmmm ... good deal and something i find interesting .
i have several older (ancient to middle aged) oem machines/boards kicking around .
i use these for "pieces-parts" to build ubuntu (and the occasional windows flavor) based machines to give away to kids that can't afford a comp (call them "the less fortunate" .
i have though that it would be nice to be able to do as you have done .
is there a website dedicated to doing such things ?
a list of boards-n-bioses...
CWB
Member
Last Activity: 05-20-2014, 08:23 PM
Joined: 01-27-2011
Location:
-
Re: another G5/661-3350 query
MB problems ... eeeyeah ...
/start rant
originally my friend had got a quote from a "mac shop" (i'll bet all that work there are left handed , but i shall digress) . the price he was quoted was for a "new" MB ... i verified this by asking him if they had cracked it open and took a look around .
he replied that they did not open it , the tech took a look at it externally and then made his (in my opinion) blind pronouncement .
i asked my friend if they mentioned replacement of any other parts ... he replied...Leave a comment:
-
Re: Holy crap my house could have caught fire!
@ kaboom :
the picture of the "screwed" panel feed line ...
that looks like the old silvery woven cloth covered tar impregnated "romex" stuff w/ rubber insulation .
what amuses me is the fact that *anyone* could be ignorant enough to not put two and two together and not think "gee , this here wire is coming out of the bottom of a meter panel , maybe i shouldn't screw (!) with it ..." .
i honestly believe that darwin awards are a good thing ... if only there were a much higher...Last edited by CWB; 02-18-2011, 08:34 AM.Leave a comment:
-
Re: another G5/661-3350 query
after getting "un-busy" and getting on the downhill side of the creeping crud that is going around i did some more checking on the supply ...
i replaced the diode that is across the transformer and double checked the drain and source leads of the driver ic ... so far so good .
i then powered up the supply and "sniffed" the transformer with a scope .
the supply is [I]trying[/I] to fire up ... it pulses for a short interval , stops and pulses again . it does this indefinitely .
it almost acts like...Leave a comment:
-
Re: Bleeder resistor questions
a bleeder resistor that is calculated to discharge (theoretically to zero) a cap in a power supply in (say) 15-20 seconds after main power is removed is about ballpark for average use .
a bleeder that "consumes" 1% (or less) of the available power will have virtually no effect on the quality of the unit it is providing power for ...
unless the design is marginal to start with and the supply has no head room under peak demand conditions .Leave a comment:
-
Re: How good is Cornell Dubiler Electronics?
yep ...CDE ... good stuff .
they have been around for a long time , more than 70 years :
[url]http://store.vintagepaperads.com/servlet/-strse-20700/1943-WWII-Cornell-Dubilier/Detail[/url]
they manufactured for mallory (certain types) .
they also made test equipment ages ago :
[url]http://www.oldtestequipmentarchives.com/item.htm?item=144[/url]
a google search for "vintage cornell dublier advertisements" will provide a visual history of the company .Re:...Leave a comment:
-
Re: another G5/661-3350 query
yeppers ...
no more difficult than nailing jelly to a tree .
it isn't about the money ... i don't believe that one can put a price on sanity .
Leave a comment:
-
Re: another G5/661-3350 query
toasty ,
you are right about the resistor , closer examination shows this .
/me builds pot of stronger coffee and wipes glasses .
trouble shooting this supply would be a lot easier with a real schematic .
with D10 shorted and the fact that it is across the primary of T1 ... i would hazard that *somewhere* there is a fuseable resistor in series with the B+ to this supply . i base this on the lack of the line fuse being ok and no "magic smoke" has been loosed .
i am going to do some more examination/checks...Leave a comment:
-
Re: Tubes, anyone?
"6GH8 was common in early color TVs, and was a major headache to many repairmen of the time, as some would work in one position of the set, but not another, and vice versa."
asides from the differences in inter-element capacitance , gain , miller capacitance (etc) between runs and manufacturers , one problem was the cathode sleeve to surface oxide boundary layer .
for some reason this would tend to mess up the operational parameters of the circuit .
RCA did extensive research into this area and had tight quality control ....Leave a comment:
-
Re: another G5/661-3350 query
a little further history ...
i recapped this supply about 8 months ago . the MB (or mid-plane board in applese) was recapped as well .
the original problem was intermittent shutdown , eventually becoming "no start" .
the physical evidence was the typical swelled and leaking caps .
sans the two raw DC input filters , [I]all[/I] the electrolytics in the supply were replaced with nichicon and panasonic caps of the FM and FC (etc) line ; the good stuff .
many of the MB caps were swelled/leaking (as denoted elsewhere...Last edited by CWB; 02-03-2011, 07:56 AM.Leave a comment:
-
Re: another G5/661-3350 query
the diode went into the shorted mode ...
i don't believe the unit suffered from catastrophic failure , based on the lack of physical evidence (nothing burnt , grenaded or charred) and cursory checks .
absolutely , a board can be damaged by messing with it to no end .
as an old BE friend of mine said about a new young engineer (after the transmitter he had been futzing with for almost the whole day took a dive) :
"yessir , he done engineered it right off the air" .
this supply goes in the comp of...Leave a comment:
-
Re: another G5/661-3350 query
the number on the case is API3PC96 .
Q1 checks ok .
nothing on the 3845 ic is dead shorted , the TOP244Y ic checks in a similar manner .
all the same , i am going to replace these two items ... cheap insurance .
just out of curiosity , any idea/thoughts as to why the numbers don't show up for the rectifier ?
the numbers on the device don't seem like "in house" markings .Leave a comment:
-
Re: another G5/661-3350 query
the link doesn't work (as of 0650 CST) .
i did find google results for "Bauteilsuche" ... i will explore that a bit further .
yeah , i am used to the zd delineation on boards .
but with this thing ... uuuggghh !
i am leaning towards a fast rectifier as well .Leave a comment:
-
Re: what do you use to glue together caps
you can play it on the safe side and use the [I]high temp[/I] hot glue .
the reason i mention the high temp hot glue sticks is that i "borrowed" a stick from my girlfriend's artsy-craftsy stuff ... the stuff was still soft and tacky 5 minutes after i applied it !
the method i use with the rtv can be a bit exacting for some people , but i have had good results over the years .
something that is bad to use is "contact cement" ... mitsubishi and a few others had some bad go-arounds with the stuff...Leave a comment:
-
Re: another G5/661-3350 query
no cross for that number ...
it seems as if that number series is about like tracking down a set of snake lips .
do you have any idea if it is a fast rectifier or a zener ?
out of circuit measurements would have to be taken and a zener test performed in order to determine what the part actually is .
that is the problem ...
if i had a good supply in front of me i could figure out what the part is .Leave a comment:
-
Re: what do you use to glue together caps
yes ... i remember those too .
do you remember the zenith triplers that would last for 1-6 months and fail ?
they pulled them and did a re-design . as i recall they had a clip-on cover for some leads .
then there were those four lead white tubular "buffer caps" ... they made a smart move going to the sprauge "orange drop" style .
the electrolytic cap and resistor in the horizontal drive to the HOT was standard fair for replacement too .
you are correct about the acetic acid crystals...Leave a comment:
-
Re: parts subbing and swapping (new and confused)
"beta" is important too (hfe) .
not just any old transistor that is correct in polarity (pnp/npn) , CE breakdown voltage , etc , is acceptable ...
the gain has to fall within a given percentage as well .
there is latitude in the specs ... but this depends on the circuit parameters .
subbing parts by other than direct suggested replacement (ie : ecg 123A) found by cross referencing in a book requires some knowledge of how semiconductors work and what is going on with the circuit you are...Leave a comment:
-
Re: what do you use to glue together caps
in addition ... the "glue" also keeps the parts from vibrating and breaking off leads due to handling/shipping/normal use .
a fair a mount of mass on top of a couple of skinny legs that is free to move around is not a good thing .
think "pendulum" .
i use hot glue or silicone rubber (the acetic acid type) . a trade name is GE RTV type 1 .
the silicone rubber that smells a bit like ammonia is worthless in my book .Leave a comment:
-
Re: Zener Diodes Always Fail Shorted. NOT.
it is rare but it does happen , zeners can go into something other than the shorted mode .
just like "regular" rectifiers ... i have seen them in both modes although the ratio is about 99:1 .
bjts make things a little more interesting ... i have seen them with CE leakage but the BE and BC checked ok .Leave a comment:
-
another G5/661-3350 query
hello to all ,
i just joined up and did a quick search for some information relating to the G5 20" swmps .
i noticed in one thread that a schematic was asked for , this is about where i am at ... or a parts list .
in addition to the half-fistful of bad caps that i replaced , D10 has turned itself into a piece of wire (no magic smoke) .
i believe this diode is in one of the smaller supplies (standby/always on perhaps) . it is in association with the TOP244Y driver IC .
the oem number is T2D46 .
i have tried to cross reference this critter...
No activity results to display
Leave a comment: