older than time PSU for automotive test machine

[scampo77]

i have a gas analyzer that measures hydrocarbons in tail pipe emmisions for cars."Sun DGA 1000" i cant buy a new one of these machines so i am really hoping i can fix this one. the info i can get off of the exterior are

moretec
mode: MPU-200PE
NO. 96070532

input 115 5A
230 3A

output
+5v -5v +12v -12v

i cant seem to find -5v and for the 12v all i can measure is 11v. i cant tell what voltage goes where because nothing is marked and i cant find a diagram anywhere. i checked the caps with a ESR meter and they all seem ok.

any advice or diagrams would help me out a lot

[rogfanther]

Re: older than time PSU for automotive test machine

Do you have any pictures of the inside ?

[ratdude747]

Re: older than time PSU for automotive test machine

i have a gas analyzer that measures hydrocarbons in tail pipe emmisions for cars."Sun DGA 1000" i cant buy a new one of these machines so i am really hoping i can fix this one. the info i can get off of the exterior are

moretec
mode: MPU-200PE
NO. 96070532

input 115 5A
230 3A

output
+5v -5v +12v -12v

i cant seem to find -5v and for the 12v all i can measure is 11v. i cant tell what voltage goes where because nothing is marked and i cant find a diagram anywhere. i checked the caps with a ESR meter and they all seem ok.

any advice or diagrams would help me out a lot

sounds like your basic AT power supply.

you have options if you want to replace it with a newer (still old if you like ) PSU.

what you could do:

option 1. find a GOOD AT psu and if the connectors are different, splice on the the connectors from the old unit. splice/short the on/off leads if your unit has no on/off switch to the psu.

option 2. find an older ATX psu. make sure is a good unit. it has to be older since ATX revision 2 dropped the -5v requirement. splice connectors. connect your on/off between (or short) the green wire (pwr on) and a black (ground)

either way if you want to replace, the standard colors that even the old unit may use are:

yellow- +12v
blue- -12v
red- +5v
white- -5v
black- ground
green (ATX only)- power on (short to ground to turn on unit)

especially with the AT units, computer PSUs were used in a lot non-computer roles... arcade games come to mint (quarter eaters).

some pictures may help (plugs used, not just guts). if it happens to use standard connectors, then it could be a simple drop in... otherwise, you either have to fix the old one or splice on plugs to a different PSU.

EDIT-

I looked uo the model... probably a modified AT or ATX psu, lots of A-power ish fakes claiming to be "refurbished" units with the same model no. you may be best to mod a better psu (delta/hipro for example) since the stock one looks to be junky quality.

[scampo77]

Re: older than time PSU for automotive test machine

the colours i have are

orange .2v
red 5.2v
yellow 12.12v
blue -10.8v

if i do go looking for a power supply will it have a big AT or ATX on it to denote the -5v i need? because his power supply doesnt have one.

i looked at old computers i have laying around here and non have the -5v.

there are x4 TO-220 cases bolted to heat sinks. would a good first step be to pull and test these? since my caps "seem" to be ok?

[kc8adu]

Re: older than time PSU for automotive test machine

how about some pics.sounds like an at supply to me.

[ratdude747]

Re: older than time PSU for automotive test machine

sounds like an AT to me as well. orange is supossed to be 3.3 v, but 3.3 was not usually on AT supplies (if it was, it was an aux plug).

since you might not have a -5v, i'd find a beefy (read: heavy and solid) ATX supply and rig a ground wire and the green pwr-on wire to the on/off switch sice only late and specialty AT units had the orange 3.3v line.

[momaka]

Re: older than time PSU for automotive test machine

any advice or diagrams would help me out a lot

If possible, please post some pictures of the inside and outside of the power supply as others have suggested - that way we know what we a dealing with. Most power supplies are basic enough to figure out without a diagram or schematic if you post good pictures.

there are x4 TO-220 cases bolted to heat sinks. would a good first step be to pull and test these?

You could, but I think they are likely fine.
Again, without pics, I can't tell you exactly what's what, but generally on PSUs of this vintage:
there are 2 NPN BJTs on the primary (high-voltage side) driving the main transformer and then the other 2 TO-220 devices would be the schottky diodes for 5v and 12v on the secondary side (likely mounted on a heatsink closer to the output wires).
In most cases, the -5v and -12v rails will be derived from regular silicon diodes near the schottky diodes on the secondary.
Occasionally, though, the -5v rail is derived from a 7905 linear regulator off of the -12v rail rather than from silicon diodes.

As you can see, there's more than a few possible combinations, which is why pictures are helpful.

[PCBONEZ]

Re: older than time PSU for automotive test machine

No 3.3v rail - it's an AT.

Not that I like this brand..... But they do still make them.
http://www.newegg.com/Product/Produc...82E16817338010
[And the old ones weren't >70% efficient.]

For 15 bucks I'd get the Athena and do a preemptive recap.
.

[momaka]

Re: older than time PSU for automotive test machine

For 15 bucks I'd get the Athena and do a preemptive recap.

Why would you do that, though? You can modify just about any ATX power supply to have a -5v rail.

[ratdude747]

Re: older than time PSU for automotive test machine

Why would you do that, though? You can modify just about any ATX power supply to have a -5v rail.

or find an old one WITH -5. I know there was a 300w AGI Atx 1 unit that had -5 (I have one in my fileserver).

also, there was a delta made 300w Compaq unit (early p4) that came in the presario 7000 with -5 (have one too).

ironically, the Ultra V of doom (or at least the 500w) had a -5 as well (gutted a couple of them already, ).

you are looking for a white wire in the pigtail for the ATX plug or one of the AT plugs.

that all assumes it really is a -5. I looked it up- AT's orange wire was the "power good" wire. so this psu may use nonstandard colors (or its ATX, which means the orange is a 3.3v line)


about the athena- I think those need more than caps... they are beyond gutless (as in flat plate heatsinks without fins, tiny 4 diodes, jumper wire everywhere, etc.). the only way to fix an athena is a sledgehammer, firearm, or e-waste bin.

[PCBONEZ]

Re: older than time PSU for automotive test machine

Why would you do that, though? You can modify just about any ATX power supply to have a -5v rail.

Because it's $15, it's easier, and probably even cheaper than a mod.
.
Also makes no sense to me to have a 3.3v rail in there with no load on it at all.
.

[PCBONEZ]

Re: older than time PSU for automotive test machine

about the athena- I think those need more than caps... they are beyond gutless (as in flat plate heatsinks without fins, tiny 4 diodes, jumper wire everywhere, etc.). the only way to fix an athena is a sledgehammer, firearm, or e-waste bin.

Yeah right. It's Athena that doesn't know anything.
http://www.newegg.com/Product/Produc...82E16817338047
.

[ratdude747]

Re: older than time PSU for automotive test machine

athenas are gutless. the absolute worst i have seen.

if i were the OP i would find an old delta or newton unit with -5V and start from there.

[370forlife]

Re: older than time PSU for automotive test machine

Yeah right. It's Athena that doesn't know anything.
http://www.newegg.com/Product/Produc...82E16817338047
.

Athena's server power supplies are typically decent FSP. But their other stuff is Sunpro and Topower.

[PCBONEZ]

Re: older than time PSU for automotive test machine

As the 300w is replacing a 200w [which presumably also a 'gutless wonder'] the fact that the Athena is a 'gutless wonder' makes exactly -ZERO- difference and the Assertation that in might is inherently stupid.
.
.
The efficiency on an old AT like that is probably around 65% which means even if the system pulled all the PSU had [which is very unlikely] it would only be using 130 watts.
.
.
A 300 watt 'gutless wonder' would be OVERKILL.
And yes, I figured all that out BEFORE I suggested it.
.

[PCBONEZ]

Re: older than time PSU for automotive test machine

athenas are gutless. the absolute worst i have seen.

You haven't seen much then.
.

[ratdude747]

Re: older than time PSU for automotive test machine

You haven't seen much then.
.

didn't know they made server stuff.

all I had seen were a bunch of sunproish gutless junkers and $5 PSUs with thin wire for sale online.

still feel uneasy about them.

I still think one could do better with a cheap used delta/newton.

[PCBONEZ]

Re: older than time PSU for automotive test machine

I certainly wouldn't choose that one if the actual load was over 200 watts, but it isn't.
.

[PCBONEZ]

Re: older than time PSU for automotive test machine

Here's a better one.
http://cgi.ebay.com/ASTEC-250W-Power...item439cd2639e
-
ASTEC is not well known as they only ever did OEM but their units are usually very high quality and very often they have all jap caps as original.
.
Some pics.
http://www.recycledgoods.com/zoom.aspx?productID=17904
.

[momaka]

Re: older than time PSU for automotive test machine

Because it's $15, it's easier, and probably even cheaper than a mod.

I'd say it depends on the tools, parts, experience, and amount of time you have.
7905 regulators are usually cheap and not hard to find. Just connect it to the -12v rail, add a 220uF cap and that's it - budget -5v rail on any PSU. You don't even need a dedicated PCB for this mod (although it's usually a good idea to have one ).
A slightly more elaborate way is to connect two 2-3A diodes to the 5v AC output of the main transformer. Then wind a few turns of wire on the main output inductor, connect one side to common anode of both diodes, connect other to 2x 470uF to 680uF caps, and again you have -5v on just about any PSU.
Better yet, just fix the old power supply - it's an AT power supply, how complex can it be ?

Also makes no sense to me to have a 3.3v rail in there with no load on it at all.

Yes, that might be a problem on some power supplies. Some will care, some won't (most probably will have slightly weird voltages due to this). It all depends on the design.

ASTEC is not well known as they only ever did OEM but their units are usually very high quality and very often they have all jap caps as original.

ASTECs are excellent.
On the two units I have/still use, though, the fan controllers seem to be quite aggressive. Raise the room temperature just a bit, and they kick the fans on high. Don't know if that's an ASTEC thing or not.

Athena's server power supplies are typically decent FSP. But their other stuff is Sunpro and Topower.

Topower is acceptable. Sunpro, however, is not in most cases, especially for their low end units - that stuff I consider a fire hazard. Raidmax RX-380K (Sunpro KY-480ATX) comes to mind as one of these.