85, 95, and 3511 PS

NOTE: Presently incorporating the procedure for complete PSU teardown and re-assembly.
Expect utter Kaos!

Moving PSU to Access Memory, Battery, or Devices
Power Supply Revisions
Max Amp and Power Draw
   400W PSU Dimensions 71G4602
   Thoughts on Shipping
   Cracked T1 on Horizontal PCB  
   T1 Transformer Model  
Checking Power Supply Voltages
   Quick Op Panel Check
   Primary Power Supply Voltages
   Drive Connector Voltages
High Quality
Side Cover Fan
   Side Cover Fan Orientation
   Case Airflow
   Side Cover Fan Construction
   Side Cover Fan Revisions
       Cover Fan Cable Assembly
   Side Cover Fan Troubleshooting
How Does The Fan Look Installed?   (Takes you to Jim Shorney's site) 
Deriving 17vdc from the Power Connector
Trying to Plug PSU Onto Planar Plug when case is Horizontal
E-Clip for PS Knob Assembly
Air Deflector on 95A PSU
Opening the 400 Watt PSU 
   Security Torx
   Security Phillips
   Remove Screws in Rear Wall 
   Removing AMP Planar Power Socket Retainer
   PSU Rear Wall Catches 
   Remove Inner Wall from Case Slots
   Thoughts on Factory PSU Assembly 
      PCB Guides 
      Horizontal PCB Guides
   95A Power Supply Exposed!
   Power Supply AC Socket
   PSU Fan Connector 
   Fan Cushion  
   Fan Control PCB 
   2 Pin Fan Connector  
Blown Transformer

Moving the Power Supply to Access Memory, Battery, or Devices

   Components like the CR2023 battery, planar memory, and devices (cabling!) on the IBM Model 95 system are either behind the PSU or require you to drop the PSU in order to get enough room to work on the device..

On the outer side of the power supply there is a spring-loaded power supply retaining knob. Rotate this about four times until it releases the power supply which you can then tilt out of the system. The power supply is not completely removed from the system unit.

NOTE! Do not try to remove the blue knob! Once the knob pops loose from the threads, you don't need to rotate it any more.

Warning! ------------------------------------------------~
When dropping the PSU, unplug the AC power cable from the PSU!

NOTE! When dropping the PSU, consider unplugging any drive power plugs from the three sockets on the front of the PSU.

NOTE! When swinging the PSU back up to reseat it, ensure drive power cables AND any SCSI cables are out of the way of the front lower edge of the PSU.

Warning!  When re-seating the PSU, after ensuring any cables are not trapped underneath the front edge, press the PSU onto the Planar PSU socket. Press the blue knob inward so it starts, then tighten it down with no more than finger pressure until firm.

Applying excessive torque WILL pop the e-clip on the screw shaft. Where that little semicircle of steel then ends up is up to chance.Maybe in the PSU case... Maybe hanging on a planar component... If you are lucky, it will fall down to the bottom of the computer's case and not short anything...

Power Supply Revisions
   The wattage is rounded up - for better look. Basically you find the "old" 335Watts PSU (FRU 92F0051) in all 8595 machines and later "small" Server 85 (those with 486SX and 8-bit planar SCSI). The 285Watt (FRU 92F2637) has been installed on the earlier Server 85 only and on some *very* few 8595-xGx, xHx and -xJx. (Ed. My 9585-xNx has a 285W PS) 

   The 400W was introduced for the Server 95A. The 9595-xLx and -xMx however use the 335W since they are souped up 8595 only. The bigger PSU (FRU 92F0267) can be identified by the LED and test-button at the top left corner, when looking at the installed PSU. The "bigger" Server 85 (486DX2 and F/W planar SCSI) have this one as well as the 3511 expansion unit. 

NOTE! The dual serial / dual parallel port planars for the 95A systems and the 9585-X/K/N planars use PTC resistors to protect the planar from excessive current. The single serial / single parallel port planars for 95 systems lack these devices. So yes, the 400W can be used in a 8595 or 9595,but watch your power draw. Personally, I can't see how you could load a 95 up unless you use huge old fashioned drives and a bunch of Type 5 cards.... Whatever. Just be careful out there...

Maximum Current and Power Draw

The system provides a separate power source for internal SCSI drives through three 4-pin connectors on the power supply (see Power Supply Connectors). The system board voltages are +5 V dc, +12 V dc, and -12 V dc.  The drive voltages are +5 V dc and +12 V dc. 

The following are the maximum current and power considerations used in designing the power supply and system board. The formulas used to determine the power requirements and the voltage regulation tolerances for adapters are in the Micro Channel architecture information in the IBM Personal System/2 Hardware Interface Technical Reference--Architectures. 

Component Maximum Current 
|                               |       MAXIMUM CURRENT       |
|                               |-----------------------------|
|                               | -12 V   | +12 V   |         |
| SYSTEM COMPONENT              |  DC     | DC      | +5 V DC |
| System board                  | 1.0 A   | 1.6 A   | 28.0 A  |
| Internal floppies (per drive} | None    | 300 mA  | 600 mA  |
| Keyboard port                 | None    | None    | 300 mA  |
| Auxiliary device port         | None    | None    | 300 mA  |
| Internal SCSI drives***       | None    | 7.0 A   | 8.0 A   |
| MCA adapters (per slot)       | 40 mA   | 175 mA  | 2.8 A   |
| *** Total for all internal drives                           |

Note Some adapters and drives draw more current than the recommended limits. These adapters and drives can be installed in the system; however, the power supply will shut down if the total power used exceeds the maximum available power.

400W PSU Dimensions 71G4602
Weight: 9.8 pounds (Imperial units! A pint's a pound the world around!)

8.50 inches high
9.25 inches long
5.75 inches wide

9.50 inches Total height with air deflector

Thoughts on Shipping
   For shipping a PSU in a system, the whole thing should be bubble packed or foam peanuts. I personally detest foam peanuts because those little dapper devils get snapped into REALLY small bits. Those bits can then slip through the PSU exhaust or the side louvers.

  Once inside a PSU, you should open it to chase the bits out. Best to tape up all vents with newspaper to keep the foam OUT.

  I personally stay away from blown foam as the ONLY padding. It is rigid, and IMHO transmits shock to the object inside. If the foamed object is then placed in a larger box with foam peanuts or bubble pack or captive air, then any shock is absorbed by the loose packing. YMMV.

  For shipping a PSU by itself, I think a box with 4" of space around the PSU leaves enough room for adequate bubble pack or captive air. Not a fan of a foamed-in PSU in a box as the lone shipping container. YMMV.

In the end, we want to keep the ferrite transformer cores happy, Blown Transformer

Cracked T1 on Horizontal PCB :(

Finally dug out another 400w from on the porch, and I heard a light metallic tinkle when moving it. Not knowing what, I took it up to the operating table today...

Took off the AMP planar connector... Took off the back wall. Unscrewed the two screw / nut combinations from the AC socket. Slowly worked the nut holding the ground cable to the PSU frame off.

Then I saw the "L" shaped light grey piece in the bottom. Faschizzle.

I do not see other damaged components, to me it looks like a physical shock cracked this...

T1 Transformer Model
I meant to say a partial transformer model

DET 9349-1 (date)

I could barely make out "SMT" on the transformer, probably Surface Mount Transformer... Of course, the small print faces a heatsink mounted FET...

Checking Power Supply Voltages PS/2 - Server 85, Model 95 and 3511 
   Some power supplies have a built-in test switch and LED on the side of the power supply (there is no need to check voltages). On those power supplies, disconnect the power supply from the system board, and remove all cables except the power cord. Power-on the power supply and push the test button. If the LED lights up, and the power supply fan runs, the power supply is OK. 

   On all other power supplies, short pin 1 to pin 2 and read the voltages on the other pins. If the voltages are correct, and the power supply fan runs, the power supply is OK.

NOTE: If you use a test button or short pins 1 and 2, the PSU will operate at a No-Load level, eg. the fan will be on low speed. This very PSU tested green with nothing attached, but when plugged into a system, the fan continuously searched high and low.

UPDATE: This is the 400w PSU fan that was continuously searching...

"But after I hooked a couple of hard disks on it, it was running fine for > 20'."

Some repressed memories came up from the depths...

If the PSU is under no-load, then the fan will be operating at an unknown low speed. PWM controllers spread out the pulses, so the slower the motor, the farther apart the pulses. Amplitude stays at 12v. So it is very possible the growly fan I heard during test was the fan controller "kicking" the fan over with widely spread pulses.

This is interesting, as it illustrates the PSU fan control functions, which up to now have been ignored (as long as it works). An experiment would be to stick a 95A PSU on a Kill-A-Watt meter and an oscilloscope to watch the waveform.

It would be more trouble than it's worth (except to be crowned "Alpha Geek") to determine at what load the fan control goes from Low to High. In closing, it is quite possible the PWM stuff needs to operate under load (how much, dunno) before it can settle down.

Quickee Op Panel Check
Thanks to Rick Starich for getting me to do this!

   Pull Op Panel out front of system. Leave PSU connected and plugged in.  Short pins 3-6 OR 5-4 and system should power up if the Op Panel board and cable are good. Nothing will happen if you short 5-6 or 3-4.

Primary Power Supply Voltages
If the voltages are correct and the power supply fan runs, the power supply is OK.

AMP socket 213516-1 Receptacle, 21 Position, 43 Deg, Metimate Datasheet 
Tyco has this as obsolete.

Power Supply Connector Voltages
-Lead Pin +Lead Pin Vdc Minimum Vdc Maximum


+ 6.2 
Note: -5vdc on pin 9 is undocumented. Didn't notice a -5v on my 95A PS 
Note: Black lead of the DMM/VOM on pin 5, red lead to the +Lead Pin. 

95A Planar Power Socket Pinout
   Top row is all +5v (Red). The middle row is all Gnd (Black). The bottom row is, from L-R, On/Off (Brown), +12v (Blue), -12v (Yellow), +5v (Red), Gnd (Black), PG (White), Gnd (Black) 

Drive Connector Voltages
-Lead Pin +Lead Pin Vdc Minimum Vdc Maximum


+ 3.7 
+ 9.0
+ 6.2 

Wire Colors for Disk Drive Power Connector
   IBM used Yellow-Black-Black-Yellow. 

If the power supply shuts down, or appears to fail at power-on, you might have one of the following problems: 
     Too many devices are set to start instantly. Check Motor-Start Jumper. 
     There are too many large-capacity devices installed. 

Or the Remote Maintenance Service Jumper is not correct.  

   But to answer your question: the Mod. 95 PSU is not known for any particular failure. There was a series of downlevel "Delta /US" made 400 Watt PSUs, which failed after a short time - but these have blown themselves to hell already and none of them has seen the year 1992. 

   The 95-PSU is rather complex inside. The main functions are distributed among a number of smaller boards and tracking down failures isn't easy - except you have blown and burned parts. In most cases however the failing components are not that obvious to find. 
   The most common failure is the "no turning on" failure with the short clicking noise and the high-pitch whistle afterwards. I don't know which component causes this - and how to repair it. 

   Malfunctions that the PSU works for some time and then -by no obvious reason- switches off (thermal problem) are only reported for *extremely* dirty PSUs, mainly accompanied by blocked fans. After some time running the internal protection circuit causes a "thermal shutdown" due to overheating. This could be fixed in most cases by cleaning the thing and replacing the fan. 

   The commonly known problem with overheating and burning the stand-by part of the PSU are not reported for the 95 PSU ... it is no Magnetek / Italy made PSU ... :-) 

High Quality
From Peter 
Hi Jim ! 
>The thing is built like the proverbial brick outhouse. 

   A guy who (professionally) repairs switched power supplies looked into a dead 95 PSU and was surprised as well. "How old did you say are the Mod. 95s ?" 
   He was confused about the fact that an almost 10 year old machine had a PSU with power factor correction ... which might become standard "by law" next year or in 2002 for the common lemming PCs. 

   If you have an AC wattmeter - plug in the PSU, shorten the "powerswitch pin" and test out the idle wattage it takes. It is much lesser than the average wattage taken from a 145W chop-suey PSU from China or elsewhere. And the 95 PSU has 380 - 400W output power ....
   Also a nice test is the "VDE 0100 Isolation Test" and the test for parasitic currents over the input noise suppression filters. The 95 supply is also a class of its own here. IBM wasn't cheap-skating on the PSUs. 

   Even the notorious Magnetek "Made in Italy" power supplies for the 35/56/76 are pretty good on their technical data and performance ... apart from the unlucky tendency to fry themselves to an early death. The concept was good - the manufacturer wasn't. (Or the quality control). 

Side Cover Fan
Part of the following was redone based on info found by Ross Barker (Ross pulled up anchor- he's on the high seas again)

Side Cover Fan Orientation


  This is a swirling debate... For now, I'd like to point out the difference between the 95 and 95A plastic end bracket for the fan. The 95A bracket has a slot and a beefier catch.

   The fan serves one purpose in either mounting orientation, that of pulling air IN through the grilles at the top front of the 95, then THROUGH the adapters, then DOWN the side wall.

Open to interpretation... The significant points- air is pulled through the top grilles, sucked through the adapter cards, down the side wall through the side wall fan. 

   Air is sucked over the top of the PSU, past the complex, over the memory, then into the PSU where it is blown out through the exhaust. Though looking at a PSU shows the memory has a blank surface in front of it, probably to force airflow past it.

NOTE: The PSU for the 3511 Enclosure has the louvers on the lower, inner edge taped off. These louvers ventilate the SIMMs on the 95 planar. YMMV, I need to source this factoid...

Side Fan Construction
From Peter- 
   But please do not forget that this thing is not just a simple "motor". It is an electronically regulated, brushless DC-motor. The electronics sits under the end facing to the rear - you can see the  printboard and some of the coils. The electronic itself consists out of some resistors and condensers, ICs, a hall-generator for measuring the rotational speed and so on. 

   Unlike to "real motors" the resistance does not change when you turn the fan ... normal DC-motors act as generators once driven. This thing doesn't. 

   However: 137 Ohms would give a current of about 125 mA - still below the specs. 

Side Fan Revisions
64F4470, EC C31557, mfd. 042391 137 ohms 
64F4470, EC C32546, mfd. 121391 1.31K Ohm 
Hosiden HMK 3404-01-092, DC 17v. 0.185A 

64F4470, EC C32546, mfd. 031892 1.32K Ohm 
Hosiden (flower symbol?) W, HMK 3404-01-092, DC 17v. 0.185A 

95A Side cooling fan fan 
ASM P/N 61G3813, mfd. 101993 1.32K Ohm 
Hosiden (flower symbol?) J, HMK 3404-01-092, DC 17v. 0.185A 

Possibly this means any fan made on or after 121391 will be a 1.3K ohm model. 

Cover Fan Cable Assembly

HMM says 61G3824, the older style is P/N 84F9284, the newer style is P/N 60G9828. For purposes of clarity, I wedged the white planar connector into the top.

The older one is black, and has a full-height pocket for the inner mounting screw.

The newer one is off-white and the bracket is redesigned to be half as high, but with a loop sticking up high enough to mate with the mounting post.

Screw appears to be a 3 to 3.5 mm by 8mm long trilobular screw, double pitch (like they stretched the screw and the thread is farther apart)

Side Fan Troubleshooting
If the access cover fan does not work, check:
   Check the spring contacts on the fan bracket to see that they stick out far enough. Over time, with repeated removal and installation of the side cover, the contacts will be pushed back into their guides. Carefully pull them out again. Make sure the free end of the spring enters the recess when not under pressure (that way it's lined up when you are using BOTH hands to install the side cover...)

   Power to fan: 17 V dc (+/- 1.4 V dc) at the two fan cable pins on the base.
If voltage is correct, check for 1.3K ohms (+/- 10%) between fan terminals (Ed. I have an older fan that has 137 ohms. Runs fine.)

   If resistance is incorrect, replace the fan. If resistance is correct, check spring clip connectors. (If good, there isn't a fan problem).

   If voltage is incorrect, unplug fan cable from connector J28 on planar and check cable assembly for continuity. If cable has continuity, replace the system board. If the cable does not have continuity, replace it.

Deriving 17vdc from the power connector
  OK, you have a 9595-3Px, fully loaded with RAID drives and memory. BUT you notice strange erratic performance after a few minutes. After checking, you notice (to your horror) that you have NO voltage (or not enough) from J28. 

  Just trot down to Best Buy and pick up the dual serial/parallel planar for $49.99 and pop it in? Or will you whip out your trusty 25W soldering iron and take charge of your own destiny? If you are of the adventurous type, read on! 

>So if J28 does not have 17vdc present, can you come off pin 9 and pin 4? 
   Yes - sure. The Pin 9 is the unused -5V source (PS/2 don't use that - it is not even mentioned in the HMM). You pick the voltage preferably at the underside ... but ... if there is no +17V at J28 ... then there is something basically wrong. The +12V should be present anyways (the HD-motors run on it) ... if the -5V is missing then the PSU had "a bad day". Or the line is cracked on the board somewhere. This should be easy to trace down. 

>That was my intent- how to derive an alternate source of 17vdc from the planar power socket... 

   Alternatively: pin 7 of the PSU-connector deliveres -12V, pin 3 +5V ... both add to +17V as well. Only need to watch the polarity. (Ed. Verify the polarity with a voltmeter/DMM. Do not assume anything with a 9595 dual serial/parallel planar. One bzzt! and you may burn something else on the planar. The Power Supply will be fine though...) 

Trying to Plug PSU Onto Planar Plug when case is Horizontal
SuperVinx  said:
   Someone gave me an 9585-ONG, formerly owned by a bank. The PSU was easy to remove, but it was hard to reseat the power connectors between the PSU and the planar while the system was horizontal. I've found that the 9585 must be in the vertical position, all the way to the right on the mounting pins, in order to seat with minimal effort.
  This came out of the blue one day. How were all these PSUs missing E-Clips on the PSU knob? 

How it happens- (from Charles)
   The ijits that used these computers before don't realize that it's the little e-clip that actually stops the screw knob from turning further. 

   If you crank on it hard enough, you WILL deform the clip, dislodging it from the shaft, USUALLY the next time the PSU is unseated.  It starts with a very hard counterclockwise turn, and then you notice that that nothing is moving as you turn the knob. Then when you pull -- pop!  The e-clip finally gives way. 

Charles Lasitter
   Does anyone know the correct E-clip size for the spring-loaded screw shaft that we all know and love in the '95?  I've had about a dozen too many of them come flying apart and of course one of the E-clips takes its own separate orbit. 

My nuts 'n bolts reply
   The .670 is, as stated, the recess width which the e-clip has to fit. .553 is the outside diameter of the e-clip. So an e-clip with an outside dimension of .553 (or a little less, hell, .450 should do) all the way up to .650 should do. 

  The thread outer diameter is roughly .310". So the outside shaft diameter will probably be a little larger, maybe .318 (standard fractional dimension, IIRC) 

   The diameter of the part where the eclip rides should be .208 plus/minus maybe .003". Thickness of the e-clip is .025". 

Bob Watts
  You can go to NAPA and ask for part number: 1311.  They are 32 ¢  each. I know they work because I installed them on my 8595 PSU. Problem taken care of. 

From the god Emperor of Microchannel
Went to NAPA. Got a few 1311s. They are tight, Bob. 

   On a lark, I went to Ace Hardware. Ambled over to the fastener center. Whipped open the Hillman External Retaining Rings box. Pulled out a 5/16th Retaining Ring, 08236-00379 for a whopping 20 cents each. 

   They aren't as loose as the IBM e-clip, but you can turn then with your fingers (the NAPA ones wouldn't) 

95 PS vs 95A PS
  Just a little factoid- the 8595/9595 power supplies do not fully enclose the well that the PS knob's screw is in. This makes it possible for an e-clip to pop off the shaft and fall into the PS. On the 95A 400W power supplies, that well is solid all around the threaded end of the knob's shaft. 

95A Air Deflector

It starts on the left front corner of the PSU. 17.2cm/6 13/16ths" wide. The air baffle extends towards the complex 8.7cm/3 1/4" inch from the outer edge of the PSU. The air baffle has a maximum height of 3cm/1.5".

Although this air deflector was available as a separate part, the ones I have are fastened with adhesive to the PSU case, and the outer side of the PSU case is tack welded to the front and back faces. So you need to diddle around and take off the inner PSU side.

95A PS   Delta model SMP-400BP?
   I opened up my 95A 400W power supply. I do NOT advise anyone to attempt to fix or modify the power supply. I take NO responsibility for what you do! You are doing this on your own! 

   This page is ONLY to expose you to the quality construction used on the 85/95 series systems! I have left many details out, because I'd rather not have people opening these power supplies. They have pretty big capacitors in there. Seen bigger, but these will hold a sufficient charge to ruin your day. 

   For entertainment only! In no way do I suggest that you try this! I don't have safety tips for the proper de-energizing of the circuitry for power supplies that have been used recently. I used a power supply that hadn't been powered up for over six months. 

Assume all heatsinks are live if this power supply was plugged in!

Opening the 400 Watt PSU (others similar)

  Here are the tools and procedures for a (relatively) painless way to open a PSU to clean it. I do not have any schematics for this or any other PS/2. Everything here is either scoured from the internet or a result of (usually painful) personal experience.

Security Torx
  Menards had the Truecraft model #6232 32 Piece Bit & Socket Magnetic Ratcheting Driver Sets (about $20). It has tamper proof T10-T40 Torx bits.
   The bits and case are Taiwanese (I'll buy from OUR china any day!) and the ratchet and sockets are US. The bits are heat treated S2 steel (good stuff). You will need the security T-15 bit.

Craftsman has a set of security bits and magnetic handle for @ $27, BUT it has the security Pillips, Torx, spanner, and others. Nice and compact.

Security Phillips
   To take off the inner side panel, you WILL need a security TP2 Phillips. The 95A PS uses a stamped metal "well" to fully surround the PS knob's threaded end. This well is fastened to the top of the case, as well as to the side panel by the security phillips. 

   I made my "security phillips" screwdriver with a cheap old phillips. Threw it into a vise and hacksawed two slots at right angles to the edges. It has four separate points sticking up around the center now. I would get a real security phillips if I was doing this a lot. It worked but I would not want to really torque on it. 

Removing the PS Knob Shaft (only needed for total PSU teardown)
   Push the knob in so the e-clip on the inner side is accessible. Use needle nose pliers or a standard screwdriver to remove it. NOTE: With 400w PSUs, the air deflector on the top edge interferes with removing the top, on later 400w PSUs the front and rear sides are tack welded to the front and top walls. In this case, just drop the inner wall of the PSU. You only need to drop the phillips screw below the PSU knob (the top phillips can remain installed).

Remove Screws in Rear Wall

To remove the PSU rear wall, you need to remove the TP2 Phillips just below the PSU fastening screw. You can leave the top TP2 alone, and leave the PSU Knob right where it is. It does not pass through any PCBs.

Remove Bottom Inner Edge Screws

Place PSU on it's outer side. Whip out your T15 Security Torx and remove both screws.

Removing the Planar Power Socket
   If you want to unmount the AMP planar power socket, you will need a small, thin bladed standard screwdriver. The retaining collar has two pairs of hooks on each side of the power socket. With the PSU laying on the outer side, look under the metal angle that the Planar Socket is mounted on. 

   See the hooks holding on the bottom of the socket? While pulling up on the collar, pry the hooks away from the socket, one end  on one side, then the other end. Move to the other side and work off the hooks again one at a time.

PSU Rear Wall Catches

Remove Inner Wall from Case Slots 
  Once all screws and the planar power connector are removed, and the Inner Wall is freed from the rear PSU case wall, then turn your attention to the top inner edge. There are three tabs from the top of the inner PSU case wall that slot into the top PSU case wall.

I ended up flexing the inner wall up and down while pulling out and up at roughly 45 degrees.

Images to come when I open one of my last, extra 400w PSUs.

Thoughts on Factory PSU Assembly
Looking at the shell, it seems that the air deflector was put on last.

The front wall has tabs that fit onto slots in the top wall of the PSU. Like the back wall, but in front... The air deflector has two alignment tabs that extend over the front wall of the case, but those tabs are not connected with adhesive.

My guess - air deflector was applied to finished PSUs, and any adhesive is under "lean-to".

For visualization of the case, the front, top, and rear walls are an inverted "U". The inner wall is a separate piece. The front wall and the bottom wall form an "L".

From my perils of pulling this 400 apart, if you wandt to fully disassemble one, you need to remove the two air deflector "tabs" that hang over the front wall of the PSU.

Disassembled Well Parts 

PCB Guides 

This is the inverted "U", front, top, and rear wall of the PSU. Note the PCB guides along the outer edge of the PSU.

Notice the metal clip at each lower end of the "U" (case upside down, clips at upper ends of "U"). These clips hold the horizontal PCB's bracket. The way this is laid out, it appears the inverted "U" slides down over the vertical PCB.

Note the PCB guides for the horizontal PCB. The single double guide at the middle of each end (front and rear) allows the horizontal PCB to be pushed over the double guide and slide forward to engage the case clips.

Vertical and Horizontal PCB Bracket  

This shows the vertical PCB bracket cut-outs, and how the clips fit over the vertical PCB. Also see the "U"s where the horizontal PCB slides in.

Vertical PCB Bracket Clips

The bracket on the vertical PCB hooks under the clips at the front and rear of the "U". Note the threaded hole for one of the two T15 Torx screws holding the front wall on.

Vertical PCB Bracket Screw 

The vertical PCB Bracket is fastened dead center with a T15 Torx.

Horizontal PCB Guides 

See the way that the corner of the bracket is secured by the clips at the corner? Also, note the double guide near the bottom right of the picture. There is a semi-circular cut-out that the PCB clears when being assembled, and once the PCB reaches the single PCB guides, the horizontal PCB is pushed to the outside wall, and the corner clips and the center double PCB guide are engaged.

Oh My God! 95A Power Supply Exposed!

   This is NOT a clone power supply! The main heatsink is 3" high, 3/16th" thick and 7" long! The conductors coming off the main circuit board are 14AWG, 600v, 105 degree rated. For those not techno-savvy, that means you could safely run 115v/15A on these conductors! The 105 rating is WAY above some common power supplies I've looked at. The fan is removed in this image.

95A Power Supply AC Socket
   It has an EMI filter, rated 115/250v, 10A at 50/60Hz, 40 degrees C.

Cx .1uF
R not in this model (no "-R" suffix)
L 0.2mH (image on socket has no "L", possible one on L, one on N?)
Cy 2200pF

Delta 10GEEW3E, 10A 115/230 volts. Mfr 9337 by Delta. Datasheet 

At this point, the "109R" model is close enough.

Burnout protection function at locked rotor condition
Current cutoff system
If the fan blades are restricted, the coil current is cut off at regular cycles to prevent overheating of the coil. When the hindrance is removed, the fan restarts automatically.

Reverse polarity protection function
No problem about fan even if positive & negative lead are connected in reverse.
However, when wiring fans with sensors or PWM speed control function, connecting positive and negative leads in reverse may damage the fans.

NOTE: Both the 329w and 400w fans do NOT have sensors, and the fan does NOT have PWM circuitry inside it.

Model 109P1212H402

DC12V 0.45A - 5.4W
Seven "squarish" blade, ribbed, uses through hole screws with nuts on inner side of PSU.

12v 0.45A 5.4W 2,800 RPM 2.5 m3/min (88.2 CFM) 53.9 Pa 40 dB

109P1212H402 page  Datasheet 

109P - Plastics
12 - 120×120mm
12 - 12V
H - 2800 RPM
4 - 25mm thick
02 - Without a sensor
Lacks 13th position, it uses a ribbed impeller body.

Model 109P1212H1021
DC12V 0.52A - 6.24W
Seven "rounded" blades, ribless, uses metal clips for mounting screws

109P - Plastics
12 - 120×120mm
12 - 12V
H -2600 RPM
1 - 38mm thick
02 - Without a sensor
1 - Plastics frame: Ribless frame (13th position)

109R1212H102(1021) Datasheet 
12v 0.52A 6.24W 2,600 RPM 2.9 m3/min (102.3 CFM) 64.7 Pa (0.260 Inch H2O) 39 dB

Fan with sticker removed

Once you carefully peel off the round black sticker from the back of the fan, you will see it has three contacts (only 12v and GND used) and the lone identifier, "12H21".

See the small fan spindle in the well. A SMALL e-clip holds the fan in the hub.

Sanyo Denki Co. DC San Ace Brushless

PSU Fan Connector

After cracking open the oyster, you might be able to oil the bearing with the fan in the case.

Remove the inner wall. Place the PSU with the fan exhaust pointing DOWN. Sparingly oil the bronze center of the fan. Spin it slowly with your fingertips until the oil seeps into the bearings. This is a tight fit, so it might take a while.

Fan Cushion 

I finally noticed this while re-assembling my sick 400 watt PSU. The fan hub is pulled onto this when the mounting screws are tightened. Vibration control?

Fan Control PCB
   The fan control PCB has two LM339N op amps on it, a few signal(?) transistors, and a few caps. Unless I destroy this (non-working) PSU I can't be totally sure of what is on the controller, but from the looks of it, ain't nothing special.

LM339N - Low-Power Low-Offset Voltage Quad Comparators. With two, I bet you can make a PWM DC motor controller...

This Fan Control might monitor both fan voltage drop and PSU output voltage drop.

The fan itself has two wires, so no tach or temperature input to the fan control. No visible temp control found yet on the PCBs (might be there, but not on Fan Control).

Think about it, you can't just monitor fan speed without monitoring PSU load. Monitoring current vice voltage drop takes higher rated components because current measuring device must be in series and must be able to handle amperage.

2 Pin Fan Connector

Molex 5051 Series Headers & Wire Housings - hooray!

2 Pin white connector marked:

MXT 29

For the fan wires:
2.50mm Pitch KK® Wire-to-Board Housing, Female, Friction Lock, for 2759/5159 Crimp Terminals, 2 Circuits

Part Number: 22-01-1022
Engineering/Old PN:5051-02

2 Pin Header on Fan Control PCB

Connector is marked:
MXT B (or "8", cramped space)

For the Fan control PCB header

Mini-Latch™ Wire-to-Board Header, Right Angle, Friction Lock, 2 Circuits, Tin (Sn) Plating
Part Number: 22-05-1022
Engineering/Old PN:5046-02A
Pins look to be .66mm / .0025"

KK® Cat Ear Crimp Terminal 5159, 22-28 AWG
Engineering/Old PN: 5159
Phosphor Bronze, Tin (Sn) Plating or Brass, Tin (Sn) over Copper Plating

24AWG, Type TR-64 AWM VW-1 1007 E44013, wires say "DENKO" and "DAIICHI"
Dai-Ichi made the small gauge wires for DC fan manufacturers.

PSU Fuse

1⁄4” x 1 1⁄4” ABC Series, Fast-Acting, Ceramic Tube  ABC-8 Datasheet 

   T8AH 250V. If this fuse blows, remove the short circuit from the output. Though if this has blown, something is wrong because the power supply should have shut down by itself!!! If the fuse blows again after removing a shorted output, I recommend you take a power supply to a real electronics repair tech.

Reassembling PSU Knob Shaft Well 

After fastening top of well to the top side of the PSU, pass the PSU Knob Shaft through the hole in the well. Now put the PSU on it's side. This makes applying compression to the PSU Knob easy.

Installing E-clip 

With  the PSU resting on the blue knob, it is much simpler to keep the shaft at the proper protrusion. Place the e-clip so the outer ends fit into the groove and use a standard screwdriver to push the clip onto the shaft.

Inserting Rear Wall 

The rear wall tabs fit into the slots in the top wall.

Blown Transformer
Unfortunate victim is Frans Huizing
   One day, smoke came from the PSU and it promptly shut itself down.  I opened it up, (yes, I have the proper tool) and found 3 pieces of ferrite loose in the supply:  part of the core of a transformer. One piece had lodged itself between what looks like a small regulator board and the main circuit board where the short  caused some physical damage to an area that is not used. Yes, the 8A fuse was blown. However, on the little circuit board on the right top corner are , what looks like, 3 resistors. The middle one has been fatally damaged.
   Now I come to my questions: Where can I find the schematic for this supply.(Delta, SMP-400BB, EC3 D30618) And can you think of any reason other than a manufacturing flaw why that xformer fell apart?

Dr Jim Shorney replies
>Hey Jim, can this be cleaned up, a new transformer installed, and a new resistor installed? I don't know of a source for schematics, and I know that Delta will NOT just hand them out to a hardware hacker...

Jim sez
   My advice: scrap it and send me the fan.  When you see catastrophic damage like that (melted and charred parts, things blown off the circuit board), there is usually a fair amount of other damage lurking in the shadows.  You would end up throwing more parts at the thing than what it is worth.

>Why the hell would a core fail like this? 

Powered ferrite cores aren't a terribly mechanically robust thing. Could have been dropped.  Or it could have been cracked by an intense high-frequency spike from a nearby (or direct) lightning strike.

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