Need help/suggestions on a dead C4P-MF

Andis
Posts: 33
Joined: Sat May 13, 2017 8:15 pm
Location: Rocky Mountains, USA

Re: Need help/suggestions on a dead C4P-MF

Post by Andis »

Photos of the PSU Circuit Board. Two shots of the front side as some of the board labels are obscured depending on the angle of the shot (I should have just removed to white Zip Strip holders/blocks that held down the 2 big Capacitors that blocked the view of the circuit board, but wasn't thinking at the time).
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C4P-PSU-Board-1.jpg
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C4P-PSU-Board-2.jpg
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Back side of the PSU Circuit Board, mirrored which is the way I prefer to compare front and back sides (note circuit board labeling is reversed. I also included a non-mirrored version after the mirrored one. Looks like something happened around the 5V adj line!
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C4P-PSU-Board-Back(mirrored).jpg
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C4P-PSU-Board-Back.jpg
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C4P-MF, 540 RevB-1/542, 527 w/12K, 527-RevA w/24K, 505-RevB
billdrom
Posts: 55
Joined: Sat Dec 26, 2009 4:08 pm
Location: Somerdale,New Jersey

Re: Need help/suggestions on a dead C4P-MF

Post by billdrom »

Also try searching eBay for" deltron t1-8c"
There are new supplys for $29 on eBay.
http://www.ebay.com/itm/DELTRON-T1-8C-Q ... 2097032948

Bill
Andis
Posts: 33
Joined: Sat May 13, 2017 8:15 pm
Location: Rocky Mountains, USA

Re: Need help/suggestions on a dead C4P-MF

Post by Andis »

Thanks a bunch Bill !!!

Funny, I just pulled the Caps this morning to take the photos and it didn't even occur to me to check for the part number on the board :roll: . Now thinking of all that time I spent looking for The Caps (the LM723CN, from memory, was the only easy thing to find), I could kick myself... Thanks for the timely post, i was just thinking about starting a search for the transformers... :cry:
C4P-MF, 540 RevB-1/542, 527 w/12K, 527-RevA w/24K, 505-RevB
gekaufman
Posts: 72
Joined: Mon Nov 23, 2015 12:57 pm

Re: Need help/suggestions on a dead C4P-MF

Post by gekaufman »

It is very likely that your power supply is easily repairable. The capacitor values aren't critical, and it's fine to go up in uf value or voltage within reason. The discoloration on the transformer and PC board are typical - I'd bet both are fine.

The original parts are axial capacitors, which are now less common, but radial caps can be adapted. I can send you a picture of one I restored.

I'd also bet the Deltron supplies on Ebay will have the same issues, as they are just as old as your supply!

- Gary
billdrom
Posts: 55
Joined: Sat Dec 26, 2009 4:08 pm
Location: Somerdale,New Jersey

Re: Need help/suggestions on a dead C4P-MF

Post by billdrom »

Mouser has 3 different 10000 ufd 16 volt radial caps in stock.

http://www.mouser.com/Passive-Component ... 19Z1yx4aw3

Different physical sizes.

$5 to $12


Jameco has one for $2.95
http://www.jameco.com/z/A10000-16-10000 ... 93681.html

You should try to fix the supply first, before orerind a new one.

Bill
Andis
Posts: 33
Joined: Sat May 13, 2017 8:15 pm
Location: Rocky Mountains, USA

Re: Need help/suggestions on a dead C4P-MF

Post by Andis »

Thanks Bill, and everybody else that's helped in this project. That was the final piece I needed (well almost, 1 item left). I just don't know electronics as in chips, Caps, Transformers, etc. well at all. I did wire my entire low-voltage system in my house (ethernet, satellite, phone) and can setup POP Radios, etc., but just not the nitty gritty, which I do want to learn.

I decided to go with a repair of the PSUs and use the Vishay Axial Capacitor, mostly due to it's long life (8000 hrs at 85C): https://www.digikey.com/products/en?key ... 02115103E3. Plus some LM723CN regulators to be on the safe side, and a 16 DIP Header on which I broke one of the pins.

However, with some forethought for once, I rechecked everything I could think of in the system (boards, chips, cables) before I placed my order at Mouser. DigiKey had most of what I needed too but I ended up on Mouser until I saw THIS (see photo below). It's the 40 pin cable assembly from my 505 board to the IO board on the back of the computer. Not sure when his happened, 35+ years ago most likely... I was REAL careful on the one re-assemble I went through this century.
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C4PMF-505Board-To-IO.jpg
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Anyways, so DigiKey has a pre-assembled one that will work (1.5ft, 40 pin, reversed DIP Headers with pin #1 at the right spot: https://www.digikey.com/product-detail/ ... ND/1122981). However, I couldn't find a pre-assembled one on Mouser so I started looking up everything I had on Mouser and finding it on DigiKey ( I'm not anal :D, I'm just tight on money, but long on time, and didn't want to pay 2 shipping charges). The Manufacturer part numbers work real well for this BTW. So my "shopping list" was getting pretty jumbled and I put it all in a text file and cleaned it up, may be of some help to other newbies in electronics (attached below).

**********************************************************************************************************
So final question (I hope), DigiKey has an LM723CN/NOBP made by Texas Instruments: https://www.digikey.com/product-detail/ ... PB-ND/6318, while Mouser has an LM723CN made by STMicroelectronics: http://www.mouser.com/ProductDetail/STM ... 3a8IzeY%3d. Is there a difference? I don't know what the NOBP implies.
**********************************************************************************************************

If I need to go with the Mouser one (no NOBP), I'll just have to roll my own 40 pin cable assembly. Otherwise I'd go with Digikey to get the pre-assembled 40 pin cable.

At least the forum got a nice (start of one anyways) parts list from me :lol:
Computer Model: C4PMF

Item: Capacitors-PSU
Manufacturer: Vishay / BC Components
Part#: MAL202115103E3
Mouser.com: All Products > Passive Components > Capacitors > Aluminum Electrolytic Capacitors > Aluminum Electrolytic Capacitors - Leaded
http://www.mouser.com/ProductDetail/Vis ... 4WT5E6s%3d
Digikey.com: Product Index > Capacitors > Aluminum Electrolytic Capacitors
https://www.digikey.com/products/en?key ... 02115103E3
Notes: Long Life (8000 hrs @ 85C), Inexpensive, there are alternatives

Item: 16 pin Ribbon Cable Plug-Gold
Manufacturer: CW Industries
Part#: CWR-130-16-0000
Mouser.com: All Products > Connectors > Headers & Wire Housings
http://www.mouser.com/ProductDetail/CW- ... LK6g%3d%3d
DigiKey.com: Product Index > Connectors, Interconnects > Rectangular Connectors - Board In, Direct Wire to Board
https://www.digikey.com/products/en?key ... 30-16-0000
Notes: Gold Pins. The original in my C4P were not tin, maybe bronze or gold, so i will spend an extra $1 per header...

Item: 16 pin Ribbon Cable Plug-Tin
Manufacturer: CW Industries
Part#: CWR-130-16-0203
Mouser.com
All Products > Connectors > Headers & Wire Housings
http://www.mouser.com/ProductDetail/CW- ... LK6g%3d%3d
Notes: Tin Pins, less expensive

Item: Voltage Reg Chip-PSU
Manufacturer: STMicroelectronics
Part#:LM723CN
Mouser.com: All Products > Semiconductors > Power Management ICs > Voltage Regulators & Voltage Controllers > Linear Voltage Regulators
http://www.mouser.com/ProductDetail/STM ... 3a8IzeY%3d
Notes: At end of life, 2000 left 06/03/2017 at Mouser. None left at DigiKey

Item: Voltage Reg Chip-PSU
Manufacturer: Texas Instruments
Part#:LM723CN/NOPB
Mouser.com: All Products > Semiconductors > Power Management ICs > Voltage Regulators & Voltage Controllers > Linear Voltage Regulators
http://www.mouser.com/ProductDetail/Tex ... rNqI2VU%3d
DigiKey.com: Product Index > Integrated Circuits (ICs) > PMIC - Voltage Regulators - Linear
https://www.digikey.com/product-detail/ ... PB-ND/6318
Notes: Not sure what the NOPB adds-loses in the chip, if anything

Item: Switchable 50 Watt 5V PSU
Manufacturer: Mean Well
Part# LRS-50-5
Mouser.com
All Products > Power > Power Supplies > Switching Power Supplies
http://www.mouser.com/ProductDetail/Mea ... iymA%3d%3d
Notes: A complete PSU replacement. See Jeff's use: http://www.osiweb.org/osiweb/osiforum/v ... v+10a#p622

Item: 40 pin Ribbon Cable Plug-Tin
Manufacturer: CW Industries
Part#: CWR-130-40-0203
Mouser.com: All Products > Connectors > Headers & Wire Housings
http://www.mouser.com/ProductDetail/CW- ... 5NKQ%3d%3d
DigiKey.com: Product Index > Connectors, Interconnects > Rectangular Connectors - Board In, Direct Wire to Board
https://www.digikey.com/products/en?key ... 30-40-0203
Notes: Mouser says gold plated pins, Photo shows Tin

Item: 40 Conducter Ribbon Cable
Manufacturer: 3M Electronic Solutions Division
Part#: 3365/40-CUT-LENGTH
Mouser.com: All Products > Wire & Cable > Flat Cables
http://www.mouser.com/ProductDetail/3M- ... xkvhUEU%3d
Notes: 1 Foot Length

Item: 40 Position Cable Assembly Rectangular DIP to DIP, Reversed 1.50
Manufacturer: CW Industries
Part#: C8PPS-4018G
DigiKey.com: Product Index > Cable Assemblies > Rectangular Cable Assemblies
https://www.digikey.com/product-detail/ ... ND/1122981
Notes: 1.5 foot. Note the 8 in C8 of part# is important for #1 pin placement. Cable is Reversed for 505 Board to IO on back of C4PMF
C4P-MF, 540 RevB-1/542, 527 w/12K, 527-RevA w/24K, 505-RevB
Andis
Posts: 33
Joined: Sat May 13, 2017 8:15 pm
Location: Rocky Mountains, USA

Re: Need help/suggestions on a dead C4P-MF

Post by Andis »

I was taking a closer look today at the backplane on my C4PMF and noticed a few things. Plus, it brought up a question, were there ever made any OSI compatible boards that used +12V and/or -9 V power? I ask because when I looked closely at the front of the backplane, I noticed that when the Factory upgraded my memory with a 24K, 527 RevA Board, they cut Pins 25 and 26 out of the power rail on the backplane, which are indicated as +5V power (pin index starting at 1). See the photo below, between the 2 lowest 48 pin connectors, near right of photo.
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527RevA_Pins25-26CutOff.jpg
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They apparently just used the power supplied to pins 23 and 24, which are shown as reserved for +12V and -9V, for the 5V power? I'm getting the pin out info from the 48 Line System Bus Diagram available on Github, the link being available from the top level of osiweb.org. So i took a closer look, and sure enough, the labeling on the circuit board shows +12v and -9V rails. See below.
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582-VoltagesCloseup.jpg
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So I flipped the backplane over and took a closer look. You can see where they cut the power supply between the two 48 pin upper connectors and the two lower 48 pin connectors. In the below photo, the 2nd from the top connector circuit powers my 527RevA memory expansion board, while the top connector circuit powers my 540 board. I always thought that the 527RevA memory expansion board needed a "dedicated" power supply. Apparently not, it just needs an "additional" PSU supply because it sure looks like my 2nd PSU powers both the 527 expansion board and the 540. This was a factory mod, and I don't think I'm misunderstanding what I am seeing. Plus, the cut is on the pin 23 & 24 circuit, which ran to all 4 connectors, so how could the labeling on the other side say +5V on one rail and +12V on another rail? I'm a tad confused here... The reference I'm using for the pin out says it's for C2-4P and C4.
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540RevBand527RevA-Share-1-PSU.jpg
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Plus, I haven't been able to find a schematic of the 527 RevA board anywhere. Admittedly, if you look at the photos of the 527 board (first photo below) and the 527 RevA board (second photo below), they look almost identical. The difference looks like the RevA just has 4 chips added that are not on the 527 board, and the set of 3 jumpers near the bottom of the photo differ, The RevA board jumps the "top 3" circuits to the left (plus has actual pins), while the 'regular' 527 board above it jumps the 4t, 5th, and 6th circuits. Photos attached for the curious....
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527-1.jpg
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527RevA-1.jpg
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Comments?
C4P-MF, 540 RevB-1/542, 527 w/12K, 527-RevA w/24K, 505-RevB
Andis
Posts: 33
Joined: Sat May 13, 2017 8:15 pm
Location: Rocky Mountains, USA

Re: Need help/suggestions on a dead C4P-MF

Post by Andis »

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Oh, I ordered my PSU/Cable parts today! Should be here in a few days :D .
C4P-MF, 540 RevB-1/542, 527 w/12K, 527-RevA w/24K, 505-RevB
nama
Posts: 357
Joined: Wed Mar 30, 2011 9:44 am
Location: New Zealand
Contact:

Re: Need help/suggestions on a dead C4P-MF

Post by nama »

I fixed a PSU problem in my C4P-MF by replacing the CA723CE regulator.

http://www.neoncluster.com/projects-osi ... pfix1.html

Phil

2P (1mhz 32k) - 502 + 8k + CEGMON + garbage collector fix BASIC, D&N MEM-CM9 + 24k, 540 (mono) [SOLD]
4PMF (2mhz 24k) - 505, 540, 527, D13 + 5.25" + Gotek
Superboard RevD - CEGMON + 610 board 24k + D13
Spares - 3 x 527, 1 x 505, Backplane
Andis
Posts: 33
Joined: Sat May 13, 2017 8:15 pm
Location: Rocky Mountains, USA

Re: Need help/suggestions on a dead C4P-MF

Post by Andis »

Glad the board's back up! While it was down I replaced the old PSU capacitors and the 723 Voltage regulators on both my PSUs. Photo below. Unfortunately, I'm still blowing fuses, even if i remove all the boards from the Backplane.

Hmm, i can't seem to post any photos, says they are too large? The board used to resize them automatically but evenly manually resizing them to under 500K the post will not accept the attachment. Anyone else run into this?

I did order a 100W 5V switched PSU for either a test or a permanent replacement :
http://www.mouser.com/ProductDetail/Mean-Well/LRS-100-5

Since I am going to have to disconnect the 'fixed' PSUs from the system to drop in the new replacement PSU, before I actually pull the existing PSUs out, I am first going to follow Klyball's suggestion and check if the fuse blows with the PSUs disconnected from the system. I know I could have done that from the get go, but I figured the caps needed replacing anyways and may as well replace the voltage regulators at the same time and see if that fixed the issue.

I'll let you you know happens
C4P-MF, 540 RevB-1/542, 527 w/12K, 527-RevA w/24K, 505-RevB
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