Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > General Electronics Technical Discussion
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 04-07-2020, 09:45 PM   #1
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Psom circuit help

I am trying to figure out where I am losing voltage, the center pin (c) on transistor should be giving me 9v but I am only getting 1.3. Which goes to pin 16 on IC1. B on transistor is outputting 11.8 but I only get 1.7 on pin 1 of IC1. Thanks Michael

https://imgur.com/2pML3nc
IC1 is a Motorola 70013FB
I have replaced the IC and transistor with no change in symptoms.
Attached Images
File Type: jpg B9CB18EA-3353-40F1-B397-ECDCE37C2230.jpg (437.1 KB, 25 views)
Hornnumb2 is offline   Reply With Quote
Old 04-07-2020, 10:01 PM   #2
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,742
Default Re: Psom circuit help

Did you connect IGN to +12V (conn pin 3) to turn on the module? Otherwise I think it stays asleep. IC1 pin 6 should have 7V then and see if 5V is also present.
Ford 1995 PSOM schematic
https://www.youtube.com/watch?v=vPbsvX2EIWc
Attached Images
File Type: jpg Ford PSOM Schematic.jpg (264.2 KB, 31 views)
redwire is offline   Reply With Quote
Old 04-07-2020, 10:57 PM   #3
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 22,644
Default Re: Psom circuit help

what is this for?
i see it has an unmarked SPI device on the schematic, an eeprom??
stj is offline   Reply With Quote
Old 04-08-2020, 08:06 AM   #4
eccerr0r
Solder Sloth
 
eccerr0r's Avatar
 
Join Date: Nov 2012
City & State: CO
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 4,869
Default Re: Psom circuit help

programmable speedometer odometer module ... the EEPROM probably keeps the odometer reading.

Looks like Ford dropped the ball on design of the power of this board, seems the protection circuit was not properly designed. Still very odd why ford designed it the way that they did, but oh well...
eccerr0r is offline   Reply With Quote
Old 04-08-2020, 10:43 AM   #5
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

I purchase a working board with wrong mileage and MPH (80 Compared to 120)
Working board voltages on IC1
1) 11.67 16) 9.01
2) 12.29 15) 5.1
3) .005 14) 113mv
4) .005 13) .005
5) .005 12) .005
6) 7.85 11) 1.06
7) 5.02 10) 1.06
8) 4.33 9) 5.1

Non working

1) 1.75 16) 1.3
2) 12.3 15) .7
3) jumping 14) .7
4) .003 13) .003
5) .003 12) .003
6) 7.75 11) .85
7) .79 10) 333mv
8) 104mv 9) 139mv
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 10:59 AM   #6
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

All parts in that video have been replaced also.
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 11:02 AM   #7
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

If I transferred the eprom to working board any idea if it would correct the 2 different MPH?
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 11:06 AM   #8
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

I am guessing the eprom is the 8 pin chip,
working boards number is:
B53AN
89 Ford
Psom.01

Non
B47AH
89 Ford
Psom.01
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 01:01 PM   #9
sam_sam_sam
Badcaps Veteran
 
Join Date: Jul 2011
City & State: Sunny Jacksonville FL
My Country: USA
Line Voltage: 120 Volts 60 HZ
I'm a: Knowledge Seeker
Posts: 2,029
Default Re: Psom circuit help

Are all of the other ic chip number same on each board and do they have the same exact configuration if they do you might be able to put your ic chip from your controller and put it in the other controller and it might work
__________________
9 PC LCD Monitor
6 LCD Flat Screen TV
30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *


These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board

All of these had CAPs POOF
All of the mosfet that are taken out by bad caps

Last edited by sam_sam_sam; 04-08-2020 at 01:06 PM..
sam_sam_sam is offline   Reply With Quote
Old 04-08-2020, 01:57 PM   #10
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

The only difference I see is there is an a adjustable pot on the original board. The working board is marked with an X.
Attached Images
File Type: jpg IMG_1018 A.jpg (1.40 MB, 12 views)
File Type: jpg IMG_1019 A.jpg (1.17 MB, 11 views)
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 03:05 PM   #11
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,742
Default Re: Psom circuit help

On the non-working board, there is no power making it to IC1 pin 2. Check diode D1 is open, or a bad trace/solder joint. You can beep it out with multimeter.

The EEPROM would store mileage and axle ratio/tire size. So swapping it would fix that. I would read the EEPROM contents in the interest of science.
redwire is offline   Reply With Quote
Old 04-08-2020, 04:12 PM   #12
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

Pin 2 is showing 12v on both, is that the wrong pin?
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 04:39 PM   #13
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,742
Default Re: Psom circuit help

If IC1 pin 2 is at 12V, but non-working board pin 1 is 1.75v then the big transistor Q5 has open-circuit E-B junction. Sorry I got mixed up with your list of measurements.
redwire is offline   Reply With Quote
Old 04-08-2020, 06:38 PM   #14
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

Could I have got a bad transistor, I do have one more that came from a different provider. They are 5101FB
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 08:26 PM   #15
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,742
Default Re: Psom circuit help

Transistor Q5 Ford 5101FB is a house-number. Ford has custom numbers and parts everywhere in this PSOM.
It should test as a PNP, not NPN. Pinout should be B-C-E and tab/heatsink is C.
There is some problem with it, I wonder if the parts you got are OK or fakes.

For a substitute I would use an 80-100V transistor (because of transients, even with MOV) tough such as D45H11, D45H11G, KSE45H11. 80V 10A.
redwire is offline   Reply With Quote
Old 04-08-2020, 08:58 PM   #16
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

So would I be better off taking the transistor and ic off the working board and putting on the non working one. I added a socket on the ic so that wouldn’t be to bad to do. Or just swap eprom (IC2) over to working one with out the pot. Thoughts?
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 10:01 PM   #17
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

Quote:
Originally Posted by redwire View Post
If IC1 pin 2 is at 12V, but non-working board pin 1 is 1.75v then the big transistor Q5 has open-circuit E-B junction. Sorry I got mixed up with your list of measurements.
I don’t have it in front of me to verify till I go back to work Friday, but i have been studying the pics and it looks like the trace is broke in the lower left hand of the photo above the through hole that has some black around it.
Attached Images
File Type: jpg 804A0824-2A0D-44B7-BBE5-2B5C1130C62A.jpg (294.3 KB, 14 views)
Hornnumb2 is offline   Reply With Quote
Old 04-08-2020, 10:38 PM   #18
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,742
Default Re: Psom circuit help

Use your multimeter to test the trace continuity, and also the E-B junction on the transistor Q5. The black corrosion is weird and might have etched the trace.

When I fix stuff I try to find the bad part because changing parts doesn't always work or can make it worse if a bad part kills new parts.
redwire is offline   Reply With Quote
Old 04-09-2020, 09:45 PM   #19
RJARRRPCGP
Badcaps Veteran
 
Join Date: Jul 2004
City & State: North Springfield, Vermont
My Country: USA
Line Voltage: 118-127V 59-63.5 Hz-> actualizo: pérdido de voltaje
I'm a: Knowledge Seeker
Posts: 5,187
Default Re: Psom circuit help

Quote:
Originally Posted by redwire View Post
Did you connect IGN to +12V (conn pin 3) to turn on the module? Otherwise I think it stays asleep. IC1 pin 6 should have 7V then and see if 5V is also present.
Ford 1995 PSOM schematic
https://www.youtube.com/watch?v=vPbsvX2EIWc
"666 Hz" -> LOL!
__________________
MSI B450 Tomahawk

Ryzen 7 "Matisse" 3700X

16 GB Corsair Vengeance LPX DDR4 SDRAM

XFX Radeon RX 580 8 GB

eVGA Supernova G3 750W



Received on November 4, 2019:
MSI GF63 Thin 9SC-649US


"There's nothing more unattractive than a chick smoking a cigarette" -Topcat

"Don't eat yellow snow!" -Salem

"did I see a chair fly? I think I did! Time for popcorn!" -ratdude747
RJARRRPCGP is offline   Reply With Quote
Old 04-10-2020, 11:20 AM   #20
Hornnumb2
Member
 
Join Date: Feb 2011
Posts: 91
Default Re: Psom circuit help

Trace was broke, now the only voltage I am missing is 4.3v on IC1 at pin 8, currently 277mv. Any Clue
Hornnumb2 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums © 2003 - 2020
Powered by vBulletin ®
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 11:12 PM.
Did you find this forum helpful?